Abstract:

 Abstraction of terminal hydrogens on a diamond (100) surface by atomic hydrogen has been considered as a possible rate-determining elementary step in the mechanism of low-pressure diamond growth by chemical vapor deposition. The author used MNDO(UHF) methods to estimate the potential barrier for this abstraction reaction. It is predicted that the theoretical values of the potential barrier for H abstraction from full dihydride (100)-(1×1):2H and monohydride (100)-(2×1):H diamond surface are 71 and 59kJ•mol respectively. The potential barrier for H abstraction from diamond (111) surface is smaller than those of diamond (100) surfaces. This results indicated that the creation of radical sites on diamond (111) surface via H abstraction is easier than that on (100) surface under the same growing condition. This conclution therefore supports the experimental result that the relative growth rate of (111) surface is greater than that of (100) surface.

Key words: Diamond film, H abstraction, Potential barrier