Thermal and package performance limitations in LDMOSFET's for RFIC applications

This paper presents a systematic study of the limitations imposed by therma l and packaging considerations on radio-frequency (RF) performance of Si bu lk and silicon-on-insulator (SOI) lateral DMOSFET's (LDMOSFET's). Several b ulk and SOI devices are studied with the help of measurements as well as tw o-dimensional device simulations incorporating electrothermal models, Model parameters are extracted and used in circuit simulators to perform RF char acterization of these devices. Further, a new three-region theory for LDMOS FET is discussed and used to evaluate the static and RF performance of the devices in nonisothermal environment. This paper shows that package plays a n important role in RF performance of SOI and bulk devices due to self-heat ing effects within the device. A detailed de and RF performance evaluation is presented. Significant drift is observed in RF performance of bulk and S OI devices due to self-heating considerations. The physical understanding o f these thermal effects within the device can facilitate design of better p ackages for bulk and SOI devices.