Influence of sputtering parameter on the optical and electrical properties of zinc-doped indium oxide thin films

The zinc doped indium oxide (IZO) films deposited with various sputter parameters such as, film thickness ranging from 200to500nm, O2∕Ar ratio ranging from 0% to 12%, and sputter power ranging from 100to250W was studied in this work. For a 200nm thick IZO film grown at room temperature in pure argon atmosphere, the resistivity was 2.4×10−4Ωcm and the average transmittance in the visible region was 80%. The root mean square roughness of IZO film was around 0.4nm regardless of the film thickness due to the IZO films exhibiting an amorphous structure. With increasing film thickness, the IZO films showed an increase in the resistivity and energy band gap. X-ray photoelectron spectroscopy analysis suggests that the IZO films with reduction of O2∕Ar ratio possess two splitting O1s binding energy levels, suggesting the IZO films were oxygen deficient and resulted in a lower resistivity.