PLD Grown SiC Thin Films on Al2O3: Morphology and Structure

Resumo

In this paper, submicron SiC thin films are obtained on α-Al₂O₃ (0001) substrates from a ceramic target in vacuum by means of pulsed laser deposition. The influence of the substrate temperature on the composition, structure and surface morphology of the experimental samples is studied using scanning and transmission electron microscopy, scanning probe microscopy, X-ray diffractometry, Fourier transform infrared spectroscopy and Raman spectrometry. It is shown that at T_sub = 1000°C the heteroepitaxial growth of 3C-SiC is observed with the following preferential orientation with respect to the substrate: [\(0001\)]Al₂O₃||[111]SiС and [\(2\bar {1}\bar {1}0\)]Al₂O₃||[\(2\bar {1}\bar {1}\)]SiС, [\(1\bar {1}00\)]Al₂O₃||[\(1\bar {1}0\)]SiС. The shape of the reflections from the {011} and {131} 3C–SiC planes on the electron diffraction pattern indicates the presence of local regions in the film that are rotated at angles of up to 7.5° around the growth axis. Thus, it is found that the 3C–SiC film obtained on α‑Al₂O₃ at a substrate temperature of 1000°C has a mosaic structure partially compensating for the mechanical stresses arising from a mismatch between the lattice parameters and thermal-expansion coefficients along the basal plane.