Gas flow sputtering for manufacture of high quality hard magnetic films
Sputter deposition of magnetic material provides some challenges. In the case of soft magnetic materials, usually thin targets and strong magnetic arrays of the sputtering cathode are used for an effective magnetron sputtering. In the case of hard magnetic material, the situation is different. The magnetic field lines are closed in the target and the magnetron is effectively acting as a diode sputtering system. Hollow cathode processes in contrast require no magnets at all to enhance the ionization. Therefore, high rate deposition of hard magnetic films becomes possible. In this paper results of gas flow sputtering (GFS), a modification of hollow cathode processes, for deposition of hard magnetic CoSm films are presented. Especially for the deposition of thick films (10 mm and more) gas flow sputtering is an economic process. Using GFS high dynamic deposition rates of several 10 mm per hour are achievable. The influence of the deposition parameters on the magnetic properties coercivity and magnetic remanence are discussed.