High-frequency performance of submicrometer channel-length silicon MOSFETs

Polycide-gate silicon n-channel MOSFETs 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/sub max/) and a unity-current-gain frequency f/sub t/ near 20 GHz for 0.5- mu m-gate-length NMOS devices. An equivalent circuit for a 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 the transit-time effect between the source and drain on microwave characteristics was analyzed.<
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