Mg Doping to Simultaneously Improve the Electrical Performance and Stability of MgInO Thin-Film Transistors

Abstract

In this paper, we have fabricated the magnesium-doped indium oxide (MgInO) thin-film transistors (TFTs) by solution process and evaluate the electrical characteristics and stability under temperature stress and positive bias stress. The MgInO TFTs show a decrease of off-state current (I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</sub> ) and an increase of threshold voltage (V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">TH</sub> ) with the increase of Mg doping concentration. For MgInO TFT with 0.75 mol% Mg doping concentration, it shows an excellent electrical characteristic (the field effect mobility of 13.77 cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> V <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> s <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> , the threshold voltage of 2.84 V, and subthreshold swing value of 0.85 V/decade) and a good stability of temperature stress and positive bias stress. The performance enhancement of MgInO TFTs is attributed to the reduced density of states and the lower interface trap density by the optimized Mg doping concentration, which is first verified by the temperature-dependent field effect measurement and capacitance-voltage method.