Non-uniform temperature and heat generation in thin-film SOI LDMOS with uniform drift doping

Abstract

The thermal behaviour of lateral double-diffused MOS (LDMOS) transistors integrated in thin-film silicon-on-insulator is investigated in this work. This study is directed towards commercial LDMOS with uniformly doped drift regions. The presented models herein are suitable for electro-thermal predictions at conduction in the linear regime. Initially, a closed form expression is provided to calculate the Joule heat generated by electron current, which is spatially non-uniform. Then, the heat flow is analysed, thereby enabling simple LDMOS electro-thermal modelling and giving insight to improve device reliability. First principles of semiconductor physics are the fundamentals to develop the model, which requires the device structural parameters and the biasing conditions as inputs. Obtained temperature distributions and maximum temperature values are demonstrated to be more accurate than using the simple uniform heat generation approach.