Amorphous-Silicon Thin-Film Transistors Fabricated at 300 $^{\circ}\hbox{C}$ on a Free-Standing Foil Substrate of Clear Plastic

Abstract

We have made hydrogenated amorphous-silicon thin-film transistors (TFTs) at a process temperature of 300 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">deg</sup> C on free-standing clear-plastic foil substrates. The key to the achievement of flat and smooth samples was to design the mechanical stresses in the substrate passivation and transistor layers, allowing us to obtain functional transistors over the entire active surface. Back-channel-passivated TFTs made at 300 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">deg</sup> C on glass substrates and plastic substrates have identical electrical characteristics and gate-bias-stress stability. These results suggest that free-standing clear-plastic foil can replace display glass as a substrate from the points of process temperature, substrate and device integrity, and TFT performance and stability.