Comprehensive model of AlInN Metal-Organic Vapor Phase Epitaxy (MOVPE) accounting for the gas-phase and surface chemistry including parasitic reactions/particle formation is developed. Experimental data and modeling results suggest that as Will ratio increases from several tens (growth of pure AlN) to several thousands (growth of AlInN), the partial AlN growth rate decreases even in the absence of strong particle formation. This effect is associated with the formation of heavy molecular weight/low diffusivity gas-phase dimer species at high ammonia concentration. At elevated pressures growth rate decreases with pressure at a weakly changing composition, which is related to the gas-phase losses of In- and Al-containing species due to reaction with AlN particles. Model allows the prediction of both the AlInN growth rate and composition versus group-III flow rates, temperature, and pressure. (c) 2011 Published by Elsevier B.V.