Improvement of properties of top-gate IGZO TFT by oxygen-rich ultrathin in situ ITO active layer

Abstract In this letter, the top-gate dual-active-layer TFT has been fabricated by in situ deposition of oxygen-rich ultrathin In-Sn-O layer on a top of the In-Ga-Zn-O (IGZO) active layer in order to suppress the hysteresis and improve negative bias illumination stability. The oxygen-rich ultrathin In-Sn-O layer can effectively reduce the oxygen vacancies concentration of the semiconductor layer from 33.16 to 1.13%. The decrease of oxygen vacancies indicates that the trap density and electron trapping are reduced, resulting in a reduced hysteresis from 0.66 to 0.02 V. Simultaneously, the negative bias illumination stability has been effectively improved from −0.89 to −0.29 V.