Flame growth of diamond films is controlled by nucleation on the substrate, and diffusion of the growth species through the boundary layer formed by the jet of hot gas. It is proposed to monitor these effects by in situ long focal distance microscopy using a Questar microscope. Edge-on observation of the impinging gas jet with this microscope, which provides 2 micron resolution at 15 cm, will allow us to map out the variation in the boundary layer thickness across the deposition area. This information will be used to study the effects of gas flow on the heat and mass transfer to the growing film. Direct high resolution observation of the substrate will allow one to make a real-time video of the growing film, and will help clarify the steps in the nucleation process. Work on electrochemical deposition will be more qualitative and exploratory, since no electrochemical diamond deposition process has yet been demonstrated. The search for a useful process will attempt to exploit analogies with electrodeposition of silicon, germanium and other refractory semiconductors. There has recently been an intense international research effort in the field of low pressure, low temperature diamond film growth. Because of the superlative properties of diamond, including hardness, thermal conductivity and chemical inertness, the potential impact of low cost diamond in many areas of technology would be very great. The goal of this research project is to investigate experimentally the kinetics of several promising diamond film growth techniques, including chemical combustion flame growth, plasma flame growth, and electrochemical deposition.
