Impacts of Trap-State Generation on Tunnel Thin-Film Transistor

Cheng-Yu, William; Hsu, Hui-Shun; Fang, Chih-Cheng; Jao, Che-Yu; Liao, Tzu-Han

doi:10.1109/ted.2018.2801361

Cited by 6 publications

(1 citation statement)

References 34 publications

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“…It indicates the endurance operation would damage the channel film and gate-dielectric/poly-Si channel interface, resulting in the generation of trap state density. The positive and negative gate bias stress effect of poly-Si tunnel TFT may generate the trap state density and lead to the degraded electrical characteristics, [32][33][34] which is known as the dynamic stress effect. Therefore, the increased V TH of poly-Si FeT-TFT within 500 endurance cycles can be attributed to the dynamic stress issue due to the maintained MW, while the reduced MW from 500 to 10 4 endurance cycles is attributed to the weakened polarization switching of the ferroelectric layer.…”

Section: Resultsmentioning

confidence: 99%

Ferroelectric Tunnel Thin-Film Transistor for Synaptic Applications

Cheng-Yu¹,

Su²,

Kao³

et al. 2023

ECS J. Solid State Sci. Technol.

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A ferroelectric tunnel thin-film transistor (FeT-TFT) with polycrystalline-silicon (poly-Si) channel and ferroelectric HfZrOx gate dielectric is demonstrated with analog memory characteristics for the application of synaptic devices. The FeT-TFT exhibits a much lower conduction current of ~0.032 times in transfer characteristics and maximum conductance (Gd) of ~0.14 to 0.2 times in potentiation and depression operation than the FeTFT due to FeT-TFT’s carrier transport mechanism: interband tunneling. This work employed pulse widths of 75, 150, and 300 ns to modulate Gd, and it was found that using a pulse width of 75 ns could achieve low asymmetry ~1 and high Gd ratio ~20.63 under consideration of operation speed. When the pulse time is increased, the potentiation and depression voltages can be significantly decreased to maintain the low asymmetry, but the Gd ratio is also reduced. In addition, the endurance characteristic of poly-Si FeT-TFT is found to be strongly related to the degradation effect of subthreshold swing due to the dynamic stress effect in the endurance measurement. This result reveals that the reliability of ferroelectric devices is not only owing to the degradation of the remanent polarization.

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Section: Resultsmentioning

confidence: 99%