The current trend of scaling down semiconductor devices has forced physicists to incorporate quantum mechanical issues in order to acquire a thorough understanding of device behavior. Simulating the behavior of nano-scale devices necessitates the use of a full quantum transport model especially for cases when the quantum effects cannot be ignored. This complication, however, can be avoided in the case of practical devices like the modern day MOSFET, by employing quantum corrections within a semi-classical framework. The semi-classical Monte Carlo model can then be employed to simulate the device characteristics. The quantum corrections can be incorporated into a Monte Carlo simulator by simply introducing a quantum potential term which is superimposed onto the classical electrostatic potential seen by the simulated particles. Figure beside pictorially depicts the essential features of this technique. The various quantum approaches available for implementation are described in the following subsections.