High-resolution Rutherford backscattering spectrometry for InAlGaN/AlGaN single quantum well structure

InAlGaN/AlGaN single quantum well (SQW) structure has been studied by means of high-resolution Rutherford backscattering spectrometry (HRBS). The HRBS spectrum of a SQW structure was clearly observed. The composition of each layer was estimated to be In0.02Al0.17Ga0.81N/Al0.28Ga0.72N from the HRBS measurement. The channeling measurement shows the high degree of the crystalline perfection that can be achieved in such epitaxial layers from the minimum yield of 3.2% in the direction of the <11-23> axis. The channeling measurement also shows atomic disorder differences between InAlGaN epitaxial layer and AlGaN epitaxial layer. Furthermore Al, Ga and In minimum yields in the InAlGaN layer were estimated to be χmin(Ga)=4.9%, χmin(Al)=9.4% and χmin(In)=6.6%, respectively. Larger normalized yield of Al than those of Ga and In in the InAlGaN layer indicates that Al atomic disorder becomes larger to compensate the compressive stress of Ga and In. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)