Failure mechanism analysis of a discrete 650V enhancement mode GaN-on-Si power device with reverse conduction accelerated power cycling test

A commercial discrete enhancement mode gallium nitride power component employing advanced package technology without conventional bond wire possesses the ability for bidirectional conduction. The gallium nitride power components can provide not only higher forward conductivity but also superior reverse conductivity. For the most part recent critical debates about the reverse conductivity of a GaN device have tended to center around their performance. However, the reliability of the device under reverse operation should be assessed in order for the advantages to be fully utilized in real applications. We present the results of reverse conduction power cycling test of a discrete 650-volt gallium nitride power device with novel package technology at temperature swings of 100 K. The result shows degradation of thermal conductivity and raising leakage current drain to source as reaching the number of cycles to failure. In physical failure analysis, delamination of a solder joint between a chip and a copper layer of an aluminum print circuit board is observed with a scanning acoustic microscope.