The interplay between transport and kinetics in selective-area growth (SAG) of compound semiconductors is discussed. A thin-film model describing transport of reactants across the boundary layer above the growth surface is developed. A dimensionless Damkohler number (Da) quantitatively determines whether the planar (blanket) deposition is in a transport-limited, reaction-rate-limited, or intermediate operating regime. Reactant profiles within the rotating-disk reactor and growth rates predicted by the thin-film model agree very well with numerically exact calculations. The efficiency of the SAG was found to be a strong function of both the Da and the pattern fill-factor (theta). The thin-film model was extended to take into account the lowering of the "effective rate constant" (averaged over both the exposed and masked zones). It was found that the product thetaDa governs the transition between transport and kinetic control of the SAG process. Predictions of the analytical SAG thin-film model were compared to both the numerically exact 2-D calculations and to experimental results from InGaAs, InP, and GaN SAG. The simple theory appears to provide an excellent qualitative and quantitative description of kinetic and transport effects in SAG. (C) 2003 Elsevier Science B.V. All rights reserved.