Large-Swing a-IGZO Inverter With a Depletion Load Induced by Laser Annealing

Abstract

In this letter, a high-performance inverter based on amorphous indium-gallium-zinc oxide thin-film transistors (TFTs) is fabricated, which consists of an enhancement mode driver and a depletion mode load. By applying an area-selective laser annealing technique, the threshold voltage (V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</sub> ) of the load TFT could be tuned from positive to negative gate voltage. Based on X-ray photoelectron spectroscopy analyses, the negative V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</sub> shift can be attributed to the increase of oxygen vacancy concentration within the device channel upon laser annealing. Meanwhile, compared with conventional inverters with an enhancement mode load, the proposed inverter shows much improved switching characteristics, including output swing range close to 100% full swing as well as an enhanced output voltage gain from -1.5 to -20.5 V/V.