Ab Initio Molecular Orbital Study on Acceleration Mechanism of Silane Plasma Chemical Vapor Deposition by Diborane

An acceleration mechanism of silane plasma chemical vapor deposition by diborane is proposed on the basis of an ab initio molecular orbital calculation. Hydrogen abstraction from the growing surface by BH2 is calculated to be much more favorable than that by SiH3 from both the kinetic and thermodynamic viewpoint. Thus, the abstraction by BH2 is predicted to occur frequently, although the concentration of BH2 is considerably lower than that of SiH3. This process creates a dangling bond on the growing surface and then the deposition rate is increased.