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DEVELOPMENT OF A TWO DEGREES OF FREEDOM LENGTH MEASUREMENT SYSTEM USING A CRYSTAL AS THE SCALE REFERENCE

以晶体为标尺基准的二自由度长度测量系统的研制

基本信息

批准号：
03555083
负责人：
HIGUCHI Toshiro
金额：
$ 10.43万
依托单位：
UNIVERSITY OF TOKYO
依托单位国家：
日本
项目类别：
Grant-in-Aid for Developmental Scientific Research (B)
财政年份：
1991
资助国家：
日本
起止时间：
1991 至 1993
项目状态：
已结题

项目摘要

We have investigated the possibility of using the lattice spacing of a crystal for metrology and accurate positioning. To carry out the research, we have built a scanning tunneling microscope (STM) with two tunneling-units (a dual tunneling-unit STM, DTU-STM), with an xy stage with two sample holders, The configuration enables simultaneous observation of a sample and the scale-reference crystal. As a result, it is possible to calibrate the lateral scales of the sample image by superposition of the crystalline lattice image. In order to access the accuracy of this measurement procedure, we have compared crystalline lattice images acquired simultaneously with the two tunneling-units. Matching of 99.98 +/- 0.03%. Although we have not measured the absolute accuracy of the system, the high repeatability of the experiment implies the procedure to give good results. We have succeeded in the software recognition of the atomic features, so it is safe to assume that an automated measurement machine, capable of measuring up to a few microns will be implemented in the near future.Study on the use of the STM and a crystal for sub-nanometer positioning control of the xy stage was also carried out. Lateral position modulation in the 10 pm order was used to measure the gradient of the surface with atomic resolution. By this technique, it becomes possible to recognize the local maximum and minimum of the topographic features, and thus implement active positioning of the xy stage using the lattice spacing as the reference. Positioning of the STM tip to a single atom was also confirmed for tens of minutes.

我们研究了利用晶体晶格间距进行计量和精确定位的可能性。为了进行研究，我们建立了一个具有两个隧道单元（双隧道单元STM， DTU-STM）的扫描隧道显微镜（STM），具有一个xy级和两个样品支架，该配置可以同时观察样品和尺度参考晶体。因此，可以通过叠加晶格图像来校准样品图像的横向尺度。为了获得该测量程序的准确性，我们比较了与两个隧道单元同时获得的晶格图像。匹配99.98 +/- 0.03%。虽然我们还没有测量系统的绝对精度，但实验的高重复性意味着该程序可以给出良好的结果。我们已经成功地在软件上识别了原子特征，因此可以肯定的是，在不久的将来，能够测量到几微米的自动测量机将被实现。研究了利用STM和晶体对xy工作台进行亚纳米定位控制的方法。采用10 pm量级的横向位置调制，以原子分辨率测量表面梯度。通过该技术，可以识别地形特征的局部最大值和最小值，从而实现以晶格间距为参考的xy阶段的主动定位。STM尖端对单个原子的定位也得到了数十分钟的确认。