Challenges in Humidity Tests on GaN-Devices

The trend towards embedded structures and increased power density of power electronics is fostered by the utilisation of Gallium Nitride (GaN) components. While the semiconductor devices seem to be able to cope with high voltage and harsh environments, the reliability focus shifts to the outside world, e.g. Printed Circuit Boards (PCB). During humidity testing of GaN devices the formation of ConductiveAnodic Filaments (CAF) in the PCB led to failures long before their predicted end of live. This paperpresents the failure mechanisms of FR-4 PCBs during the High Humidity High Temperature ReverseBias (H3TRB) testing.