Enhancement of bias and illumination stability in thin-film transistors by doping InZnO with wide-band-gap Ta2O5

Abstract

Thin-film transistor (TFT) with Ta2O5-doped InZnO (TIZO) channel layer was demonstrated. The TIZO-TFT exhibited smaller subthreshold swing and higher capability of carrier controlling when bearing nitrogen pre-annealing than the InZnO-TFT. Detailed studies showed that Ta had an effect of suppressing oxygen out-diffusing during thermal annealing, resulting in improving of the stability under positive gate bias stress. Furthermore, the TIZO-TFT displayed better stability under light illumination than InZnO-TFT, owing to its wider band gap and lower absorption after doped with wider-band-gap Ta2O5.