IBM claims graphene field-effect transistors at GHz frequencies

With a top-gate design and a gate length 150 nm, IBM achieved a cut-off frequency of 26 GHz for its graphene transistors.

By Suzanne Deffree, Managing Editor, News -- Electronic News, 12/19/2008

IBM Researchers today announced that they have demonstrated the operation of graphene field-effect transistors at GHz frequencies, claiming the highest frequencies reported so far using the non-silicon electronic material.

IBM is a long-time proponent of graphene -- a special form of graphite, consisting of a single layer of carbon atoms packed in "honeycomb lattice" -- as a material for building nanoelectonic circuits smaller than those in today's silicon-based computer chips.

The company in March announced that it discovered a way to suppress unwanted interference of electrical signals that are created when shrinking graphene. That development was followed closely by research from the University of Maryland that found that electrons travel more than 100 times faster in graphene than in silicon.

Specifically, IBM said today that its scientists have fabricated nanoscale graphene field-effect transistors and demonstrated the operation of graphene transistors at the GHz frequency range, establishing scaling behavior for the first time.

With a top-gate deisgn and a gate length 150 nm, IBM's team achieved a cut-off frequency of 26 GHz for graphene transistors, the company said.

IBM researchers expect that by improving the gate dielectric materials, the performance of these graphene transistors could be further enhanced. They expect that THz graphene transistors could be achieved in an optimized graphene transistor with a gate length of 50 nm. IBM said its researchers also plan to pursue RF circuits based on these high-performance transistors.

Today's news, said IBM, is an important milestone for the Carbon Electronics for RF Applications (CERA) program sponsored by DARPA, as part of the effort to develop the next-generation of communication devices.

The graphene field-effect transistor work is performed by inter-disciplinary collaboration at IBM TJ Waston Research Center.