Naoto Matsuo1, Yasuyuki Takanashi1, Akira Heya1 and Kazuhiro Kanda2
1Department of Materials Science & Chemistry, Graduate School of Engineering University of Hyogo, Himeji 671-2201
We investigated the characteristics of a-Si film with thicknesses of 1 and 50 nm those were irradiated by soft X-ray from the undulator source. The cohesion of Si atoms were observed after X-ray irradiation for 1 nm-thick a-Si, but it was not observed for 50 nm-thick a-Si. The average roughness Ra of 1 nm-thick-Si film were changed from 0.63 to 1.7 nm by soft X-ray irradiation. The electric resistivity of it also increased corresponding to the change of the surface roughness. Although the TO phonon peak was not observed for 1 nm-thick a-Si, it was observed for 50 nm-thick a-Si. For these phenomena, the mechanism that the electron excitation by photon becomes the trigger of the cohesion was discussed.
amorphous-silicium, soft X-ray, undulator, cohesion, electron excitation
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