Open AccessLocally non‐uniform oxidation in self‐terminating thermal oxidation assisted wet etching technique for AlGaN/GaN heterostructure
Author(s) -
Liu Jingqian,
Wang Jinyan,
Xu Zhe,
Jiang Haisang,
Yang Zhenchuan,
Wang Maojun,
Yu Min,
Xie Bing,
Wu Wengang,
Ma Xiaohua,
Zhang Jincheng,
Hao Yue
Publication year - 2015
Publication title -
electronics letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.375
H-Index - 146
ISSN - 1350-911X
DOI - 10.1049/el.2015.1755
Subject(s) - etching (microfabrication) , materials science , thermal oxidation , heterojunction , layer (electronics) , optoelectronics , oxide , transmission electron microscopy , thermal , scanning electron microscope , isotropic etching , reactive ion etching , composite material , nanotechnology , metallurgy , physics , meteorology
The oxidation mechanism in self‐terminating wet etching technique with thermal oxidation of AlGaN layer followed by etching in KOH solution is investigated. Spike‐shape remnants of oxidised AlGaN are observed at the initial stage of wet etching in KOH solution, which could be completely etched away after enough etching time. Transmission electron microscope/energy dispersive spectroscopy analysis indicates the existence of crystalline AlGaN inside the remnants. Finally, a possible explanation is given that the oxide channels from AlGaN surface towards AlGaN/GaN interface generated during thermal oxidation are firstly etched away at the initial stage of KOH wet etching, then after enough time these remnants with non‐ c axis crystal orientation surfaces exposed to KOH solution could be completely etched away leaving GaN layer beneath unaffected, which realises self‐terminating etching.