Indium–tin oxide coatings via chemical solution deposition

• Published in: Thin solid films Vol. 392; no. 2; pp. 243 - 248
• Main Authors: Tomonaga, Hiroyuki, Morimoto, Takeshi
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Lausanne Elsevier B.V 30.07.2001; Elsevier Science
• Subjects: Annealing; Cross-disciplinary physics: materials science; rheology; Electrical properties and measurements; Exact sciences and technology; Indium–tin oxide; Liquid phase epitaxy; deposition from liquid phases (melts, solutions, and surface layers on liquids); Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Physics; Wet coating process; Wet coating process; Annealing; Indium–tin oxide; Electrical properties and measurements; Chemical solution; Inorganic compounds; Electrical conductivity; Oxides; Experimental study; Coatings; Conducting materials; Optimization; Thin films; Tin oxides; Crystal growth from solutions; Spin-on coating; Optical materials; Indium oxides
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/S0040-6090(01)01035-5

Thin films of indium–tin oxide (ITO) were formed on glass substrate via a chemical solution deposition method. Indium nitrate coordinated with 2,4-pentanedione and ethylene glycol, and tin oxalate were used as the raw materials of the coating solution. Composition ratios of Sn/In were varied between 0 and 14 mol%. The solutions were coated on non-alkali glass substrate using a spin-coating process. Then, the coated glass was fired in air to thermally decompose the precursors and to densify the coating. The resistivity of the coatings fired in air at 300°C was 5.0 Ω cm and decreased at higher firing temperatures. The resistivity of the coatings fired at 700°C was 2.8×10 −3 Ω cm, which is more than 10 times higher than that of ITO coatings formed by the sputtering process. A post-annealing in non-oxidizing atmospheres such as vacuum, N 2, Ar and H 2/Ar after the firing lowered the resistivity of the coating. Treatment in hydrogen-containing atmosphere was particularly effective in lowering the resistivity of the coating to 6.2×10 −4 Ω cm. It was found that the decomposition of organic residues and formation of oxygen vacancies in the coatings were promoted by the hydrogen treatment.