Abstract

Reaction chemistry and transport properties play an important role in the chemical vapor deposition (CVD) of diamond and other materials. We examine the near surface region of species gradients, the boundary layer, that develops between the bulk gases and the growing diamond surface in a low-pressure combustion reactor. We present optical emission spectra from low-pressure combustion growth of diamond when a premixed, flat hydrocarbon flame, (here, an ethylene-oxygen mixture) is lifted and stabilized on a heated substrate at low pressure (typically below 100 torr). We collect two-dimensional optical emission spectra from species such as CH, C₂ and OH with an intensified CCD array to determine species presence and concentrations in the flame and in the boundary layer near the growing material. These studies provide information to help elucidate the mechanism for diamond growth under these conditions, as well as analyzing the relationship between the detailed chemical reaction kinetics and transfer of heat and mass from the activation region.

© 1995 Optical Society of America