Observations of Surface Defects and Related Phenomena to Surface Defects

利用扫描LEED显微镜、扫描隧道显微镜（SIM）和高分辨率电子能量损失能谱对固体表面的结构和缺陷进行了研究。三年来取得的成果如下：用高分辨率电子能量损失能谱研究了在TiC （ll）单晶表面形成的单层石墨。单层石墨在TiC上声子谱的色散表明单层石墨与衬底之间存在异常键合状态。在计算的基础上，讨论了粘接状态。原价。金属薄膜外延生长的阶段。利用LEED、AES、-SIM和扫描LEED显微镜研究了不同金属薄膜在Si（001）和Si (111) 7x7表面外延生长的初始阶段。我们发现了一些LEED超结构，其中一些结构是由SIM确定的。此外，通过扫描LEED显微镜还发现了一层au单层膜在Si （ll）上的振荡扩散。扫描LEED显微镜与STM的结合，提高了扫描LEED显微镜的空间分辨率。用该技术研究了单层石墨在TiC （ll）上的化学键合状态和Si（001）相邻表面从单畴到双畴的相变。利用超高真空扫描电镜研究了Si（001）上形成的金属岛的电迁移，对于电迁移驱动力的来源，发现由珀耳帖效应引起的局部温差导致电迁移在表面张力的作用下向高温方向移动。项目期间已发表论文20篇。

Structures and defects in solid surfaces have been investigated by scanning LEED microscopy, scanning tunneling microscopy (SIM) and high-resolution electron energy-loss spectroscopy. The results obtained in 3 years are as follows :1. Bonding state of monolayer graphite formed on TiC (lll)The monolayer graphite formed on a single crystal surface of TiC (lll) has been investigated by high-resolution electron energy-loss spectroscopy. The dispersion of phonon spectra of the monolayer graphite on TiC shows anomalous bonding state between monolayer graphite and substrate. The bonding &tate is discussed based on the calculation.2. initial. stage of epitaxial growth of metal film. s. on Si surfacesInitial stage of epitaxial growth of various metal films on Si (001) and Si (111) 7x7 has been investigated by LEED, AES, -SIM and scanning LEED microscopy. We found a number of super-structures by LEED and several structures of them were determined by SIM. Furthermore, oscillatory diffusion of a Au-monolayer film on Si (lll) was discovered by scanning LEED microscopy.3. Combination of scanning LEED microscopy with STMThe spatial resolution of scanning LEED microscopy has been improved by combination with STM. The chemical bonding state of monolayer graphite on TiC (lll) and a phase transition from single to doublle domain for Si (001) vicinal surfaces are investigated by this technique.4. Electromigration of metal islands on Si (001)Electromigration of metal islands formed on Si (001) has been investigated by ultrahigh vacuum SEM, For the origin of the driving force dn electromigration, it is found that local temperature difference due to the Peltier effect causes electromigration towards the direction to the high temperature by the effect of surface tension.The 20 papers have been published during the term of this project.