Gas flow sputtering for manufacture of high-quality hard magnetic films

Sputter deposition of magnetic materials is challenging. In the case of soft magnetic materials, thin targets and strong magnetic arrays of sputtering cathode are usually used for effective magnetron sputtering. In the case of a hard magnetic material, the situation is different. The magnetic field lines are closed in to the target, and the magnetron effectively behaves as a diode sputtering system. In contrast, hollow cathode processes require no magnets to enhance ionization. Therefore, high rate deposition of hard magnetic films becomes possible with hollow cathodes.