Kinetic study of the formation of carbonization layer on Si surface and the afterward SiC film growth

• Main Authors: Chih Yih Li, 李志毅
• Other Authors: Lu Sheng Hong
• Format: Others
• Language: zh-TW
• Published: 1996
• Online Access: http://ndltd.ncl.edu.tw/handle/49543608563876850356

碩士 === 國立臺灣科技大學 === 化學工程研究所 === 84 === Carbonization layer on Si surface is a necessity for overcoming the defects that caused by the lattice mismatch between SiC and Si when heteroepitaxially growing of SiC film on Si substrate by chemical vapor deposition (CVD). The purpose of this study is to explore the mechanism of carbonization and the subsequent SiC film growth to gain a better quality of SiC film. Acetylene (C2H2) and Propane (C3H8) were selected to carbonize Si substrate at a cold-wall low pressure chemical vapor deposition system. By changing environmental gases during carbonization, it is found that etching pits, which is usually accompanied in carbonization of Si surface, was caused by thermal effect while carbon source played the role to prevent the formation of etch pits by forming silicon carbide on Si surface. Also, acetylene was found to be a better carbon source gas than propane because of its high carbonization rate. The mechanism of carbonization is basically a Langmuir-Hinshelwood type of surface reaction. A good surface morphology and stoichiometry of carbonization layer can be achieved at a reaction condition of total pressure 5 Torr , the concentration of acetylene 0.08 Torr , reaction temperature 1200*C and reaction time 8 min. With respect to the subsequent film growth of SiC , silane (SiH4) , acetylene (C2H2) and hydrogen (H2) were used as the reactant gases. At a reaction condition of total pressure 5 Torr , SiH4 concentration 0.06 Torr , C2H2 concentration 0.06 Torr , substrate temperature 1200*C, a film with good surface morphology and SiC crystalline was obtained. The quality of the carbonization layer can effect a lot the subsequent film growth of SiC in both film morphology and crystalline.