Browsing by Author "Tai, Y. -H."

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Analysis of the Short-Term Response in the Drain Current of a-IGZO TFT to Light Pulses
(2017-07-01)
Liu, H. -W.
;
Chan, P. -C.
;
Lin, J. -H.
;
Chang, C. -Y.
;
Tai, Y. -H.
In this letter, the response in the drain current (I-D) of the amorphous indium-gallium-zinc oxide thin-film transistors under positive-bias illumination stress is measured with respect to time in less than 5 s under light pulseswith altering frequencies and duty ratios. The curves of I-D under the light pulses are affected by the different defect-reacting rates under illumination and in the dark. By taking the derivative of ID, the trend of the change in the number of defects becomes clear. The total behavior of I-D in response to light pulses can be fairly predicted by the integral of the derivative terms with a correction factor of charge trapping.
Boosted Gain of the Differential Amplifier Using the Second Gate of the Dual-Gate a-IGZO TFTs
(2012-12-01)
Tai, Y. -H.
;
Chiu, H. -L.
;
Chou, L. -S.
;
Chang, C. -H.
;
光電工程學系
A dual-gate amorphous InGaZnO4 (a-IGZO) thin-film transistor (TFT) has two gate electrodes. The primary gate electrode is at the bottom, and the other is on the top. The drain current of the TFT can be controlled by both the bottom and top gates. This phenomenon provides great flexibility for the circuit design. In this letter, we propose the differential amplifier circuit using the top gate of the dual-gate a-IGZO TFT as an input for positive feedback to boost the gain. It is experimentally verified that the gain of the differential amplifier circuit is increased three times larger than those without the feedback loop.
Degradation of a-IGZO Thin-Film Transistors Under Negative Bias and Illumination Stress in the Time Span of a Few Seconds
(2018-05-01)
Tai, Y. -H.
;
Liu, H. -W.
;
Chan, P. -C.
;
Chiu, S. -L.
;
電機學院
This letter investigated the time response behavior of amorphous indium-gallium-zinc oxide (a-IGZO) thin-film transistors (TFTs) under negative gate bias and illumination stress (NBIS) in sub-seconds. For the first time, significant degradation even in periods as short as sub-seconds under NBIS was observed. The stretchedexponential behavior of threshold voltage shift (Delta Vth) revealed similar mechanisms for short-and long-term NBIS. As a-IGZO TFTs operate at a very high speed, the non-negligible Delta Vth owing to the influence of fast oxygen vacancy needs to be considered to ensure a-IGZO TFT circuits function well in real applications.