Surface modifications of metals induced by soft X-ray laser pulse irradiations

軟X線レーザーの照射による金属の表面改質

石野 雅彦; Faenov, A. Ya.*; 田中 桃子; 長谷川 登; 錦野 将元; 保 智己*; Pikuz, T. A.*; 大場 俊幸*; 海堀 岳史; 河内 哲哉

Ishino, Masahiko; Faenov, A. Ya.*; Tanaka, Momoko; Hasegawa, Noboru; Nishikino, Masaharu; Tamotsu, Satoshi*; Pikuz, T. A.*; Oba, Toshiyuki*; Kaihori, Takeshi; Kawachi, Tetsuya

軟X線レーザーによる表面加工への応用展開の可能性を探るために、波長13.9nm,パルス幅7psの軟X線レーザーをアルミニウム,銅,金の表面にそれぞれ集光照射した。照射後の試料表面を電子顕微鏡で観察したところ、アルミニウム表面に100nm程度の直径を有する円錐状ナノ構造を持つ表面改質領域が形成されていることを発見した。このアルミニウム表面に形成される改質構造は銅や金に形成される構造とは異なっており、軟X線レーザー照射によって形成される新規な構造として興味深い。アルミニウム表面に形成されるナノ構造を利用することにって、軟X線レーザーによる立体構造の形成が可能になると期待できる。

We irradiated the soft X-ray laser (SXRL) pulses having a wavelength of 13.9 nm, the duration time of 7 ps to aluminium (Al), copper (Cu) and gold (Au) surfaces. After the irradiation processes of SXRL beam with laser flux of 14 mJ/cm for Al case and of 21 mJ/cm for Cu and Au cases, the modified surfaces were observed with the visible microscope, the scanning electron microscope, and the atomic force microscope. The surface modifications caused by the SXRL irradiations were clearly seen on the surfaces, and it was found that the conical structures having around 100 nm in diameters were formed on the Al surface under a single pulse shot. The conical structures were formed in the features with the average depth of about 40 nm, and this value was in accordance with the attenuation length of the SXRL beam for Al. The modified structure on Al surface induced by SXRL pulse irradiations is different from those of Cu and Au surfaces. The modified structure formed on Al surface induced by the SXRL pulse exposure is interesting as the newly structure. Hence, the SXRL beam would be a candidate for a tool of micromachining, which enable to fabricate of three dimensional structures with nano-meter size on Al surface.