1200 V trench gate NPT-IGBT (IEGT) with excellent low on-state voltage

A new 1200 V-rating trench gate NPT-IGBT (nonpunchthough-insulated gate bipolar transistor) and NPT-IEGT (NPT-injection enhancement gate transistor) have been developed. Previous works have reported the IE (carrier injection enhancement) effect with regard to relatively high voltage devices (Kitagawa et al., 1993; Udrea and Amaratunga, 1995; Horz et al., 1995; Omura et al., 1997). In this paper, the IE-effect was employed in a 1200 V-rating trench gate NPT-IGBT for the first time. The IE-effect was adopted mainly by fabrication of some p-base regions not contacted to the emitter electrode. By numerical simulation, it is found that the IE-effect is effective in reducing on-state voltage for 1200 V-rating NPT-IGBT. On the basis of these investigations, a 150 A-rating IGBT chip was fabricated. The on-state voltage for this new device is as low as 1.8 V at 85 A/cm/sup 2/ without sacrificing its ruggedness to withstand destruction and its blocking voltage margin.