Optimization of MW-PACVD diamond deposition parameters for high nucleation density and growth rate on Si3N4 substrate

We use orthogonal designs of experiments to optimize the process parameters for high diamond nucleation density and growth rate. The diamond films were deposited on Si3N4 substrate in a MW-PACVD reactor with a gas mixture of methane and hydrogen. The process pressure, the substrate temperature, the total gas how and the methane concentration were varied in selected ranges. The optimal conditions for the nucleation and growth stages are different. This investigation proves that the nucleation is favored by low process pressures and methane concentrations between 1.2 and 1.6% in hydrogen, while the growth rate is enhanced mainly by increasing the reactor pressure. By using statistical analysis the variance was calculated in order to evaluate the degree of influence of the different parameters and their interaction effects. Trend analysis was done to describe the effects of each parameter on the results. (C) 1997 Elsevier Science S.A.