We will have the last presentation on these non-classical MOSFETs. We will continue on these compound semiconductor materials and heterostructure FEDs. So, under the heterostructure FEDs, we will talk of the high electron mobility transistors and some heterostructures as well as changing the normal materials like using strain and quantization. So, we saw that the short channel effects in a MOSFET also come into picture. So, in order to and these short channel effects manifest in terms of the threshold voltage shift in the negative direction, also sub threshold slope becomes larger. Both effects are due to the 2D field effect on the channel region. These effects can be reduced by increasing the channel doping density accompanied by the reducing the channel thickness. Now, in fact, increasing the channel doping in the channel adversely affects the mobility. As all of us know, it also affects the velocity overshoot effect in a MOSFET, MOSFET. This is because the initial velocity will be smaller. So, the overshoot effect will be smaller. So, the actual benefit that you usually see will get reduced if the doping is high. So, in order to work, these can be overcome. See, the whole problem is when it increases the ionized impurity scattering is upon which comes into picture. So, one has to reduce this effect. So, this can be reduced and the high mobility and the high electron concentration can be achieved if we can separate the channel, where the electron moment is there, separate the channel from the region, where the doping concentration is made high. So, this is achieved using the high, using the hetero junction and hetero junction field effect transistors. So, we take a look at hetero junctions now because that is the one which we discussed today. Hetero junctions are formed by two dissimilar semiconductors. For example, germanium on silicon that is hetero junction, gallium arsenide on germanium that is hetero junction. Now, there are two types normally people can talk of. You can have conductivity of the same type in the two materials. For example, p-tap germanium p-tap silicon, p-tap gallium arsenide p-tap germanium that is called isotide. Alternately other name is an isotide which is the common type of hetero junction that you encounter that is one region is p-type other region is n-type. For example, you talk of p-type gallium arsenide n-type aluminum gallium arsenide or aluminum arsenide. So, hetero junction requirements what are requirements? Most important requirement is the lattice match requirements. When you grow one material on the other there should be very good lattice match between the two. In the sense lattice constant of the two materials must be comparable. If you are going trying to grow gallium arsenide trying to grow silicon on germanium there is problem because the lattice constants are quite different. Silicon is 5.43, germanium is 5.65, but on the other hand if I want to grow gallium arsenide on germanium there is no difficulty because both have lattice match. Now, what we are looking out for is hetero junction consisting of aluminum gallium arsenide on gallium arsenide. Aluminium arsenide has got excellent lattice match with gallium arsenide. So, aluminum gallium arsenide also has excellent lattice match with gallium arsenide. So, you can grow a gas aluminum gallium arsenide on gallium arsenide very easily and you can vary this top layer. Bandgap you can vary by varying x equal to 0 to 1. x equal to 0 as I pointed out earlier would mean aluminum component is 0 and gallium is not g is gallium. Gallium is 1. So, you will have aluminum G A A S, x equal to 0 would give you gallium arsenide and x equal to 1 will give you aluminum arsenide. So, you can vary x and vary the bandgap of the layer which are depositing on gallium arsenide. So, take a look at this. If you take a look at the gallium arsenide the lattice constant is 5.6533. Aluminium arsenide also has got very close lattice match very marginal misfit factor. So, you can grow aluminum arsenide directly on gallium arsenide or you can have an alloy of aluminum gallium and arsenide and gas. Here x equal to 0 it is gallium arsenide the band structure is like this x equal to 1 it is aluminum arsenide band structure is like this. So, notice this is a direct band gallium arsenide that does not matter for us because we are local for micro electronics it is a direct bandgap even up for up to 2 electron which can be used. It is bandgap minimum bandgap which is a direct bandgap is 1.43 electron volts. But there is also a valley as we pointed out earlier at this place from the central moment of zero position with the at a different momentum you have got a bandgap is equal to 1.8. So, normally the electrons will reside here and the transition will be between these two and if the electrons get high energy they can go move into this region at high fields here the my pretty mass is higher. So, now what we are saying is let us use this gallium arsenide. Now, if I have an alloy of aluminum gallium arsenide if I vary from x equal to 0 to 1 you have 1.43 the direct bandgap tracking with this direct bandgap of aluminum arsenide. So, the direct bandgap will vary from 1.43 to 3.02 and indirect bandgap 1.8 will vary from 1.8 to 2.17 linearly it will vary. Now, just I want to mention also aluminum arsenide is a indirect bandgap semiconductor. So, if I change completely from gallium arsenide to aluminum arsenide will get indirect. So, if you move from gallium arsenide to the aluminum arsenide you will have certain composition of x you will have direct bandgap beyond that you will have indirect bandgap. But the point that we are trying to make up do is show is that you can vary the move from the direct bandgap to smaller. So, wider bandgap and ultimately to indirect bandgap. So, this is the indirect bandgap with bandgap 2.17. Let us see how it varies from a graph form notice 1.43 will vary linearly with 3.02 direct 1.8 will vary linearly with the 2.17 as x is varied from 0 to 1 x is 0 will give you gallium arsenide bandgap direct is 1.43 indirect is 1.8 as senior 1.43 1.8 and if you go to this other end x equal to 1 that is aluminum arsenide direct is 3.02 indirect is 2.17 here. So, when you vary the direct component will vary linearly from 1.43 to 3.02 the indirect component will vary from 1.8 to 2.12. Now, what happens is this see for example, here if you see there is direct component, indirect component. Direct band component is smaller than the indirect. So, actual bandgap is this here indirect component is smaller compared to direct component. So, the bandgap is actually 2.17. So, lower is the one which gives the bandgap. So, as a vary x from 0 to about 0.3 or so, you will it will be direct bandgap semiconductor where direct component is smaller than one indirect component. As you move beyond this composition x greater than about 0.3 0.2 0.4 0.6 like that 0.3 beyond that the direct component is larger than the indirect component. So, it becomes indirect bandgap. So, what we are trying to tell is you can grow gallium arsenide or aluminum gallium arsenide on gallium arsenide and the composition of the L gas depending upon x you can have direct or indirect, but the bandgap always you can get higher than that of gallium arsenide. So, you get a good hetero junction here. If you want to look at other materials like indiabosphide or gallium indi-marsenide you can mix gallium arsenide with indi-marsenide and make a compound gallium indi-marsenide. For example, here x equal to 0 will give you indi-marsenide x equal to 0 bandgap is direct bandgap 0.36 and gallium arsenide also is in there is a direct bandgap that is x equal to 1 this component is 0 gallium arsenide is 1.43. So, both ends stream ends you have got direct bandgap. So, I can have gallium indi-marsenide throughout a parent bandgap material. Why do we talk of that mobility of indi-marsenide is very high. So, gallium indi-marsenide mobility will be higher than that of gallium arsenide. You can have a bandgap somewhere in between. For example, if I have something like 0.4 or 0.5 you will have bandgap which varies very close to 1. So, why we talk of gallium indi-marsenide you can make hydro junction with gallium indi-marsenide or indi-marsenide because x equal to 0.47 gallium 0.47 indi-marsenide 0.53 the lattice constant is 5.88 angstrom which matches with the indi-marsenide. You can grow gallium indi-marsenide or indi-marsenide on indi-marsenide on indi-marsenide make high mobility transistors using that. We will today focus on the aluminum gallium arsenide gallium arsenide. So, what is the hydro junction? If I take a look at the homo junction for example, if I talk of silicon n type material p type material. When you talk of the same material bandgap of material 1 is the same as the bandgap of material 2. The electron affinity that is the energy gap between the vacuum level and the conduction band E c chi is the same in both cases silicon is 4.05. Now, if I take n type permeable is very close to conduction band and the permeable here is close to the vanus band. When you put them together you can see that if you put them together the permeable here is higher than permeable here. Therefore, the in the system from the theory of cochlear model we know that when you form a junction electron from this region where electron concentration is high will flow to this p region which would actually deplete the region on the surface and you will have a band bending upwards here. And from here the holes from this side will move from left to right depleting this. When this depletes the band will move down here. In fact you can just quickly see I will see where I can show that to you. See for example, if you see the when you form the energy band diagram you know that permeable is flat and n type material permeable is here conduction band, valence band and because of the band depletion layer it will go like that. So, this is the conduction band is the valence band. Correspondingly the zero level whatever chi was there it will be there that is the vacuum level. So, that is chi and this is also chi. So, you get same chi. So, there is no discontinuity discontinuity in the energy band diagram. So, notice somewhere here that is joint it bends up that bends down. So, the electric field as because this is depleted the electric field is like that and it charges here plus charges here. This is the standard theory of homo junction homo junction means band gaps are same chi is the same there is there is a continuity everywhere. Vacuum level represents the change in the potential and with respect to vacuum level the conduction band will be located. So, we will go back to our theory of the hetero junction. So, same thing holds good in the case of hetero junction. Here we are talking of a band gap which is wider compared to wider band gap V G 1 compared to another band gap narrower band gap V G 2. So, the Fermi level is higher here compared to this. So, when you join them and here one more thing is chi 1 there is the energy difference between the vacuum level and the conduction band chi 1 is smaller than chi 2. This is the basic Anderson's theory of model. This model holds good up to certain level to understand, but actually there is much more than that what we say happens. So, let us try to understand it what happens in energy band diagram. When you join them together the energy band diagram bends up here exactly the same way as we saw here. The energy band diagram bends here, it bends up here on this side and it continues to bend up because this bends up that bends down. Now, let us go back here. So, when you put them together because I will get transferred here this will be depleted till the whole side transferred. So, this will be depleted. So, what you will get will be vacuum level there will be plus potential here minus potential here. So, vacuum level will bend exactly same way as we have in the homo junction because the energy band at the vacuum level does not have any discontinuity. It represents the way the potential varies. So, that is continuity. If you take a look at the condition band in the entire material wider band gap material it has depleted and bent up. All through here chi 1 is the vacuum level. Chi 1 is the electron affinity here same thing is here, but when you come from that side vacuum level bends down here because of potential variation like that plus here minus there. So, the conduction band also bends up down like this till we come to the junction. Now, you can see at the junction all through here this chi 2 from the top to bottom is chi 2 and when you come here the gap between the vacuum level and the conduction band in the p type material is chi 2. Whereas, at the same point the joining point of the entire material which is wider band gap there the chi 2 is the electron affinity is chi 1. Chi 1 is less than chi 2. So, these two conduction bands do not meet at the same point there is a sudden discontinuity here, discontinuity here. That is the specialty of the heterostructure. The energy band diagrams are not continuous there is a notch here. So, if there is a notch here it is almost like the notch that you see in the MOSFET. So, if there are electrons some so on this side if electrons are injected on to this side they will get collected here and those electrons cannot cross up this barrier they will get they remain there. It is like what you have in the case of the I am sorry this is similar to what you have in the case of the MOSFET. See for example, in the case of MOSFET you should recall what you have is the oxide. The oxide is there that is like that. Then if you have p type semiconductor you have got a permeable like this then you have got this like this conduction band e c and e v and you have of course this like this oxide. This is oxide and this is a p c gap and you have the metal. Now, you can see there is high band gap here about 3.3 electron volts is there. So, when it is inverted here the electrons get locked here electrons remain here they cannot go up. That is why you will have to got when you invert it here when it has become n type you have got electrons locked in that notch. So, whenever there is a notch like this there is a barrier like this there will be electrons collected there. You can make use of that as the channel. If I connect the two ends of this channel by source and drain you can make a MOSFET. So, exactly same that is the similar type of notch is there in the case of hetero junction that is this. You have got this bending here there is a notch here. So, the band bending is actually such that so much that there are electrons collected here. So, now what you can do will be before I go into the structure I just give what will be the value of this. So, this notch is actually equal to you can see that is chi 1 or chi 2 minus chi 1 that is the first order theory and that is delta e c is the discontinuity in the conduction band. And if that band gap e g 1 is larger than e g 2 this is actually e g 1. So, e g 2 will be e g 1 plus delta e c plus delta e v. Therefore, delta e v that is the discontinuity here also discontinuity will be delta e g minus delta e c. So, what we are trying to say is this is first order theory, but in practice here it looks as if delta e c is chi 2 minus chi 1, but even in materials which there is chi 2 minus chi 1 is not that much you see a difference and that is governed by how much is the band gap difference between the two. So, the delta e c ultimately is related to e g 1 minus e 2 that is delta e g. So, it is seen that experimentally that delta e c by delta e g is about 0.6 to 0.64 for al gas gas system al gas is remaining at a mass time. So, delta e g for x equal to 0.4 from this particular thing for x equal to 0.4 delta e g is something like 1.43 plus 0.5. So, delta e g is 0.5. So, delta e g is 0.5 delta e c is 0.5 plus 0.64 is 0.32. So, you will have delta e c of 0.3 to electron volts if the band gap of this region is 0.5 e g 2 plus 0.5 electron volts in al gas you can get that. The value different now if delta e c is 0.3 to electron volts and if delta e g is 0.5 delta e v if this is point delta e g is 0.5 delta e g is 0.32 this is 0.18 that is what you put here. So, what you have is now al gas gas system which can be used as a gate you can have a channel here this region can be used as a channel this is an undoped which actually turns out to be very lightly doped 10 to power of 13 and there is a depletion layer here we saw the p region is depleted and there will be small depletion layer in the n plus aluminum gallium arsenide also this is the electric field distribution here. So, what you will have will be if I do not have any gate connected put here this region is not depleted. So, conduction band goes like this gets depleted then because of this work function high difference etcetera and delta g difference it snaps down here by delta e c 0.3 or 0.32 then it rises up because there is a depletion layer here electric field is in that direction therefore the conduction band will rise up here. The point that we have to note down here is that in the case of conventional junction there is no delta e c. So, this would have gone up like that straight away like this, but in this case because of this delta e c this starts on lower end then the that rise up to the same amount. So, that the electron distribution here and here match together. So, in other words you will have a total potential drop across this which is some of the which is more than the conventional built-in voltage of the MOSFET or the VN junction and the delta e c delta e c by q. So, what we are telling is I can actually have a transistor made by this this is a gate region this is a channel region n plus region over that an undoped galae martinite channel region n plus lume galae martinite over that rectifying contact. So, if I do not have rectify contact what will happen we will see. So, we have also a source and drain region that is heavily doped n plus region which is usually realized by gold germanium alloying on to this region it goes through that. So, because of the l gas gas structure you have that notch here and electrons are present here throughout this region. If the electrons are present here throughout the region if I n plus region here and n plus region here when I apply voltage between the drain this we can call it a drain and the source when I apply voltage the electrons there is electric field from here to here. Therefore, electrons will be injected from here to the channel they will be collected here there will be current flow, but now if I do not have the gate is saw and you did not have the gate there is a channel here, but this there is a region which is not depleted. So, if I have a source drain connected like this realized like this not only there will be current flow through this particular layer there will also be current flow through this heavy doped n plus layer. In fact, the entire current will be masked or controlled by the current flow through this heavy doped region. If it is current flow through the heavy doped region the mobility will be very low there is no use. So, what you do is put a metal gate here. So, the metal gate here you can the work function will be such that you can either deplete it completely or if it is not depleting completely you can apply a negative voltage and deplete it. So, in from the mass spread theory we know that the voltage required to deplete the entire n plus layer is called the pinch of voltage V p 0. Now, the voltage if the pinch of voltage if the depletion built in voltage is different from the pinch of voltage is lower than that you have to apply gate voltage which is which is equal to V b i minus V p 0 we saw it in the mass spread theory threshold voltage of the mass spread is V b i minus V p 0. That means it is a gate voltage that must apply to pinch of the channel. So, you can apply V b i minus V p 0 that is actually the point at which the channel will be conducting your current flow. Now, let us go further on that. So, the function of the gate is to depletely deplete the n plus layer it also has the job of controlling the charge in this particular region. You can see once it is fully depleted it is like the mass spread metal insulating layer and the channel where inertia layer is there. So, by applying voltage to the gate I will control the channel charge here. So, you can have right equation that exactly similar to the mass spread where we have u c oxide W by 2 L into V g s minus V th threshold. But if V th threshold will be different from that of the mass spread and mass spread we will see what it is. So, in one way it looks like a mass spread because there is a short key barrier, other way it looks like a mass spread because this metal depleted layer and the channel. The n plus source drain contacts are found by allowing this the electrons are transferred through the gallium arsenate region where the doping concentration is very low. Since the doping concentration is very low the ionized impurity scattering is absent. Therefore, you get very high mobilities you get mobilities as I as ideal 8500 centimeter square per volt second at room temperature you reduce the temperature to 77 degree Kelvin you get 250000 centimeter square per volt second these are reported values in literature. You go down even down you will get much higher mobility what is that due to you can see a mobility effective mobility depends upon the lattice scattering mobility as the temperature goes up lattice scattering mobility goes down mobility governed by lattice because lattice vibrations increase if lattice vibrations increase the scattering of the electrons by the lattice atoms increases. Therefore, mobility goes down ionized impurity scattering when you go to lower temperature the ionized impurity scattering increases. Therefore, the ionized the scattering decided by the impurities increases therefore, mobility governed by the ionized impurity scattering goes down that is because when you go down to lower temperature the velocities of the electrons are very lower. So, therefore, if there is an ion present the electron actually will move very close to as it goes to the close to the atom the impurity if it goes close to the impurity it gets deflected by the little static force. If the velocity is lower it gets deflected more towards this if electron gets it gets more towards this ion when it moves like that. If the velocity is high the chance of deflection is less because it slips through that layer very fast. When you go to lower temperatures velocities are lower so scattering probabilities are higher therefore, mobility falls. Now, the combined effect of that is 1 by mu lattice plus 1 by mu i so that is this combined effect. If the doping concentration is high it can be if you reduce the temperature mobility is reduced practically, but if the doping is 0 very little this component is 0. So, only this particular component is there mu i is there therefore, what you will have will be the what you will have in that case will be like this what you will have will be the temperature versus mobility. So, room temperature you may have about 8500 centimeter square per volt second that is good lower temperature T equal to 77 degree Kelvin you will have 250000 centimeter square per volt second. So, you will get very high mobility because other component you have eliminated by removing the dopants. So, that is about that. So, the extent of electron concentration depends upon delta E c because higher the notch higher the notch more chance of the having the electrons more chance of bending here there will be more electrons will be present. So, the delta E c if it is higher you will get more electrons, but be more current flow for a given voltage. Now, delta E c depends upon mole fraction because delta E c depends upon delta E g delta E g depends upon how much is the band gap of l gas higher than that of gallium arsenide how much higher the electron aluminum concentration higher will be the band gap there higher will be the delta E g and higher will be delta E g. In that case you do not choose very high aluminum concentration because aluminum itself is unstable it gets oxidized etcetera and also it gives rise to trap centers and it affects the mobility. So, highest value of x that you choose is about 0.3 aluminum concentration which will give about 1.9 electron volt as the band gap. So, now one of the things that you want to see is when you deplete the hole this top channel completely because there was already this particular delta E c was present there will be charges. How do you turn off the device what should be the voltage that you must apply to the device to turn it off that is actually the threshold voltage. So, this was the diagram that we have drawn conduction band. Now, you have got you have to apply voltage equal to V b i minus V p 0 to deplete this region that is from the gate side. Now, in thermal equilibrium you have got both the electron distributions here here is very little because it is undoped here is high from the theory of junctions and Schottky barrier you know that the thermal equilibrium transfer electron from here at here will be 0. Now, there are electrons there because of the psi band bending in the conventional homo junction there are no electrons there at that point there is no because there is no notch. Now, the band bending is more than that in the conventional junctions by an amount equal to delta E c and because of the delta E c more band bending is there. When you have that particular thing you have this thermal equilibrium achieved because band bending is more than that often the conventional junction you will have virtually like an inversion layer here. Now, you must to remove the inversion layer here you must reduce the band bending by whatever extra amount of delta E c by q is there you must reduce. So, the amount that you must reduce that band bending is actually delta E c by q. So, the polarity of this voltage drop across this layer is plus here minus here. If I want to reduce that voltage by delta E c by q that is V f I must apply voltage plus on the right hand side and minus on the left hand side P is made plus with respect to 1. That means you must have a forward bias to the junction so that the barrier height is reduced by delta E c which is delta E c by q. So, what we are telling is if I have this mass fat I apply V B I minus V P 0 the whole thing will be depleted. But across this layer there is built in field there is a electrons here to remove the electrons I must apply plus here minus here. So, V B I minus V P 0 is actually negative total potential plus here because the charges are plus here, donors. Donors these are the donors plus here minus here. So, electric field is towards the gate here, but from a gas to a semiconductor this is N P field is like this there is 0 field here that depletion layers meet here. But there is also there are also electrons here if I just to deplete it come up to this point there are electrons here on the interface. Now, to remove those electrons I must reduce this barrier I must apply plus here minus here or in other words once it is depleted completely if I increase the voltage by another term or by a value equal to delta E c by q if I make this more negative whole thing is depleted. So, there is this depletion layer actually will slightly fall because this gets forward biased. So, what you do is add a voltage equal to minus to this point this is already depleted. So, that minus delta E c by q that you apply here goes across this junction minus here plus here which is actually equivalent of forward biased in this which removes which reduces the barrier. So, electrons from here are actually removed in fact they are taken to the gate. So, when you do that when you apply more negative voltages whatever see there is connection between the source and this particular channel if you take a look at this here when I apply a negative voltage to this after this depletion if I increase further the negative charge is transferred from the channel to this to this gate to transfer this voltage completely from here to here to voltage additional voltage that I must apply delta E c by q. Once I apply more delta minus delta E c by q after depleting the whole thing I apply additional minus delta E c by q all the electrons will be transferred from here to here that is what is happening here. So, if I apply a voltage V of equal to V by minus V p3 required to deplete this and delta E c by q required to remove the electrons from here back into this gate the channel will be turned off that will be actually the threshold voltage. We call it we do not call it threshold voltage here by convention they call it as the gate voltage that must be applied for it to turn off the hemp. So, here the V of can be positive or negative depending upon what is this value delta E c by q let us say it is what we said this it will be something like 0.3 delta E c 0.3 electron volts. So, this quantity will be 0.3 volts. Now, I can adjust the doping and adjust the V p0 depending upon the doping depending upon barrier head I have between the short key and the aluminum gallium arsenide you have got V b i I can adjust the doping and the thickness. So, that V b i minus V p0 is more than 0.3 volts if V b i minus V p0 is more than 0.3 volts if because this 0.3 volts V off will be positive. So, I can have V off either a positive or negative supposing this term this is negative supposing this term is minus 0.1 volts this is 0.1 minus 0.3 volts you will have V off is minus 0.4 volts. So, we can have enhancement or depression type of high alternative transistors using this hemp structures. So, the doping you remember you are not adjusting the doping here is un doped all the doping that you are talking of the doping in this particular layer and gas layer. So, increase in the doping is not affecting the mobility of electrons here it is only adjusting the threshold voltage. So, you can have independent control of threshold voltage without affecting the doping here you can adjust the thickness here and the thickness controls the capacitance. As I pointed out the working of this is now once this is depleted the gate gets coupled out to this channel here. So, you can talk of write the equation similar to that of MOSFET and the I d V d gas characteristics transfer characteristics have be I d is equal to in the case of MOSFET u n c ox a w by 2 l into V g s minus V threshold square. Here instead of V threshold we have V off given by this term negative or positive negative means depletion type positive means enhancement type and C s in the case of MOSFET it is the channel thickness in the case of MOSFET it is the oxide capacitance in the case of MOSFET it is channel capacitance that is this quantity. So, in the case of MOSFET or I am sorry HEMT is also called MOSFET that is modulation doped FET MOSFET MOSFET HEMT all are same. In the case of MOSFET or HEMT C s is you can increase the CFS by reducing the thickness of that layer that is that layer. But then to adjust the threshold to adjust the V off you must actually increase the V P 0 if you want increase keep that when you reduce that you must increase it to adjust that doping to keep the V P 0 same when you reduce the you must increase N d. So, there is an upper limit to N d because as you go to higher and higher doping concentration the metal semiconductor contact will not go long by modifying it will become omic contact because of tunneling current between the small deficient layer form between the N d and this quantity. So, upper limit on the doping these doping on that controls the doping on this layer. So, there is a lower limit on A that you can choose you may use something like few nanometers 100 nanometers of that order you can choose 0.2 micrometer or even slightly lower because the upper level on doping concentration is something like 10 to over 18 that you can do because of the limitation of the Schottky-Berrero. So, a non-scented edification mode types can be made with bijecting V P 0 bijecting that you can get positive or negative you can reduce A then V P 0 goes down V off can be made positive by reducing that. Now, GM can be increased by as I pointed out GM can be increased by reducing the channel thickness this can be done by increasing the doping or the V off adjustment upper limit on N d instead of over 18. So, that limits how much you can do here. So, what we are pointing out is you are able to increase the doping here in the aluminum gallium arsenide layer without increasing the doping in the region where the electrons are flowing. All that you are doing is tailoring the doping and thickness in the other wider band gap material where the electrons are not flowing you can tailor that tailor the threshold voltage and the substrate is undoped mobility is high. So, you get very good characteristics. Now, here also I am sorry just here also what you do is in addition to this algeas doped layer when you do that you all usually in practice you put a thin layer of undoped aluminum gallium arsenide just about 1 or 2 nanometers that is because if the whole thing is doped the entire layer up to the channel is aluminum gallium arsenide every doped then these electrons which are moving on the channel see the effect of the doped layer some scattering is there to overcome that you put a thin layer of algeas here. In fact, the optimization of that layer also is involved the transfer depth in 110th adjustment. Now, quickly run through the thing the characteristics this is just to show you that people have made this type of devices at 300 degrees Kelvin the transfer character the output characteristics ID versus VDS you can see it saturates like this red curve is the 0.2, 0.4, 0.6 gate voltage and as VDS is varied from 0.5, 1, 1.5, 2 volts low voltage current 10, 20, 40, 60 milli amperes per division here. The most important thing we note is the current here current here at this gate voltage at 300 degree Kelvin is something like 0.2, 0.4, 10, 20, 30, 35 milli amperes whereas here it is what it 50 milli amperes 10, 20, 30, 40, 35, 40 and 45. So, about 10 milli amperes higher much higher current you get a lower temperature this is because of the mobility. Notice also this current rises steeply here with the linear region because the mobility is high the conduct tunnel conductance is high. Therefore, the current rises steeply the on the resistance of this higher atom mobility transistor is very low compared to on the resistance of the same at room temperature. By lowering the temperature mobility is increased and on the resistance is reduced very good for digital application. In digital application you want very low on the resistance. This is the saturation current ID versus transfer characteristics in the linear region you can see that the there is a crossing over and the current rises steeply at lower temperature because of improved mobility. Also notice that there is a threshold voltage increase when you go to lower temperature this is attributed to the freezing of electrons in the aluminum gallium arsenide layer. So, therefore, you must apply more voltage I am not going down to details of that. This is the transconductor this is the saturation ID versus vigorous transconductor you see you can see the transconductor this is very steeply rising in the gate voltage. You get transconductor tens increases from about 225 milliampere per volt 225 milliampere per volt here to about 400 milliampere per volt at this point for about 0.5 volts it is the transconductor tens is much higher because the transconductor tens depends upon mobility. Transconductor tens on the resistance everything improves because of the mobility go to lower temperature you get higher mobility higher transconductor tens by big factor. In fact, such high transconductor tens also tells you it is not due to velocity saturation it is due to the velocity overshoot if at all in addition to because of the high mobility. In summary of first part of this few more things I will discuss. Hydro structures enable special separation of electrons from the dopant electrons atoms very high mobility it can be attained enhancement of carrier mobility can be further enhancement can be achieved using materials such as indium gallium arsenide as channel materials. What we are using is gallium arsenide room temperature mobility is about 8500, but if you go to indium gallium arsenide you can get much higher mobility at least 2 to 3 times more than mobility than this at even at room temperature. Alternately we can use strain layers let us see what is that. If the region where this is in addition to these hemp etcetera even if you use commercial MOSFETs you can go to use silicon itself and subject the strain silicon to strain. If you have longitudinal tensile strain that is if you have tensile strain along the length of the channel it is stretched then the electron mobility improves. Stretch it along the length of the channel electron mobility improves. So, n channel devices you can actually stretch it by depositing silicon nitride on the top of the finish device that gives you rise to tensile stress which stretches the channel along the channel length which actually increases the electron mobility. The internal people have tried this out that were sort fine. Now, at the same token if it is a p channel device if I stretch it along the channel by tensile stress the mobility goes down. I am not getting down to the physics of that due to time I just do not discuss it at this moment. So, it goes down, but if you compress it if I subject the channel to compressive stress then the whole mobility goes up. So, the moral of the story is if I have n channel transistors that region you subject it to longitudinal tensile stress along the channel by putting silicon nitride on the top of that channel of the gate you can increase the electron mobility of n channel device. Wherever you have p channel devices you subject the channel to compressive stress how do you compress it between the source and drain for example, between the source and drain p for example, if I have the channel here, if I have the p plus here and if I have p plus here this is n I am talking of p channel device oxide here and then the gate. Now, what I should do is I must compress it in this direction because this is the p channel I must compress the p channel how do I do that you put introduce here silicon germanium silicon germanium alloy here. When you do this implantation or diffusion introduce also on both sides silicon germanium this actually because these atoms are bigger compared to the silicon atom the channel is in between the two layers which actually has bigger atoms. So, it pushes this channel in this direction that leads to compressive stress. So, the p channel devices p channel gets compression compressed along the length of the channel the mobility of holes goes up. This is the trick that the analog device I am sorry Intel here have done this all that I have said here is good in p channel it is silicon devices and the source and drain regions are formed by using silicon germanium channel is in compressive stress increases mu p. In n channel MOSFET electron mobility is increased by top layer nitride which introduces tensile stress. Now, new materials last few slides strain germanium, strain silicon all these can be used to increase the mobility over and above that. If I have silicon I can subject it if I have tensile stress you know electron mobility can be increased. If I subject to compressive stress you know that electron whole mobility can be compressive whole mobility can be increased. You can have germanium you can enhance the mobility over and above what it has got electron mobility and hole mobility by subjecting to strain how to do that. You can do that growing this similar metals we said for hydro structures you must have lattice match, but if I use lattice mismatch structures. For example, I have silicon here which has lattice constant 5.43 between the atoms I grow germanium on the top of that lattice constant is 5.65 silicon germanium will be in between either I go silicon germanium or silicon germanium if I grow thick layer the lattice will be that of this silicon germanium, but in between you can see the if it is thick layer it will relax to its own lattice constant and there will be broken bonds defective layer, but if I use the layer very thin there compared to this silicon layer then the silicon layer forces is back. This is a this is there is no strain here there is there are defects here thick that is why you cannot go thicker layers of hydro structures, but if I grow very thin layer then the thinner layer gets compressed by the bottom it is it is pulls pulls it back when you have one layer or the other the top layer is thin and the bottom layer is thick that actually pushes it like that compresses, because it tries to the bottom layer tries to pull it along that direction. So, that bond length increases like that there is compressive stress on this. So, bigger lattice atoms that is germanium and silicon will get compressed. So, if it compresses it is good for P channel if I have silicon germanium on germanium silicon germanium is smaller lattice constant compared to germanium you will have tensile stress you can make n channel MOSFET firm mobility. So, that is what is done there. So, this gives you actually there are you know this as you grow there is a critical thickness up to which you get this strain layer beyond that there is no strain layer it is defective. See for example, if I am growing germanium silicon germanium when germanium is x germanium is 0.2 I can grow at about 0.1 1000 angstrom that is 0.1 micron layer thickness which is strained with the which has no defect that is like this I can grow. If I grow more than that thickness then it it will be it will be like this defective layer. So, this tells you that if you want more germanium you know thickness that you grow will be very little. For example, if x small fractions of germanium you can grow hardly between 2 nanometers of germanium which is strain layer with the which is defect free. So, this layer is defect free, but it has higher mobility compared to that. So, now we will see how the strain induced layer can be introduced. So, the one or the approach of silicon substrate graded silicon germanium then relaxed silicon germanium which actually has that is constant more than that of silicon. If I grow silicon layer on the top of that it will be strained and it will experience compressive stress because along the horizontal direction compressive stress because that is constant of this is smaller compared to that and this relax the layer. So, it will start to stretch it it will it will stretch it. So, since it is tensile stress you can use that for or this will actually because that is constant of this is smaller compared to that and this relax the layer. So, it will start to stretch it it will it will it will it will stretch it. So, since it is the announced electron mobility by controlling the x in this layer you can control this lattice constant of this layer. So, bigger the lattice constant more will be tensile stress more the x here bigger the lattice constant more will be stress here more will be the strain more will be the mobility. So, you can see x is 0.13 you get much better than the classical reported mobility of electrons if you make x point to it you get even higher. So, this is one of the approaches which was reported in literature by some of the authors. So, electron mobility in strain silicon on the silicon germinium is higher because of we have taken experiences tensile strain. Now, there is one we can get dual channel this has reported in literature few years back silicon graded silicon germinium x gives 40 the most fraction of germinium and then you grow on this relaxed layer means actually the lattice constant is ground by how much x is there. On the top of that you go grow strained you grow silicon germinium with most fraction y larger than that of x. That means y larger than that of x means actually germinium content is more compared to the germinium content is here. So, if germinium content that is about 12 nanometers if the germinium content is more in this layer. That means it is lattice constant is more compared to the bottom layer if the lattice constant is more it will be experience because of this layer it will compress it it will try to bring it equal to this particular layer. So, there will be compressive test on the carriers here. So, if it compressive stress you get the compressive stress y is larger than that of x. How much is the compressive stress depends upon how much is y compared to x. So, because compressive stress the whole mobility in this layer can be increased tremendously. So, these are the results which are reported experimentally. For example, if y is 0.6 and x is 0.3 y is greater than x it is double. You get a mobility for this is as a function of vertical electric field for a given electric field you get the whole mobility which is about 300, 10 meter square per volt second nothing much to boast of. But I go to y 0.8 that is 80 and 50 much higher y you get mobility which is getting down to 800. Whole mobility 800 much more than that in silicon you go to 100 that is germinium itself there strain germinium then you get mobility much more than 1000 centimeter square per volt second that is the whole mobility. So, it is a power of using the strain layers. Similarly, if I put on this layer silicon strain layer I can get because this is smaller than this I can get tensile test I can make n channel here I can get p channel devices n channel device that is 12 channel MOSFETs I can make here. So, the whole mobility sensor factor is about 10 x there and electron mobility is announced approximately by factor of 2 all that they can be seen in that case and this is actually the result that you get whole mobility announcement you get if you use silicon germinium at source end but this is using strain layer you get much larger whole mobility compared to what we seen by using the silicon germinium at source end rate. Now, the last one what I am trying to point out here is actually we can have the heterostructure on insulator this is high. So, you can have the you can grow relaxed silicon germinium on that ok and you can grow strain layer here and put it upside down and bond on the silicon with oxide edge the top layer you can get strain silicon layer. So, what I am trying to point out is by using these combination of this bulk layers mount it upside down on the bottom layer and etching down the remain unwanted layer like this you can get strain silicon for example, here you can have this layer bonded on to the buried layer you can see here you have got silicon strain silicon put upside down bottom you have got this is coming at the bottom like this and bond it and etch the unwanted layer you get structures like the high. So, what a summary processing use stress has been used to achieve significant mobility enhancement in short channel devices ok silicon silicon germinium material systems has the potential to achieve very large improvements in mobility. For example, 10x hole mobility enhancement for strain silicon germinium have been reported. Hydro junction devices such as hemp enable very high mobility transistors using dope wideband gap semiconductors with that I conclude my discussion on non-classical MOSFET where we have covered where is the germinium channel.


I would ask members of the public who are in the gallery and departing after First Minister's questions, if they could please do so quickly and quietly, as we are hoping to resume our next item of business shortly indeed. The next item of business is a members' business debate on motion 5082 in the name of Rhoda Grant on fair tax week. The debate will be concluded without any questions being put, and I would ask those members who would wish to speak in the debate to please press the request to speak buttons now. I call on Rhoda Grant to open the debate around seven minutes, Ms Grant. Thank you, Presiding Officer. I would like to start by thanking those who signed my motion allowing this debate to take place. I would also refer members to my register of members' interests in that I am a member of the co-op party, a party that holds the fair trademark and also actively campaigns for its promotion, not just the fair trademark itself but for the very ethos that lies behind it. The motion was lodged to mark fair tax week in June this year. The debate is as pertinent today as it would have been then, possibly more so because we are facing a cost of living crisis. Many people are concerned about how they are going to afford the very basics for survival this winter. Tax is our investment in society. Into the society that we wish to live in, the money that we pay should be invested in creating better and more caring society to provide security to our citizens. Therefore, taxation should be viewed as a positive contribution to society. The fair trademark seeks to highlight that. It seeks to recognise the companies that have paid the correct rate of tax at the correct time in the correct jurisdiction. Companies take pride in the fact that they contribute to our collective wellbeing. Sadly, not every company wants to make that investment. It is estimated that shifting tax liability has led to a loss to the exchequer that is equal to 28 per cent of the tax that is collected. Income that should have been invested in the NHS and other essential services. Instead, it was off-shore to boost fat cats and shareholders' dividends. It is not illegal, but it should be. The United Nations principles for responsible investment state earnings that are reliant on tax planning rather than genuine economic activity are vulnerable to changes in tax regulation and enforcement. They go on. Even if specific tax regulations are not changed, more proactive enforcement by regulators suggests that earnings risk resulting from those strategies is increasing. As countries and their tax authorities become increasingly concerned with the exploitation of loopholes in international tax frameworks and are under fiscal pressure to fund additional government programmes, the incidence of tax disputes and litigation will increase. Therefore, staking a company's future success on a strategy based on tax avoidance is not only morally wrong but also risky. Tax avoidance is not only a concern to Governments but also to citizens. The Institute of Business Ethics annual survey showed that 47 per cent of respondents were concerned about corporation tax avoidance. That topped the list of public concerns for nine years in a row. Those findings are in line with the fair tax foundation polling. The foundation found that 74 per cent of people would rather shop with a business who are paying their fair share of tax. We in the UK can take steps to stop tax avoidance and offshoring, but we must also try and build global consensus to ensure that corporations pay their taxes where they are earned. That requires agreement between Governments and I urge the UK Government to initiate those discussions and to broker a global response. However, there are things that we can do in Scotland to promote the payment of fair taxation. The Scottish Government and the whole of the Scottish public sector procure services from the private sector. We need to use stringent procurement methods to ensure that companies pay their taxes, and that must be an essential requirement in all public contracts. We could also use that for licensing. For example, did the Scotland bidders have to show that they had paid their taxes where their profits were earned? Were they required to continue to pay their fair taxes on profits made from our renewable energy? The fair tax mark allows companies who do pay their tax at the correct rate and the correct jurisdiction at the correct time to be easily identified. That accreditation can be trusted by procuring authorities, allowing them simply to ask contractors and suppliers whether they achieve the fair tax mark. Councils across Scotland have been calling for ethical action in procurement by signing up to the councils for fair tax declaration. South Lanarkshire, Edinburgh, Midlothian and Dundee have already signed, but we need more councils to sign up as well. The public agree that 66 per cent of people believed that the UK and Scottish Governments and local councils should at least consider a company's ethics and how they pay their taxes part of the procurement process. During the pandemic, 80 per cent of people believed that businesses benefiting from Government bailouts should only have received that bailout if they had agreed to the conditions that prohibit tax avoidance. Frankly, I believe that they should not have received a bailout if they had not paid their fair share of tax in the past, given that those very taxes were what paid for that bailout. Many companies and organisations have received the fair tax mark accreditation, and I want to pay tribute to them. There are those that you would expect, such as the co-op party and co-op societies such as Scot-Mid and the co-op group, organisations that have fair practice at their very core. The Government-owned companies such as Scottish Water have achieved the accreditation, as have large PLCs such as SSE and smaller firms such as Glasgow-based accountancy firms such as Brett Nicholls Associates and North Berwick-based Gerba Caravans. It is a long list, but it is not long enough. We need to make sure that all companies that work with Government at any level should attain that accreditation. Presiding Officer, in conclusion, I believe that we must change the culture around taxation. It should be acknowledged and valued when companies pay their fair tax in the country where they make that profit. It is fair to their workers and it is fair to customers. That payment is their investment in our society. That payment enables Governments to provide the services and securities that we all require. I welcome the opportunity to speak in this fair tax week debate and congratulate Rona Grant on securing it. Ms Grant has outlined the issues really well. Fair tax week is an opportunity to celebrate the companies and organisations that are proud to promote responsible tax conduct. Paying a fair share of tax is one of the principal ways that businesses contribute to society, helping to fund the public services that we all rely on. Championing a level playing field for businesses, fair tax week allows for an opportunity to highlight the importance of fair tax principles in protecting and advancing public services here in Scotland as well as across the UK. Presiding Officer, the growth of tax havens and unethical corporate tax conduct have become the subject of much debate here in Scotland across the wider UK and across the globe. Aggressive tax avoidance negatively distorts national economies and undermines the ability of business to compete fairly, both domestically and internationally. Indeed, as an example, eight large tech companies in the UK made an estimate £9.6 billion in profit from sales to Scotland and UK customers in 2019. However, by moving money out of the UK, those companies ended up declaring a fraction of those profits into the air accounts of their UK subsidiaries, radically reducing the tax liabilities. Amazon, eBay, Adobe, Google, Cisco, Facebook, Microsoft and Apple faced UK corporation tax liabilities of £297 million in 2019, putting the total amount of tax avoided by the companies in the UK at an estimated £1.5 billion in 2020, the latest year that we have figures for. Emma Harper for giving way. Did she agree or did she find interesting the points that Rhoda Grant was making in relation to the Scotland contracts and trying to make sure that we get transparency from the companies that have been awarded options to lease? Would she also agree that we need to look at companies that the Scottish Government is contracting with such as Amazon and should be expecting higher standards from them or not awarding contracts to them if they do not meet those standards? Emma Harper. I thank Ms Clark for the intervention. I am interested in how any company can be transparent in how they look at taxation, and as much of the taxation powers are not part of what this devolved settlement is about, I would look to the UK Government to help to support any opportunity to have the likes of Amazon, as you have mentioned, to declare their tax in a better, more fair and appropriate way. As I was talking about the amount of money that the 1.5 billion in 2020 that those companies had avoided paying tax, that money could have been invested in our country's infrastructure, our culture, our civic society or, indeed, topically, here to invest in the most in need with the cost of living crisis. Rhoda Grant mentioned that but, instead of aggressively working to tackle this issue and make companies pay the fair share, we have seen the UK Government spending three and a half times more chasing fraud and error in the benefit system than they spend pursuing tax dodging millionaires. The DWP is spending 510 million pounds, vastly more, to prevent fraud and error in the benefit system and to collect more debt from people on universal credit. The DWP estimates that it can claw back 3.15 billion from benefit claimants, while the HMRC estimates that 3 billion could be raised from putting additional resources into chasing tax dodgers. In 2020, the pandemic tax gap of unpaid revenues was 70 billion. It is simply astonishing that this is receiving less additional resources than social security fraud and error. I ask the minister for a commitment that the Scottish Government when we receive full taxation powers, which is currently reserved, will focus its efforts on working with business to ensure that they pay their fair share in tax and that we will not spend billions to penalise the most vulnerable in society. In conclusion, fair taxation and corporate tax are so important for investing in public services. We are the thread that binds our communities together, so I thank the fair tax foundation for all the hard work that it does to support the companies and pay their fair share. Thank you. I now call Jamie Halcro Johnston to be followed by Kara Mock in around four minutes, please, Mr Halcro Johnston. Thank you, Deputy Presiding Officer. Firstly, can I congratulate Rhoda Fife on securing today's debate on fair tax week? Fairness is one of the core principles of governance, and as Rhoda Grant's motion touches on the public show an overwhelming desire for taxation to be fair, for it to be applied in an even-handed way and for businesses as well as individuals to pay their share. The fair tax market at the centre of the fair tax foundation's work deals with the tax affairs of businesses and organisations. It is worth remembering that businesses operate in a competitive market. For that competition to work, there must be rules and rules that provide a level playing field for everyone, rules that do not distort competition or embed the position of those who are already successful. This is not to ignore the obvious interest that we all have as a Parliament in gaining revenue that can be used as support public services and the spending that Government undertakes. We have seen an increased interest in cracking down on tax evasion and the sort of aggressive avoidance activity that takes advantage of legal loopholes, constructing tax affairs in such a way as to reduce transparency. Governments across the UK have taken action. In 2013, the UK Parliament voted to support the general anti-abuse rule, sometimes referred to as the general anti-avoidance rule. In 2014, this Parliament followed implementing a Scottish anti-avoidance rule through the Revenue, Scotland and Tax Powers Act. Both are part of a package of measures that have been taken to tighten up tax regulation while also trying to reduce the burden on those businesses and organisations who are paying. Of course, where tax liabilities arise is not precise. They often depend on self-reporting. Tax arrangements can be reasonably construed in different ways, and it is often a clear intention of tax rules to allow for exemptions and deductions to provide support to organisations or to encourage positive practices. There remain, unfortunately, many mechanisms for evasion and avoidance. However, HMRC's central measure of liabilities versus payment is the tax gap. We have seen a positive decline in the gap between what is estimated to be due and what actually ends up in the hands of the state, with stabilisation at a lower level in recent years. However, this is not a definitive conclusion of the issue. Tax rules are regularly changing and the approach is taken to evade or avoid them evolved to. However, the spirit of the law is, of course, not a value neutral or necessarily objective judgment, particularly where complicated tax regimes are involved. Despite work under several Governments to promote simplifications, the complexity of corporate tax remains. The ultimate decision on who is paying their fair share must be for independent bodies working on the basis of what is due. Uncertainty, over such standard lies within the fair tax foundation itself. Last year, Richard Murphy, who has given evidence to this Parliament's committees in the past and who claims creation of the fair tax mark, resigned from the foundation in part due to concerns about the mark's international standards. As a broader point, I would also caution against increasing the administrative burden on procurement policy. It is good as a point of principle for the public sector to make ethical procurement decisions. Too often, we have been perplexed that a small number of large suppliers to the public sector continue to secure public contracts at the expense of smaller and more local ones. Procurement reform has attempted to address this gap, but fundamentally many businesses do not feel they can compete as a result of the administrative burden requirements placed upon them. While small businesses may have more straightforward tax arrangements, they may also be less likely to be able to justify in time and cost the investment of being accredited by those standards. Deputy Presiding Officer, it is certainly positive that we are discussing ensuring that tax is fair and that businesses, as well as individuals and other sorts of organisations pay their way. While bodies such as the Fair Tax Foundation are making a positive and useful contribution to the discussion, I would be cautious before applying too great a reliance on the standards and the potential costs that they could create. I'm afraid not. I now call Karen Mocken to be followed by Michelle Thomson. Around four minutes, please, Ms Mocken. Thank you, Deputy Presiding Officer. I thank my colleague Rhoda Grant for bringing this important debate to the chamber. In the first instance, I refer members to my register of interest as a member of the co-operative party. In a week in which we have debated the impact of the cost-of-living crisis, it is only right that we support fair trade week, and debate in this chamber the importance of ensuring that every company is held firmly to account, as well as note the positive steps taken by the co-operatives and other companies. It has been known for years that powerful co-operations and super-rich individuals are exploiting a rigged global system that allows them to avoid paying their fair share of tax. As always, it is the poorest people in our country, the low-paid workers who pay the price. We have spent this week in this chamber talking about how people in our communities are struggling to afford necessities such as food and heat. It is appalling that we should need to celebrate companies that pay the correct level of tax and the correct jurisdiction at the correct time. It should be the norm, but, alas, the actions of the super-rich bring us here today. Extreme economic inequality is being fuelled by an epidemic of tax evasion and avoidance that has reached an unprecedented scale. In that context, I thank the fair tax mark for their work in celebrating those companies who do and for making individuals, companies and parliamentarians alike talk about responsible tax conduct. Governments should take note that polling by the Fair Trade and Fair Tax Foundation shows broad public support for the fair tax mark and for a greater interest in tax behaviour. 66 per cent believe that Governments and local councils should at least consider a company's ethics and how they pay their tax when letting public contracts. 80 per cent believe that all businesses benefiting from Government bailouts should have to agree a set of conditions. 77 per cent believe that all companies, whatever their size, should have to publicly disclose the taxes that they do or do not pay in the UK. 74 per cent of the public would rather shop with businesses or work with businesses, which can prove that it pays its fair share of tax. Part of what we can do is engage with the public, and by doing that we can put increased pressure on companies to behave properly on Governments globally to reform a broken system. I congratulate the co-op movement for its part in achieving the fair tax mark for highlighting the practices of tax avoidance and for supporting the Fair Tax Foundation's call to ensure that advanced reform of Scots public procurement rules and allowing contracting authorities to explicitly reward good tax conduct when awarding public contracts. Those businesses must make public commitment to shun avoidance, profit shifting and any artificial presence in tax havens and that they should make full as possible financial disclosure and make full as possible disclosure of their beneficial owners and persons of significant control. I hope that the minister will respond to those points. Also, significantly, the Fair Tax Foundation has opposition to any efforts by the UK Government to reverse the planned UK corporation tax rate increase, as doing so would further facilitate and international race to the bottom. Surely, no-one wants to go there. I thank my colleague Rhoda Grant for bringing this debate to the chamber. I hope that this debate allows us all to raise this important issue, ensuring that companies in Scotland, in the UK and across the world are held properly to account. I now call on Michelle Thomson, who will be the last speaker before I ask the minister to respond around four minutes please, Ms Thomson. It is a pleasure to take part in this debate and I thank Rhoda Grant for bringing the debate and for her very good speech. I have had an interest in taxation issues for a number of years and not just because I have to pay quite a bit of it. Back in 2016, when an MP was a sponsor of a double taxation treaties bill, the bill sought to write some injustices such as the fact that if African countries were able to access the corporate taxes that were due, the money would exceed the total amount of aid the rest of the world supplies. The bill reached second reading and, although it was not fully picked up and full by the UK Government, it did bring some changes. It has already highlighted one of the problems with the UK tax system as a whole is its complexity and large number of loopholes. Of course, there is a huge industry to milk those loopholes, limited resource and government agencies to plug them, and limited appetite from the UK Government to narrow the tax gap, which stood at £32 billion in 2021. I am reminded of the joke about an accountant's children being told the story of Cinderella and interrupting to ask, but mum, when the pumpkin changed into a golden coach, would that be classed as income or a capital gain? In Scotland, despite our Government having very limited powers over taxation, I applaud the efforts that the Scottish Government has been making to create a fairer and more efficient taxation system in those areas within its control. On rereading Tom Arthur's excellent reform Scotland blog in June of this year in the Government's framework for tax, he explained the need for fairness, transparency and engagement, and good guardianship. I suspect that those hark back to the four principles of good taxation set out by Adam Smith in 1776. One of those fairness, and by which Smith meant the ability to pay, appears to be a guiding light for the framework for tax. Similarly, Smith argued for certainty, by which he meant taxpayer should be clearly informed about how and why taxes are being levied. In other words, he argued for what we termed transparency today. Again, I note how Tom Arthur has taken forward this concern. He knows that there is considerable scope for improvement and has pointed out that 61 per cent of people in Scotland know very little about the tax system. Transparency and fairness are fundamental to further progress. It is fair to say that we are on a journey but have some way to go before we reach our destination. One further thought is that it is difficult to conceive of any tax that does not have unintended consequences. That is inevitable, as a way in which individuals respond to tax changes may be very different to the intentions of Government. I am sure that we have all seen examples that we can relate to. My own concerns about the world that we live in include the growth of shell firms and not least the massive abuse that is enabled by the existence of Scottish limited partnerships. Despite huge efforts over the years, the UK Government who are responsible for the relevant legislation has steadfastly refused to reform, so we are making progress but we have a huge way to go. I like to thank everybody who has participated and encourage members to continue the conversation because it affects everybody in Scotland. I also like to thank the local authorities that have signed up as fair tax councils and the fair tax foundation for the work that they are doing in this regard. Of course councils are independent, corporate bodies with their own powers and responsibilities will strongly encourage them to endorse the principles of the fair tax declaration. Fair tax week is a recognition of the businesses paying the correct amount of corporation tax and the correct jurisdiction at the correct time. Across the chamber we all agree that our tax system should be fair and that businesses have an ethical obligation to deal openly with their tax affairs and to pay the correct amount of tax. After all the money that we raise through our taxes is spent to benefit people across the country. The debate is not just about the levels of tax that individuals and companies are paying but about the values of our tax system. Since the devolution of powers over taxation, the Scottish Government has created a fairer and more progressive approach to the tax system following a distinctive Scottish approach to taxation. That approach continues to be founded in Adam Smith's Four Canons of Taxation, namely certainty, proportionality, convenience and efficiency. Another cornerstone of our approach is taking a tough approach to tackling tax avoidance issues. As has been mentioned by Jamie Halcro Johnston, the Scottish Government has introduced its own general anti-avoidance rule, GAR, established by the Revenue Scotland and Tax Powers Act 2014. It is wider than the corresponding UK GAR because its focus is on not just a narrow abuse rather than the wider test of artificiality, which is what the Scottish GAR covers. During the pandemic, we implemented measures to ensure that grants and funds did not go to recipients with links to tax havens. As a consequence of the House agreement, we are exploring what else we can do in that regard. It is also important to recognise that corporate taxation and the issues that go with it are reserved to Westminster, and the Scottish Government is constrained in what we can't do in that regard at a point well-made by Emma Harper. Of course, there was further devolution or indeed those powers were transferred as a consequence of Scotland becoming a normal independent country. We would be in a position to do much more in that regard than we currently are at the moment. The Scottish Government strongly condemns companies and individuals who artificially arrange their affairs to pay less tax. After all, every penny that is lost to the tax avoidance is a penny less to be spent helping people and businesses of Scotland at this very difficult time. Of course, those powers lie with UK Government and HMRC and we strongly urge them to do more to tackle tax avoidance and evasion. As has been highlighted by a number of members to work internationally for co-operation across tax jurisdictions to establish processes that allow those issues to be addressed—what are global issues to be addressed in a global context—the points that Michelle Thomson made about the international aspects of that and the impact on certain countries in Africa is extremely well-made and the points that she makes about the complexity of the UK tax system, which makes progress in many of those areas more complicated and difficult than it might otherwise be. I know that Michelle Thomson has a significant interest, not just in good tax practices but in wider aspects of corporate governance, and I thank her for the work that she takes forward in that regard. I want to talk a bit about procurement, which has been mentioned on more than one occasion this afternoon. First, I want to recognise that the £14 billion public sector procurement spend in Scotland is something that the Scottish Government and myself are responsible for. Procurement absolutely recognises a lever that we can ensure to use to the full extent to progress other wider social, environmental and societal agendas. It is important to recognise that we already use the procurement levers that we have within the constraints that exist. Of course, we do not control employment law either, but we have done significant work to move the real living wage agenda, the fair work agenda forward. We have done significant work to support and encourage and shift as much spend as possible towards SMEs within Scotland, something that we have had significant success in, compared to other parts of the UK, and also through the sustainable procurement duty to further the community wealth building agenda. We are very focused—you can rest assured—on looking to do everything that we can in that regard. Of course, it is important to recognise the constraints that we operate with regard to procurement. The public contracts Scotland regulations 2015 already require that public bodies exclude bidders who have been found to have breached their legal obligations in relation to the payment of tax or social security. They also allow public bodies to exclude bidders where they can demonstrate such a breach of legal obligations by any other appropriate means. However, neither the Scottish Parliament or the Scottish ministers have the power to exclude companies from public contracts on the basis of offshore tax planning practices that Westminster allows. That is an important point to recognise because those powers, as I said, are reserved. I can continue to work with procurement officials and, as we are interested in this area, to explore further opportunities for us to tighten up those practices. However, as I said, it is hugely important to recognise that, because those powers are not devolved, there are legal restrictions that limit how far we can go, and we are not able to go as far, frankly, as we would like in that regard. In conclusion, it has been a very helpful and useful debate. It is good to get those issues raised. I know that my colleague Tom Arthur has responsibility for tax. He will be watching this very closely in this regard as well. It is important to recognise that, through our Scottish approach to taxation, we are committed to ensuring that individuals and businesses pay the right amount of tax at the right time and place. We are also committed, as I have indicated in the House agreement, to take forward and explore any further measures that it can execute in that regard within the limited powers that we have.


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Hi guys, what is up? Welcome to my channel. So for today's video, we are going to be talking about my absolute favorite thing in the world to talk about eyeshadow palettes. I'm going to be sharing with you my top picks for my favorite eyeshadow palettes for the year 2019. Now, if you are interested in my other makeup product favorites for the year, I did just post that video. So check that out. I just had to give eyeshadow palettes their own full video so I can give them all the moment that they deserve. So if you are interested in seeing my favorite eyeshadow palettes, then just keep watching. Eyeshadow palettes are obviously my biggest weakness. I have a huge collection of them. I review them constantly on my channel, so I had a lot of eyeshadow palettes to narrow down. The ones that I chose, these ones are just really what stood out to me this year, what I found myself constantly going back and reaching or what I found to be extremely inspiring. I'm actually pretty proud because I managed to narrow it down to less than 15 palettes. I'm surprised honestly at some of the ones that I left out and I'm sure you guys will be too. So I think we're going to organize it by price range.  So of course we have to start off with Pat McGrath. Let's get the good stuff out of the way. I picked two of her palettes this year that were my favorite. They're probably not going to be a surprise to you. This one in particular is the bronze seduction palette. I love the four special shades right here and then I love the more neutral part of this palette. It just is one of the most inspiring palettes to me that she came out with this year. If you don't watch my channel regularly, Pat McGrath has my favorite eyeshadow formula. So it would be so wrong of me not to put any of her palettes in this video. But this one by far was my favorite palette that she came out with this year. I'm so obsessed with this. It came out earlier this year. I think it's Bergdorf Goodman. They have like a lilac version of this and I'm honestly considering getting it if they decide to restock it because this palette is just incredible. I'm super obsessed with this pink color right here and the duo creams are intense. So such a good palette. I definitely think if you are really into more luxurious makeup products, everybody should invest in at least one Pat McGrath palette. Here's another one to look into and I feel like my review wasn't as glowing as I actually have ended up loving it. And this is the Midnight Sun Palette. So this is the packaging. I don't know where the packaging for the bronze seduction went, but here's the packaging for this beauty. And the thing with Pat McGrath, if you aren't familiar, is it's basically like art that you are purchasing. That is why it is so expensive, but the packaging is just super luxurious. So here's what the Midnight Sun looks like. And at first I wasn't super in love with this color story, but as I've gotten to know it more, I really have learned to appreciate it more. It's perfect for every day. Of course the quality is incredible. I really love this purple shade right here. I mean, as you can see, I always love a good purple shadow look. So this is the color that stands out to me the most and I really like the tones here on the more neutral side. Great for every day. What I love about Pat McGrath palettes in general is I feel like they are perfect for everybody because most of the time they have very neutral wearable colors that people can use for every day. And then you have those four special shades where they really glam up the look if you want to play around a little bit. So these two by far were some of my favorite palettes this year that released. Moving into Natasha Genona. Again, I picked two palettes. So the first one is the Beba Palette. Now this is what the packaging looks like here and it is an all neutral palette. I mean, let's be honest here. These are the only colors that I really go for on an everyday basis. A lot of people were underwhelmed by this palette, which is obviously very reasonable because they're just boring neutral colors. But that's what you go for, you know?  This is definitely a staple palette. If you ask me, this is a palette you want to take to travel with you or if you don't know what kind of makeup look you want to do, I will find myself grabbing for this. It's just great for everyday. And then of course the formula in here is incredible. Every single eyeshadow in here is consistent, great quality, blends. It's shiny when it needs to be. It just does what it's supposed to do, blends out super easily. It's really just a foolproof palette. 100% recommend this. If you are interested, again, it might not catch your eye at first, but if you're a neutral wearer, you will probably reach for this palette a lot. And then the next one, which I'm surprised I ended up picking out, is the Metropolis palette from Natasha. And what I liked about this first off was that she cut her pan size basically in half and cut the price of the palette in half. So you're getting 28 shades here for literally half the price of her full size 28 pans. So the value of here was consistent with her regular line and I like that you're paying less for less product because I have so many eyeshadow palettes, there's no need for me to buy a lot of product. But I love this palette and at first I was very overwhelmed by it. I thought it was sporadic. I thought some of the colors were too close to each other. The longer I've had this, the more I find myself reaching for it. I find it to be extremely versatile for many different occasions. Now like I said, I am a neutral color wearer, but just with me doing YouTube and doing makeup in general for Instagram and all of that good stuff, I do actually reach for odd colors quite a lot and this is a great palette to really amp up a look, make it different, not just an everyday look, but you can also do an everyday look. I really think if you're looking to invest in a very good, more full size Natasha Denona palette, this is a great way to go because you do still get a lot of colors. It's not quite as expensive as her other palettes and you get such a great range. I just think this is a great range for normal people and it allows you to mix up if you want to play with your makeup more. That being said, this one is much more neutral, so you'll probably use this more, but this one I just think is really fun. You'll know what colors you use, but I really like this. This was another palette that she came out with that had a very consistent formula with her regular line, that formula that made her brand popular, so this really stole the show for me this year. I also picked out a couple of Tom Ford quads that I wanted to talk about with you guys. Now, I've mentioned this in a few videos. I really got into Tom Ford eyeshadow quad. I've been using them kind of off-camera more so because I feel like they're just more wearable. I kind of throw them on their really great throw on eyeshadow palettes, but I haven't talked about them too much, so I did want to share the two this year that I've been absolutely loving. So we are going to start off with the one that I am currently wearing on my eyes and this is the Daydream palette. So you guys know how much I love purples and this is what it looks like. It is really stunning. I know it looks a little scary because they all have that shimmer finish, but I used three of the shades on my eyes today and it's completely fine without having any mattes. I love the formula in here. You can use these wet or dry and these are just absolutely stunning colors. The thing with Tom Ford eyeshadows that make them different from many others is I feel that there's just something so elegant about the way that they look on the eye that you just don't get with a lot of other shadows. With the Tom Ford shadows, you're not really going to get very defined looks or very intricate looks like the things you see on Instagram. These are really about everyday wear, throwing them on, looking elegant and pretty and that's just how I feel about the line. Super stuffed, really great stuff. So if you like purple Daydream, it's absolutely stunning. I stared at it at the counters every time I went to a Tom Ford counter and finally this year I decided to get it and I do not regret it. The other one that I really enjoy is African violet. Now this one, I feel like it's pretty unique to his line. That's why I like it so much. It just kind of stands out. So in here you're getting two mattes and then you're getting a shimmer and then a bit more of a metallic. So this one I like because you are getting a range of different finishes. It's probably not as unique as I think it is but specifically in his line it's very unique. Again, here we are with the purple. You know how I feel about that and then you get really warm tones. I really like purple with warm tones sometimes. I think it looks really good. So I think this is a really pretty mix of colors. These three, if you want a more neutral look, can add the purple in for a little bit of pop but I really enjoy this one. I think it is very different. It's very pretty. The quality, it blends like butter. Tom Ford is not a brand that you want to invest in if you don't have the money. However, if you do have the money, they are really special to own and I really enjoy the experience that I have wearing them and applying them and how they make me feel. Not a necessity but a really great treat yourself item because you're only getting four shadows. But he has some beautiful quads in his line. I know I need to do a video on the quads that I have but moving on, one of my favorite palettes this year is from Vizzy Art and this is the liaison palette. Now that I'm looking, there's like a lot of purple palettes in here. You can see what kind of colors I always go towards. This palette is so phenomenal. I feel like the quality in here is better than most Vizzy Art shadows which is a big statement because their shadows are one of the best in the business to begin with but I am so in love with the curation of this palette. I just think the colors that they decided to pair together just really makes sense. It really makes it very easy to create a look on the eye without having to think too hard. I love these really cool topy purple colors to start off the look and the shimmers in here are absolutely insane. They're the kind of color where it'll go all the way down your arm. They're so creamy and pigmented and every time I wear this palette, I create such a stunning look. If you've been eyeing this palette, I would recommend that you pick it up. It was one of my favorites this year. One of the best Vizzy Art has ever come out with. So I hope to see them come out with another one of these nine-pan kind of color story palettes sometime soon. If they're as great as this one, oh my gosh, any color story would be great. The next palette that we have is from Huda Beauty and this is a newer palette. This is the Mercury Retrograde palette and I love everything about this palette. From the packaging to the concept, the color stories, the quality. I just think it is a fantastic palette. Now I will be completely upfront in that I haven't used this palette a ton because the colors in here aren't the most wearable for me. However, every time I do use it, I am so in love with the look that I create. I think the reason why this is one of my favorite shadow palettes of the year is simply because it is such a unique concept. I don't have a palette like this in my collection. The textures in here are really fun and you can just create a really pretty galactic look and of course we do have a lot of purple shades and just really fun shades in here. I wish I could use this palette more than I have but it's just not everyday kind of friendly but it's one of those palettes where it makes me happy to own. I feel inspired having it in my hand. Just watch it. I mean, Huda always does such a fabulous job with their palette releases but I feel like they really did step outside of the box with this one and they did a very good job with it. I have a couple of ABH palettes that I wanted to share with you and so the first one I wanted to talk about is the Jackie Aina collaboration palette from ABH. This palette isn't really geared for the type of makeup wear that I am. The only time I really use this palette is if I want a really deep eye but this palette creates quite a statement on the eye which I really like. This palette never really got its full moment because ABH all of a sudden went crazy and started releasing all of these palettes so I definitely wanted to give this palette a moment because the colors in here are beautiful. This palette is beautifully curated. You can create a lot of different looks with this palette and that's what I think makes it really special is the amount of looks you can get is endless. You can get a neutral look. You can get a purple look. You can get a rainbow look. It really is such a unique palette and the way that Jackie curated it she did a fabulous job so it's super versatile. This came out towards the end of summer. The quality of it is really nice and I just really like how inspired I feel when I have this palette in my hands and all of the different looks that I imagine creating. Love the colors that she chose. Really wonderful palette. If this is limited edition I would say definitely pick it up if you can before it sells out because it's a really fabulous palette. It's not a palette that I reach for every day but it is a palette that really sparks a joy inside of me, you know? The next one I'm very surprised that I'm showing it but it is so good and every look I create I love it and this is the Norvina Volume 1. I feel bad mentioning it because I don't know this whole release of all three of them in like a month was ridiculous but I can't deny that this palette isn't absolutely amazing. I feel like the quality in here is better than the regular ABH formula. You can create some really neat, unique looks with this palette and I mean I'm really just bragging on this palette because I was shook by the quality. I want her to come out with a big one like this of pure like neutrals and I feel like the collection would be complete with a whole palette of neutrals but no, honestly, like I think the shimmers are in here are phenomenal all of the mattes blend beautifully and this is a majority purple palette and with those types of pigments it can be hard to create a good shadow but they really did it with this. I was highly impressed by this. This is the one I would recommend you pick up if you are interested in it. I genuinely would be lying if I didn't say this is one of my favorite palettes that released this year. Alright, so the last few are more affordable items. I want to take a moment to talk about Kaleidos eyeshadow palettes. They are an indie brand. I think they're a brand that is really onto something. They're creating a very unique brand. The concept of it is very unique and they're just bringing something different to the table. So they have a few I believe about six eyeshadow palettes out. I picked my top three to share with you guys because they are stunning. They're pretty affordable palettes and I just love the packaging of them. These are their Futurism eyeshadow palettes and they're very similar concepts to Pat McGrath. Like this reminds me of Pat McGrath but like 10% of the price and just super gorgeous palettes. The quality is really nice. It's not amazing luxury quality eyeshadows. There are some particular shadows that do require a little bit more work but they are affordable and I think sometimes we forget that. So not the best quality ever but it's good quality and the colors are amazing and their shimmer formula is really really good. So their mattes I think could use a little bit more work but their shimmers are phenomenal. So this one is the Futurism one sci-fi green. So if you like this color story I would recommend that one. I also really love the color story of Futurism 3 Astro Pink. So take a look at this packaging. Like such a unique cool concept that this brand has. I'm telling you this turquoise is so unbelievably incredible and I just really love these shades right here. Even the mattes to the shimmers this is just a really great curated palette in particular as well. And then they came out with a couple of other palettes a few months later and this is the Electric Turquoise and this one was super fun for the summer. Again these particular shimmers are amazing and I just really love how inspired this brand makes me feel. I feel like they have some really fresh ideas in the industry that are just really unique. So definitely keep an eye out for this brand. They create really great stuff. Make sure you support them so that they continue to grow because they have a lot to offer in the makeup industry for the future. So the last two palettes that I chose are from Colourpop. I really tried to keep you guys a nice range and Colourpop is one of my favorite affordable eyeshadow brands. I'm very picky about eyeshadows. Typically I prefer high end luxury shadows but Colourpop really does a good job for their price range. Definitely I'm not saying they have luxury quality eyeshadows. I can tell the difference but these get the job done. I'm highly impressed. I would say these work at about a high end range kind of quality point. So the first one that I want to talk about is the Sweet Talk Palette. This collection from Colourpop was by far my favorite collection that they came out with. I wish I had purchased more but I didn't at that time but I really love this palette. Now it does have a couple glitters that I know a lot of you guys don't like but I love the tones in here. It was perfect for the spring and summer and I just found myself reaching for this palette a lot. I just feel like every look I create with this palette it's really feminine and soft and very pretty and it's just one of my favorite palettes that Colourpop has ever come out with in general. One of my favorite palettes that I've used this year. I've not heard anybody say they don't like Colourpop shadows. Even all of my subscribers, we love luxury makeup and a lot of you guys have told me that you also like Colourpop because they create good products and the packaging is cute too. The other palette that I loved, this is a new one but I am head over heels for is their Going Coconut palette. So this is from one of their nine pan monochromatic palettes. They have a whole collection. I think some are better than others but for the most part if there's a color story you're kind of looking for definitely look into that line. They're super cheap especially if you get them while they're on sale. I think I got those for like eight bucks but all my neutral lovers. This palette is absolutely amazing. I think this is going to be my new travel palette for a while. It has all of the neutral neutrals that I love and I'm comfortable with and I feel like are very flattering on me. Very like shades and then the perfect crease shade in every shade with every depth so that I can really blend and create depth in my makeup looks. This one was my favorite Colourpop palette for a while but this one has definitely taken over so good and the quality is very great as well for eight dollars. It just, I don't know how Colourpop does it honestly. That is all I have for today's video. We had a lot of talk about palettes my favorite thing to talk about. I hope you guys enjoyed it. I really do feel like I'm leaving palettes out but I know I had to be cutthroat in this one. I didn't want it to be another hour long video. So I hope you guys enjoyed this video and I hope you found it helpful. I want you to comment your top three favorite eyeshadow palettes of this year down below. Thank you guys so much for watching. If you are not yet subscribed to my channel I sure do hope you take the time to do so. I hope you are still working on your New Year's resolutions and I will see you guys in the next video. Bye guys have a good one.