Measurement of stable species present during filament-assisted diamond growth

Abstract

We have measured mole fractions of two of the major stable species at the surface of a silicon substrate during filament‐assisted diamond growth as a function of the filament‐to‐substrate distance. Input gases were methane and hydrogen. A quartz probe withdrew gases at the growing surface, and the gases were sampled with an on‐line mass spectrometer. Close to the filament the methane is largely consumed, with most of the remaining gas phase carbon in the form of acetylene. Mass spectral results are compared to compositions calculated with a detailed chemical kinetics model. Our initial analysis suggests that diamond growth comes mainly from reaction of acetylene, ethylene, methane, or methyl radical.