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

在这项研究中，我们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电子显微镜。在该系统中，观测图像被记录为连续的数字化帧，并用计算机对每一帧进行分析。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。验证了该系统对N原子对比度很弱、Ga、N原子间距为0.113 nm的GaN原子图像的有效性。因此，我们将该系统应用于原位高分辨透射电子显微镜，并在原子尺度上研究了t-BN的力学行为、反应润湿前沿反应产物的形成机理和氮化硅的裂纹扩展行为。对采用等离子体化学气相沉积方法生长的t-BN薄膜的力学性能进行了研究，发现薄膜具有显著的柔韧性和弹性，当其反复弯曲到最小曲率半径约4 nm时不会发生永久变形。在含钛合金熔体与碳化硅基体的反应过程中，TiC在扩散前沿以逐层方式生长，扩散前沿的形态取决于合金熔体中解离的基体的化学成分。在对氮化硅的裂纹扩展行为和断口的研究中，裂纹扩展只发生在氮化硅颗粒与晶间玻璃膜的界面上。悬挂键在该区域的集中是裂纹沿界面扩展的根源。

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.