Lateral RF SOI power MOSFETs with f/sub T/ of 6.9 GHz

Abstract

For the first time, lateral RF power MOSFETs have been fabricated in a silicon-on-insulator technology. Fabrication was performed on a 1.2-μm SOI CMOS logic process using an additional p/sup -/ angle implant. The devices exhibit a breakdown voltage in excess of 35 V, a unity current gain frequency (f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</sub> ) of 6.9 GHz, a maximum oscillation frequency (f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">max</sub> ) of 10.1 GHz, a transconductance (g/sub m/) of 28 mS, and leakage currents of under 10 nA. A class A RF amplifier was also constructed and measured. It yielded an efficiency of 25% (identical to a similarly rated bulk LDMOSFET) with a maximum power output of 0.115 W. The excellent RF performance of these devices, combined with the inherent advantages of SOI CMOS for mixed-signal circuitry, is very promising for future integrated RF power amplifiers.