Annealing temperature stability of Ir and Nj-based Ohmic contacts on AlGaN/GaN high electron mobility transistors

摘要

Ti/Al/Ir/Au Ohmic contacts on AlGaN/GaN high electron mobility transistors (HEMTs) show promising electrical performance, with lower specific contact resistance than obtained with the more conventional Ti/Al/Ni/Au metallization. HEMTs with both types of metallization have been measured up to 550 ℃. We find that the dc performance of devices with Ir-based contacts is significantly better at each temperature up to this maximum value, with higher transconductance (g_m), saturated drain-source current (I_(DSS)), and more stable threshold voltage (Vth). These contacts look very promising for HEMT power amplifier applications involving high temperature operation.