2000-A/1-mΩ Power MOSFET’s in Wafer Repair Technique

Abstract

Power MOSFET’s with a current capability of up to several thousand amperes and hence an active device area significantly exceeding the typical IC chip size can only be realized if a wafer repair technique is used. The authors have developed a suitable wafer repair technique and have realized circular power MOSFET’s with a diameter of 3 cm. The devices are suited to control up to 2000-A drain current and exhibit an on-resistance of RDS(on) = 0.9 mΩ. To contact such a device, a pressure contact system adequate to the high current value is used. Typical switching times are about 100 ns. Such a large-area MOSFET was used in a MOSFET-GTO (gate turnoff thyristor) cascode circuit to switch anode currents up to 1200 A / 1000 V. The total switching time was significantly reduced, and a smaller snubber capacitor could be employed as compared with the GTO in a conventional circuit. © 1990 IEEE