Résumé
The initial growth of InN grown by MOVPE was investigated by a combination of atomic force microscopy (AFM) and X-ray specular reflectivity for five different thin films ranging from 57 to 750 angstrom. Both AFM and specular reflectivity measurements show that during the initial growth the surface is not completely covered but that instead a discontinuous layer resembling quasi two-dimensional islands is formed. Dots with heights between 30 and 100 nm appear at the same time; the number density of these dots decreases with increasing thickness. At 750 angstrom the surface is completely covered and obtains a granular aspect. The surface coverage of the discontinuous wetting layer is discussed in relation with the apparent porosity calculated from the specular reflectivity data