Development of electron beam nonostructure analysis system and its application

近年来，纳米结构分析对于开发新型功能纳米结构材料变得越来越重要。最近，我们进行了纳米衍射研究的局部结构分析的几种新材料的纳米结构，如磁性纳米颗粒膜和非晶合金。为了更详细地分析局部结构，需要在同一局部区域从不同方向进行纳米衍射和高分辨电子显微研究。当我们在高放大率下观察样品中的局部结构区域时，通过倾斜样品，感兴趣的观察位置很容易超出观察屏幕。这使得我们难以在各种取向方向下对局部区域进行高分辨率观察和纳米衍射。这主要是因为观察位置并不正好在倾斜x轴和y轴的交叉点上。利用投影透镜偏转线圈，研制了一种大角度倾斜时样品位置偏移的自动校正系统。还开发了必要的软件，以倾斜的试样台朝向任意方向。该系统利用电视监视器搜索步进倾斜的像逃逸，计算机利用卷积算法计算逃逸矢量。利用投影透镜偏转补偿具有逃逸矢量的图像逃逸。这个系统的优点是，我们不需要观察衍射图案，在样品向我们的预期样品取向倾斜，虽然倾斜过程仍然需要相当长的时间（5-10毫米）。为了实现HREM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器，以便将来更精确和快速地改变方向。本研究为高分辨电子显微术和纳米衍射技术在纳米区域晶体结构分析中的应用奠定了基础。

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.