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Studies on Surface Reaction Mechanisms in Atomic Layr CVD by HREELS

HREELS研究原子层CVD表面反应机理

基本信息

批准号：
08455019
负责人：
YASUDA Yukio
金额：
$ 5.44万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1998
项目状态：
已结题

项目摘要

In this study, we have investigated the effects of hydrogen atoms on the initial oxidation process, the local bonding structure of SiO 2 and the epitaxial growth process of SiGe films by Si_2H_6- and GeH_4-source molecular beam epitaxy, using high-resolution electron energy loss spectroscopy (HREELS) and reflection high energy electron diffraction (RHEED) . The main results are shown below.We applied a random sequential adsorption model to the experimental results of the initial oxidation on H-terminated Si (100) surfaces. It was found out that oxygen atoms preferentially adsorb on one of two back-bond sites of a surface Si atom on H-terminated Si (lO0) - lx1 and -2x1 surfaces. The preferential adsorption of oxygen atoms cannot be observed on clean Si (100) surfaces, which means that this finding shows something of the oxidation control by hydrogen. Moreover, it was also made clear that the oxidaton hardly progresses into the Si substrate until all back-bond sites of surface Si aotms a … More re occupied by oxygen atoms. This shows that hydrogen is effective for the realization of an abrupt SiO_2/Si interface.In the initial oxidation process of H-terminated Si (111) - lx1 surfaces, oxygen atoms randomly adsorb on the sites between surface and subsurface Si atoms below an oxygen coverage of 2.5 monolayer (ML) . In addition, we clarified that the local bonding structure of Si-O-Si species is hardly influenced by the orientaion of Si substrartes and by the adsorbing hydrogen atom.It was found in the SiGe epitaxial growth on Si (100) and Si (l11) surfaces that the dissociative adsorption rates of Si _2H_6 and GeH _4 are significantly dependent upon the surface orientation and the atomic element at the adsorption sites. This suggests that the surface reactions of Si_2H_6 and GeH_4 molecules are ruled by the electronic states of the substrate surface. The role of atomic hydrogen irradiation in the growth rate of SiGe films is to reduce the density of adsorption sites for the hydride gases and to suppress the surface segregation of Ge atoms. These findings support the realizaiton of the surface reaction control with hydrogen. Less

本文利用高分辨电子能量损失谱（HREELS）和反射高能电子衍射（RHEED）研究了氢原子对Si_2H_6和GeH_4源分子束外延SiGe薄膜的初始氧化过程、SiO_2局域成键结构和外延生长过程的影响。主要结果如下：我们将随机序贯吸附模型应用于H端Si（100）表面初始氧化的实验结果。发现氧原子优先吸附在H封端的Si（100）-1x 1和-2x1表面上表面Si原子的两个背键位之一上。在清洁的Si（100）表面上不能观察到氧原子的优先吸附，这意味着这一发现显示了氢对氧化的控制。此外，还清楚地表明，直到表面Si的所有背键位都被氧化，氧化才很难进入Si衬底。 ...更多信息被氧原子占据。在氢封端的Si（111）-1x 1表面的初始氧化过程中，氧原子随机地吸附在表面和次表面Si原子之间的位置上，氧覆盖率低于2.5个单层（ML）。此外，本发明还提供了一种方法，在Si（100）和Si（111）表面上外延生长的SiGe中，发现Si_2H_6和GeH_4的解离吸附速率与表面取向和吸附位上的原子元素密切相关。这表明Si_2H_6和GeH_4分子的表面反应受衬底表面电子态的控制。原子氢辐照在SiGe薄膜生长速率中的作用是降低氢化物气体的吸附位密度，抑制Ge原子的表面偏析。这些结果支持了用氢控制表面反应的实现。少