Effects of Zn content on structural and transparent conducting properties of indium-zinc oxide films grown by rf magnetron sputtering

Indium-zinc oxide (IZO) films were grown on glass substrates by rf magnetron sputtering using targets of 50 mol % In2 O3 -50 mol % In2 O3 (ZnO)3 and In2 Znk Ok+3 (k=3, 4, 5, and 7) at room temperature and 300 °C. The difference in Zn content between the films and the sputter targets varied with the growth temperature. The structural, electrical, and optical properties of the IZO films were investigated as a function of Zn content. The crystal structure of IZO films grown at room temperature changed from amorphous to crystalline at a Zn content (Zn (Zn+In)) of 68 at. %. IZO films grown at 300 °C using a target of 50% In2 O3 -50% In2 O3 (ZnO)3 had a Zn content of 40 at. % and its x-ray diffraction peaks were matched with those of ITO. As the Zn content in IZO thin films grown at 300 °C increased from 40 to 74 at. %, the conductivity and optical band gap energy decreased.