標題: Structural and Stress Properties of A1GaN Epilayers Grown on A1N-Nanopatterned Sapphire Templates by Hydride Vapor Phase Epitaxy
作者: Tasi, Chi-Tsung
Wang, Wei-Kai
Ou, Sin-Liang
Huang, Shih-Yung
Horng, Ray-Hua
Wuu, Dong-Sing
電子工程學系及電子研究所
Department of Electronics Engineering and Institute of Electronics
關鍵字: A1GaN;nanopatterned sapphire substrate;hydride vapor phase epitaxy;stress;transmission electron microscopy
公開日期: 1-Sep-2018
摘要: In this paper, we report the epitaxial growth and material characteristics of AlGaN (Al mole fraction of 10%) on an AlN/nanopatterned sapphire substrate (NPSS) template by hydride vapor phase epitaxy (HYPE). The crystalline quality, surface morphology, microstructure, and stress state of the AlGaN/AlN/NPSS epilayers were investigated using X-ray diffraction (XRD), atomic force microscopy (AFM), and transmission electron microscopy (TEM). The results indicate that the crystal quality of the A1GaN film could be improved when grown on the A1N/NPSS template. The screw threading dislocation (TD) density was reduced to 1.4 x 10(9) cm(-2) for the AlGaN epilayer grown on the A1N/NPSS template, which was lower than that of the sample grown on a flat c-plane sapphire substrate (6.3 x 10(9) cm(-2)). As examined by XRD measurements, the biaxial tensile stress of the AlGaN film was significantly reduced from 1,187 MPa (on A1N/NPSS) to 38.41 MPa (on flat c-plane sapphire). In particular, an increase of the Al content in the overgrown AlGaN layer was confirmed by the TEM observation. This could be due to the relaxation of the in-plane stress through the AlGaN and AlN/NPSS template interface.
URI: http://dx.doi.org/10.3390/nano8090704
http://hdl.handle.net/11536/148382
ISSN: 2079-4991
DOI: 10.3390/nano8090704
期刊: NANOMATERIALS
Volume: 8
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