High rate deposition of tin-doped indium oxide films by reactive magnetron sputtering with unipolar pulsing and plasma emission feedback systems

Tin-doped indium oxide (ITO) films were deposited on the unheated alkali-free glass substrates (AN100) by reactive magnetron sputtering using an indium–tin alloy target with an unipolar pulsed power source feeding 50 kHz pulses and a plasma control unit (PCU) with a feed back system of oxygen plasma emission intensity at 777 nm. In order to achieve very high deposition rates, depositions were carried out in the ‘transition region’ between the metallic and the reactive (oxide) sputter modes where the target surface was metallic and oxidized, respectively. Stable depositions were successfully carried out in the whole ‘transition region’ with an aid of PCU. The lowest resistivity as the transparent ITO films deposited on unheated alkali-free glass was 7.5×10−4 Ucm with the deposition rate of 650 nm/min. The electrical and optical properties of the films could be controlled systematically in the very wide range.