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Atomic-scale structure control of silicon-metal interface and its macroscopic functional properties

硅-金属界面的原子尺度结构调控及其宏观功能特性

基本信息

批准号：
05452101
负责人：
HASEGAWA Shuji
金额：
$ 4.8万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1993
资助国家：
日本
起止时间：
1993 至 1994
项目状态：
已结题

项目摘要

We have installed a new sample holder in a UHV chamber for measurements of electrical properties, connected to a small MBE-RHEED system developed in the last year. This system enables in-situ analyzes and measurements of (1) surface structures and chemical compositions, (2) surface conductivity, (3) Hall effect, (4) field effect, and (5) photoconductivity. We continued the studies on the correlation between the microscopic atomic arrangements/electronic states of surfaces and their macroscopic electrical properties.First of all, from the surface field effect measurements, it is clarified that the Si (111) -7x7 clean surface is metallic and the Si (111) -<square root>3x<square root>3-Ag surface is semiconducting. By exposing oxygen gas onto the 7x7 clean surface, the gradual change form metallic surface to semiconducting one caused by surface oxidation is revealed as a change in field effect. Photoconduction with monochromatic light illuminations is also found to be crucially dependent on the surface superstructures. By depositing Ag of about one monolayr on the Si (111) -<square root>3x<square root>3-Ag surface maintained at 150K,new superstructures such as <square root>21x<square root>21 and 6x6 are found. And the surface conductivity remarkbly changed with the formations of these structures.From the experiments above mentioned, we could proved our assumption on the structure-dependent surface conductivity that the carrier concentrations in the surface space-charge layr changes depending upon the surface structures and electronic states. Studies like this on the correlation between the atomic-scale structures and electrical properties are expected to lead to device applications.

我们在 UHV 室中安装了一个新的样品架，用于测量电性能，并连接到去年开发的小型 MBE-RHEED 系统。该系统能够对 (1) 表面结构和化学成分、(2) 表面电导率、(3) 霍尔效应、(4) 场效应和 (5) 光电导率进行原位分析和测量。我们继续研究表面的微观原子排列/电子态与其宏观电学性质之间的相关性。首先，从表面场效应测量中，阐明Si(111)-7x7清洁表面是金属性的，而Si(111)-<square root>3x<square root>3-Ag表面是半导体性的。通过将氧气暴露在 7x7 的清洁表面上，由表面氧化引起的从金属表面到半导体表面的逐渐变化被揭示为场效应的变化。还发现单色光照明下的光电导很大程度上取决于表面上层结构。通过在维持在150K的Si(111)-<square root>3x<square root>3-Ag表面上沉积约一层单层Ag，发现了新的超结构，例如<square root>21x<square root>21和6x6。并且表面电导率随着这些结构的形成而发生显着的变化。从上述实验中，我们可以证明我们关于结构相关的表面电导率的假设，即表面空间电荷层中的载流子浓度根据表面结构和电子态而变化。像这样关于原子尺度结构和电性能之间相关性的研究预计将导致设备应用。