MIT Chip

A team of researchers from MIT and a German university said that they've discovered a material with greatly enhanced capacitance, possibly lowering the operating voltage and allowing chips to run even faster then today.

The MIT researchers plus a team from the University of Augsburg in Germany said that they had constructed a system from lanthanum aluminate grown on top of strontium titanate.

The researchers were impressed by the amount of charge that the materials sucked up at room temperature, but that it took place too slowly for the type of high-speed switching that occurred in today's chips. On the other hand, the researchers noted, the sample might have been too "dirty" - or not pure enough - to produce an accurate result.

Capacitance is defined to be the amount of charge Q stored in between the two plates for a potential difference or voltage V existing across the plates. (C=Q/V) Put another way, the voltage is defined as the amount of charge (Q) divided by the capacitance. (V=Q/C) By increasing the capacitance, the amount of voltage is decreased.

That, in turn, is one of the keys to increasing the performance of a chip used in notebooks or other devices. Lower operating voltages mean lower power is required to run a chip at a given speed, meaning that the battery life of a mobile device increases. Designers also have the option of increasing clock speed, the point of the MIT efforts.

Typically, companies like Intel achieve lower voltages by physically shrinking the distance between the gates of a transistor, and increasing the capacitance. Intel recently tried a new angle: what it calls a "tri-gate transistor," which uses the same silicon-based materials that its other chips use, with a redesigned physical structure that includes conducting channels on three sides of a vertical "fin" structure.

MIT Chip

In MIT's approach, lanthanum aluminate consists of alternating layers of lanthanum oxide and aluminum oxide. The lanthanum-based layers have a slight positive charge; the aluminum-based layers, a slight negative charge, MIT said. The result is a series of electric fields that all add up in the same direction, creating an electric potential between the top and bottom of the material.

Normally, lanthanum aluminate and strontium titanate don't conduct electrical current. But if the material gets thick enough, it does - producing a conductive channel like a transistor.

The researchers found that the materials may produce a large capacitance at an "infinitesimal" voltage, MIT said. "The channel may suck in charge — shoomp! Like a vacuum," Raymond Ashoori, an MIT professor of physics, said in a statement. "And it operates at room temperature, which is the thing that really stunned us."

The MIT researchers said that the technique might not be explained by today's understanding of physics. They also acknowledged that the phenomenon must be further explored, perhaps with a more refined sample and experimental equipment. And there's another problem: the billions of dollars already spent to make semiconductors the conventional way, with a silicon-based process.

Triscone cautions that wholesale changes to the way computer chips are manufactured will inevitably face resistance. "So much money has been injected into the semiconductor industry for decades that to do something new, you need a really disruptive technology," he says.

"It's not going to revolutionize electronics tomorrow," Ashoori said. "But this mechanism exists, and once we know it exists, if we can understand what it is, we can try to engineer it."

For more from Mark, follow him on Twitter @MarkHachman.
