Electrical and optical characteristics of Co-sputtered amorphous Ce-doped indium-zinc-oxide thin-film transistors

We report the electrical and the optical characteristics of amorphous cerium-gallium-zinc-oxide (a-CIZO) thin-film transistors (TFTs) as a function of the cerium content inside the a-CIZO channel layers. The a-CIZO films were systematically prepared by using a co-sputtering method with a combination of RF-sputtered indium-zinc-oxide (IZO) at a fixed power of 50 W and cerium-oxide (CeO2) at powers from 15 to 30 W. The Ce content in the CIZO layers increased with increasing RF power on the CeO2 target. The a-CIZO TFT at the optimum power of 15 W exhibited a mobility of 2.5 cm2/Vsec, a threshold voltage (V T ) of 0.22 V, ΔV T shifts of less than 5.2 V under negative bias stress, and a Ion/Ioff ratio of 2.40 × 1010.