Ge Layer-resolved Distribution During Deposition on the Si(100) Surface Studied by Simulation

• Main Authors: Chen-Mei Chen, 陳貞梅
• Other Authors: Deng-Sung Lin
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/56163186913218653607

碩士 === 國立交通大學 === 物理研究所 === 91 === 　This thesis studied the growth process of Ge on the Si(100) surface and the Ge site correlation on the Ge/Si(100) surface by simulation. It is known that deposited Ge atoms randomly replace Si atoms on the Si(100) surface. Si atoms that are replaced diffuse along dimer rows to nearby steps. Therefore, the step edges would gradually advance forwards. A fraction of deposited Ge atoms already on the surface is buried in the second atomic layer by this process. In this growth scenario, the indiffusion of Ge atoms is not involved. At 1-ML Ge coverage, the simulation results also showed that 0.4-ML deposited Ge atoms reside in the second atomic layer. If the Ge coverage is more than 1 ML, the deposited Ge atoms started to occupy at the third atomic layer. At 2-ML Ge coverage, 0.4 ML deposited Ge atoms are in the third atomic layer and 0.85 ML deposited Ge atoms are in the second atomic layer. These simulation results are in good agreement with existing experimental results. 　Previous reports show that the deposited Ge atoms have a very long Ge site correlation length at coverage of 0.28 ML, leading to the formation of zig-zag trains in dimer rows. At Ge coverage of 0.05 ML, the simulation results showed that the site correlation length (the length of the zig-zag trains in the STM images) of the deposited Ge atoms is found to be 22.4 unit length, and the length distribution is wide. As the Ge coverage increases, the site correlation length decreases. At Ge coverage of 0.5 ML, the site correlation length is found to be 4.7 unit length, which is the shortest for the coverage between 0 ~ 1 ML. These simulation results also correlate well with the experimental results.