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

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