Electric-field and thermally-activated failure mechanisms of AlGaN/GaN High Electron Mobility Transistors

摘要

Main failure modes of AlGaN/GaN HEMTs can be divided into three categories: 1) Catastrophic increase of gate leakage, accompanied by an increase in trap density which closely resembles time dependent dielectric breakdown effects of MOS structures; 2) hot-electron and trap-induced effects, which induce increase in parasitic drain resistance and threshold voltage shifts; 3) thermally-activated degradation of drain current, which has been observed especially during long-term accelerated tests, with a very wide range of activation energies, from 1.05 eV to 2.47 eV. In the following, some recent results concerning these three failure modes are presented, together with some hypothesis on the degradation mechanisms involved.