Correlation of thermal annealing effect, crystallinity and electrical characteristics in c-axis crystallized InGaZnO thin-film transistors

A low off-state current of 1.6 × 10^-14 A/μm and a small subthreshold gate swing of 152 mV/decade were achieved in a novel thin film transistor using a c-axis crystallized InGaZnO semiconductor that could be obtained at a low substrate temperature range of 150 °C. From experimental results, we found that the lowered off-state current is mainly attributed to the formation of rich Ga-O bonds to reduce oxygen vacancies, and the c-axis crystallized structure of IGZO to increase the potential barrier on the source side due to the increase of local trap states at the grain boundary.