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arXiv · 2604.11149

Band Tail State Broadening in IGZO TFTs After pBTI-Induced Negative VT Shift Revealed via DC and 1/f Noise Measurements

R. Asanovski·P. Rinaudo·A. Chasin·Y. Zhao·H. F. W. Dekkers·M. J. van Setten·D. Matsubayashi·N. Rassoul·A. Belmonte·G. S. Kar·B. Kaczer·J. Franco
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Abstract

We investigate the origin of negative threshold voltage shifts in back-gated amorphous IGZO TFTs under positive bias and high temperature stress. Combined DC and 1/f noise measurements reveal that the stress does not generate new dielectric traps but instead broadens the IGZO conduction band tail states. A recovery experiment confirms that the associated threshold voltage, subthreshold swing, and noise degradation are reversible. Simulations using an in-house Poisson solver confirm the experimental observations that high-temperature stress increases hydrogen doping and the density of sub-gap states.

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R. Asanovski, P. Rinaudo, A. Chasin, Y. Zhao, H. F. W. Dekkers, M. J. van Setten, D. Matsubayashi, N. Rassoul, A. Belmonte, G. S. Kar, B. Kaczer, J. Franco. 2026-04-13. Band Tail State Broadening in IGZO TFTs After pBTI-Induced Negative VT Shift Revealed via DC and 1/f Noise Measurements. https://doi.org/10.1109/led.2026.3675648

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