Laser detection of surface acoustic waves as a method of measuring an Ar ion beam modification of carbon thin film

Kitazawa, Shinichi; Putra, P.; Sakai, Seiji; Narumi, Kazumasa; Naramoto, Hiroshi; Yamamoto, Shunya; Chiba, Atsuya

Pulsed energy impacts are expected to generate the elastic waves reflecting the elastic properties of impacted substances. Among the generated waves, the surface acoustic waves (SAW) can be more specific to the surface structures and can be used effectively in the characterization of thin films in a non-destructive way. In the present study, pulsed laser impacts were employed to generate SAWs on a thin film and the SAWs are detected with a laser reflection technique. To test the effectiveness of this method, an amorphous carbon films were irradiated with 13 keV Ar ions at room temperature in a broad range and the SAW propagation velocity was evaluated as a function of Ar ion dose. The present preliminary experiment using pulsed laser suggests the successful detection of SAW from typical substances with different modulus of elasticity such as fcc metals, oxides and semi conducting materials.