X-Ray Interference and Crystal Truncation Rod Observation of GaN and GaInN Layers Grown on Sapphire with AlN Buffer Layer

Abstract

X-ray CTR measurement was conducted for GaN and GaInN layers grown on sapphire substrates with low-temperature grown AlN buffer layers. It is to study the crystalline structure of the GaN and GaInN layers formed on the sapphire substrates with the buffer layers. The GaN and GaInN/GaN layers on the sapphire substrates with the low-temperature grown AlN buffer layers had the Al polarity ((0001)A). The surfaces were found to be covered with N. The thicknesses of the GaInN layers were measured accurately to be 4.02nm and 40.5nm for the samples designed to have 4nm and 40nm-thick GaInN layers, respectively. Indium compositions for 4nm- and 40nm-thick GaInN layers were determined to be 8.8% and 11%, respectively.