標題: Nonpolar a-plane GaN grown on r-plane sapphire using multilayer AlN buffer by metalorganic chemical vapor deposition
作者: Chiang, C. H.
Chen, K. M.
Wu, Y. H.
Yeh, Y. S.
Lee, W. I.
Chen, J. F.
Lin, K. L.
Hsiao, Y. L.
Huang, W. C.
Chang, E. Y.
材料科學與工程學系
電子物理學系
Department of Materials Science and Engineering
Department of Electrophysics
關鍵字: GaN;Crystal morphology;Nonpolar;MOCVD
公開日期: 15-一月-2011
摘要: Mirror-like and pit-free non-polar a-plane (11-20) GaN films are grown on r-plane (1-102) sapphire substrates using metalorganic chemical vapor deposition (MOCVD) with multilayer high-low-high temperature AlN buffer layers. The buffer layer structure and film quality are essential to the growth of a flat, crack-free and pit-free a-plane GaN film. The multilayer AlN buffer structure includes a thin low-temperature- deposited AlN (LT-AlN) layer inserted into the high-temperature-deposited AlN (HT-AlN) layer. The results demonstrate that the multilayer AlN buffer structure can improve the surface morphology of the upper a-plane GaN film. The grown multilayer AlN buffer structure reduced the tensile stress on the AlN buffer layers and increased the compressive stress on the a-plane GaN film. The multilayer AlN buffer structure markedly improves the surface morphology of the a-plane GaN film, as revealed by scanning electron microscopy. The effects of various growth V/III ratios was investigated to obtain a-plane GaN films with better surface morphology. The mean roughness of the surface was 1.02 nm, as revealed by atomic force microscopy. Accordingly, the multilayer AlN buffer structure improves the surface morphology and facilitates the complete coalescence of the a-plane GaN layer. (C) 2010 Elsevier B.V. All rights reserved.
URI: http://dx.doi.org/10.1016/j.apsusc.2010.10.059
http://hdl.handle.net/11536/25881
ISSN: 0169-4332
DOI: 10.1016/j.apsusc.2010.10.059
期刊: APPLIED SURFACE SCIENCE
Volume: 257
Issue: 7
起始頁: 2415
結束頁: 2418
顯示於類別:期刊論文


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