Si基富Ge含量Si_(1-x-y)Ge_xC_y异质结构的热退火行为研究

Studies on Thermal Annealing Behavior of Si_(1-x-y)Ge_xC_y Heterostructure with Rich Ge and High C Content on Si(100) Substrate

研究了Si基富Ge含量的Si1 x yGexCy 异质结构的热退火行为。采用等离子体增强化学气相淀积 (PECVD)法在Si(10 0 )衬底上淀积一层厚度为 170nm的Si1 x yGexCy 薄膜 (x～ 0 .7,y～ 0 .15) ,并在其上覆盖一Ge层。将样品分别在 6 50℃和 80 0℃下进行N2氛围下热退火 2 0min。用拉曼谱 (Raman)、俄歇电子能谱 (AES)以及X射线光电子能谱(XPS)等方法对样品进行研究。研究结果表明 ,低温PECVD法生长的Si1 x yGexCy 薄膜是一种亚稳结构 ,Ge/Si1 x yGexCy/Si异质结构在 6 50℃下呈现不稳定性 ,薄膜中的Ge、C相对含量下降 ,且在界面处出现Ge、C原子的堆积。经过 80 0℃下退火 2 0min的样品中C含量基本为 0 ,Ge相对含量下降至约 2 0 %左右 ,且薄膜的组分比较均匀。

The thermal annealing behavior of Si 1 x y Ge xC y heterostructure with rich Ge and high C content on Si (100) substrate was studied. The Si 1 x y Ge xC y(x～70%, y～15%) thin film with a Ge cap were grown on Si (100) substrate by Plasma enhanced Chemical Vapor Deposition (PECVD) and then thermally annealed among N 2 atmosphere at 650℃ and 800℃ respectively for 20 minutes. Raman, Auger Electron Spectroscopy (AES) and X ray Photoelectron Spectroscopy (XPS) were used to analyze the samples. The results show that the as grown Ge/Si 1 x y Ge xC y/Si heterostructure is metastable. After annealing at 650℃, Ge and C contents in the thin films decreased and at the same time Ge and C atoms piled up on the interfaces. After annealing at 800℃, the composition of C in the film decreased to 0, that of Ge decreased to about 20%, and the composition of the film was uniform.