Masami Yamaoka

Thin film structure and adhesion of sputtered TiNi layers on silicon

Abstract Thin film stress, adhesion and structure at different argon pressures have been investigated in the system Ni(200–800 nm)/Ti(100–400 nm)/Si, prepared in a d.c. planar magnetron sputtering apparatus. The adhesion between titanium and silicon has been found to decrease at low argon pressure (0.67 Pa (5 mTorr)) and to increase at high argon pressure (2.67 Pa (20 mTorr)) X-ray diffraction analysis revealed a highly oriented Ni(111) layer near the boundary between nickel and titanium, and the X-ray fluorescence method showed that the density was higher at an argon pressure of 0.67 Pa. The adhesion change is considered to be influenced mainly by the change in stress of the nickel film; that is, the modulus of elasticity seems to vary with crystalline orientation and density, which are affected by the argon pressure.