Ultrahigh‐speed growth of GaN by hydride vapor phase epitaxy

Abstract

AbstractWe demonstrate the ultrahigh‐speed growth of thick GaN layers by hydride vapor phase epitaxy (HVPE) and present an investigation of the properties of the resulting GaN crystals. A series of GaN layers with a thickness of around 700 μm were grown homoepitaxially on freestanding GaN substrates at various growth rates ranging from 107–1870 μm/h, using a conventional atmospheric HVPE reactor. The growth rate increased almost linearly with the feed rate of source materials, reaching 1870 μm/h when the HCl flow rate is 650 sccm. The surfaces of all the homoepitaxial layers were specular, and no cracks or pits were observed. The X‐ray rocking curve measurement showed that the full width at half maximum values did not depend on the growth rate, and had small values of 23–30 arcsec for (0002) reflections and 39–58 arcsec for (30‐32) reflections. Plan‐view cathodoluminescence imaging revealed that the dislocation density had virtually no dependence on the growth rate and had small values of around 3 × 106 cm‐2 even at the highest growth rate (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)