Studies of Diamond Growth Mechanisms in a Hot Filament Reactor

Abstract

The incorporation of methane into low-pressure CVD diamond thin films has been compared to that of acetylene. 13CH4 and 12C2 H2 were used as the hydrocarbon sources in a heated-filament CVD diamond growth process at a total concentration of 0.5% hydrocarbon in 99.5% hydrogen. Results indicated that methane and/or methyl radical is the dominant carbon source for diamond growth in a hot filament reactor under steady state conditions and that acetylene is rapidly hydrogenated to methane. Results also indicated that diamond surface reactions play an important role in determining the relative methane to acetylene ratios.

Growth of Diamond from Atomic Hydrogen and a Supersonic Free Jet of Methyl Radicals

“…This result is important in light of the rapid interconversion of .CH, and C,H,, in the presence of H., that occurs in the usual filament-assisted CVD process (2). Whereas 13C isotopic tracer studies by Chu et al (18) under conditions of partial scrambling have suggested that .CH3 is the more important growth species, some fast-flow depositions (10) have suggested that C2H2 contributes as well. The present results are a direct probe of the relative importance of -CH, versus C,H, under specialized, but well-characterizable.…”