Synthesis and Characterization of Interface of Heteroepitaxial Diamond Films on Silicon by MPECVD

• Main Authors: Vick X. J. Guo, 郭行健
• Other Authors: Han C. Shih
• Format: Others
• Language: en_US
• Published: 1999
• Online Access: http://ndltd.ncl.edu.tw/handle/18261026137866460850

博士 === 國立清華大學 === 材料科學工程學系 === 88 === Heteroepitaxial growth of diamond films on (001) silicon has been successfully achieved by a three-step process (i.e. carburization, biasing, and growth) in a MPECVD system using the mixture of CH4 diluted in H 2 as the precursor gas. By HRTEM observation, the deposited films after carburization steps are amorphous. The layer thickness increases with carburization time but fluctuates after prolonged carburization. This amorphous layer is considered to act as a buffer layer to resist the energetic ion bombardment during bias step. Furthermore, it provides an extra carbon source to facilitate diamond nucleation. With constant biasing conditions and constant CH4 gas concentration, the 120 min carburization is found optimal toward the heteroepitaxy of diamond on silicon in this study. Interfacial defects are found to be misfit dislocations, microtwins and stacking faults. These defects are responsible for the random misorientation of the heteroepitaxial diamond films on silicon. A concise scheme is presented to determine the crystallographic misorientation of heteroepitaxial structures by utilizing the geometry of Laue circle in a SAD pattern. Also, procedures and tools are proposed for the rapid preparation of cross-sectional TEM specimens free of contamination and artifacts. With suitable modification, this method is applicable to various material systems.