Analysis and Simulation of Low-Frequency Noise in Indium-Zinc-Oxide Thin-Film Transistors

Abstract

Low-frequency noise (LFN) is investigated in a set of indium-zinc-oxide thin-film transistors (IZO TFTs) with fixed channel width ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$W$ </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">$10~\mu \text{m}$ </tex-math></inline-formula> ) and different channel lengths ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$L\,\,=10$ </tex-math></inline-formula> , 20, 30, and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$40~\mu \text{m}$ </tex-math></inline-formula> ) from sub-threshold, linear to saturation regions. The drain current noise power spectral density is measured as a function of effective gate voltage and drain current. The variation slopes of normalized noise with effective gate voltage are in the range of −1.27 and −1.48, which are close to the prediction of the mobility fluctuation mechanism. According to the <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-\Delta \mu $ </tex-math></inline-formula> model, the flat-band voltage noise spectral density and Coulomb scattering coefficient are extracted. Subsequently, variations of noise with the drain current in the above threshold region are analyzed by considering the band-gap distribution of the tail states. Finally, the BSIM model is also used to model 1/ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$f$ </tex-math></inline-formula> noise in the IZO TFTs. The noise parameter <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$NOIB$ </tex-math></inline-formula> is extracted which is inversely proportional to the effective gate voltage. Good agreements are achieved between the simulated and measured results in the linear region.