Structure analysis of metalic and semiconductor heterojunction by the lattice image of high resolution electron microscope

本项目旨在分析半导体异质结异质界面的原子结构，这是下一代超级计算机的候选者。该项目包括样品制备技术的改进和高分辨电子显微镜点阵成象新技术的开发两大部分工作，通过对GaAs/AlAs、GaAs、由于机械减薄，在预减薄时，最合适的试样厚度小于50 μ m。在此厚度下，最终离子减薄时的辐照损伤降低到最低水平。发现在[100]方向照射下可以观察到普通高分辨技术难以观察到的异质界面。GaAs和AlAs在[100]光照下呈现不同的晶格图像。通过该技术在GaAs/AlAs异质界面处检测到一个原子高度台阶。

The present project intended to analyze the atomic structure of the heterointerfaces of semiconductor heterojunction which is highly expected as a candidate of the supercomputer of next age. The project sonsisted of two majour works which were the improvement of specimen preparation techniue and the development of new technique on the lattice imaging of high resolution electron microscope.the specimen preparaton technique was highly improved by the various kinds of testing of many heterojunctions shch as GaAs/AlAs, GaAs, GaSb/ so on. The most suitable specimen thickness at the presthinning due to the mechanical thinning was found to be less than fiftee micro meter. At this thickness the irradiation damages at the final ion thinning was reduced at the lowest level. The most suitable ion thinning conditions which were different between different heterojunctions were also found for each materials.It was found that the heterointerface which is hardly observable by the ordinal high resoluton technique can be observed by the illumination in the [100] direction. GaAs and AlAs appeared as the different lattice image pattern at the [100] illumination. By the technique one atomic height step at the GaAs/AlAs heterointerface was detected.