Thermal etching rate of GaN during MOCVD growth interruption in hydrogen and ammonia ambient determined by AlGaN/GaN superlattice structures

Publication date: 1 October 2017
Source:Journal of Crystal Growth, Volume 475
Author(s): Feng Zhang, Masao Ikeda, Shuming Zhang, Jianping Liu, Aiqin Tian, Pengyan Wen, Yang Cheng, Hui Yang
Thermal etching effect of GaN during growth interruption in the metalorganic chemical vapor deposition reactor was investigated in this paper. The thermal etching rate was determined by growing a series of AlGaN/GaN superlattice structures with fixed GaN growth temperature at 735°C and various AlGaN growth temperature changing from 900°C to 1007°C. It was observed that the GaN layer was etched off during the growth interruption when the growth temperature ramped up to AlGaN growth temperature. The etching thickness was determined by high resolution X-ray diffractometer and the etching rate was deduced accordingly. An activation energy of 2.53eV was obtained for the thermal etching process.