Lower Gas Pressure Enhanced Diamond Nucleation on Alumina by Microwave Plasma Chemical Vapor Deposition

Under lower gas pressure, the high-density nucleation of diamond films on alumina was successfully achieved by microwave plasma-enhanced chemical vapor deposition (MPCVD). It was found that the nucleation density increased with the decreases of gas pressure. Based on these results, a kinetic model for diamond nucleation in MPCVD system was proposed. The critical gas pressure corresponding to the highest nucleation density was also discussed.