Surface control and passivation of GaN‐based electron devices

Abstract

Although significant progress has been achieved in GaN-based high-power/high-frequency electronic devices, surface-related problems still need an immediate solution. In particular, the so-called current collapse and gate leakage effects not only degrade microwave-output performance but also impede the reliable operation of the devices. This paper reviews surface-related issues in GaN FETs and AlGaN/GaN HFETs, particularly focusing on the correlation with surface disorder, surface defects and surface states. The surface-passivation and insulated-gate structures are also discussed for the reliability improvement of GaN-based devices.