Samsung Researchers Inch Closer to Commercial Graphene Transistors

New transistor design uses metal-semiconductor junction to preserve nanolayer's high electron mobility

Samsung Electronics Comp., Ltd. (KSC:005930), a South Korean firm perhaps best known for its smartphones and memory sticks, is among the companies racing to create transistors from graphene.  Graphene is a very special type of carbon, in which carbon atoms are sp2-bonded in repeating hexagonal units forming a one-atom thick sheet.

Graphene is highly conductive, which could lead to super-efficient transistors measuringjust a few atoms wide.  But to create reliable, commercializable designs, researchers must find a way to get graphene to do a better job at shutting off current (as the transistor key function is to act as a switchable gate to the flow of electricity).  "Plain" graphene can not shut off current due to its semi-metallic nature.

Past-research has largely focused on making graphene into a semiconductor.  But that approach creates new issues, cutting the electron mobility from 200 times that of silicon, to much less than silicon -- a performance killer.

_{Companies are racing to implement graphene transistors. [Image Source: i09]}

The Samsung design instead opts to use a special graphene-silicon Schottky barrier to halt the flow of electricity.  A Schottky barrier allows for a metal-semiconductor (or semi-metal-semiconductor) junction.  By keeping the graphene semi-metallic, the strong electron mobility is preserved.

Samsung calls its special graphene Shottky transistors "barristors" (a blend of "barrier" and "transistor").  It owns 9 patents on the technology.

_{Samsung calls its special graphen transistor a "barristor". [Image Source: Samsung]}

On the recent refinements, published [abstract] in the prestigious Science journal, researchers at Samsung's Advanced Institute of Technology demoed basic processing.  The company writes:

In addition, to expand the research into the possibility of logic device applications, the most basic logic gate (inverter) and logic circuits (half-adder) were fabricated, and basic operation (adding) was demonstrated.

Now with the fundamentals in place Samsung must come up with the processes to mass-produce its barristors on the nanometer scale.  If it can do that, it could offer a unique advantage to its smartphones and to business partners like Apple, Inc. (AAPL) that rely on its chips.

Of course, other companies like Intel Corp. (INTC) and International Business Machines, Inc. (IBM) are also hotly pursuing graphene designs, so it's unlikely Samsung will be alone when this technology inally reaches the commercial stage.