GaN-based HEMTs tested under high temperature storage test.

In this work, the impact of 1000 h thermal storage test at 325 degrees C on the performance of gallium nitride high electron mobility transistors grown on Si substrates (GaN-on-Si HEMTs) is investigated. The extensive DC- and pulse-characterization performed before, during and after the stress did not reveal degradation on the channel conduction properties as well as formation of additional trapping states. The failure investigation has shown that only the gate and drain leakage currents were strongly affected by the high temperature storage test. The physical failure analysis revealed a Au inter-diffusion phenomenon with Ni at the gate level, resulting in a worsening of the gate-AlGaN interface. It is speculated that this phenomenon is at the origin of the gate and drain leakage current increasing. (C) 2011 Elsevier Ltd. All rights reserved.