超高真空CVD生长的Si_(1-x)Ge_x合金组分变化与表面偏析现象

Surface Segregation and Content Variation in Si_(1-x)Ge_x Growth on Si in Ultra High Vacuum by Chemical Vapor Deposition

系统分析了利用超高真空CVD技术在Si衬底上外延Si1-xGex 合金的体内组分分布情况和Ge的表面偏析现象。用SIMS对Si和Ge的组分作了深度剖析。在生长过程中 ,组分均匀 ,在表面Ge浓度减小 ,Si浓度没有明显变化。在不经HF酸清洗和在HF酸中去掉表面自然氧化层的两种情况下 ,用XPS分别对外延层表面进行了定量分析 。

SiGe epilayers were grown on Si substrate by UHV/CVD.The epilayers were studied by SIMS and XPS.SIMS results showed that Ge content on the surface was found to be less than the uniform Ge content in the epilayers and that no variation in Si content was observed on the surface.The surface chemical composition was analyzed with XPS for the samples with or without dipping into a dilute HF(10%) solution.The XPS results showed that spontaneous oxidation of the epilayers in air is responsible for the Ge depletion on the surface.