Development of High resolution Image Processing System for Nano-scale Mesurement

本研究开发了一种新的数字图像记录和处理系统，并将该系统应用于原位高分辨率透射电镜。该系统将观测到的图像记录为连续的数字化帧，并对每一帧进行计算机分析。该系统使我们能够在处理或记录过程中获得无退化的显微镜图像。我们证实了该系统获得GaN原子图像的有效性，该图像具有非常弱的N原子对比度，Ga与N原子之间的原子间距离为0.113 nm。因此，我们将该体系应用于原位高分辨率透射电镜，研究了t-BN的力学行为、反应产物在反应润湿前沿的形成机理以及氮化硅在原子尺度上的裂纹扩展行为。在ICP-CVD生长的t-BN薄膜的力学性能方面，发现薄膜具有显著的柔韧性和弹性，反复弯曲至最小曲率半径约4nm时不会发生永久变形。在含ti合金熔液与SiC衬底反应过程中，TiC在扩散前沿呈逐层生长模式，扩散前沿的形貌取决于合金熔液中解离衬底的化学成分。在对氮化硅裂纹扩展行为和断口表面的研究中，裂纹扩展仅发生在氮化硅晶粒与晶间玻璃膜的界面处。悬垂键在该区域的集中是裂纹沿界面扩展的原因。

In this study, we developed anew digital image recording and processing system and applied this system to in-situ high-resolution transmission electron microscopy. In this system, observed images were recorded as continuous digitalized frames and each frame were analyzed by computer. This system enabled us to get degradation-free microscope images during processing or recording. We confirmed the validity of this system to obtain the atomic image of GaN, which have very weak contrast of N atoms and 0.113 nm of interatomic distance between Ga and N atoms. Thus, we applied this system to in-situ high-resolution transmission electron microscopy and studied on the mechanical behavior of t-BN, formation mechanism of the reaction product at the reactive wetting front and crack propagation behavior of silicon nitride on an atomic scale.In the case of the mechanical properties of t-BN film grown by ICP-CVD, it was revealed that the film has remarkable flexibility and resiliency, such tha no permanent deformation occurred when it was bent repeatedly to the minimum radius of curvature f about 4nm. In the processes of reaction between Ti-containing molten alloy and SiC substrate, TiC grew in a layer by layer mode at the spreading front, and the morphology of the spreading front depend on the chemical composition of the dissociated substrate in the molten alloy. In the study on the crack propagation behavior and fractured surface in silicon nitride, the crack propagation took place just at the interface between silicon nitride grain and intergranular glassy film. The concentration of dangling bonds at this region is the origin for the crack propagation along the interface.