Etching-induced damage in heavily Mg-doped p-type GaN and its suppression by low-bias-power inductively coupled plasma-reactive ion etching

• Published in: Japanese Journal of Applied Physics Vol. 60; no. SB; p. SBBD03
• Main Authors: Kumabe, Takeru, Ando, Yuto, Watanabe, Hirotaka, Deki, Manato, Tanaka, Atsushi, Nitta, Shugo, Honda, Yoshio, Amano, Hiroshi
• Format: Journal Article
• Language: English
• Published: Tokyo IOP Publishing 01.05.2021; Japanese Journal of Applied Physics
• Subjects: Bias; Cathodoluminescence; Current voltage characteristics; Damage; Depth-resolved CL; Electron beams; Etching; Etching damage; GaN; ICP-RIE; Inductively coupled plasma; Low temperature; Magnesium; Nitrogen; p-GaN; Penetration depth; Photoluminescence; Reactive ion etching; Spectrum analysis
• ISSN: 0021-4922; 1347-4065
• DOI: 10.35848/1347-4065/abd538

Inductively coupled plasma-reactive ion etching (ICP-RIE)-induced damage in heavily Mg-doped p-type GaN ([Mg] = 2 × 1019 cm−3) was investigated by low-temperature photoluminescence (PL) and depth-resolved cathodoluminescence (CL) spectroscopy. From PL measurements, we found broad yellow luminescence (YL) with a maximum at around 2.2-2.3 eV, whose origin was considered to be isolated nitrogen vacancies (VN), only in etched samples. The depth-resolved CL spectroscopy revealed that the etching-induced YL was distributed up to the electron-beam penetration depth of around 200 nm at a high ICP-RIE bias power (Pbias). Low-bias-power (low-Pbias) ICP-RIE suppressed the YL and its depth distribution to levels similar to those of an unetched sample, and a current-voltage characteristic comparable to that of an unetched sample was obtained for a sample etched with Pbias of 2.5 W.