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STUDIES ON INTERSURFACE DIFFUSION IN NANO-STRUCTURE EPITAXY

纳米结构外延中的面间扩散研究

基本信息

批准号：
09450008
负责人：
NISHINAGA Tatau
金额：
$ 9.15万
依托单位：
The University of Tokyo
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 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09450008/
关键词：
GaAs molecular beam epitaxy intersurface diffusion μ-RHEED MBE surface diffusion pyramid structure macro-step AィイD2s2ィエD2 molecules

项目摘要

In the present study, the surface diffusion of Ga between two growing surfaces in molecular beam epitaxy (MBE) of GaAs was studied first. We call such diffusion as an inter-surface diffusion. The intersurface diffusion governs the growth of micro/nano structures and one of the key elementary growth processes which determine the appearing and disappearing of a certain facet. It turned out that the amount and the direction of the intersurface diffusion depends strongly on As pressure. It was found that the top size of a truncated pyramid or ridge can be controlled by changing arsenic pressure. For instance, the top of truncated pyramid is decreased during the growth at lower As pressure while it is increased under higher As pressure. By rotating the substrate, it was possible to get uniform truncated pyramids with controlled top size so that one can grow dot structures on the tops.In the next step, the order of reaction of AィイD2s2ィエD2 and AィイD2s4ィエD2 with Ga in MBE growth was studied. It was found that under a low As pressure the order was the first while under high As pressure it was the second for both As species. As for As4 the result shows good agreement with well known results reported by Foxon and Joyce while the presence of the second order reaction regime for AィイD2s2ィエD2 has not been reported.

本文首先研究了GaAs分子束外延中Ga在两生长面之间的表面扩散。我们称这种扩散为表面间扩散。表面间扩散控制着微/纳米结构的生长，是决定某一刻面出现和消失的关键基元生长过程之一。事实证明，表面间扩散的量和方向强烈依赖于As压力。研究发现，可以通过改变砷压来控制截棱锥或脊的顶部尺寸。例如，在较低的As压力下，截头金字塔的顶部在生长过程中减少，而在较高的As压力下，截头金字塔的顶部增加。通过旋转衬底，可以得到具有可控顶部尺寸的均匀截棱锥，从而可以在顶部生长点结构。下一步，研究了MBE生长中A_xD_2s_2_xD_2和A_xD_2s_4_xD_2与Ga的反应顺序。结果表明，在低As压力下，两种As物种的顺序均为第一，而在高As压力下，顺序均为第二。至于As 4，该结果与Foxon和Joyce报道的众所周知的结果显示出良好的一致性，而A β D2 s2 β D2的二级反应机制的存在尚未报道。