Computational Study of Gas‐Phase and Surface Kinetics in a Clamshell Type Microwave Plasma Chemical Vapor Deposition Reactor for Diamond Growth

Gas phase kinetics and surface reactions play an important role in the deposition of diamond in a microwave plasma‐assisted chemical vapor deposition (MPCVD) process. Understanding the distribution of various radicals and neutral species in the MPCVD cavity will help in predicting the growth rate and quality of the grown diamond. In this work, flow field, temperature distribution and chemical reactions are simulated in a clamshell‐type MPCVD cavity using 3D computational fluid dynamics (CFD). The simulations are performed for a range of microwave powers (3–5 kW), cavity pressures (75–125 Torr), methane inlet concentrations (4%–6%), and substrate temperatures (800–1000°C). The plasma generated in the MPCVD cavity is modeled as a volumetric heat source. The gas‐phase and surface kinetics are included and the growth rate of the diamond is predicted. The computational methodology is validated with an experimental growth profile. The effect of various operating conditions on the distribution of methyl radical and atomic hydrogen is predicted. The optimum operating conditions for high and uniform growth rate of diamond are identified from the 3D CFD analysis.