Effect of Stress Voltage and Temperature on the Reliability of AlGaN/GaN HEMTs for RF and Microwave Application

Abstract

The mean‐time‐to‐failure (MTTF) of AlGaN/GaN high electron mobility transistor is demonstrated by considering both voltage and temperature dependent electrical degradation in on‐wafer devices. The characteristics of threshold voltage shift (ΔVT) and gate leakage current (Ig_leak) after off‐state step and VDS = 0 step stress test are reported. The devices under test are being DC stressed (high operation life‐time test) in semi‐on‐state conditions at constant power dissipation of 2 W mm−1 for more or less than 200 h until the maximum drain current (Idmax) drops by 15%. Under low stress voltage (10 V), we find activation energies (Ea) and voltage acceleration factor (γ) to be 0.32 eV and 0.09 V−1, respectively, while increasing stress voltage up to 20 V results in increased activation energies of 0.68 and 0.16 eV. The MTTF is estimated to be 1.16 × 104 h at VDS = 20 V, while stressing at low bias gives a high MTTF of 2.20 × 104 h at VDS = 10 V.