Thin films of indium oxide (IO) were prepared by a three stage process involving forced plasma oxidation (FPO) of reactively evaporated indium. Applications of IO films produced using this technique include transparent, antistatic coatings for the continuous processing of polyethylene terephthalate (PET). The films were characterized by sheet resistance and optical transmittance measurements, and ESCA. Experiments were performed to determine the effect of FPO exposure time on sheet resistance Rs and optical transmittance T, which were then monitored over a one year period to determine the stability of the films. A model is developed to explain the effects of (i) elapsed time since deposition, and (ii) FPO exposure time on resistivity and absorption coefficient. Film thicknesses ranged from 135 to 500 A, and FPO time ranged from 0 to 30 sec. There exists an optimal FPO time (~5 sec) for each thickness. Over the course of 350 days, stable values for Rs and T for the best films of each thickness ranged from ~2 x 107 Ω/□ and 97% (@ 550 nm) for the 135 A films to ~2 x 105 Ω/□ and 94% (@ 550 nm) for the 500 A films. Indium oxide films are degenerate n-type semiconductors which rely on oxygen vacancies to allow adjacent indium atoms to donate valence electrons to the conduction mechanism. These oxygen vacancies also inhibit carrier mobility. An optimum indium-to-oxygen (ln:O) ratio exists for a given film structure. The FPO process was found to effect both the ln:O ratio and film structure. The optimum FPO time for a given thickness film is determined by the balance between film restructuring and oxygen incorporation.
Library of Congress Subject Headings
Thin films; Protective coatings; Electronics--Materials
Mechanical Engineering (MS)
Department, Program, or Center
Mechanical Engineering (KGCOE)
Elli, David Dawson, "Forced plasma oxidation of reactively evaporated indium as a transparent antistatic coating for ponyethylene terephthalate" (1986). Thesis. Rochester Institute of Technology. Accessed from
RIT – Main Campus