Roles of Gate Voltage and Stress Power in Self-Heating Degradation of a-InGaZnO Thin-Film Transistors

Abstract

Roles of gate voltage (V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">G</sub> ) and stress power in self-heating (SH) degradation of amorphous InGaZnO thin-film transistors have been clarified. Normally observed positive threshold voltage (V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</sub> ) shift is attributed to the electron trapping mechanism, which is enhanced by both the effective V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">G</sub> and stress power. The effective V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">G</sub> plays a dominant role in most cases, while stress power takes control only if it is high enough. Following the positive V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</sub> shift, a second-stage negative V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</sub> backshift is also observed and is attributed to the water-related positive charges generation mechanism. It is enhanced by both stress power and effective V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">G</sub> for which stress power is found to be the dominant factor.