STRUCTURAL DYNAMICS OF EPITAXY AND QUANTUM MECHANICAL APPROACH

本研究于1995年4月至1997年3月进行。在此期间，举行了6次会议，其中包括1997年1月25日和26日在科比举行的一次总结本研究结果的会议。本项目的目的之一是为理论和实验科学家提供一个共同的讨论场所，以便通过量子力学方法和复杂的实验来深入理解外延的结构动力学。第一原理量子力学计算表明，电子计数模型能很好地解释吸附原子生长后重构表面的原子结构。在此基础上，利用电子计数模型进行了Monte Carlo模拟，很好地解释了（001）GaAs上A、B台阶行为的差异。在实验部分，利用扫描隧道显微镜（STM）研究了吸附原子在Si重构表面上的行为，发现重构对二维岛的形貌有影响。用微探针-RHEED/SEM分子束外延技术研究了III族原子的表面扩散长度，发现掺入扩散长度强烈依赖于As压力，并且由于III族原子寿命的As压力依赖性，（111）B和（001）表面间的扩散方向随As压力的增加而反转两次。虽然，理论和实验工作之间仍有很大的差距，但这种努力掩埋的差距是非常重要的。

The present research has been conducted from April of 1995 to March of 1997. During this period, 6 meetings were held including one meeting to summarize the results of the present research which was held in Kobe on 25th and 26th of January, 1997. One of the aims of the present project is to provide a common place for the discussions among the theoretical and experimental scientists for obtaining deep understandings in the structure dynamics of epitaxy by quantum mechanical approach and by sophisticated experiments. It has been shown by lst principle quantum mechanical calculation that electron counting model can explain very well the atomistic structure of reconstructed surface with growing adatoms. Basing on this, Monte Carlo simulation was conducted with the help of electron counting model and it was found that the difference in the behavior of A and B steps on (001) GaAs is well explained. Monte Calro simulation for the growth of two-component crystal was also conducted.In the experimental part, the behavior of ad-atom on Si reconstructed surface was studied by using scanning tunneling microscope (STM) and it was found reconstruction influences the morphology of 2D islands. The surface diffusion length of group III atoms until incorporation was studied by using microprobe-RHEED/SEM MBE.It was found that the diffusion length of incorporation depends strongly on As pressure and that the direction of inter-surface diffusion between (111) B and (001) surfaces is reversed twice as As pressure is increased due to the As pressure dependency of group III atom life time. Although, there is still a large gap between theoretical and experimental works, this kind of effort to bury the gap is very important.