Irradiation- and Bias-Stress-Induced Defects and Gate Leakage in GaN-based HEMTs

Abstract

During last several decades, GaN-based HEMTs are increasingly popular for use in space-based, high-power, and high-frequency electronics due to their large band gap, high breakdown electric field and high mobility two-dimensional electron gas (2DEG) at the heterointerface. In this work, the irradiation and bias stress response are investigated. The non-monotonic response to different fluence of proton irradiation, caused by evolution of defect concentrations, highlights crucial role of ionization-induced defect passivation and activation, as well as the generation of new defects via displacement damage. Besides, temperature-dependent noise measurements verify that the activation energy for FeGa defects is 0.56 ± 0.05 eV, aligning with theoretical predictions and other spectroscopic observations. This research revises and expands upon prior studies, offering a more physically accurate calibration of the Dutta-Horn model for low-frequency (LF) noise in AlGaN/GaN HEMTs. Also, dehydrogenation of ON−H impurity centers, along with the subsequent rise in the concentration of ON impurity centers in the AlGaN and/or AlN layers, plays a significant role in the threshold-voltage hysteresis and increased gate leakage current detected at cryogenic temperatures in stressed devices. These findings provide valuable insights into the instabilities that influence the reliability and radiation response of GaN-based HEMTs in the application of cryogenic environments.