Investigations of boundary layer formation as a function of nitrogen concentration and reactor pressure during microwave plasma deposition of diamond films

Summary form only given. Recent studies within our group have focused on the effects of nitrogen on diamond film growth. Very small concentrations of nitrogen have been shown to enhance CVD diamond film growth, while larger concentrations may result in rough growth. In any CVD growth, within several gas phase mean free paths of the surface, the composition of the gas is perturbed by the effects of the reactions occurring at the surface. A chemical boundary layer with temperature and concentration gradients is formed, through which species diffuse to reach the surface. Boundary layer transport in CVD diamond film growth has been studied for hydrogen, carbon and oxygen species. The transport of nitrogen has been less studied. Also the transport mechanisms and growth are somewhat specific to deposition conditions. Our deposition conditions are based on use of a five inch discharge 2.45 GHz microwave plasma reactor, and transport over wide areas has also been less studied.