Defect reduction in photon-accelerated negative bias instability of InGaZnO thin-film transistors by high-pressure water vapor annealing

We investigated the effects of high-pressure water vapor annealing (WHPA) under negative bias temperature illumination stress and light incidence on amorphous InGaZnO thin-film transistors. WHPA could improve device reliability and reduce the hump occurrence. It was attributed to the effective reduction and passivation in oxygen vacancies under WHPA. By comparing the experimental and technology computer-aided design simulation, we could confirm that the low-density of deep-donor-like oxygen vacancy (Vo) states near the valance band maximum contributed to the reduction of photo-excited single ionized oxygen vacancies (Vo+) and double ionized oxygen vacancies (Vo2+) as shallow-donor states near the conduction band minimum.