Graphene: A new beginning for semiconductor devices beyond silicon

Abstract

Currently, graphene is a topic of very active research fields due to its exceptional electronic properties. For various RF circuit applications, including low-noise amplifiers, the unique ambipolar nature of graphene field-effect-transistors can be utilized for high-performance frequency multipliers, mixers, and highspeed radiometers. Direct current (DC) and radio frequency (RF) measurements were performed on graphene field-effect transistors to find out the DC and RF properties. Two sets of GFETs were measured; first chip was fabricated with SiC process and the second with CVD process. The SiC GFET impedance levels were too high to measure RF properties. RF-measurements were performed on CVD GFETs. The CVD GFET cut-off frequency was found to be approximately 80 MHz, which is in the same range as the calculated cut-off frequency. MOSFET small-signal model was used for GFETs and the model parameters are presented .The results of the DC measurements were analyzed and the data was fitted according to an existing device resistance model. The curve-fit to total device resistance gives estimations on parameters such as contact resistance, residual charge carrier concentration and conductivity mobility.