FBSOA of dielectrically isolated LD MOSFETs and LIGBTs

Dielectrically isolated lateral power devices are used in high voltage ICs for smart power applications. LDMOSFETs are preferred in high frequency applications, while LIGBTs are used in applications requiring low forward voltage drops. It is important that these devices exhibit a good FBSOA for achieving controlled turn-on and turn-off and for short circuit protection. In this paper, the FBSOA of LDMOSFETs and LIGBTs is reported based on extensive two dimensional numerical simulations and measurements performed on fabricated devices. The dependence of the FBSOA of the LDMOSFET on the drift region length and epi-thickness has been studied. In the case of the LIGBT, a comparative study of different structures which improve the FBSOA is presented