LOW RESISTANCE INDIUM TIN OXIDE-FILMS ON LARGE-SCALE GLASS SUBSTRATE

Preparation of low resistance indium tin oxide (ITO) films on large scale glass substrate has been studied for architectural applications. Coatings were carried out by a plasma enhanced deposition technique using sintered ITO pellets as the starting material and high deposition rate of more than 4000 angstrom/min was achieved. Scanning tunneling microscopy observation revealed that surface morphology of the thick (about 1-mu-m) film was strongly dependent on the substrate temperature. Crystallinity and electrical properties were also dependent on the temperature and closely related to the surface morphology. The films deposited on 125-degrees-C substrate were composed of a mixture of amorphous and polycrystalline phases and showed a hazy appearance caused by light scattering at the rough surface. The polycrystalline ITO films with a clean and transparent appearance as well as the minimum resistivity of 1.7 X 10(-4) OMEGA-cm were obtained on 180-degrees-C substrate. Coatings on architectural size glass substrate (1.8 m X 3.2 m) were carried out and minimum sheet resistance of less than 1.25-OMEGA/sq was obtained. Sheet resistance less than 2-OMEGA/sq was observed over 88% of the surface area. The transparency and durability of the film were confirmed to be enough for practical use.