Development of electron beam nonostructure analysis system and its application

近年来，纳米结构分析已成为开发新型功能纳米结构材料的重要手段。最近，我们对磁性纳米颗粒膜和非晶态合金等几种具有纳米结构的新材料进行了局部结构分析的纳米衍射研究。为了进行详细的局部结构分析，有必要从不同的角度对同一局部区域进行纳米衍射和高分辨电子显微镜研究。当我们在高倍率下观察样品中的局部结构区域时，通过倾斜样品很容易使感兴趣的观察位置离开观察屏。这使得我们很难在不同的取向方向下对局部区域进行高分辨率的观测和纳米衍射。这主要是因为观测位置不完全在倾斜的x轴和y轴的交叉点上。利用投影仪-透镜-偏转线圈，研制了一套大角度倾斜试件位置漂移的自动校正系统。还开发了使试件工作台向任意方向倾斜所需的软件。在该系统中，电视监视器搜索逐级倾斜的图像逃逸，计算机利用卷积算法计算逃逸矢量。利用投影仪镜头偏转来补偿带有逃逸矢量的像散。这个系统的优点是，在样品向我们预期的样品取向倾斜时，我们不需要观察衍射图，尽管倾斜过程仍然需要相当长的时间(5-10 mm)。为了实现高分辨率电子显微镜的自动倾斜，我们需要开发一种具有快速运动的精密样品驱动装置，以便在未来更精确、更快速地改变方向。本研究将为纳米级晶体结构的高分辨电子显微镜和纳米衍射分析技术奠定基础。

In recent years, nano-structure analysis has been becoming important to develop new types of functional nanostructured materials. We recently performed nano-diffraction studies for local structure analysis of several new materials with nano structures such as magnetic nano-granular films and amorphous alloys. For the purpose of detailed local structure analysis, it is necessary to make nano-diffraction and HREM study at the same local area from different orientations. When we observe a local structural area in a specimen under a high magnification, the observation position of interests easily goes out of the observation screen by tilting the specimen. This makes our high-resolution observation and nano-diffraction of local areas difficult under various orientation directions. This is primarily because the observation position is not exactly on the cross-point of tilting x and y-axes. We have developed an auto-correction system for the specimen positional-shift on large angle specimen-tilting taking advantage of the projector-lens-deflection coils. Software necessary to tilt the specimen stage toward an arbitrary orientation was also developed. In this system the image-escape by a step-wise tilt is searched by the TV-monitor, and the escape-vector is calculated by computer using the convolution algorism. The image-escape with the escape-vector is compensated using the projector-lens-deflection. The merit of this system is that we need not observe the diffraction patterns during the specimen tilting towards our intended specimen orientation, though the tilting procedure still takes a considerable time (5-10 mm). In achieving an auto-tilt for the HREM purpose, we need to develop a precision-specimen drive with a quick movement to change more precisely and quickly the orientation in future. The present investigation will be the primary step for the nano-area crystal structure analysis technique with HREM and nano-diffraction.