Electrical, optical and chemical properties of indium-tin oxidized films grown by sequential electron beam deposition of indium and tin

A novel technique of layer-by-layer deposition of indium and tin by electron beam deposition and subsequent annealing in oxygen atmosphere to form indium tin oxide was attempted here. The tin content in the sample was varied by changing the relative thickness of the indium and tin layers. The as-deposited samples did not result in the expected layered structures as evidenced by the Auger depth profile plots. Instead, an In-Sn alloy of almost uniform composition was achieved. Resistivity measurements on as-deposited samples by the four-point probe technique yielded a graph typical of binary eutectic alloys. These samples were also highly reflective and exhibited no optical transmission. Annealing 50% Sn samples at 500°C for 60 min in flowing oxygen gas resulted in 50% transmission in the range from 330 nm to 820 nm with a resistivity of 4.56 × 10-4 Ω cm. Many samples were tin deficient after annealing, resulting in poor optical transmission data. Possible reasons for the absence of tin after annealing are discussed. © 1992