Growth and characterization of AlGaN films and AlGaN/GaN heterostructures on (11-20) Al2O3 substrates

• Main Authors: Shih-Wei Lin, 林世偉
• Other Authors: Jyh-Rong Gong
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/05465103103106849884

碩士 === 逢甲大學 === 材料科學所 === 93 === The purpose of this study is to explore the characteristics of AlGaN films and AlGaN/GaN heterostructures grown on (11-20) Al2O3 substrates using atomic layer epitaxy. Trimethylaluminum (TMA), trimethylgallium (TMG) and ammonia (NH3)were used as the sources of Al, Ga, and N atoms that were carried into the reactor by purified H2. The surface morphology, crystallinity and optical properties of AlGaN films and AlGaN/GaN heterostructures were characterized by Nomarski interference optical microscopy , scanning electron microscopy (SEM), transmission electron microscopy (TEM), x-ray diffractometry (XRD), and absorption spectroscopy. The experimental results indicate that the properties of the AlGaN films and AlGaN/GaN structures deposited on the (11-20) Al2O3 substrates are comparable to those of the films and structures grown on the (0001) Al2O3 substrates. From the results of TEM diffraction patterns, AlGaN films were found to exhibit certain crystallographic relationship with (11-20) Al2O3 substrates. The <0001>AlGaN and <01-10>AlGaN were found to be in parallel to <11-20>sapphire and <01-10>sapphire, respectively.