Influence of Low Temperature AlGaN Intermediate Layers on the Properties of GaN Films

• Main Authors: Bing-Hong Shih, 施炳宏
• Other Authors: Jyh-Rong Gong
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/93872811789871032874

碩士 === 逢甲大學 === 光電物理研究所 === 92 === Abstract The purpose of this study is to explore the effect of LT-AlXGa1-XN interlayers on the high temperature-grown GaN films. The III-nitride films were grown on (0001) sapphire substrates by atomic layer epitaxy (ALE). Groups III metalorganics and NH3 were used as the sources of Al, Ga, and N atoms that were carried into the reactor by purified H2. The surface morphologies and optical properties of GaN films were investigated by Nomarski interference optical microscopy (OM), X-ray diffractometry (XRD), photoluminescence (PL) spectroscopy, and transmission electron microscopy (TEM). An optimized LT-AlXGa1-XN interlayer thickness for each Al content is determined based on the full width at half maximum (FWHM) of the near band edge emissions from GaN films. The optimized LT-AlN, LT-Al0.8Ga0.2N, LT-Al0.6Ga0.4N, and LT-GaN thickness were 5nm, 10nm, 15nm, and 20nm, respectively. The result indicates that the LT-AlXGa1-XN interlayer thickness is very critical to the quality of HT-GaN film deposited subsequently. TEM observations show that threading dislocations in the HT-GaN films can be blocked by the LT-AlGaN interlayers.