SPUTTERING OF INDIUM-TIN OXIDE

In this paper we have brought together investigations by ourselves of the sputtering of thin films of Indium-Tin Oxide (ITO), onto substrate s which are at ambient temperature, in which we sought to produce film s with the highest electrical conductivity and visible transparancy. T he work included investigations of the optimum alloy ratio, stoichiome try control techniques and different reactive sputtering systems. Thes e continuously operating systems are compared with new ion-assisted, s uccessive-layer anodisation processes for their preparation. Our inves tigations of the optimum doping of the indium oxide with tin have demo nstrated that the addition of any tin will result in a loss of perform ance, compared to that achieved with stoichiometry control through the amount of oxygen incorporated into the pure indium oxide, The sputter ing of a compacted oxide target was the easiest, only a small amount o f non-critically controlled oxygen had to be added to the sputtering a tmosphere to give adequate electrically conducting and visible-transmi tting films. Better films could be made more quickly reactively from m etal targets but were much more critical in the control of the conditi ons which they required. The use of alloy targets and successive ion-a ssisted plasma anodisation techniques made this a much less critical p rocess.