The design, characterization, and modeling of RF LDMOSFETs on silicon-on-insulator material

This paper presents the first results of a practical 30 V RF LDMOSFET in silicon-on-insulator (SOI) material. Its complete electrical characteristics, DC and radio frequency (RF), are presented. Bulk silicon LDMOSFETs are popular in RF power applications, and SOI promises to improve device characteristics, enhance integration and provide high-temperature robustness. This work demonstrates that SOI LDMOSFETs can deliver performance comparable to bulk Si using an SOI CMOS foundry with only minimal process enhancements. To investigate the impact of feature sizing in the LDD and gate length on the static and RF performance, 12 devices were fabricated. Characterization was done at the wafer level and devices were packaged and used to construct a class A RF amplifier. The devices exhibited a subthreshold slope of 214 mV/decade, a transconductance of 30 mS, and f/sub T/ up to 10.9 GHz. The amplifier had a maximum power output of 115 mW, gain of 14 dB, and a drain efficiency of 27% at P/sub out,/ /sub max/.