標題: Surface evolution and effect of V/III ratio modulation on etch-pit-density improvement of thin AlN templates on nano-patterned sapphire substrates by metalorganic chemical vapor deposition
作者: Wang, Tzu-Yu
Tasi, Chi-Tsung
Lin, Ku-Yen
Ou, Sin-Liang
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: AlN;V/III ratio modulation;Nano-patterned sapphire;Etch pit density
公開日期: 15-Oct-2018
摘要: A low defect-density AlN template film using V/III ratio modulation and nano-patterned sapphire substrate (NPSS) was achieved by metalorganic chemical vapor deposition. In contrast to conventional high-quality AlN/NPSS obtained with high coalescence thickness ( > 6 mu m) using high growth temperatures ( >= 1250 degrees C), this study reveals the high crystallinity of AlN with the lower thickness of 2.55 mu m grown under a lower temperature of 1130 degrees C. It could effectively increase the heater lifetime and reduce the epi-wafer warpage. The growth of AlN/NPSS dominated by epitaxial lateral overgrowth achieves a dramatic reduction of full width at half maximum values along (10 (1) over bar2) plane from 1640 to 714 arcsec, and lowest dislocation density of approximately 1 x 10(8) cm(-2), as well as a ultra-low etching pit density of 2.3 x 10(5) cm(-2). The crack-free AlN/NPSS with a compressive stress owing to the tensile stress was relaxed by the existence of some key-shaped holes upon the patterned region. Details of the surface evolution, mechanism and dislocation behavior of AlN/NPSS will be discussed and these results demonstrate this low-defect template technique of high potential for AlGaN-based device applications.
URI: http://dx.doi.org/10.1016/j.apsusc.2018.06.017
http://hdl.handle.net/11536/145256
ISSN: 0169-4332
DOI: 10.1016/j.apsusc.2018.06.017
期刊: APPLIED SURFACE SCIENCE
Volume: 455
起始頁: 1123
結束頁: 1130
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