Numerical Simulation of Gas Phase Reaction for Epitaxial Chemical Vapor Deposition of Silicon Carbide by Methyltrichlorosilane in Horizontal Hot-Wall Reactor

Abstract

Methyltrichlorosilane (CH3SiCl3, MTS) has good performance in stoichiometric silicon carbide (SiC) deposition and can be facilitated at relatively lower temperature. Simulations of the chemical vapor deposition in the two-dimensional horizontal hot-wall reactor for epitaxial processes of SiC, which were prepared from MTS-H2 gaseous system, were performed in this work by using the finite element method. The chemistry kinetic model of gas-phase reactions employed in this work was proposed by other researchers. The total gas flow rate, temperature, and ratio of MTS/H2 were the main process parameters in this work, and their effects on consumption rate of MTS, molar fraction of intermediate species and C/Si ratio inside the hot reaction chamber were analyzed in detail. The phenomena of our simulations are interesting. Both low total gas flow rate and high substrate temperature have obvious effectiveness on increasing the consumption rate of MTS. For all cases, the highest three C contained intermediates are CH4, C2H4 and C2H2, respectively, while the highest three Si/Cl contained intermediates are SiCl2, SiCl4 and HCl, respectively. Furthermore, low total gas flow results in a uniform C/Si ratio at different temperatures, and reducing the ratio of MTS/H2 is an interesting way to raise the C/Si ratio in the reactor.

Surface Kinetic Mechanisms of Epitaxial Chemical Vapour Deposition of 4H Silicon Carbide Growth by Methyltrichlorosilane-H2 Gaseous System

“…Both chemical reaction kinetics and physical transfer phenomena are contained in our simulation. The calculated methods of heat and mass transfer, fluid flow and chemical kinetic mechanism in the gas phase were elaborated in our previous work [ 49 ] and are not repeated here. Assumptions in our calculations are as here: the gas mixture in the reactor is treated as an ideal gas, and the flow is assumed to be laminar due to the low Mach number [ 50 ]; the change of total volume of gas phase is neglected [ 31 ]; and surface reactions take place over the top surface of the substrate plate only [ 31 ].…”

“…All the simulation steps were calculated by finite element method, using the commercial software COMSOL Multiphysics. In order to facilitate the generation of regular meshes to better the convergence of calculation, the substrate is assumed to be adhered to the susceptor [ 49 ].…”