Laser-induced changes of silicon carbon films studied by vibrational spectroscopy

Mixtures of silicon and carbon deposited on glass at low temperatures form thin films of an amorphous but reactive material. Such layers have been modified by laser beams and investigated by IR and Raman spectroscopy. KrF laser pulses form nanocrystalline SiC. Continuous Ar+ or frequency doubled Nd:YAG laser irradiation of thick films produce microcrystalline silicon carbide beside of microcrystalline silicon and graphite and causes a redistribution of material. By optical modelling of the IR spectra the dielectric functions of the amorphous films and of the modified material were determined. Raman spectra show C-C, C-Si, and Si-Si valence bond vibrations and give information about the chemical composition and crystalline structure of the films. (C) 2002 Elsevier Science B.V. All rights reserved.