Avalanche ruggedness of 800V Lateral IGBTs in bulk Si

Abstract

Avalanche capability of 800V rated Lateral IGBTs (LIGBTs) fabricated using bulk CMOS technology has been investigated for the first time for both turn-on and turn-off. The LIGBTs have been designed for 65kHz operation in energy-efficient, compact off-line power supplies. Measurements of the device during turn-on revealed failures under high line voltages. The device was analysed using a combination of measurements and simulations which revealed that the dynamic avalanche was the cause of failure. An optimised LIGBT has been designed, simulated, fabricated and tested. The optimised device exhibits higher breakdown voltage and improved turn-on avalanche capability. Moreover, the optimised device showed improved avalanche capability during turn-off and reduced likelihood of latch-up.