Abstract The article presents the results of development of selective etching of p-GaN over Al0.25Ga0.75N in Cl2/Ar/O2 ICP plasma for fabrication of normally-off p-GaN gate GaN HEMTs using a laser reflectometry system for precise control of the etched material thickness. By optimizing etching process parameters such as oxygen flow, ICP power and chamber pressure, high etching selectivity of p-GaN over Al0.25Ga0.75N were obtained, with values up to 56:1. High etching selectivity and the control of etch rates of p-GaN and Al0.25Ga0.75N layers withing a wide range by changing the ICP process parameters enabled application of developed etching processes in the technology of fabrication of normally-off AlGaN/GaN HEMTs with a p-GaN gate. High threshold voltage of around 1.6 V and current densities up to 400 mA/mm were obtained. Electrical measurements have shown that the shortest 1 min Al0.25Ga0.75N overetch time after selective etching of the p-GaN layer results in best electrical parameters of fabricated devices.

中文翻译：

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在 Cl2/Ar/O2 ICP 等离子体中选择性蚀刻 Al0.25Ga0.75N 上的 p-GaN，用于制造常关断型 GaN HEMT

摘要 本文介绍了在 Cl2/Ar/O2 ICP 等离子体中在 Al0.25Ga0.75N 上选择性蚀刻 p-GaN 的发展结果，用于制造常关 p-GaN 栅极 GaN HEMT，使用激光反射计系统精确控制蚀刻材料的厚度。通过优化氧流量、ICP 功率和腔室压力等蚀刻工艺参数，获得了比 Al0.25Ga0.75N 更高的 p-GaN 蚀刻选择性，其值高达 56:1。高蚀刻选择性和通过改变 ICP 工艺参数在大范围内控制 p-GaN 和 Al0.25Ga0.75N 层的蚀刻速率，使已开发的蚀刻工艺能够应用于常关型 AlGaN/GaN HEMT 制造技术中p-GaN 栅极。获得了大约 1.6 V 的高阈值电压和高达 400 mA/mm 的电流密度。