• Title/Summary/Keyword: gate electrode

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A Study on Improvement of a-Si:H TFT Operating Speed

  • Hur, Chang-Wu
    • Journal of information and communication convergence engineering
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    • v.5 no.1
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    • pp.42-44
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    • 2007
  • The a-Si:H TFTs decreasing parasitic capacitance of source-drain is fabricated on glass. The structure of a-Si:H TFTs is inverted staggered. The gate electrode is formed by patterning with length of $8{\mu}m{\sim}16{\mu}m$ and width of $80{\sim}200{\mu}m$ after depositing with gate electrode (Cr) $1500{\AA}$ under coming 7059 glass substrate. We have fabricated a-SiN:H, conductor, etch-stopper and photoresistor on gate electrode in sequence, respectively. The thickness of these, thin films is formed with a-SiN:H ($2000{\mu}m$), a-Si:H($2000{\mu}m$) and $n^+a-Si:H$ ($500{\mu}m$). We have deposited $n^+a-Si:H$, NPR(Negative Photo Resister) layer after forming pattern of Cr gate electrode by etch-stopper pattern. The NPR layer by inverting pattern of upper gate electrode is patterned and the $n^+a-Si:H$ layer is etched by the NPR pattern. The NPR layer is removed. After Cr layer is deposited and patterned, the source-drain electrode is formed. The a-Si:H TFTs decreasing parasitic capacitance of source-drain show drain current of $8{\mu}A$ at 20 gate voltages, $I_{on}/I_{off}$ ratio of ${\sim}10^8$ and $V_{th}$ of 4 volts.

Impacts of Dopant Activation Anneal on Characteristics of Gate Electrode and Thin Gate Oxide of MOS Capacitor (불순물 활성화 열처리가 MOS 캐패시터의 게이트 전극과 산화막의 특성에 미치는 효과)

  • 조원주;김응수
    • Journal of the Korean Institute of Telematics and Electronics D
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    • v.35D no.10
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    • pp.83-90
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    • 1998
  • The effects of dopant activation anneal on GOI (Gate Oxide Integrity) of MOS capacitor with amorphous silicon gate electrode were investigated. It was found that the amorphous silicon gate electrode was crystallized and the dopant atoms were sufficiently activated by activation anneal. The mechanical stress of gate electrode that reveals large compressive stress in amorphous state, was released with increase of anneal temperature from $700^{\circ}C$ to 90$0^{\circ}C$. The resistivity of gate electrode polycrystalline silicon film is decreased by the increase of anneal temperature. The reliability of thin gate oxide and interface properties between oxide and silicon substrate greatly depends on the activation anneal temperature. The charge trapping characteristics as well as oxide reliability are improved by the anneal of 90$0^{\circ}C$ compare to that of $700^{\circ}C$ or 80$0^{\circ}C$. Especially, the lifetimes of the thin gate oxide estimated by TDDB method is 3$\times$10$^{10}$ for the case of $700^{\circ}C$ anneal, is significantly increased to 2$\times$10$^{12}$ for the case of 90$0^{\circ}C$ anneal. Finally, the interface trap density is reduced with relaxation of mechanical stress of gate electrode.

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Electrical stabilities of half-Corbino thin-film transistors with different gate geometries

  • Jung, Hyun-Seung;Choi, Keun-Yeong;Lee, Ho-Jin
    • Journal of Information Display
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    • v.13 no.1
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    • pp.51-54
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    • 2012
  • In this study, the bias-temperature stress and current-temperature stress induced by the electrical stabilities of half-Corbino hydrogenated-amorphous-silicon (a-Si:H) thin-film transistors (TFTs) with different gate electrode geometries fabricated on the same substrate were examined. The influence of the gate pattern on the threshold voltage shift of the half-Corbino a-Si:H TFTs is discussed in this paper. The results indicate that the half-Corbino a-Si:H TFT with a patterned gate electrode has enhanced power efficiency and improved aperture ratio when compared with the half-Corbino a-Si:H TFT with an unpatterned gate electrode and the same source/drain electrode geometry.

Fabrication of gate electrode for OTFT using screen-printing and wet-etching with nano-silver ink

  • Lee, Mi-Young;Song, Chung-Kun
    • 한국정보디스플레이학회:학술대회논문집
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    • 2009.10a
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    • pp.889-892
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    • 2009
  • We have developed a practical printing technology for the gate electrode of organic thin film transistors(OTFTs) by combining screen-printing with wet-etching process using nano-silver ink as a conducting material. The screen-printed and wet-etched Ag electrode exhibited a minimum line width of ~5 um, the thickness of ~65 nm, and a resistivity of ${\sim}10^{-6}{\Omega}{\cdot}cm$, producing good geometrical and electrical characteristics for gate electrode. The OTFTs with the screen-printed and wet-etched Ag electrode produced the saturation mobility of $0.13cm^2$/Vs and current on/off ratio of $1.79{\times}10^6$, being comparable to those of OTFT with the thermally evaporated Al gate electrode.

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$Ta/TaN_x$ Metal Gate Electrodes for Advanced CMOS Devices

  • Lee, S. J.;D. L. Kwong
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.2 no.3
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    • pp.180-184
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    • 2002
  • In this paper, the electrical properties of PVD Ta and $TaN_x$ gate electrodes on $SiO_2$ and their thermal stabilities are investigated. The results show that the work functions of $TaN_x$ gate electrode are modified by the amount of N, which is controlled by the flow rate of $N_2$during reactive sputtering process. The thermal stability of Ta and $TaN_x$ with RTO-grown $SiO_2$ gate dielectrics is examined by changes in equivalent oxide thickness (EOT), flat-band voltage ($V_{FB}$), and leakage current after post-metallization anneal at high temperature in $N_2$ambient. For a Ta gate electrode, the observed decrease in EOT and leakage current is due to the formation of a Ta-incorporated high-K layer during the high temperature annealing. Less change in EOT and leakage current is observed for $TaN_x$ gate electrode. It is also shown that the frequency dispersion and hysteresis of high frequency CV curves are improved significantly by a post-metallization anneal.

Fabrication & Properties of Field Emitter Arrays using the Mold Method for FED Application (Mold 법에 의해 제작된 FED용 전계에미터어레이의 특성 분석)

  • ;;;;K. Oura
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.07a
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    • pp.347-350
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    • 2001
  • A typical Mold method is to form a gate electrode, a gate oxide, and emitter tip after fabrication of mold shape using wet-etching of Si substrate. In this study, however, new Mold method using a side wall space structure is used in order to make sharper emitter tip with a gate electrode. Using LPCVD(low pressure chemical vapor deposition), a gate oxide and electrode layer are formed on a Si substrate, and then BPSG(Boro phospher silicate glass) thin film is deposited. After, the BPSG thin film is flowed into a mold as high temperature in order to form a sharp mold structure. Next TiN thin film is deposited as a emitter tip substance. The unfinished device with a glass substrate is bonded by anodic bonding techniques to transfer the emitters to a glass substrate, and Si substrate is etched using KOH-deionized water solution. Finally, we made sharp field emitter array with gate electrode on the glass substrate.

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Numerical Analyses on Snapback-Free Shorted-Anode SOI LIGBT by using a Floating Electrode and an Auxiliary Gate (플로우팅 전극과 보조 게이트를 이용하여 스냅백을 없앤 애노드 단락 SOI LIGBT의 수치 해석)

  • O, Jae-Geun;Kim, Du-Yeong;Han, Min-Gu;Choe, Yeon-Ik
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.49 no.2
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    • pp.73-77
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    • 2000
  • A dual-gate SOI SA-LIGBT (shorted-anode lateral insulated gate bipolar transistor) which eliminates the snapback effectively is proposed and verified by numerical simulation. The elimination of the snapback in I-V characteristics is obtained by initiating the hole injection at low anode voltage by employing a dual gate and a floating electrode in the proposed device. For the proposed device, the snapback phenomenon is completely eliminate, while snapback of conventional SA-LIGBT occurs at anode voltage of 11 V. Also, the drive signals of two gates have same polarity by employing the floating electrode, thereby requiring no additional power supply.

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Optimization and Characterization of Gate Electrode Dependent Flicker Noise in Silicon Nanowire Transistors

  • Anandan, P.;Mohankumar, N.
    • Journal of Electrical Engineering and Technology
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    • v.9 no.4
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    • pp.1343-1348
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    • 2014
  • The low frequency noise in Silicon Nanowire Field Effect Transistors is analyzed by characterizing the gate electrode dependence on various geometrical parameters. It shows that gate electrodes have a strong impact in the flicker noise of Silicon Nanowire Field effect transistors. Optimization of gate electrode was done by comparing different performance metrics such a DIBL, SS, $I_{on}/I_{off}$ and fringing capacitance using TCAD simulations. Molybdenum based gate electrode showed significant improvement in terms of high drive current, Low DIBL and high $I_{on}/I_{off}$. The noise power sepctral density is reduced by characterizing the device at higher frequencies. Silicon Nanowire with Si3N4 spacer decreases the drain current spectral density which interms reduces the fringing fields there by decreasing the flicker noise.

The Fabrication of a-Si:H TFT Improving Parasitic Capacitance of Source-Drain (소오스-드레인 기생용량을 개선한 박막트랜지스터 제조공정)

  • 허창우
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.8 no.4
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    • pp.821-825
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    • 2004
  • The a-Si:H TFTs decreasing parasitic capacitance of source-drain is fabricated on glass. The structure of a-Si:H TFTs is inverted staggered. The gate electrode is formed by patterning with length of 8 ${\mu}m∼16 ${\mu}m. and width of 80∼200 ${\mu}m after depositing with gate electrode (Cr) 1500 under coming 7059 glass substrate. We have fabricated a-SiN:H, conductor, etch-stopper and photoresistor on gate electrode in sequence, respectively. The thickness of these thin films is formed with a-SiN:H (2000 ), a-Si:H(2000 ) and n+a-Si:H (500). We have deposited n+a-Si:H ,NPR(Negative Photo Resister) layer after forming pattern of Cr gate electrode by etch-stopper pattern. The NPR layer by inverting pattern of upper gate electrode is patterned and the n+a-Si:H layer is etched by the NPR pattern. The NPR layer is removed. After Cr layer is deposited and patterned, the source-drain electrode is formed. The a-Si:H TFTs decreasing parasitic capacitance of source-drain has channel length of 8 ~20 ${\mu}m and channel width of 80∼200 ${\mu}m. And it shows drain current of 8 ${\mu}A at 20 gate voltages, Ion/Ioff ratio of 108 and Vth of 4 volts.

A Study on the New Discharge AND Gate and Drive Scheme for the Cost Down of the PDPs (PDP의 가격절감을 위한 새로운 방전 AND Gate 및 구동기술에 관한 연구)

  • 염정덕
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.52 no.6
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    • pp.267-273
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    • 2003
  • The plasma display panel with the electrode structure of new discharge AND gate and its driving scheme were proposed and the driving system for experiment was developed. And operation of these discharge AND gate was verified by the experiment of PDP addressing with floating electrode. This discharge AND gate operated by the operation speed of 8$mutextrm{s}$ and the operation margin of 100V. The address operation margin of 10V also obtained. It was known to be able to control the discharge of the adjoining scan electrode accurately. Because proposed method uses the DC discharge the control of the discharge can be facilitated compared with conventional discharge AND gate. Moreover, because the input discharge and the output discharge of discharge gate are separate, the display discharge can be prevented from passing discharge gates. Therefore, it is possible to apply to the large screen plasma display panel. And the decrease of contrast ratio does not occur because the scanning discharge does not influence the picture quality.