Microstructures of Co-Cr Films Prepared by Sputter-deposition at high Ar pressures

Abstract

Co-Cr films were prepared sputter-deposition at room temperature and at elevated Ar pressures up to 100 Pa which enables low voltage discharges. It was found by a SEM observation of the films that a dense fine structure at low Ar pressures changes to a large grained columnar structure with clear boundaries at Ar pressures of 10 to 50 Pa through a transition structure with smaller grain sizes. The grain size, however, decreases at higher Ar pressures more than 50 Pa disagreeing with the Thornton model. The grain size was reduced greatly by a Ti underlayer retaining the clear grain boundaries espcially for depositions at high Ar pressures. The crystal orientation and the deposition temperature might little affect the structure. It is concluded that the micro structure of the Co-Cr films with Ti underlayer deposited at high Ar pressures and at room tamperature have a fine and isolated columner structure, which may be one of the suitable structures for high density recorgding media.