Effects of substrate-bias on the structure of sputter-deposited Co–Pt film

Co–Pt films were deposited onto (001)-oriented Si substrates by d.c.-sputtering method, and the effects of substrate bias on the composition and structure of the Co–Pt films were investigated. Co–Pt films deposited at room temperature are composed of a disordered Co–Pt phase of face-centered cubic structure. The crystalline quality of the Co–Pt film is improved significantly with increasing the substrate bias up to −150 V. Moreover, the composition of the films is also affected by the substrate bias, Co content decreases with increasing the substrate bias. This phenomenon is explained in terms of preferential resputtering of Co by the incident particles generated by the bias voltage.