Hollow-cathode-enhanced magnetron sputtering

A hollow cathode arc electron source has been added to a conventional planar magnetron sputtering system to form a triode magnetron. The hollow cathode source was chosen in place of a filament for high emission current at low energy, lifetime, and ease of operation in high magnetic fields and reactive gases. The electrons emitted from the hollow cathode produced additional gas ionization, resulting in a denser plasma at constant voltage. Up to 60% of the hollow cathode emission current could be directly coupled into the discharge current of the magnetron. Increases in the discharge current and the deposition rate of up to 10 X were recorded over the conventional magnetron at the same voltage. The hollow cathode enhanced magnetron discharges were also capable of high current operation at voltages down to 20 V, which is below the sputter threshold. The pressure of operation could also be reduced significantly, and the magnetron could be operated at full power as low as 5 X I0-5 Torr in argon. © 1986, American Vacuum Society. All rights reserved.