Low pressure radio frequency and microwave discharges for d.c. sputtering of ferromagnetic materials
This paper describes a d.c. diode sputtering system in which the sputtering discharge is sustained by an r.f. or microwave plasma excited with a helix coil surrounded by eight SmCo magnets. The discharge is characterized in terms of the discharge d.c. current through the cathode. The microwave and r.f. excitation and two different configurations of the magnets are compared. The production of r.f. or microwave discharge in a magnetic field makes it possible to operate this system even at low pressures down to 0.01 Pa.