The crystallization of amorphous silicon layers deposited by sputtering or electron beam evaporation onto different substrates by diode laser crystallization via the melt is investigated. First we present the influence of different laser crystallization parameters like laser fluence and scan velocity on the grain size and on the crystal orientation for sputtered a-Si on glass substrates. Then we demonstrate how silicon nitride or silicon dioxide buffer layers influence the crystallization behavior (e.g. grain size) of sputtered and of electron beam evaporated a-Si films. Crystallization is performed by a cw diode laser (wavelength 808 nm) and is characterized by electron backscatter diffraction (EBSD), optical microscopy, and x-ray diffraction (XRD). Large grains are achieved only if absorption and cooling down procedures are well adjusted. In our experiments large grains of 100 µm in size are generated from electron beam evaporated a-Si films only on a SiN buffer layer, whereas sputtered a-Si leads to large grains on glass as well as on SiN and on SiO2. A higher fraction of the preferred crystalline orientation of (100) was observed for crystallites less than 10 µm in size. This can be explained by the nucleation and growth behavior of the crystallites.