Sputtering in a Crossed Electromagnetic Field

This paper describes the effects of a magnetic field on cathodic sputtering in a crossed field discharge. Optimum conditions of gas pressure, magnetic field, and discharge type are suggested for the fabrication of thin-film circuit elements. Pure copper, tantalum, and titanium films were sputtered in an argon atmosphere at the maximum deposition rates of 2500, 1200, and 1000 Å/min, respectively. Very efficient sputtering at low gas pressure was achieved by the application of a magnetic field greater than 1000 gauss, and the sputtering rate shows a maximum at an ion cutoff field. In the presence of a partial pressure of oxygen, titanium dioxide films exhibiting a dielectric constant of about 20 were fabricated at deposition rates of 200 Å/min by reactive sputtering from a titanium cathode. The Au/TiO2/Ti system provides a capacitance of 0.1 to 0.3µF/cm², with dissipation factors from 0.01 to 0.02 and TCC values ranging from +100 to +200 ppm/°C.