A Simplified and Universal Mechanism Model for Prediction of Gallium Nitride Thin Film Growth Through Numerical Analysis

C.K. Hu, C.J. Chen,T.C. Wei, Tomi T. Li, C. C. Wang, C. Y. Huang, Y.J. Lin

The crucial parameter required for predicting epitaxial thin film growth rates and uniformity is the chemical mechanism occurring in the gas phase and at the surface. To date, few studies have investigated the gallium nitride epitaxial mechanism in solid state lighting. A simplified chemistry derived from experimental observation has been used for this purpose. In this study, three numerical mechanism models are presented for verifying the growth rate of the gallium nitride (GaN) mechanism, and their results are compared with the growth rate results of previous literature studies. To reduce the calculation time of numerical analysis in commercial software, a numerical procedure is performed for simplifying the complicated mechanism of an epitaxial thin-film process. The mechanism models are developed through rate of production analysis. All the solution results could be compared in one schematic diagram, and the differences among these three mechanisms are extremely pronounced in high temperatures. The simplified reaction mechanisms are then used as input for a two-dimensional computational fluid dynamics code FLUENT, enabling the accurate prediction of growth rates. Validation studies are presented for two different laboratory-scale reactors. For each study, the predictions reasonably agree with the experimental data, indicating the universality of the reaction mechanisms.