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关于表面氢的平均信息。然而，为了发展表面氢介导的纳米制造技术，人们希望建立一种新的方法来分析表面局部存在的氢。本研究项目的目的是在原子尺度上阐明局部存在的表面氢的行为。为此，(A)我们结合了新引入的低能弹性反冲探测分析(LE-ERDA)和扫描隧道显微镜(STM)来定量分析表面氢的量。(B)利用新的装置，我们发展了对局部存在的表面氢的行为的理解，并尝试将它们应用于由表面氢介导的纳米制造技术。(1)在把握LE-ERDA宏观信息与STM微观信息相关性的基础上，分析了氢致表面修饰在表面局部区域引起的表面钝化、结构稳定、自组织等过程。特别是，对于氢致自组织，对于金属/半导体表面，如In/Si(100)、Al/Si(100)和Ag/6H-SiC(0001)，我们发现金属纳米团簇的形成和特殊的氢端接表面相依赖于初始表面结构。(2)基于上述结果，我们尝试了利用氢中介的表面修饰过程来实现表面局部区域的纳米制造。我们的目标是建立利用扫描隧道显微镜局域抽氢的纳米制造工艺。我们成功地对Si(100)4XL-H表面进行了STM图案化，并在抽氢区域发现了特殊的Si(100)c(8x2)局域表面相。这些结果为更好地理解局域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.