Simulation studies of plasma and electron density distribution in a MPCVD reactor under the excitation of pulsed microwaves

Microwave plasma chemical vapor deposition (MPCVD) method is the most promising method for growing large area and high quality single crystal diamond, which has extraordinary properties enabling next generation power and RF devices. In a typical process of MPCVD diamond growth, plasma is generated by exciting methane and hydrogen gas with microwaves in an enclosed reactor. The growth rate and the quality of the grown diamond is strongly influenced by the plasma characteristics in the reactor, which is largely dependent on the microwaves applied to it. Application of pulsed microwaves may lead to lower energy consumption comparing with that in traditional growth process with continuous microwaves at the same growth rate, which however has not been intensively studied. Here we report the simulation results of plasma and electron density distribution in a MPCVD reactor under the excitation of pulsed microwaves (at 2.45 GHz) with variant pulse duration and duty. The results can offer insights for the design of future MPCVD reactors and diamond growth process.