Highly-conducting indiumtin-oxide transparent films fabricated by spray CVD using ethanol solution of indium (III) chloride and tin (II) chloride

Abstract

Tin-doped In 2O 3 (indiumtin-oxide) films were deposited by a simple and inexpensive spray CVD system. An ethanol solution of indium (III) chloride and tin (II) chloride was sprayed onto a glass substrate heated at 300–350 °C in air using a perfume atomizer. The average optical transmission in the visible range was higher than 83% for the films as-deposited and the films annealed at 600 °C in N 2–0.1% H 2. The resistivities of the as-deposited ITO films were on the order of 10 −4 ohm/cm; the minimum resistivity was 1.9×10 −4 ohm/cm. Annealing at 600 °C in a N 2–0.1% H 2 atmosphere reduced the minimum resistivity to 9.5×10 −5 ohm/cm (thickness, 190 nm; composition, approximately 4.4 at.% Sn; carrier concentration, 1.8×10 21 cm −3; mobility, 40 cm 2/V s); this resistivity is probably the lowest among films prepared by chemical processes, and approximately compatible with the reported minimum, 7.7×10 −5 ohm/cm deposited by a PVD process (pulsed laser deposition) by Ohta et al. [Appl. Phys. Lett., 76 (19) (2000) 2740].