Microscopic Analysis of Surface Hydrogen and its Application to Nano-Fabrication Techniques

到目前为止，已经应用了几种表面分析技术来获得表面氢的平均信息。然而，为了发展表面氢介导的纳米加工技术，需要建立一种新的方法来分析驻留在表面的局部氢。本研究项目的目的是在原子尺度上阐明局部驻留的表面氢的行为。为此，(A)我们将新引入的低能弹性反冲检测分析（LE-ERDA）与扫描隧道显微镜（STM）相结合，对表面氢的量进行定量分析。(B)使用新装置，我们已经了解了局部驻留的表面氢的行为，并尝试将其应用于表面氢介导的纳米制造技术。值得特别提及的新发现如下。(1)在充分把握LE-ERDA获得的宏观信息与STM获得的微观信息之间的相关性的基础上，我们分析了氢介导的表面修饰在表面局部引起的表面钝化、结构稳定、自组织等过程。特别是在氢诱导的自组织方面，对于金属/半导体表面，如In/Si (100), Al/Si（100）和Ag/6H-SiC(0001)，我们发现金属纳米簇的形成和特殊的氢端表面相依赖于初始表面结构。(2)基于上述结果，我们尝试采用氢介导的表面修饰工艺对表面局部区域进行纳米加工。目的是建立STM局部抽氢纳米加工工艺。我们成功地对Si (100) 4xl-H表面进行了STM图像化，并在氢提取区域发现了Si (100) c （8x2）特有的局部表面相。这些结果为更好地理解局部表面氢的行为提供了关键。

So far, several surface analytical techniques have been applied to obtain average information on surface hydrogen. However, in order to develop nano-fabrication techniques mediated by surface hydrogen, it is desired to establish a novel method that can analyze hydrogen residing locally on the surface. The purpose of this research project is to elucidate the behavior of locally residing surface hydrogen on atomic scale. For this purpose, (A) we have combined newly introduced low-energy elastic recoil detection analysis (LE-ERDA) for quantitative analysis of the amount of surface hydrogen with scanning tunneling microscopy (STM). (B) Using the new apparatus, we have developed understanding of the behavior of locally residing surface hydrogen, and attempted their application to nano-fabrication techniques mediated by surface hydrogen. The new findings worthy of special mention are as follows.(1) With a good grasp of correlation between macroscopic information obtained by LE-ERDA and microscopic information from STM, we analyzed several processes in surface local area induced by hydrogen-mediated surface modification such as surface passivation, structure stabilization, selforganization. In particular, as for the hydrogen-induced self-organization, for metal/semiconductor surfaces such as In/Si (100), Al/Si (100) and Ag/6H-SiC (0001), we found the formation of metal nano-clusters and the peculiar hydrogen-terminated surface phases dependent on the initial surface structure.(2) Based on the above results, we attempted a nano-fabrication of surface local area using hydrogenmediated surface modification processes. We aimed establishment of nano-fabrication processes using local hydrogen extraction by STM.We succeeded in the STM patterning of the Si (100) 4xl-H surface, and found the peculiar local surface phase of the Si (100) c (8x2) on the hydrogen extracted area.These results cause the key of better understanding o the behavior of locally residing surface hydrogen.