Bias-Temperature-Illumination Stability of Aqueous Solution Processed Fluorine Doped Zinc Tin Oxide (ZTO:F) Transistor

Novel fluorine doped zinc tin oxide (ZTO:F) thin-film transistor (TFT) was fabricated by an aqueous sol-gel method and their bias-temperature-illumination stability were observed. ZTO:F TFT optimized at Sn:Zn = 1:1 composition exhibits high field-effect mobility of 11.52 cm 2 /V·s at a process temperature of 350°C. In particular, the TFT displays a small negative threshold voltage shift of approximately 1 V under positive bias-temperature-illumination stress. This is attributed to asymmetry of the recombination for photo-generated holes with the free electrons at the ZTO:F channel/gate dielectric interface due to the substitution of oxygen by fluorine with different electrovalence.