The effect of nitrous oxide plasma treatment on the bias temperature stress of metal oxide thin film transistors with high mobility

•The mobility of ITZO TFTs reached 33.2 cm2/V s and more suitable for BCE type.•Higher concentrations of carbon-related bonds were found on ITZO surface than IGZO.•Poor ITZO TFTs BTS might be due to higher induced current and more carbon-related bonds.•N2O plasma can improve both IGZO and ITZO TFTs BTS for 44.4% and 14.5%, respectively.

In this work, the effects of nitrous oxide plasma treatment on the negative bias temperature stress of indium tin zinc oxide (ITZO) and indium gallium zinc oxide (IGZO) thin film transistors (TFTs) were reported. ITZO TFTs were more suitable for the back channel etched-type device structure because they could withstand both Al- and Cu-acid damage. The initial threshold voltage range could be controlled to within 1 V. The root cause of poor negative bias temperature stress for ITZO was likely due to a higher mobility (∼3.3 times) and more carbon related contamination bonds (∼5.9 times) relative to IGZO. Finally, 65″ active-matrix organic light-emitting diode televisions using the ITZO and IGZO TFTs were fabricated.