Tin oxide thin films deposited by spray CVD using ethanol solution of tin (II) chloride

Abstract

Indium-tin-oxide (tin-doped In 2 0 3 ) thin films are widely used for flat panel displays and solar cells etc. The authors reported elsewhere low resistivity ITO films deposited by spray chemical vapor deposition using ethanol solution of indium chloride and tin (II) chloride. Indium is a rear element whose price is increasing as the results of mass production of flat panel displays. Recently the powders of indium oxide including ITO damage the human lungs. As an approach to fabricate environmentally-benign alternative transparent conducting materials, undoped tin oxide (Sn0 2 ) was deposited by the same process using ethanol solution of tin (II) chloride although the resistivity is much higher since doping with antimony or fluorine was avoided. The lowest resistivity of the as-deposited films was 6.2 X 1 o-3 ohm cm for the 138 nm-thick film deposited at 255°C. The resistivity increased at the higher temperature. Excellent step coverage was observed when deposited on silicon substrates with stripes (depth, 1 micron).