Selective deposition of GaAs-based microstructures on a patterned SiO2/GaAs substrate was realized by molecular beam epitaxy. The growth mechanism was investigated experimentally by studying both the diffusion and desorption mechanisms of GaAs on SiO2 surfaces. A model describing the diffusion and desorption of adatoms on the patterned surface is presented. The theoretical considerations are used to determine experimentally the diffusion length and the sticking coefficient of Ga(As) on SiO2 as a function of temperature. The growth results are applied to the fabrication of GaAs-based quantum well microsctructures. Finally, the optical properties of InGaAs and AlGaAs heterostructures were examined by micro-photoluminescence spectroscopy, indicating the good quality of the material deposited by this method. (C) 2008 Elsevier B.V. All rights reserved.