中文摘要：

采用固源分子束外延技术,以α-Al2O3（0001）为衬底,在不同衬底温度下制备了6H-SiC薄膜。利用反射式高能电子衍射、原子力显微镜、X射线衍射对生长样品的结构和结晶质量进行了表征。结果表明：在衬底温度为1 100℃时生长的薄膜质量较好,在较低温度（1 000℃）和较高温度（1 200℃）条件下生长的薄膜质量较差。同时发现,衬底温度为1 000℃时生长的薄膜面内存在拉应变,随着衬底温度的升高,应变转变为压应变。在衬底温度为1 100℃生长的薄膜受到的应变较小。这可能是薄膜与衬底的晶格失配和热膨胀系数差异共同作用的结果。

英文摘要：

6H-SiC thin films were prepared on α-Al2O3（0001） substrate at different substrate temperatures by solid-source molecular beam epitaxy.The microstructure and crystalline quality of the SiC thin films were characterized by reflection high energy electron diffraction,X-ray diffraction and atomic force microscopy.The results show that the 6H-SiC film with better crystalline quality is obtained at the substrate temperature of 1 100 ℃,while the films with poorer crystalline quality are obtained at both lower substrate temperature（1 000 ℃） and higher substrate temperature（1 200 ℃）.There is tensile strain in the plane of the film grown at the sub-strate temperature of 1 000 ℃.As the substrate temperature increases,the stress changes to be compressive.There are few stresses on the film grown at the substrate temperature of 1 100 ℃.These stresses are probably induced by the mismatch of both the lattice con-stant and the coefficient of thermal expansion of the film and substrate.