Deposition of SiC and AlN thin films by laser ablation

SiC and AlN thin films were deposited on silicon substrates by KrF excimer laser ablation from SiC and AlN tar gets. They were characterized by FTIR a nd Raman spectroscopy, X-ray diffraction, Auger electron spectroscopy, scan ning and transmission electron microscopy. Improvements in crystalline SiC thin film deposition by laser ablation combined with laser surface activati on were reported recently [M. Diegel. F. Falk, H. Hobert, R. Hergt, H. Staf ast, Appl. Phys. A, Vol. 66, 1998, p. 183]. These investigations were exten ded by using an intermediate layer of AlN. Crystalline AlN films were depos ited on Si at a substrate temperature of 750 degrees C. Laser activation of the film surface during deposition deteriorates the AlN film properties. A s next step SiC was deposited onto the AIN layers. At the relatively low te mperature of 800 degrees C an AIN buffer layer improves the quality of SIC films. Modellings of LR reflection spectra revealed that the SiC/AlN films on Si(lll) can be simulated by optical methods. For both materials high dep osition rates of approximately 50 nm/min at a moderate substrate temperatur e were obtained. Thus, film preparation for optical applications where a fi lm thickness of some 100 nm is required seems to be realistic. (C) 1999 Els evier Science B.V. All rights reserved.