Physics of current limited failures during avalanche for 600V Fast Recovery Diodes

Fast Recovery Epitaxial Diodes (FREDs) in the 600V voltage range are widely used for the design of Switch Mode Power Supply or snubberless DC-DC converters, where the devices can operate close to their intrinsic limitation in terms of maximum sustainable energy during avalanche operation. Experimental characterization of 600V rated FREDs in avalanche conditions has highlighted a failure due to a current level limitation. The mechanism cannot be attributed to the achievement of an avalanche energy threshold, therefore a current dependent mechanism is involved in the failure of the device. In this work this failure mechanism is addressed and the relevance of the termination design is highlighted.