Design and modeling of a microwave plasma enhanced chemical vapor deposition system

A Chemical Vapor Deposition (CVD) is a chemical process often used in semiconductor industry to produce high quality, high performance, solid material and thin films. In order to produce desired deposit using CVD, a wafer or a substrate is exposed to one or more violated precursors which react and/or decompose on the substrate surface and this also produces some volatile by-products which are then removed by gas flow through the reaction chamber. If the chemical reaction in CVD is initiated by microwave plasma then it is called Microwave Plasma Enhanced Chemical Vapor Deposition (MPECVD). A crucial issue for a roll-to-roll thin film cell production system is the deposition rate of the microcrystalline layer and this can be tackled using MPECVD. This technique has gained popularity in diamond and graphene fabrication. This paper discusses about the designing of an MPECVD chamber operated at 2.45 GHz of frequency using Finite Element Method (FEM) simulation. The design consists of a coaxial waveguide and a cylindrical chamber at the center connected using 4 slots in each direction. The placement of slot affects the resonant mode in the chamber. Hence the slot placements in the middle and the bottom positions of the plasma chamber produce the TE 111 and TM 011 mode inside the plasma chamber at 2.45 GHz, respectively. Detailed analysis will be presented using FEM simulations.