IBM Demos 100 GHz Graphene Transistor


Last week, IBM announced that its researchers had demonstrated a radio frequency graphene transistor with the highest cut-off frequency observed so far for any graphene device--100 GHz.

Graphene is a single atom thick layer of carbon atoms bonded in a hexagonal honeycomb-like structure. This form of carbon has unique electrical, optical, mechanical and thermal properties.

"A key advantage of graphene lies in the very high speeds in which electrons propagate, which is essential for achieving high-speed, high-performance next generation transistors, said Dr. T.C. Chen, vice president of science and technology at IBM Research. "The breakthrough we are announcing demonstrates clearly that graphene can be utilized to produce high performance devices and integrated circuits."

IBM said the graphene wafers were synthesized by thermal decomposition of a silicon carbide substrate. The graphene transistor has a metal top-gate architecture and a gate insulator stack using a polymer and a high-dielectric constant oxide. The gate length was 240 nanometers. State-of-the-art silicon transistors with the same gate length have a cut-off frequency of about 40 GHz, well below that of the graphene transistor.

IBM said there is "plenty of space" for further optimization of graphene transistor performance by scaling down the gate length.

Development of millimeter wavelength devices like IBM's graphene transistor will not only allow higher speed computers but enable improved performance in wireless devices such as the Sony 11 Gbps wireless transceiver described elsewhere in this week's RF Report.

Doug Lung is one of America's foremost authorities on broadcast RF technology. He has been with NBC since 1985 and is currently vice president of broadcast technology for NBC/Telemundo stations.