Flexible zinc oxide thin-film transistors using oxide buffer layers on polyethylene napthalate substrates

摘要

We report on the fabrication and characterization of flexible ZnO thin-film transistors (TFTs) using multilayer oxide buffer layers. ZnO-TFTs on polyethylene napthalate (PEN) substrates were fabricated by pulsed laser deposition (PLD) at room temperature (RT). ZnO films were characterized by Hall effect measurements. The electron mobility and the carrier density were 52.4 cm²/Vs and 3.2×10¹⁷ cm⁻³. Top-gate-type TFTs were fabricated from a thin film of HfO2 dielectric as a high-k material gate insulator. A transconductance, gm, of 1.7 mS/mm, an on/off-current ratio of 2.4×10⁶ and a threshold voltage, Vth, of −1.2 V were achieved for a ZnO TFT with a SiO2/TiO2 buffer layer.