Effect of a thin Ni layer on hydrogenation and thermal release characteristics of Ti thin films

Carbon and oxygen contamination on the Ti surface strongly influences hydro gen absorption and desorption, and it can even passivate the surface comple tely. The effect of C and O on the hydrogen absorption and thermal release on Ti films was investigated by using high-energy non-Rutherford backscatte ring and elastic recoil detection techniques. The experimental results show that the concentration gradient in the region of about 300 nm near the sur face is very large due to the joint contamination of about 1.26 X 10(16) at oms/cm(2) of C and 2.5 x 1016 atoms/cm(2) of O; also, the thermal releasing temperature increased greatly. A thin Ni film coated on the Ti film may co nsiderably reduce the contamination of gaseous impurities, in particular C, and prevents further oxidation and improve the absorption and desorption o f hydrogen. (C) 2000 American Vacuum Society. [S0734-2101(00)00405-X].