Modeling of Low-Frequency Noise Related to Conduction Mechanisms in Amorphous Oxide Semiconductor Thin-Film Transistors

We develop a low-frequency noise (LFN) model for amorphous oxide semiconductor thin-film transistors (AOS TFTs) that accounts for the band-gap density of states (DOSs) of AOSs. The model uses a charge-based approach for calculating the normalized drain current power spectral density (PSD). By comparing the model with experimental results, we show that it is applicable to various AOS TFTs. The dominant noise source is carrier number fluctuation with correlated mobility for both AOS band-gap states (at low gate voltages) and oxide traps (at high gate voltages). AOS TFTs with high-k gate dielectrics may also require including additional mobility fluctuation (Hooge noise) due to the higher noise level in the subthreshold regime. The channel charge-based DC and noise models are strongly correlated in AOS TFTs, including for band-gap states in AOS.