Study of Evaluation of Silicide/Silicon Interfaces by Tunneling Spectroscopy and Effects of H-Termination

本研究的目的是澄清肖特基势垒高度的决定因素与金属/半导体接触的特性，了解接触电阻率和肖特基势垒高度之间的相关性，并制定一种方法，以控制肖特基势垒高度。本文研究了在Si（001）衬底上外延生长CoSi_2薄膜的形成过程和电学性质，并对Si（001）表面H终端控制界面反应和引入Si_xGex/Si（100）异质结构控制肖特基势垒高度进行了研究。本研究取得的主要结果如下：1.在Co/Si（100）界面处，低温退火时Co原子向Si衬底中扩散形成CoSi，高温退火时Si原子向硅化物薄膜中扩散形成CoSi_2。发现CoSi_2的形成受掺杂离子的影响 ...更多信息 纯度和浓度。此外，还阐明了无针孔、原子级平整的CoSi_2薄膜的生长条件。讨论了肖特基势垒高度和接触电阻率等电学特性与局域晶体结构的关系.本文研究了H封端的Si（100）表面的稳定性，并用扫描隧道显微镜和扫描隧道光谱（STM/STS）研究了表面Si-H键的局域电子结构。通过H端处理，减少了界面缺陷，改善了电特性。可以得出结论，H-终止处理是非常有用的，以形成一个理想的金属/Si界面.本文研究了Ti/Si_<0.8>Ge_<0.2>/Si（100）接触的界面固相反应和电性能。通过460 ℃以上的退火，n型和p型Si_<0.8>Ge_<0.2>/Si（100）衬底的肖特基势垒高度都降低了。从肖特基势垒高度的控制和界面反应的角度来看，在金属/Si界面上引入SiGe膜是形成极低电阻率接触的有效方法。少

The purpose of this study is to clarify the determining factors of Schottky barrier heights connected with the characteristics of metal/semiconductor contacts, to understand the correlation between contact resistivities and Schottky barrier heights and also, to develop a method in order to control Schottky barrier heights. The formation processes and the electrical properties of epitaxially-grown CoSi_2 films on Si(001) substrates have been investigated and, moreover, the H-termination of Si(001) surfaces to control the interfacial reaction and the introduction of Sil-xGex/Si(100) heterostructures to control Schottky barrier heights have been examined. The main results obtained by this study are as follows :1. AtCo/Si(100) interfaces, CoSi is formed by the diffusion of Co atoms into Si substrates at low annealing temperature and CoSi_2 by the diffusion of Si atoms into silicide films at high annealing temperature. It has been found that the CoSi_2 formation is affected by the doping im … More purities and concentrations in substrates. Moreover, the growth conditions to form pinhole-free and atomically-flat CoSi_2 films have been clarified. The relation between the electrical properties such as Schottky barrier heights and contact resistivities and the local crystallographic structures has been also discussed.2. The stability of H-terminated Si(100) surfaces has been studied, and the local electronic structures of surface Si-H bonds have been examined by scanning tunneling microscopy and scanning tunneling spectroscopy (STM/STS). The reduction of interfacial defects and the improvement of electrical characteristics have been realized by H-termination treatments. It can be concluded that the H-termination treatment is very useful to form an ideal metal/Si interface.3. The interfacial solid-phase reactions and the electrical properties of Ti/Si_<0.8>Ge_<0.2>/Si(100) contacts have been investigated. The Schottky barrier heights of both n-and p-type Si_<0.8>Ge_<0.2>/Si(100) substrates are lowered by annealing above 460ﾟC.It has been concluded that the introduction of SiGe films to the metal/Si interface is very effective to form a very low resistivity contact from a viewpoint of the control of Schottky barrier heights and interfacial reactions. Less