High-rate deposition of Ta-doped SnO2 films by reactive magnetron sputtering using a Sn–Ta metal-sintered target

Ta-doped SnO2 films were deposited on glass substrate (either unheated or heated at 200 °C) by reactive magnetron sputtering with a Sn–Ta metal-sintered target using a plasma control unit (PCU) and mid-frequency (mf, 50 kHz) unipolar pulsing. The PCU feedback system precisely controlled the flow of the reactive and sputtering gases (O2 and Ar, respectively) by monitoring either discharge impedance or the plasma emission of the atomic O* line at 777 nm. The planar target was connected to the switching unit, which was operated in unipolar pulse mode. Power density on the target was maintained at 4.4 W cm− 2 during deposition. The lowest obtained resistivity for the films deposited on heated substrate was 6.4 × 10− 3 Ωcm, where the deposition rate was 250 nm min− 1.