Published online by Cambridge University Press: 22 February 2011
Reaction and transport models describing the deposition of thin films of ternary compoundsemiconductors by Metalorganic Vapor Phase Epitaxy (MOVPE) are being developed. The growth of AlxGa1−x As (0≤x≤1) films from trimethyl-aluminum (TMA1), trimethyl-gallium (TMG) and arsine has been used as a typical example. A kinetic model of the process including both gas phase and surface reactions has been coupled to a two-dimensional transport model of a horizontal reactor with a flat susceptor. The model predicts reported experimental observations on growth rates and film compositions [1] using a single adjustable parameter, the activation energy of the the AlAs growth reaction. A parametric study was performed to identify operating conditions maximizing the thickness andcompositional uniformity of the deposited films. All inlet flow rates considered in this work were higher than the ones required to suppress transverse buoyancy-driven recirculations in the reactor [2,3]. Such conditions permit the growth of abrupt heterojunctions byrapidly switching various precursors on and off. Our results indicate that the most promising operating conditions coincide with the transition from kinetic limited to diffusion limited growth, which occurs at temperatures between 800 K and 850 K for typical experiments [1]. The optimal inlet mole fraction of the limiting group-III species was found to be about 6×10−4 for such cases.