Interface charge trapping and hot carrier reliability in high voltage SOI SJ LDMOSFET

This paper demonstrates and explains the effects of hot carrier injection and interface charge trapping correlated with impact ionization under normal on-state conditions in a highly dense low-resistance Super-Junction LDMOSFET. The study is done through extensive experimental measurements and numerical simulations using advanced trap models. The introduction of the SJ structure in the drift region of the LDMOSFET allows a shorter length and significantly higher drift doping both of which result in very low on-state resistance for a given breakdown voltage 170V. However careful design and optimization of the Super-junction layers is needed to avoid the combined effects of parastic JFET effect, impact ionization and charge trapping. The paper discusses these complex phenomena and gives solutions to increase robustness against instability problems.