Investigation of a Simplified Mechanism Model for Prediction of Gallium Nitride Thin Film Growth through Numerical Analysis

Abstract

A numerical procedure was performed to simplify the complicated mechanism of an epitaxial thin-film growth process. In this study, three numerical mechanism models are presented for verifying the growth rate of the gallium nitride (GaN) mechanism. The mechanism models were developed through rate of production analysis. All of the results can be compared in one schematic diagram, and the differences among these three mechanisms are pronounced at high temperatures. The simplified reaction mechanisms were 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 types of laboratory-scale reactors (vertical and horizontal). A computational study including thermal and flow field was also performed to investigate the fluid dynamic in those reactors. For each study, the predictions agree acceptably well with the experimental data, indicating the reasonable accuracy of the reaction mechanisms.

Numerical Verification of Gallium Nitride Thin-Film Growth in a Large MOCVD Reactor

“…This study is an extension of our earlier work [15]. A numerical verification method for the growth of gallium nitride thin films in a large MOCVD reactor was demonstrated.…”

“…The new information from this study and the previous study [15] provides a usefully simplified mechanism for predicting the blue-LED process which had not been developed in previous literature, and the accuracy is reliable for 0-D and 2-D numerical modeling. The mechanism can provide not only for academic investigation of the GaN mechanism, but also for R&D study of the blue-LED in industry.…”

“…In a previous study [15], we presented a novel, useful, and simplified mechanism for predicting the blue-LED process: we simplified the complicated chemical mechanism [15] in previous studies through rate of production (ROP) analysis. The optimized reaction mechanism model was then employed as the input to a 2D CFD code, enabling the accurate prediction of growth rates for GaN thin film.…”

“…The Grashof number characterizes the significance of natural convection in the reactor. Moreover, the flow-stability criteria can be defined using some critical values of the dimensionless groups that represent the ratio of the relative strengths of the different forces in the reactor [15]. The usual phenomena in a MOCVD reactor are force convection, force convection (rotation), and natural convection [6], all of which exert interactive effects during epitaxy processing.…”

“…In this section, the most uniform result (n = 160) is chosen for verification, and the simplified reaction mechanism [15] model is employed as the input to the 2D CFD code for predicting the growth rates for GaN thin films. The input parameters, listed in Table 1, are the practical application parameters used at ITRI for growing µ-GaN (undoped GaN thin films).…”