Increasing the operating frequency in high-power distributed microgate bipolar switches

The dynamic turn-off losses can be decreased, and the operating frequency increased in high-power distributed microgate bipolar switches (MGBSs) by optimizing the device design so as to ensure that the charge extracted from the high-ohmic base and the built-in impurity charge would have opposite signs. In particular, in MGBS with a hole-extracting cathode gate and an anode buffer layer, this is achieved by using p type doping of the base instead of the n type. A special analytical model has been constructed that describes the MGBS turn-off process. It is established that, at a voltage of ∼5 kV, the losses per turn-off operation can be reduced from 200 to 100 mJ/cm2 and the frequency increased from 0.5 to 1.0 kHz.