Low-Temperature Deposition of Dielectric Films Using Synchrotron Radiation-Assisted Gas-Source CVD

研究了同步辐射辅助化学气相沉积（CVD）在低温下沉积介质薄膜的方法。在这里研究的方法中，在真空紫外（VUV）区域用SR照射干净的半导体表面，同时用源气体照射表面，从而增强源气体的光子诱导分解和半导体表面的化学反应。制备干净、化学性质稳定的半导体表面是制备高质量介电膜的关键。因此，我们研究了Si表面的以下清洗工艺：(1)用SR辐照去除Si上的天然氧化物，(2)用紫外（UV）臭氧去除碳污染，(3)用稀释氢氟酸（HF）溶液清洗Si表面。我们已经阐明了紫外线臭氧氧化的初始阶段的氢端硅表面。此外，红外光谱测量表明，在HF溶液中处理的Si表面的微观粗糙度与溶液的pH值密切相关。利用光子激发解吸（PSD）、光发射和红外（IR）吸收光谱研究了硅烷在硅表面吸附的四乙氧基硅烷（TEOS）等硅烷的sr诱导反应。我们观察到在SR辐照下醇氧分子中烷氧基的分解。通过光电发射和红外测量证实，ST在VUV区分解醇氧化合物分子形成氧化硅膜。在这项研究中，我们发现醇氧化合物是一类很有前途的氧化硅源材料。

We have investigated the method of depositing dielectric films at low temperature using synchrotron radiation (SR)-assisted chemical-vapor-deposition (CVD). In the method investigated here, a clean semiconductor surface is irradiated by SR in the vacuum ultraviolet (VUV) region while dosing the surfaces with source gases, thereby enhancing both photon-induced decomposition of source gases and chemical reactions on the semiconductor surface.It is quite important for deposition high-quality dielectric film to produce a clean, chemically stable semiconductor surface. We have therefore investigated the following cleaning processes of Si surfaces : (1) removal of native oxide on Si by SR irradiation, (2) Removal of carbon contamination using ultraviolet (UV) ozone, and (3) Cleaning of Si surface with dilute hydrofluoric acid (HF) solution. We have elucidated the initial stages of UV ozone oxidation of hydrogen-terminated Si surfaces. Futhermore, it was demonstrated with infrared spectroscopic measurements that microscopic roughness of Si surface treated in HF solution strongly depends on the pH of the solution.SR-induced reactions of silicon alkoxides such as tetraethoxysilane (TEOS) adsorbed on Si surface have been investigated using photon-stimulated desorption (PSD), photoemission and infrared (IR) absorption spectroscopy. We observed the decomposition of the alkoxyl group in alkoxide molucules due to SR irradiation. It was confirmed with photoemission and IR measurements that ST in the VUV region decomposes alkoxide molecules to form silicon oxide film. In this study, we found that alkoxide is a promising class of source materials for silicon oxide formation.