Investigation of GaN layers grown by high temperature vapor phase epitaxy

Abstract

AbstractFirst experimental results on the growth of GaN films by a modified high temperature vapor phase epitaxy method (HTVPE) are presented. The method bases on a novel growth reactor, which was developed to overcome the drawbacks of conventional HTVPE. GaN films were deposited either on (0001) sapphire substrates or on MOVPE‐grown GaN templates of 15×15 mm2 with growth rates in the range of 2–7 µm/h. The influence of the substrate temperature and ammonia flow on the structural properties of the deposited films was systematically investigated in experiments on MOVPE templates. It is shown that the structural quality of the templates can be well reproduced in the overgrown layers. The layer quality and the stress relations are found to depend very sensitively on the ammonia flow in the carrier gas. Growth experiments with a direct, high‐temperature deposition of GaN films on sapphire demonstrated a strong dependence of the nucleation process on the substrate temperature and the carrier gas composition. The potential of HTVPE for the heteroepitaxial growth of GaN films on sapphire is discussed. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)