Effects of AlN buffer on the physical properties of GaN films grown on 6H-SiC substrates
Effects of AlN buffer on the physical properties of GaN films grown on 6H-SiC substrates
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DOI：
10.1007/s10854-015-3948-5
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发表时间：
2016-02
期刊：
影响因子：
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通讯作者：
Zhen Huang;Yuantao Zhang;Baijun Zhao;Fan Yang;Junyan Jiang;Gaoqiang Deng;Baozhu Li;H. Liang
中科院分区：
文献类型：
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作者：
Zhen Huang;Yuantao Zhang;Baijun Zhao;Fan Yang;Junyan Jiang;Gaoqiang Deng;Baozhu Li;H. Liang
本研究采用金属-有机化学气相沉积方法在6H-碳化硅衬底上制备了含氮化铝缓冲层的1.5μm厚GaN薄膜。为了确定AlN缓冲层的生长条件对GaN薄膜的结晶质量和应力状态的影响，进行了两系列实验。通过优化AlN缓冲层的生长条件，GaN薄膜的(0002)半峰宽和摇摆曲线分别提高到136和225弧秒。得到了表面光滑、均方根粗糙度为0.332 nm的薄膜，并观察到了良好的光学性能。同时，AlN缓冲层的生长温度和厚度在一定程度上降低了GaN薄膜中的穿线位错密度和拉伸应力。此外，拉曼光谱和低温光致发光光谱证实了GaN薄膜中的应力值，这表明GaN薄膜中的拉应力越低，薄膜的结晶度越高。
In this study, 1.5-μm-thick GaN films with AlN buffer were prepared on 6H-SiC substrates by metal-organic chemical vapor deposition. To determine the effects of growth conditions of AlN buffer on crystalline quality and stress state of GaN films, two series of experiments were carried out. By optimizing growth conditions of AlN buffer, the full width at half maximum values of (0002) androcking curves of GaN films were improved to 136 and 225 arcsec, respectively. A smooth surface was obtained with a small root-mean-squared roughness of 0.332 nm and the excellent optical property was observed. Simultaneously, threading dislocation density and tensile stress in GaN films were reduced by increasing AlN buffer growth temperature and its thickness in some extent. Besides, stress values in GaN films were confirmed by Raman and low-temperature photoluminescence spectra, which indicated that the lower tensile stress in GaN film, the higher the film crystallinity.