X-ray reflectivity and atomic force microscopy studies of MOCVD grown Al x Ga 1− x N/GaN superlattice structures

作者：Yuanzhang Wang, Jinchai Li, Shuping Li, Hangyang Chen, Dayi Liu, Junyong Kang · 发表于：Journal of Semiconductors · 年份：2011 · DOI：10.1088/1674-4926/32/4/043006 · 被引用次数：10 · 研究领域：GaN-based semiconductor devices and materials、Metal and Thin Film Mechanics、Silicon Carbide Semiconductor Technologies

The grazing incidence X-ray reflectivity (GIXR) technique and atomic force microscopy (AFM) were exploited to obtain an accurate evaluation of the surfaces and interfaces for metalorganic chemical vapor deposition grown Al x Ga 1− x N/GaN superlattice structures. The X-ray diffraction results have been combined with reflectivity data to evaluate the layer thickness and Al mole fraction in the AlGaN layer. The presence of a smooth interface is responsible for the observation of intensity oscillation in GIXR, which is well correlated to step flow observation in AFM images of the surface. The structure with a low Al mole fraction ( x = 0.25) and thin well width has a rather smooth surface for the R rms of AFM data value is 0.45 nm.