A DC reactive sputtering process for thin transparent conducting films of indium tin oxide was developed at RIT for a variety of uses. Thin films were sputtered in a CVC-601 batch sputterer from a 200mm indium-tin target in an argon/oxygen ambient onto 3-inch silicon wafers and 2x3-inch glass slides. An experiment utilizing a central composite design with variables of oxygen flow, argon flow, and DC power was performed. As-sputtered films exhibited characteristics of either high resistivity and high transmittance due to an abundance of oxygen in the film, or low resistivity and low transmittance due to an oxygen deficiency in the film. Process repeatability was poor. Films with a variety of characteristics were annealed on a hotplate in an air ambient. Low resistivity, low transmittance films tended to increase transmittance during the anneal, coupled with a further decrease in resistivity. The sputtering process with anneal yielded films of resistivity 1.75*10-3 Ω-cm, average transmission of 76.0 percent over the visible spectrum (400-700 nm), background corrected for a glass substrate, for a thickness of 2000 A, index of refraction near 2.13, and a deposition rate greater than 150 A/min.
"DC Reactive Sputtering of Transparent Conducting Indium Tin Oxide,"
Journal of the Microelectronic Engineering Conference: Vol. 7
, Article 14.
Available at: http://scholarworks.rit.edu/ritamec/vol7/iss1/14