Study of the structural quality of GaN epitaxial layers obtained by hydride vapor phase epitaxy using a low-temperature buffer layer

Abstract

The structural quality and surface morphology of low-temperature (LT) buffer layers after deposition and high-temperature (HT) annealing and HT GaN layers grown on LT buffer layers by hydride vapor phase epitaxy have been investigated. The HCl flow rate through the Ga source varied from 0.3 to 2 L/h, and the carrier gas N2 flow rate was either 18 or 60 L/h. It is established that the structural quality of LT GaN buffer is determined to a great extent by the HCl and N2 flow rates; the best results are obtained at HCl and N2 flow rates of 0.3 and 18 L/h, respectively. These GaN layers are characterized by a mirror surface and a rocking curve half-width of 360". It is suggested that the layer structure is improved due to the increase in the lateral growth rate.