Importance of the n-base width in the turn-off performance of TIL GATT´s

The influence of the n-base width on the turn-off performance of two interdigitation level (TIL) gate-assisted turn-off thyristors (GATT´s) has been investigated. Devices with n-base width WnB= 250 and 360 µm, respectively, were comparatively tested. The two sets of high-power, 1.7-cm²area, gold-diffused TIL GATT´s processed in identical conditions have low on-state losses, good turn-on sensitivity, and exhibit a high degree of immunity to internal noise signals. The investigations have shown that the TIL GATT´s with WnB= 360 µm could possess a better efficiency of the turn-off time tqreduction in comparison with their counterparts having a thinner n base. The main physical mechanisms explaining the lack of incompatibility at the fundamental level between a larger n base and a reduced value of tqin TIL GATT´s are described in detail. The results of this work show that the high blocking voltage capability, which is mainly a function of the base thickness WnBand doping, is in no way a hindrance in achieving a substantial reduction of tqin TIL GATT´s with an adequate gate-assist signal.