Degradation of InSnZnO Thin-Film Transistors Under Negative Bias Stress
Zhendong Jiang, Meng Zhang, Sunbin Deng, Man Wong, Hoi Sing Kwok
Abstract
Degradation of InSnZnO thin-film transistors (TFTs) under negative bias stress (NBS) is systematically studied in this work. A two-stage degradation behavior is observed for the first time. Utilizing TCAD simulations, a degradation model is introduced, in which the first stage of ON current ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${I}_{\text {on}}$ </tex-math></inline-formula> ) increase is dominated by an electron concentration increase resulting from energy band bending and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{H}_{{2}}\text{O}$ </tex-math></inline-formula> ionization while the second stage of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${I}_{\text {on}}$ </tex-math></inline-formula> decrease is dominated by an HC effect caused by the extra carriers and NBS-induced lateral electric field. Furthermore, the model is verified by a low-frequency noise measurement.