Date: 23/12/2008

World's fastest graphene transistor operates at GHz frequencies

IBM researchers announced that they fabricated & demonstrated the operation of nano-scale graphene field-effect transistors at GHz frequencies, and achieved the highest frequencies reported so far using this novel non-silicon electronic material.

Graphene is a special form of graphite, consisting of a single layer of carbon atoms packed in honeycomb lattice, similar to an atomic scale chicken wire. Graphene has attracted immense worldwide attention and activities because its unusual electronic properties may eventually lead to vastly faster transistors than any transistors achieved so far.

The operation speed of a transistor is determined by the size of the device and the speed at which electrons travel. The size dependence was one of the driving forces to pursue ever-shrinking Si transistors in semiconductor industries. A key advantage of graphene lies in the very high electron speed with which electrons propagate in it, essential for achieving high-speed, high-performance transistors.

The IBM found that the operation frequency increases with diminishing device dimension and achieved a cut-off frequency of 26 GHz for graphene transistors with a gate length of 150 nm, the highest frequency obtained for graphene so far. 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 nanometers.