600- and 1200-V bipolar-mode MOSFET's with high current capability

600-V 25-A and 1200-V 20-A bipolar-mode MOSFET's (T-BIFET) with 100-A and 75-A maximum current capability, respectively, have been developed, based on a new pattern design theory for high latch-up current density. It is also shown than an n+-buffer layer improves a tradeoff between the forward voltage and the turn-off time, compared with an ordinary n-buffer layer.