Threshold Voltage Uniformity Enhancement for Low-Temperature Polysilicon Thin-Film Transistors Using Tilt Alignment Technique

Hsieh, Szu-I; Chen, Hung-Tse; Chen, Yu‐Cheng; Chen, Chi‐Lin; King, Ya‐Chin

doi:10.1149/1.2197947

Cited by 6 publications

(5 citation statements)

References 7 publications

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“…Previous research works for minimizing variation of TFT characteristics have been primarily conducted from device and process optimization perspective [11][12]. In [11], the authors proposed a multi-finger (MF) structure to effectively decrease the variation of charging time.…”

Section: Related Workmentioning

confidence: 99%

“…Tile alignment is another technique to reduce the variation of threshold voltage and mobility by taking advantage of periodic GBs in a sequential lateral solidification process [12]. Since the shifting of electrical characteristics between neighboring transistors is mainly due to the GBs in the channel [5], uniform number of GBs is expected to reduce the variation of electrical characteristics.…”

Section: Related Workmentioning

confidence: 99%

See 1 more Smart Citation

Variation-tolerant and self-repair design methodology for low temperature polycrystalline silicon liquid crystal and organic light emitting diode displays

Ho¹,

Lu²,

Mohapatra³

et al. 2011

16th Asia and South Pacific Design Automation Conference (ASP-DAC 2011)

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In low temperature polycrystalline silicon (LTPS) based display technologies, the electrical parameter variations in thin film transistors (TFTs) caused by random grain boundaries (GBs) result in significant yield loss, thereby impeding its wide deployment. In this paper, from a system and circuit design perspective, we propose a new self-repair design methodology to compensate the GB-induced variations for LTPS liquid crystal displays (LCDs) and active-matrix organic light emitting diode (AMOLED) displays. The key idea is to extend the charging time for detected low drivability pixel switches, hence, suppressing the brightness non-uniformity and eliminating the need for large voltage margins. The proposed circuit was implemented in VGA LCD panels which were used for prediction of power consumption and yield. Based on the simulation results, the proposed circuit decreases the required supply voltage by 20% without performance and yield degradation. 7% yield enhancement is observed for high resolution, large sized LCDs while incurring negligible power penalty. This technique enables LTPS-based displays either to further scale down the device size for higher integration and lower power consumption or to have superior yield in large sized panels with small power overhead.

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Section: Related Workmentioning

confidence: 99%

Section: Related Workmentioning

confidence: 99%

Variation-tolerant and self-repair design methodology for low temperature polycrystalline silicon liquid crystal and organic light emitting diode displays

Ho¹,

Lu²,

Mohapatra³

et al. 2011

16th Asia and South Pacific Design Automation Conference (ASP-DAC 2011)

View full text Add to dashboard Cite

show abstract

“…The merits of LTPS TFTs compared with other TFTs, such as amorphous Si (α-Si) TFTs and amorphous oxide semiconductor (AOS) TFTs, include higher mobility, the ability to fabricate CMOS structures and better stability. However, threshold voltage (V T ) variation for LTPS TFTs, [6][7][8] which stems from the polycrystalline structure of LTPS film, is generally worse than that for α-Si and AOS TFTs with amorphous channel materials. Because V T variation induces brightness variation between pixels, especially for organic light-emitting displays as well as μ-LED displays where luminance is controlled by TFT channel current, a V T -compensation circuit with additional TFTs is needed, 9,10) which limits further improvement of display performance.…”

Section: Introductionmentioning

confidence: 99%

Threshold voltage uniformity improvement by introducing charge injection tuning for low-temperature poly-Si thin film transistors with metal/oxide/nitride/oxide/silicon structure

Goto,

Suwa,

Katayama

et al. 2024

Jpn. J. Appl. Phys.

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LTPS TFTs with MONOS structure was fabricated to investigate the feasibility of suppressing threshold voltage variations between TFTs. By applying relatively high positive and negative gate bias voltages, threshold voltage could be tuned positively and negatively by injecting charges to charge trap layer, respectively. Stability of threshold voltage against positive gate bias at a level close to the actual circuit operation was not degraded compared to the case of as-fabricated TFT. Uniformization of threshold voltage distribution could be achieved in a preliminary test using 16 TFTs by converging threshold voltages with a target value by tuning threshold voltages for each TFT.

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“…However, the poly-Si TFTs suffered poor uniformity with large variations on the device characteristics due to the narrow laser process window for producing largegrained poly-Si TFTs. The device variation becomes a serious problem for analog circuit realization on the LCD panel [6]. For this reason, the design of on-panel analog circuits is a challenge for SOP applications.…”

Section: Introductionmentioning

confidence: 99%

On-glass digital-to-analog converter with gamma correction for panel data driver

Wang

Ker

2008

2008 15th IEEE International Conference on Electronics, Circuits and Systems

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An on-glass 6-bit R-string digital-to-analog converter (DAC) with gamma correction for panel data driver is proposed. The proposed circuit ,which is composed of folded R-string circuit, segmented digital decoder, and reordering decoding circuit, has been designed and fabricated in a 3-μm lowtemperature poly-Si (LTPS) technology. The area of the proposed circuit is effectively reduced to about one sixth compared with the conventional one.I.

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Threshold Voltage Uniformity Enhancement for Low-Temperature Polysilicon Thin-Film Transistors Using Tilt Alignment Technique

Cited by 6 publications

References 7 publications

Variation-tolerant and self-repair design methodology for low temperature polycrystalline silicon liquid crystal and organic light emitting diode displays

Variation-tolerant and self-repair design methodology for low temperature polycrystalline silicon liquid crystal and organic light emitting diode displays

Threshold voltage uniformity improvement by introducing charge injection tuning for low-temperature poly-Si thin film transistors with metal/oxide/nitride/oxide/silicon structure

On-glass digital-to-analog converter with gamma correction for panel data driver

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