HIGH-FREQUENCY PERFORMANCE OF SUBMICROMETER CHANNEL-LENGTH SILICON MOSFETS

Polycide-gate silicon n-channel MOSFET's were fabricated on the basis of a standard 0.5-mu-m MOS technology and measured over the 1.5-26.5-GHz frequency range, in order to investigate the effects of channel-length reduction on device behavior at high frequency. Excellent microwave performances were obtained with a maximum operating frequency f(max) and a unity-current-gain frequency f(t) near 20 GHz for 0.5-mu-m gate-length NMOS devices. An equivalent circuit for MOSFET with its parasitic elements was extracted from measured S-parameter data. The influence of gate resistance, gate-to-drain overlap capacitance, substrate conductivity, and transit-time effect between the source and drain on microwave characteristics was analyzed.