We present an analysis of compositional variations in the growth of the compound semiconductor, InxGal-xAs, by metal organic chemical vapor deposition (MOCVD). A three dimensional transport model for fluid flow, heat, and mass transfer is solved using the finite element method. The Delta Lattice Parameter (DLP) model is used to describe the thermodynamics of the solid solution, and the Hertz-Langmuir equation is used to calculate the evaporation rate of indium from the growing crystal. Wall depletion is incorporated by allowing for explicit wall deposition of In vapor throughout the reactor.
Comparison of model predictions with experimental observations by MOCVD of InGaAs in a horizontal reactor suggests that transport phenomena lead to composition variations across the substrate, and that solution thermodynamics have little effect on the InAs incorporation rate at a given deposition temperature. However, thermodynamic factors appear to influence the change in indium incorporation with growth temperature.