AFM studies of polycrystalline calcium sulfide thin films grown by atomic layer deposition

Abstract

Polycrystalline CaS thin films were grown on Al2O3 films deposited on Si-wafer using the atomic layer deposition (ALD) technique. The surface structure of these films was studied by AFM and compared with respective SEM images. The polycrystalline film surfaces comprise regular shaped crystallites. First report of a possible growth mechanism is presented, on studying the variation of morphological features (i.e., roughness and size of crystallites) with thickness and growth rate.