GaN-based HEMTs tested under high temperature storage test

► We assessed the impact of high temperature storage test on GaN HEMTs. ► We observed that only the gate and drain leakage currents were strongly affected by this test. ► The physical failure analysis revealed a Au inter-diffusion phenomenon at the gate level, affecting the gate-AlGaN interface. ► We speculated that Au inter-diffusion was at the origin of the gate leakage current increase.