Crystallization and decrease in resistivity on heat treatment of amorphous indium tin oxide thin films prepared by dc magnetron sputtering

The relation between the decrease in resistivity and crystal growth of an indium-tin-oxide (ITO) thin film which was prepared on a substrate at room temperature and then heated from room temperature to similar to 533 K in a vacuum was studied. Two steps of resistivity decrease on heat treatment at around 383 K and 493 K were observed. That at the lower temperature took place while keeping the amorphous state, being due to a small increase in carrier concentration and also a slight improvement of Hall mobility. The other decrease at the higher temperature is due to crystallization from the amorphous state, which gave rise to the great increase in carrier concentration. (C) 1999 Elsevier Science S.A. All rights reserved.