Investigation of indium diffusion into solution-processed oxide TFTs with ZTO active layer and IZO source/drain electrodes

We have investigated the indium diffusion in oxide-based thin film transistors (TFTs) fabricated with zinc tin oxide (ZTO) active layer and indium zinc oxide (IZO) source/drain electrode by employing a solution-process. Oxide TFTs were fabricated with spin-coating process using solution with chloride-, acetate- and nitrate- based precursors. After spin-coating, ZTO active layer and IZO source/drain electrodes were annealed sequentially by rapid thermal annealing (RTA). Rutherford backscattering spectrometry (RBS) result shows that 16.8% of indium atoms in IZO source/drain electrodes are diffused into ZTO active layer after annealing process. The In-diffusion into ZTO active layer cause a considerable negative shift of threshold voltage in solution-processed ZTO TFTs.