Analysis of stray magnetic field at the substrate and effect of applying external magnetic field in facing targets sputtering

Abstract

The distribution of magnetic field in a facing targets sputtering (FTS) apparatus and the effect of applying external magnetic field along the film plane were investigated. When ferromagnetic Co–Zr–Ta plates were used as the targets, the magnetic field at the center of the target surface was stronger than that of the surface of paramagnetic Al targets because of the high permeability of the Co–Zr–Ta targets, although the weaker one was needed for uniform sputtering yield of the target surface. Furthermore, when Co–Zr–Ta targets were used, slightly broader distribution of magnetic field was found around the central plane between the two targets. Thus, the magnetic field of about 20 Oe was applied at the surface of the substrate and uniaxial in-plane magnetic anisotropy was induced in the amorphous Co–Zr–Ta films deposited by the FTS apparatus. Therefore, the external field along the film plane was applied transversely to the direction of plasma confining field during deposition of the films. The soft magnetic properties of the Co–Zr–Ta films were improved by applying the external field and magnetic anisotropy of the films could be easily controlled regardless of the direction of the plasma confining field.