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Study on mechanism of generating an ultra flat surface by MBE

MBE产生超平坦表面的机理研究

基本信息

批准号：
09450062
负责人：
FURUKAWA Yuji
金额：
$ 8.19万
依托单位：
TOKYO METROPOLITAN UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1998
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09450062/
关键词：
MBE ultra precision Silicon 分子線エピタキシ

项目摘要

Epitaxial growth is molecular deposition along crystalline orientation of substrate. Si-Si Molecular Beam Epitaxy (MBE), one of the epitaxial growth methods, is physical thermal process. That is, Si molecules given thermal energy from heated substrate can migrate on the substrate, reach to the lower potential energy positions and be caught there. So it is expected that the potential energy of the generated surface becomes more even, hence the newly surface becomes geometrically flat and crystallographically aligned. The present study made the relation clear between the substrate orientation, the surface migration and the property of the generated surface.In the experiment, pure Si was homo-epitaxially grown up onto the same substrate temperature (800ﾟC), the number of supplied molecules and the grown time. The orientation of the Si substrate was only varied (001), (113), (111), (331) and (110), which belong to <110> crystal zone.The generated surface, which was observed by the help of … More Atomic Force Microscope (AFM) in suitable environment, was different to the substrate orientation. Each generated shape consisted of the specific crystal planes in which the density of dangling bonds was lower into the substrate. It was thought that these planes were slower deposition rate than the others because the planes were difficult to transfer the thermal energy of molecules. Then, the generated surface on (111) was the smoothest one. On the other hand, the generated surface on (331) was the roughest one.These results were clarified that the dangling bonds take the thermal energy of molecules away and the amount of this lost energy depended on the density of dangling bond. Thus, if the density of dangling bonds on the substrate orientation is the lowest, the density of the dangling bonds in the lower potential energy positions is relatively higher than another positions on the substrate and easy to lose the thermal energy of molecules. Therefore, the generated surface on this substrate could be flattened. Less

外延生长是指分子沿着衬底的晶体取向沉积。Si-Si分子束外延（MBE）是一种物理热过程外延生长方法。也就是说，从被加热的衬底获得热能的Si分子可以在衬底上迁移，到达较低势能的位置并在那里被捕获。因此，预期生成的表面势能变得更加均匀，因此新表面在几何上变得平坦，在晶体学上排列。本研究明确了基体取向、表面迁移和生成表面性质之间的关系。实验中，在相同的衬底温度（800℃）、供体分子数和生长时间下，对纯Si进行了均匀外延生长。Si衬底的取向只有（001）、（113）、（111）、（331）和（110），属于<110>晶体区。在合适的环境下，利用原子力显微镜（AFM）观察所得表面与基体取向不同。每个生成的形状都由特定的晶体平面组成，其中悬浮键的密度较低。人们认为这些平面的沉积速度比其他平面慢，因为这些平面难以传递分子的热能。则（111）上生成的曲面为最光滑的曲面。另一方面，在（331）上生成的表面是最粗糙的。这些结果表明，悬空键带走了分子的热能，而这种损失的能量的多少取决于悬空键的密度。因此，如果在底物取向上悬空键的密度最低，则在底物上势能较低位置的悬空键的密度相对高于底物上的其他位置，并且容易损失分子的热能。因此，在该基板上生成的表面可以被平面化。少