Low Temperature Solution-Processed Zinc Tin Oxide Thin Film Transistor with O2 Plasma Treatment

We fabricated solution-processed ZTO TFTs at annealing temperature of 350 degrees C with employing O-2 plasma treatment on active layer in order to improve the electrical characteristics of ZTO TFTs fabricated at low temperature. Threshold voltage of solution-processed ZTO TFTs without plasma treatment was larger than 35 V but reduced to 20.74 V with 15 ml/min and 300 W of O-2 plasma treatment since oxygen vacancies in ZnO center dot SnO2 and SnO2 would increase and then electron concentration are also increased by ion bombardment from O-2 plasma treatment. Saturation mobility and Subthreshold Swing (S.S) of TFTs without plasma treatment was 0.09 cm(2)/V.sec and 1.65 V/decade respectively, but saturation mobility increased to 0.58 cm(2)/V.sec and S.S decreased to 1.20 V/decade, respectively, with 15 ml/min and 300 W of O-2 plasma treatment, since ZnO center dot SnO2 is produced which could work as semiconducting material, rather Zn(OH)Cl is vanished which could work as impurity by O-2 plasma treatment.