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Anenome
10-27-2010, 09:04 PM
A group of UCLA researchers and engineers have developed a new fabrication process for graphene transistors using a nanowire as the self-aligned gate.

A group of UCLA (http://www.edn.com/common/jumplink.php?target=http%3A%2F%2Fwww.ucla.edu%2F)( University of California, Los Angeles) researchers and engineers have used a new fabrication method to create what they say is the highest speed graphene transistors to date, with a cutoff frequency up to 300 GHz.

Graphene, a one-atom-thick layer of graphitic carbon, has in recent years been heralded as a possible replacement to silicon in semiconductors (http://www.edn.com/article/473477-Graphene_could_replace_silicon_in_semiconductors_u niversity_says.php). But the material is not without challenges.The UCLA group, lead by professor of chemistry and biochemistry Xiangfeng Duan, noted that traditional techniques for fabricating graphene often lead to deteriorations in device quality. As such, the team developed a new fabrication process for graphene transistors using a nanowire as the self-aligned gate.

"This new strategy overcomes two limitations previously encountered in graphene transistors," Duan said in a statement. "First, it doesn't produce any appreciable defects in the graphene during fabrication, so the high carrier mobility is retained. Second, by using a self-aligned approach with a nanowire as the gate, the group was able to overcome alignment difficulties previously encountered and fabricate very short-channel devices with unprecedented performance."

The UCLA group noted that with a cutoff frequency up to 300 GHz, the resulting transistors are comparable to today's transistors from high-electron mobility materials such gallium arsenide or indium phosphide. The group is currently taking additional efforts to scale up the approach and further boost the speed.

Duan worked with two other researchers from the California NanoSystems Institute at UCLA, Yu Huang, an assistant professor of materials science and engineering at the Henry Samueli School of Engineering and Applied Sciences, and Kang Wang, a professor of electrical engineering at the Samueli School, on the technique.(Full article (http://www.edn.com/article/510523-UCLA_claims_300_GHz_graphene_transistors.php))

Note, this won't result in 300 ghz chips, get your head out of the clouds :P What significant is that graphene could replace silicon ultimately.

brandonjclark
10-28-2010, 01:12 PM
How abundant is graphene? Will the fabrication process ever be EASIER and LESS COSTLY than silcon-based transistors?

Anenome
10-29-2010, 01:57 AM
How abundant is graphene? Will the fabrication process ever be EASIER and LESS COSTLY than silcon-based transistors?
How abundant is graphene??? Dude, it's just carbon. It's the "lead" on the end of your pencil.

There've been a lot of searches for new materials to embed circuits into for a lot of reasons, including cost, but now increasingly because we're hitting hard-walls in nano-sized transistors that are going to require new materials to keep getting things smaller and faster.

One of the best materials they've found is apparently diamond! And diamond is apparently one of the best heat-conductors in the known world, meaning that you can very rapidly shunt heat away from all areas in the chip, which makes sure a local buildup doesn't happen.

Because of this property, some people wanted to make cooking pans with a layer of diamond in them, which would help make sure every part of the pan was the same temp as the rest :P

So, long story short, I don't have the answers to your questions, but this is yet another "candidate" material that may prove to be the answer to future chip requirements.