Zhang Wenhui, Zhang Hezhi, Zhang Song, Wang Zishi, Liu Litao, Zhang Qi, Hu Xibing, Liang Hongwei
School of Microeletronics, Dalian University of Technology, Dalian 116024, China.
Jiangsu Xinguanglian Technology Company Co., Ltd., Wuxi 214192, China.
Materials (Basel). 2023 Mar 30;16(7):2775. doi: 10.3390/ma16072775.
A high aluminum (Al) content -(AlGa)O film was synthesized on c-plane sapphire substrate using the gallium (Ga) diffusion method. The obtained -(AlGa)O film had an average thickness of 750 nm and a surface roughness of 2.10 nm. Secondary ion mass spectrometry results indicated the homogenous distribution of Al components in the film. The Al compositions in the -(AlGa)O film, as estimated by X-ray diffraction, were close to those estimated by X-ray photoelectron spectroscopy, at ~62% and ~61.5%, respectively. The bandgap of the -(AlGa)O film, extracted from the O 1s core-level spectra, was approximately 6.0 ± 0.1 eV. After synthesizing the -(AlGa)O film, a thick -GaO film was further deposited on sapphire substrate using carbothermal reduction and halide vapor phase epitaxy. The -GaO thick film, grown on a sapphire substrate with a -(AlGa)O buffer layer, exhibited improved crystal orientation along the (-201) plane. Moreover, the scanning electron microscopy revealed that the surface quality of the -GaO thick film on sapphire substrate with a -(AlGa)O intermediate buffer layer was significantly improved, with an obvious transition from grain island-like morphology to 2D continuous growth, and a reduction in surface roughness to less than 10 nm.
采用镓（Ga）扩散法在c面蓝宝石衬底上合成了高铝（Al）含量的（AlGa）O薄膜。所获得的（AlGa）O薄膜平均厚度为750 nm，表面粗糙度为2.10 nm。二次离子质谱结果表明薄膜中Al成分分布均匀。通过X射线衍射估计，（AlGa）O薄膜中的Al成分分别约为62%和61.5%，与通过X射线光电子能谱估计的结果相近。从O 1s芯能级光谱中提取的（AlGa）O薄膜的带隙约为6.0±0.1 eV。在合成（AlGa）O薄膜后，采用碳热还原和卤化物气相外延法在蓝宝石衬底上进一步沉积了厚的 -GaO薄膜。生长在具有（AlGa）O缓冲层的蓝宝石衬底上的 -GaO厚膜在（-201）平面上表现出改善的晶体取向。此外，扫描电子显微镜显示，具有（AlGa）O中间缓冲层的蓝宝石衬底上的 -GaO厚膜的表面质量显著提高，从晶粒岛状形态明显转变为二维连续生长，表面粗糙度降低至小于10 nm。
