Effect of high-pressure oxygen annealing on negative bias illumination stress-induced instability of InGaZnO thin film transistors

Negative-bias illumination stress (NBIS) of amorphous InGaZnO (IGZO) transistors can cause a large negative shift ( > 7.1 V ) in threshold voltage, something frequently attributed to the trapping of photoinduced hole carriers. This work demonstrates that the deterioration of threshold voltage by NBIS can be strongly suppressed by high-pressure annealing under 10 atm O 2 ambient. This improvement occurred through a reduction in oxygen vacancy defects in the IGZO film, indicating that a photoinduced transition from V O to V O 2 + was responsible for the NBIS-induced instability.