Demonstration of Fe‐Doped GaN Buffer HEMT to Achieve <i>f</i> _MAX of 167 GHz

This research article demonstrates the successful implementation of a Fe‐doped GaN buffer layer in AlGaN/GaN HEMTs to significantly enhance RF performance. A 4 X 75 μm multi finger AlGaN/GaN HEMT device was fabricated as the base structure for this study. The device is optimized using various techniques to improve its performance in high‐frequency applications. The optimizations led to a substantial improvement in cutoff frequency f T of 122 GHz which is 3.8 times from the conventional device to the optimized device. Additionally, the maximum oscillation frequency f MAX capability has shown a significant increase while drain‐induced barrier lowering (DIBL) is reduced by 75%, highlighting the effectiveness of the Fe‐doped GaN buffer layer. The resulting optimized AlGaN/GaN HEMTs shows great promise for high‐performance mmWave applications providing enhanced speed and efficiency for next‐generation communication systems.