Gate-overlapped lightly doped drain poly-Si thin-film transistors for large area-AMLCD

Choi, Kwon‐Young; Lee, Jong‐Wook; Han, Min‐Koo

doi:10.1109/16.678541

Cited by 25 publications

(5 citation statements)

References 18 publications

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“…Recently, polycrystalline silicon thin-film transistors (TFTs) have become attractive devices for active matrix liquid crystal displays (AMLCDs) [1][2][3][4][5], memory devices [6][7][8], photodetector amplifier [9], scanner [10][11], and linear image sensors [12][13][14]. Low temperature poly-Si TFT technology is drawing attention as potential a technology for building fullyintegrated AMLCDs system on glass [5,11,15].…”

Section: Introductionmentioning

confidence: 99%

A novel uniformly doped barrier modulated ultra-deep-submicron poly-Si thin film transistor with very low subthreshold slope

Asthana

Goswami

Basak

et al. 2014

Semicond. Sci. Technol.

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In this paper, the characteristics of a novel device structure, uniformly doped ultra-deepsubmicron poly-Si barrier modulated thin film transistor (BM-TFT), are investigated and compared with conventional poly-Si TFT. Use of uniform doping provides a solution from problems associated with random dopant fluctuations. The suppression of the leakage current of the TFT by introducing barrier modulation is verified and presented. The device is optimized with respect to channel length, doping of channel, spacer dielectric and gate dielectric material. Simulations resulted in I OFF of ~2 × 10 −11 A μm −1 , I ON of ~2mA μm −1 , I ON /I OFF of 10 8 , subthreshold slope of 144 mV/dec and DIBL of 119 mV V −1 for PolyGate/HfO 2 /Poly-Si coplanar BM-TFT at temperature. of 300 K, gate length of 60 nm, oxide thickness of 5 nm, film thickness of 10 nm, low-k spacer thickness of 20 nm and V DD of 2.5 V.

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Section: Introductionmentioning

confidence: 99%

A novel uniformly doped barrier modulated ultra-deep-submicron poly-Si thin film transistor with very low subthreshold slope

Asthana

Goswami

Basak

et al. 2014

Semicond. Sci. Technol.

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“…Other problems, such as leakage reduction, and stability and reliability enhancement, have been dealt with using offset gates, lightly doped drains (LDD), gate overlapped structures, etc. [3][4][5] Unfortunately, those approaches introduce additional resistances to the devices. Besides, aluminum was recognized as a material useful for the metal-induced crystallization of poly-Si.…”

Section: Introductionmentioning

confidence: 99%

Effect of Series Resistance on Field-Effect Mobility at Varying Channel Lengths and Investigation into the Enhancement of Source/Drain Metallized Thin-Film Transistor Characteristics

Duy

Baek

Son

et al. 2011

Jpn. J. Appl. Phys.

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The degradation in device performance due to parasitic resistance along the source and drain electrodes is a serious problem in thin-film transistor fabrication. The effect of this series resistance on the field-effect mobility has been discussed and solutions for the reduction of this unexpected resistance were studied in this work. From the derivation of the drain current, it was shown that the additional resistance had a greater influence on short-channel devices. The ratio of the series resistance to the channel resistance determined the amount of degradation to the field-effect mobility. A thin-film transistor using an aluminum-metallized source/drain was suggested; it showed an improvement in comparison with the conventional doped source/drain device, with a maximum mobility of 105 cm2 V-1 s-1. However, significant degradation of the mobility in the short-channel cases exposed the limitations of the structure. By employing doping for the source/drain metallized structure the maximum mobility reached a value of 150 cm2 V-1 s-1. The decrease in the mobility caused by the channel length decrease was also improved. This study clearly explained the problem of additional resistance on the field-effect mobility of thin-film transistors and the achievements of a device using a self-aligned fabrication process with metallized electrodes.

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“…9) A lightly doped drain (LDD) or gate-overlapped lightly doped drain (GOLDD) structure has been widely used to suppress the electric field near the drain junction. 10,11) However, it is necessary to use an additional photomask in the fabrication process, which might degrade the electric characteristics of TFTs owing to the large series resistance induced by LDD regions. However, the channel length of a shorter channel sub-TFT could be limited by the feature size, and the short sub-TFT near the drain electrode would have a prejudicial effect on the reliability of the entire TFT.…”

Section: Introductionmentioning

confidence: 99%

New Bidirectional T-Shaped Triple-Gate n-Type Polycrystalline Silicon Thin-Film Transistors Formed by Low-Temperature Sequential Lateral Solidification Process to Reduce of Kink Effects

Choi¹,

Han²

2011

Jpn. J. Appl. Phys.

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A new bidirectional T-shaped triple-gate device structure, which suppresses the kink effect of sequential lateral solidification (SLS)-processed polycrystalline silicon thin film transistors (poly-Si TFTs), is proposed and fabricated without any additional process. The proposed poly-Si TFTs have a lateral grain growth in channels, similar to TFTs fabricated by SLS or continuous wave (CW) laser crystallization. The whole current flow of the proposed device is mainly affected by the grain boundaries of lateral grain growth. The bidirectional T-shaped triple-gate structure has incorporated a channel located parallel to the lateral grain growth direction, and the another channel located vertically to the lateral grain growth direction. It is verified from experimental and simulation results that the proposed bidirectional T-shaped triple-gate TFT effectively suppresses the kink current of poly-Si TFT with anisotropic mobility in the triple-gate structure. Our experimental results show that the proposed bidirectional T-shaped triple-gate TFT can suppress the kink effect more effectively than the conventional dual-gate TFT, and L-shaped dual-gate TFT and can improve reliability under the high drain bias condition. The proposed device demonstrates that bidirectional operation is possible for integrated circuits compared with the L-shaped dual-gate structure that shows only fixed one-directional behavior. The proposed device exhibits a very low output conductance in the saturation regime, and this result indicates that higher output resistance is obtained in the proposed bidirectional T-shaped triple-gate TFT.

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Gate-overlapped lightly doped drain poly-Si thin-film transistors for large area-AMLCD

Cited by 25 publications

References 18 publications

A novel uniformly doped barrier modulated ultra-deep-submicron poly-Si thin film transistor with very low subthreshold slope

A novel uniformly doped barrier modulated ultra-deep-submicron poly-Si thin film transistor with very low subthreshold slope

Effect of Series Resistance on Field-Effect Mobility at Varying Channel Lengths and Investigation into the Enhancement of Source/Drain Metallized Thin-Film Transistor Characteristics

New Bidirectional T-Shaped Triple-Gate n-Type Polycrystalline Silicon Thin-Film Transistors Formed by Low-Temperature Sequential Lateral Solidification Process to Reduce of Kink Effects

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