Effects of Heat‐Treatment on Indium‐Tin Oxide Films

Highly conductive and transparent films of indium‐tin oxide have been sputter‐deposited from an oxide target. The effects of annealing in oxidizing or reducing atmospheres on the electrical and optical properties of these films have been determined. The electron concentration and related optical properties are reversible functions of the oxygen partial pressure in the annealing atmosphere. The form of this relationship is consistent with a defect model in which most of the Sn dopant is present in neutral complexes with interstitial oxygen. The Hall mobility and refractive index are changed irreversibly by annealing as a result of subtle changes in film structure.