The paper deals with the global, reactor scale modelling and simulation of metal organic vapour phase epitaxy (MOVPE) growth of GaAs-based III-V compound semiconductor thin films in large production scale Planetary Reator (R) with various wafer load configurations. Reactor hardware and growth process improvements that aim at increased reactant utilisation efficiency, reduced gas consumption and improved layer thickness and compositional uniformity control at low wafer edge exclusion are discussed. The modelling approach consists of the computation of macroscopic gas phase transport phenomena in the process zone e.g. flow, heat and mass transfer, including thin film deposition on hot surfaces. Modelling and simulation results are used to guide the reactor chamber design, gas inlet layout and the choice of process parameters leading to overall productivity enhancement and increased robustness of the process. The model accuracy for MOVPE growth of the AlGaAs and GaInP material system in large reaction chambers is demonstrated, and the advantages of using modelling to optimise hardware and process design are highlighted. (c) 2007 Elsevier B.V. All rights reserved.