Xu Yu, Zhang Chunfu, Cheng Yaolin, Li Zhe, Cheng Ya'nan, Feng Qian, Chen Dazheng, Zhang Jincheng, Hao Yue
Wide Bandgap Semiconductor Technology Disciplines State Key Laboratory, School of Microelectronics, Xidian University, Xi'an 710071, China.
Materials (Basel). 2019 Nov 7;12(22):3670. doi: 10.3390/ma12223670.
This report systematically investigates the influence of different carrier gases (O, N, and air) on the growth of gallium oxide (GaO) thin films on c-plane sapphire substrates by using the mist-CVD method. Although XRD and Raman measurements show that the pure corundum-structured α-GaO with single (0006) plane orientation was successfully obtained for all three different carrier gases, the crystal quality could be greatly affected by the carrier gas. When O is used as the carrier gas, the smallest full-width at half maximum (FWHM), the very sharp absorption cutoff edge, the perfect lattice structure, the highest growth rate, and the smooth surface can be obtained for the epitaxial α-GaO film as demonstrated by XRD, UV-VIS, TEM, AFM (Atomic Force Microscope), and SEM measurements. It is proposed that the oxygen content in carrier gas should be responsible for all of these results. XPS (X-ray photoelectron spectroscopy) analysis also confirms that more oxygen elements can be included in epitaxial film when O is used as the carrier gas and thus help improve the crystal quality. The proper carrier gas is essential for the high quality α-GaO growth.
本报告通过喷雾化学气相沉积（mist-CVD）法系统地研究了不同载气（氧气、氮气和空气）对在c面蓝宝石衬底上生长氧化镓（GaO）薄膜的影响。尽管X射线衍射（XRD）和拉曼测量表明，对于所有三种不同的载气，均成功获得了具有单一（0006）面取向的纯刚玉结构α-GaO，但晶体质量会受到载气的显著影响。当使用氧气作为载气时，通过XRD、紫外可见光谱（UV-VIS）、透射电子显微镜（TEM）、原子力显微镜（AFM）和扫描电子显微镜（SEM）测量表明，外延α-GaO薄膜可获得最小的半高宽（FWHM）、非常尖锐的吸收截止边缘、完美的晶格结构、最高的生长速率和平滑的表面。研究表明，载气中的氧含量是造成所有这些结果的原因。X射线光电子能谱（XPS）分析也证实，当使用氧气作为载气时，外延薄膜中可以包含更多的氧元素，从而有助于提高晶体质量。合适的载气对于高质量α-GaO的生长至关重要。
