Using surface acoustic wave (SAW) propagating in the layered structure of oxide/piezoelectric substrate, a responsibility of the oxide thin films for the laser irradiation has been investigated. Amorphous Ti-O, Si-O and Si-X-O, where X is other metal elements, films were formed on the surface of the SAW device composed of quartz or LiTaO3 substrate and several hundred Al electrode fingers for oscillating and detecting the SAW. A KrF excimer laser with 248nm in wavelength was used for the irradiation. The center frequency of the SAW devices was immediately decreased by the irradiation of the laser pulses. Although the response to the irradiation was reversible for lower laser energy, the change of the center frequency was irreversible for the laser energy density higher than 20mJ/cm2. It is considered that the response appeared in the frequency shift is generated by a change of an elastic stiffness of the films lowered by an absorption of the laser energy.

Effects of ultraviolet (UV) laser irradiation on the local crystal structure have been investigated for amorphous Ti-O thin films sputtered on ST-cut quartz substrates. The irradiation was conducted with a pulsed KrF excimer laser of 248nm in wavelength. There were few changes in the optical transmission spectra of the films before and after the irradiation. The crystal structure of the films was characterized by electron diffraction, XPS and EXAFS analyses. The results obtained from these analyses suggest the films gradually crystallize to a TiO2 crystal with the rutile type structure by the increasing of the laser pulses.