X‐ray diffraction reciprocal lattice space mapping of a‐plane AlGaN on GaN

In this study, the anisotropic strain in a‐plane AlGaN on GaN was investigated by X‐ray diffraction (XRD) analysis using AlGaN/GaN heterostructure grown on r‐plane sapphire. An a‐plane GaN layer is compressively strained, particularly in the m‐axis direction. According to XRD reciprocal lattice space mapping, the AlGaN layer was strained under tensile stress and grown almost coherently to the underlying GaN layer. The tensile stress in the AlGaN layer in the c‐axis direction is approximately 1.7 times larger than that in the m‐axis direction. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)