Browsing by Author "Liu, Kuan-Hsien"

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Effects of Varied Negative Stop Voltages on Current Self-Compliance in Indium Tin Oxide Resistance Random Access Memory
(2015-06-01)
Lin, Chih-Yang
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Chang, Kuan-Chang
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Chang, Ting-Chang
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Tsai, Tsung-Ming
;
Pan, Chih-Hung
We have previously investigated the automatic current compliance property for indium tin oxide (ITO) resistance random access memory (RRAM). Traditionally, for the purpose of protecting RRAM, it is necessary to set equipment current compliance during the set and forming processes of RRAM devices. ITO RRAM devices, however, have an intrinsic capability to limit their current. This letter examines this ITO RRAM current compliance in depth by applying a varied stop-voltage measurement method, where different negative stop voltages were adopted to manipulate oxygen ions. Combined with material analysis and conduction current fitting, a model was established.
Gate Insulator Morphology-Dependent Reliability in Organic Thin-Film Transistors
(2016-02)
Chen, Hua-Mao
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Chang, Ting-Chang
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Tai, Ya-Hsiang
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Chiang, Hsiao-Cheng
;
Liu, Kuan-Hsien
In this letter, we investigated the gate insulator morphology affecting on the electric characteristic variation for organic thin-film transistors (OTFTs). From the transfer characteristics, there is a result with leakage current when the gate voltage is lower than the threshold voltage, which is due to the gate insulator thickness variation. Furthermore, regardless of whether the OTFT is operated under positive or negative bias stress, the more severe degradation happened in the hump region of transfer characteristics. Because a thinner gate insulator causes a high electric field, more charges are trapped in a gate dielectric stack.
Improvements in the reliability of a-InGaZnO thin-film transistors with triple stacked gate insulator in flexible electronics applications
(2015-11-30)
Chen, Hua-Mao
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Chang, Ting-Chang
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Tai, Ya-Hsiang
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Chen, Kuan-Fu
;
Chiang, Hsiao-Cheng
This study examined the impact of the low-temperature stacking gate insulator on the gate bias instability of a-InGaZnO thin film transistors in flexible electronics applications. Although the quality of SiNx at low process/deposition temperature is better than that of SiOx at similarly low process/deposition temperature, there is still a very large positive threshold voltage (V-th) shift of 9.4 V for devices with a single low-temperature SiNx gate insulator under positive gate bias stress. However, a suitable oxide-nitride-oxide-stacked gate insulator exhibits a Vth shift of only 0.23 V. This improvement results from the larger band offset and suitable gate insulator thickness that can effectively suppress carrier trapping behavior. (C) 2015 Elsevier B.V. All rights reserved.
Influence of an anomalous dimension effect on thermal instability in amorphous-InGaZnO thin-film transistors
(2014-10-21)
Liu, Kuan-Hsien
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Chang, Ting-Chang
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Chou, Wu-Ching
;
Chen, Hua-Mao
;
Tsai, Ming-Yen
This paper investigates abnormal dimension-dependent thermal instability in amorphous indium-gallium-zinc-oxide (a-IGZO) thin-film transistors. Device dimension should theoretically have no effects on threshold voltage, except for in short channel devices. Unlike short channel draininduced source barrier lowering effect, threshold voltage increases with increasing drain voltage. Furthermore, for devices with either a relatively large channel width or a short channel length, the output drain current decreases instead of saturating with an increase in drain voltage. Moreover, the wider the channel and the shorter the channel length, the larger the threshold voltage and output on-state current degradation that is observed. Because of the surrounding oxide and other thermal insulating material and the low thermal conductivity of the IGZO layer, the self-heating effect will be pronounced in wider/shorter channel length devices and those with a larger operating drain bias. To further clarify the physical mechanism, fast ID-VG and modulated peak/base pulse time ID-VD measurements are utilized to demonstrate the self-heating induced anomalous dimension-dependent threshold voltage variation and on-state current degradation. (C) 2014 AIP Publishing LLC.
Investigation of channel width-dependent threshold voltage variation in a-InGaZnO thin-film transistors
(2014-03-31)
Liu, Kuan-Hsien
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Chang, Ting-Chang
;
Wu, Ming-Siou
;
Hung, Yi-Syuan
;
Hung, Pei-Hua
This Letter investigates abnormal channel width-dependent threshold voltage variation in amorphous indium-gallium-zinc-oxide (a-IGZO) thin-film transistors. Unlike drain-induced source barrier lowering effect, threshold voltage increases with increasing drain voltage. Furthermore, the wider the channel, the larger the threshold voltage observed. Because of the surrounding oxide and other thermal insulating material and the low thermal conductivity of the IGZO layer, the self-heating effect will be pronounced in wider channel devices and those with a larger operating drain bias. To further clarify the physical mechanism, fast IV measurement is utilized to demonstrate the self-heating induced anomalous channel width-dependent threshold voltage variation. (C) 2014 AIP Publishing LLC.
Investigation of on-current degradation behavior induced by surface hydrolysis effect under negative gate bias stress in amorphous InGaZnO thin-film transistors
(2014-03-10)
Liu, Kuan-Hsien
;
Chang, Ting-Chang
;
Chang, Kuan-Chang
;
Tsai, Tsung-Ming
;
Hsieh, Tien-Yu
This study investigates the electrical instability under negative gate bias stress (NGBS) induced by surface hydrolysis effect. Electrical characteristics exhibit instability for amorphous InGaZnO (a-IGZO) Thin Film Transistors (TFTs) under NGBS, in which on-current degradation and current crowding phenomenon can be observed. When the negative gate bias is applied on the TFT, hydrogen ions will dissociate from ZnO-H bonds and the dissociated hydrogen ions will cause electrical instability under NGBS. The ISE-Technology Computer Aided Design simulation tool and moisture partial pressure modulation measurement are utilized to clarify the anomalous degradation behavior. (C) 2014 AIP Publishing LLC.