Cross-sectional hydrogen content and mass density profiles of DLC film by neutron and X-ray reflectivity

中性子/X線反射率法によるDLC膜の水素分布と質量分布の厚さ方向分布

尾関 和秀*; 米村 雅雄*; 増澤 徹*; 斎藤 秀俊*; 大越 康晴*; 平栗 健二*; 武田 全康  

Ozeki, Kazuhide*; Yonemura, Masao*; Masuzawa, Toru*; Saito, Hidetoshi*; Ogoe, Yasuharu*; Hirakuri, Kenji*; Takeda, Masayasu

DLC膜中の水素量は、DLC膜の機械的特性や膜そのものの微視的構造に大きく影響を与えるため、特性を制御したDLC膜を作成するために重要な因子である。本研究ではH/CH比を変えながら、プラズマCVD法によりDLC膜を作成して、その水素量と膜密度の厚さ方向分布を中性子反射率法とX線反射率法を併用して求め、ERDAの結果と比較した。また、表面のO/Cの原子数比をXPSによって調べた。これらの結果を総合すると、水素存在量と膜密度は表面から深くなるにしたがって増加し、XPSの結果とも比較すると、表面の水素密度は膜の内部よりも小さいことが明らかになった。

Hydrogen content in the DLC film is very important factor because it greatly influences on its mechanical properties and microstructure such as hardness, wear resistance, surface roughness, and sp3/sp2 ratio. In the present study, we prepared the DLC film using plasma CVD technique varying H/CH ratio from 0 to 9. Cross-sectional hydrogen content and mass density profiles of the films were defined by neutron and X-ray reflectivity measurements, and the results were compared with that from ERDA analysis. And O/C atomic ratio of the oxide layer of the film surface was also analyzed using XPS. From the neutron and X-ray reflectivity analysis, hydrogen content and mass density in the DLC film increased with film depth from the surface, and average hydrogen content showed more than 30 % in all films. By combining with XPS results, it is clarified that hydrogen content in the surface layer was lower than that in bulk layer.