Review of technology for normally-off HEMTs with p-GaN gate

This paper reviews the most relevant technological issues for normally-off HEMTs with a p-GaN gate. First the operation principle and the impact of the heterostructure parameters are discussed. Then, the possible effects of the dry etching process of p-GaN are shortly mentioned. Thereafter, the role of the metal/p-GaN interface and the impact of the thermal processes on the electrical characteristics are widely discussed. Finally, recent alternative approaches proposed to avoid the use of the p-GaN dry etching are presented.