Conductivity modulation in the channel inversion layer of very narrow mesa IGBT

It was experimentally found that the short-circuit withstand capability of very narrow mesa IGBTs is degraded because of CIBL. In this paper, we report, for the first time, that conductivity modulation in the channel inversion layer of narrow mesa IGBT is the cause of CIBL. It is shown that the combination of the conductivity modulation and avalanche generation due to MOSFET-Mode operation causes short-circuit failure. We also propose a new cell design principle of narrow mesa IGBTs for low on-state voltage drop and good short-circuit withstand capability.