Deposition of SiC and AlN thin films by laser ablation

Abstract

SiC and AlN thin films were deposited on silicon substrates by KrF excimer laser ablation from SiC and AlN targets. They were characterized by FTIR and Raman spectroscopy, X-ray diffraction, Auger electron spectroscopy, scanning and transmission electron microscopy. Improvements in crystalline SiC thin film deposition by laser ablation combined with laser surface activation were reported recently [M. Diegel, F. Falk, H. Hobert, R. Hergt, H. Stafast, Appl. Phys. A, Vol. 66, 1998, p. 183]. These investigations were extended by using an intermediate layer of AlN. Crystalline AlN films were deposited on Si at a substrate temperature of 750°C. Laser activation of the film surface during deposition deteriorates the AlN film properties. As next step SiC was deposited onto the AlN layers. At the relatively low temperature of 800°C an AlN buffer layer improves the quality of SiC films. Modellings of IR reflection spectra revealed that the SiC/AlN films on Si(111) can be simulated by optical methods. For both materials high deposition rates of approximately 50 nm/min at a moderate substrate temperature were obtained. Thus, film preparation for optical applications where a film thickness of some 100 nm is required seems to be realistic.