This study investigated the metal–oxide–semiconductor gate characteristics of recessed-gate AlN/GaN metal–oxide–semiconductor-heterojunction-field-effect transistor with N2/NH3 thermal treatment. The gate-channel mobility in recessed-gate structures formed by the inductively coupled plasma-reactive ion etching method is degraded due to plasma-induced damage. The application of thermal treatment to etch-damaged GaN surfaces was observed to re-form a clear step-terrace structure, effectively reversing the effects of the etching damage. A corresponding enhancement in peak field-effect mobility was experimentally verified, with an increase from a pretreatment value of 656 to 1042 cm2/V·s after thermal treatment. Concurrently, an improvement of the lower gate-leakage current by 1–2 orders of magnitude was measured. This thermal treatment method can reduce crystal defects at deep levels of 1.8–2.9 eV below Ec on the etched GaN surface. In particular, this N2/NH3 thermal treatment approach could potentially contribute to the reduction of deep levels such as atomic displacement, gallium vacancies, and those complexes generated by inductively coupled plasma-reactive ion etching.

中文翻译：

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N2/NH3 热处理后常闭 AlN/GaN MOS-HET 的嵌入式 MOS 栅极特性的改善


本研究研究了经过 N2/NH3 热处理的凹栅 AlN/GaN 金属氧化物半导体异质结场效应晶体管的金属氧化物半导体栅极特性。电感耦合等离子体反应离子刻蚀方法形成的凹门结构中的栅极-通道迁移率由于等离子体诱导的损伤而降低。观察到对蚀刻损坏的 GaN 表面进行热处理以重新形成清晰的阶梯式平台结构，有效地逆转了蚀刻损伤的影响。实验验证了峰值场效应迁移率的相应增强，热处理后处理前值从 656 cm2/V·s 增加到 1042 cm2/V·s。同时，测量到较低的栅极漏电流提高了 1-2 个数量级。这种热处理方法可以减少蚀刻 GaN 表面低于 Ec 1.8-2.9 eV 的深层晶体缺陷。特别是，这种 N2/NH3 热处理方法可能有助于减少深能级，例如原子位移、镓空位以及电感耦合等离子体反应离子刻蚀产生的那些复合物。