REVERSE-BIASED SAFE OPERATING AREA OF EMITTER SWITCHED THYRISTORS

The reverse biased safe operating area (RBSOA) of 600V and 2500V EST d evices has been analyzed by numerical simulation for the first time an d compared with those for the IGBT and MCT. The dependence of the RBSO A upon the P-base resistance in the main thyristor structure of the ES T has also been investigated. Two types of destructive failure mechani sms have been identified: one due to the voltage-induced avalanche mul tiplication, and the other associated with current-induced latch-up of the parasitic thyristor. It is demonstrated that, although the voltag e-induced limit is identical for all three devices, the current-induce d RBSOA for the EST can be improved over the IGBT and MCT with little sacrifice of the on-state characteristics. In addition, a comparison o f the RBSOA with the forward biased safe operating area (FBSOA) has be en performed.