碳化硅异质外延薄膜生长及表面缺陷研究

Study of SiC surface defects on sapphire/nitride compound substrates

讨论了引入Ⅲ Ⅴ族氮化物为蓝宝石与碳化硅中间的缓冲层 ,用常压气相外延手段在蓝宝石 /Ⅲ Ⅴ族氮化物复合衬底上异质外延碳化硅薄膜的过程 .在C面 (0 0 0 1)蓝宝石上成功地生长出SiC薄膜 .扫描电子显微镜显示薄膜表面连续、光滑 ,证明良好的氮化物缓冲层对碳化硅薄膜异质生长具有重要的意义 ,同时在表面发现直径为 1～ 10 μm的六角形缺陷 .对缺陷面密度与工艺参数的关系进行了分析 ,并对缺陷产生的机理进行了探讨 ,认为反应产生物的腐蚀是产生六角形缺陷的来源 .

The single crystal silicon carbide film growing on the sapphire substrate with a Nitride buffer layer using APCVD (Atmospheric Pressure Chemical Vapor Deposition) is discussed. With the introduction of the Ⅲ Ⅴ nitride buffer layer, the quality of the SiC film is greatly improved. SEM imaging shows that the films are continuous over the growth region. A kind of hexagon surface defects with diameters ranging from 1～ 10?μm is also found on the sapphire substrate. Relations between the density of the defects and the deposited time, temperature and precursor flow rates are also discussed. The erosion effects of silicon on sapphire is considered to be the reason for these surface defects, and this conclusion is supported by experiment data of this hetero epitaxial process.