Optimization of Gallium Nitride Metalorganic Chemical Vapor Deposition Process

This paper investigates the simulation, response surface modeling, and optimization of the metalorganic chemical vapor deposition (MOCVD) process for the deposition of gallium nitride (GaN). Trimethylgallium (TMG alpha) and ammonia (NH3) are the precursors carried by hydrogen into the rotating-disk reactor. The deposition rate of GaN film and its uniformity form the focus of this study. Computational fluid dynamics (CFD) model simulates the deposition of the GaN film. CFD model is employed to identify two design variables, inlet velocity and inlet precursor concentration ratio, which significantly affect the deposition rate and uniformity of GaN film. Compromise response surface method (CRSM) is used to generate response surfaces for average deposition rate and uniformity. These response surfaces are used to generate the Pareto front for the conflicting objectives of optimal rate of average deposition and uniformity. Pareto front captures the trade-off between deposition rate and uniformity of the GaN film. It is observed that for the whole range of design variables, there are numerous options to get stable uniformity levels than deposition rate. The optimal inlet velocity and precursor concentration for different objective functions considered tend to be near the upper bounds.