Failure modes on low voltage power MOSFETs under high temperature application

HEV (hybrid electrical vehicle) is one of the harshest applications for standard technology of power devices and converters. High temperature capability and passive/active thermal cycle ageing must be evaluated. The authors present first results on ageing and failure modes for a 75 V/350 A MOSFET module from a low voltage/cycled DC current test bench. The module is without base plate and bond wires are used for electrical connections. For this kind of low voltage and high current module, paper shows that the principal modes of failure relate to the environment close to the chip (connections and passivations).