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nanotimes News in Brief

11-11/12 :: November/December 2011

Graphene // A Hydrogenation Technique Triples Transistor Performance in Epitaxial Graphene

© Text: PennState

devices has been demonstrated on the wafer-scale by researchers in Pennsylvania State University (USA).

A

The researchers demonstrated a 3x improvement in electron mobility of epitaxial graphene grown on the silicon face of a 100mm silicon carbide wafer, as well as a similar improvement in radio-frequency transistor performance.

“There are two faces to a silicon carbide wafer,” explains EOC materials scientist Joshua Robinson. “Graphene grown on the carbon face usually has higher electron mobility, but that’s because beneath the graphene layer grown on the silicon face there is a carbon-rich buffer layer bound to the silicon carbide that acts to scatter electrons, thus reducing their mobility. If you can get rid of the buffer layer, the electrons will go much faster, which means your devices will work faster. It is also easier to control the thickness of the graphene on the silicon face, which is crucial if you want to make highly uniform wafer- scale devices. That’s what we’ve been able to do.”

False color SEM image of a graphene transistor (left) and gates of various lengths (right). Top gate is 75nm. © Joshua Robinson, Penn State EOC

technique that uses hydrogen to improve transistor performance on real-world graphene