InP thin films grown by solid source molecular beam epitaxy on InP(001) substrates have been studied by atomic force microscopy (AFM). The morphology of the films is highly dependent on growth temperature and the P2:In incident flux ratio. High substrate temperatures and low flux ratios result in a large density of micron-sized, three-dimensional islands and a poor overall surface morphology. By contrast, relatively low substrate temperatures and high flux ratios lead to very smooth surfaces with a negligible defect density. The results indicate that a high incident P2 flux is required to generate a sufficient phosphorus supply for the growth of morphologically smooth InP thin films.
