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采用超高真空化学气相沉积(UHV-CVD)系统,用低温Ge缓冲层技术在Si衬底上外延了张应变Ge薄膜。扫描电镜(TEM)图表明Si基外延Ge薄膜拥有低的位错密度,原子力显微镜(AFM)测试Ge层表面粗糙度仅为1.2 nm。对Si基外延Ge薄膜进行了不同温度下的退火,并用双晶X射线衍射(DCXRD)曲线和Raman谱进行表征。结果表明,Si基外延Ge薄膜受到的张应变随退火温度呈线性增加,当退火温度达到850℃时Si和Ge发生严重的互扩散,这种互扩散改变了室温PL谱,影响外延Ge薄膜特性。
The ultra-high vacuum chemical vapor deposition (UHV-CVD) system is used to epitaxially strain the tensile strain Ge thin film on the Si substrate by using the low-temperature Ge buffer layer technology. Scanning electron microscopy (TEM) images show that Si-based epitaxial Ge films have low dislocation densities and surface roughness of Ge layers is only 1.2 nm by atomic force microscopy (AFM). The Si-based epitaxial Ge films were annealed at different temperatures and characterized by double-crystal X-ray diffraction (XRD) and Raman spectroscopy. The results show that the tensile strain induced by Si-based epitaxial Ge films increases linearly with the annealing temperature. When the annealing temperature reaches 850 ℃, Si and Ge undergo serious interdiffusion, which interferes with the PL spectra at room temperature and affects the epitaxial Ge film properties .