Electrical stability of flexible a-IGZO TFT under strained condition

Abstract

We report the effect of tensile strain on the electrical performance of flexible a-In-Ga-Z-O (a-IGZO) thin-film transistor (TFT). Positive bias stress (PBS) measurement with Vgs = 20 V and Vds = 0 V in a-IGZO TFTs show positive transfer shift due to the trapping of negative charges, likely electron trapping. We observed that tensile strained TFT with 2 mm bending radius exhibits a positive ΔVTh (V) ~2.3 V shift compared to flat condition TFT (ΔVth (V) ~1.5 V) after 3.6K seconds stress. It clearly revels that more charges are trapped at the gate insulator/a-IGZO interface when the Fermi level is shifted downward by PBS with strained geometry.