AlGaN/GaN High Electron Mobility Transistor (HEMT) devices are promising candidates for high-frequency and high-power applications due to their exceptional electron transport properties. However, their performance can be further enhanced through post-gate metal annealing (PGMA), which helps to optimize device characteristics and reliability. This paper reviews the impact of post-gate annealing on AlGaN/GaN HEMT devices and the subsequent improvements in electrical characteristics, focusing on critical parameters such as barrier height, ideality factor, drain current, and leakage current. The findings indicate that PGMA contributes to improved device performance, including a decrease in gate reverse leakage current and improvement in Schottky barrier height (ΦB) and Ideality factor (η). Additionally, when the device is subjected to gate reverse bias stress (at a step of − 5 V) for 2 min, it is observed that Pt/Au exhibits superior performance but faces challenges related to adhesion compared to Ni/Au.