Low-Frequency Noise Modeling of Amorphous Indium–Zinc-Oxide Thin-Film Transistors

Abstract

An improved model for the low-frequency noise (LFN) of amorphous indium–zinc-oxide thin-film transistors (a-IZO TFTs) is developed in this article. For a-IZO TFTs, the LFN is not only attributed to the oxide traps in the gate insulator but also affected by the discrete trap centers in the active-layer film. This makes the device has excess noise in the subthreshold region, which is obviously different from monocrystalline silicon (c-Si) MOSFETs. Therefore, we put forward an accurate and physically meaningful model to characterize this excess noise. For the subthreshold region, the charge of tail states in the channel is considered to describe the excess subthreshold noise, and the channel density of states (DOS) is extracted, confirming the effectiveness of the model. For the above-threshold region, the classic carrier number with correlated mobility fluctuation ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Delta N$ </tex-math></inline-formula> – <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Delta \mu $ </tex-math></inline-formula> ) mechanism has been investigated to explain the noise behavior. Furthermore, the proposed unified model is validated, and it has been successfully applied to a-IZO TFTs with different tail-state densities.