• Title, Summary, Keyword: asymmetric double gate

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Analysis of Tunneling Current for Bottom Gate Voltage of Sub-10 nm Asymmetric Double Gate MOSFET (10 nm이하 비대칭 이중게이트 MOSFET의 하단 게이트 전압에 따른 터널링 전류 분석)

  • Jung, Hakkee
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.19 no.1
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    • pp.163-168
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    • 2015
  • This paper analyzed the deviation of tunneling current for bottom gate voltage of sub-10 nm asymmetric double gate MOSFET. The asymmetric double gate MOSFET among multi gate MOSFET developed to reduce the short channel effects has the advantage to increase the facts to be able to control the channel current, compared with symmetric double gate MOSFET. The increase of off current is, however, inescapable if aymmetric double gate MOSFET has the channel length of sub-10 nm. The influence of tunneling current was investigated in this study as the portion of tunneling current for off current was calculated. The tunneling current was obtained by the WKB(Wentzel-Kramers-Brillouin) approximation and analytical potential distribution derived from Poisson equation. As a results, the tunneling current was greatly influenced by bottom gate voltage in sub-10 nm asymmetric double gate MOSFET. Especially it showed the great deviation for channel length, top and bottom gate oxide thickness, and channel thickness.

Analysis of Anomalous Subthreshold Characteristics in Ligtly-Doped Asymmetric Double-Gate MOSFETs (Asymmetric Double-Gate MOSFET의 Subthreshold 특성 분석)

  • 이혜림;신형순
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.40 no.6
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    • pp.379-383
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    • 2003
  • The subthreshold characteristics of Double-Gate MOSFETs are analyzed for various Tsi. In the lightly-doped asymmetric device, it is found that the subthreshold current dramatically increases as the Tsi increases and this phenomenon is due to the linear distribution of potential in the channel region with low depletion-charge. Further, we derived an analytical equation which can explain this phenomenon and verified the accuracy of analytical equation by comparing with the result of device simulation.

Analysis of Subthreshold Swing Mechanism by Device Parameter of Asymmetric Double Gate MOSFET (소자 파라미터에 따른 비대칭 DGMOSFET의 문턱전압이하 스윙 분석)

  • Jung, Hakkee
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.19 no.1
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    • pp.156-162
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    • 2015
  • This paper has analyzed how conduction path and electron concentration for the device parameters such as oxide thickness, channel doping, and top and bottom gate voltage influence on subthreshold swing of asymmetric double gate MOSFET. Compared with symmetric and asymmetric double gate MOSFET, asymmetric double gate MOSFET has the advantage that the factors to be able to control the short channel effects increase since top and bottom gate oxide thickness and voltages can be set differently. Therefore the conduction path and electron concentration for top and bottom gate oxide thickness and voltages are investigated, and it is found the optimum conditions that the degradation of subthreshold swing, severe short channel effects, can reduce. To obtain the analytical subthreshold swing, the analytical potential distribution is derived from Possion's equation. As a result, conduction path and electron concentration are greatly changed for device parameters, and subthreshold swing is influenced by conduction path and electron concentration of top and bottom.

Analysis of Threshold Voltage for Symmetric and Asymmetric Oxide Structure of Double Gate MOSFET (이중게이트 MOSFET의 대칭 및 비대칭 산화막 구조에 대한 문턱전압 분석)

  • Jung, Hakkee
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.18 no.12
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    • pp.2939-2945
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    • 2014
  • This paper has analyzed the change of threshold voltage for oxide structure of symmetric and asymmetric double gate(DG) MOSFET. The asymmetric DGMOSFET can be fabricated with different top and bottom gate oxide thickness, while the symmetric DGMOSFET has the same top and bottom gate oxide thickness. Therefore optimum threshold voltage is considered for top and bottom gate oxide thickness of asymmetric DGMOSFET, compared with the threshold voltage of symmetric DGMOSFET. To obtain the threshold voltage, the analytical potential distribution is derived from Possion's equation, and Gaussian distribution function is used as doping profile. We investigate for bottom gate voltage, channel length and thickness, and doping concentration how top and bottom gate oxide thickness influences on threshold voltage using this threshold voltage model. As a result, threshold voltage is greatly changed for oxide thickness, and we know the changing trend greatly differs with bottom gate voltage, channel length and thickness, and doping concentration.

Analytical Model for the Threshold Voltage of Long-Channel Asymmetric Double-Gate MOSFET based on Potential Linearity (전압분포의 선형특성을 이용한 Long-Channel Asymmetric Double-Gate MOSFET의 문턱전압 모델)

  • Yang, Hee-Jung;Kim, Ji-Hyun;Son, Ae-Ri;Kang, Dae-Gwan;Shin, Hyung-Soon
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.45 no.2
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    • pp.1-6
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    • 2008
  • A compact analytical model of the threshold voltage for long-channel Asymmetric Double-Gate(ADG) MOSFET is presented. In contrast to the previous models, channel doping and carrier quantization are taken into account. A more compact model is derived by utilizing the potential distribution linearity characteristic of silicon film at threshold. The accuracy of the model is verified by comparisons with numerical simulations for various silicon film thickness, channel doping concentration and oxide thickness.

Relation of Oxide Thickness and DIBL for Asymmetric Double Gate MOSFET (비대칭 이중게이트 MOSFET에서 산화막 두께와 DIBL의 관계)

  • Jung, Hakkee
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.20 no.4
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    • pp.799-804
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    • 2016
  • To analyze the phenomenon of drain induced barrier lowering(DIBL) for top and bottom gate oxide thickness of asymmetric double gate MOSFET, the deviation of threshold voltage is investigated for drain voltage to have an effect on barrier height. The asymmetric double gate MOSFET has the characteristic to be able to fabricate differently top and bottom gate oxide thickness. DIBL is, therefore, analyzed for the change of top and bottom gate oxide thickness in this study, using the analytical potential distribution derived from Poisson equation. As a results, DIBL is greatly influenced by top and bottom gate oxide thickness. DIBL is linearly decreased in case top and bottom gate oxide thickness become smaller. The relation of channel length and DIBL is nonlinear. Top gate oxide thickness more influenced on DIBL than bottom gate oxide thickness in the case of high doping concentration in channel.

Analysis of Conduction-Path Dependent Off-Current for Asymmetric Double Gate MOSFET (비대칭 이중게이트 MOSFET의 차단전류에 대한 전도중심 의존성 분석)

  • Jung, Hakkee
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.19 no.3
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    • pp.575-580
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    • 2015
  • Asymmetric double gate(DG) MOSFET is a novel transistor to be able to reduce the short channel effects. This paper has analyzed a off current for conduction path of asymmetric DGMOSFET. The conduction path is a average distance from top gate the movement of carrier in channel happens, and a factor to change for oxide thickness of asymmetric DGMOSFET to be able to fabricate differently top and bottom gate oxide thickness, and influenced on off current for top gate voltage. As the conduction path is obtained and off current is calculated for top gate voltage, it is analyzed how conduction path influences on off current with parameters of oxide thickness and channel length. The analytical potential distribution of series form is derived from Poisson's equation to obtain off current. As a result, off current is greatly changed for conduction path, and we know threshold voltage and subthreshold swing are changed for this reasons.

Conduction Path Dependent Threshold Voltage for the Ratio of Top and Bottom Oxide Thickness of Asymmetric Double Gate MOSFET (비대칭 이중게이트 MOSFET의 상하단 산화막 두께비에 따른 전도중심에 대한 문턱전압 의존성)

  • Jung, Hakkee
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.18 no.11
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    • pp.2709-2714
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    • 2014
  • This paper has analyzed the change of threshold voltage and conduction path for the ratio of top and bottom gate oxide thickness of asymmetric double gate MOSFET. The asymmetric double gate MOSFET has the advantage that the factor to be able to control the current in the subthreshold region increases. The analytical potential distribution is derived from Poisson's equation to analyze the threshold voltage and conduction path for the ratio of top and bottom gate oxide thickness. The Gaussian distribution function is used as charge distribution. This analytical potential distribution is used to derive off-current and subthreshold swing. By observing the results of threshold voltage and conduction path with parameters of bottom gate voltage, channel length and thickness, projected range and standard projected deviation, the threshold voltage greatly changed for the ratio of top and bottom gate oxide thickness. The threshold voltage changed for the ratio of channel length and thickness, not the absolute values of those, and it increased when conduction path moved toward top gate. The threshold voltage and conduction path changed more greatly for projected range than standard projected deviation.

Influence of Ratio of Top and Bottom Oxide Thickness on Subthreshold Swing for Asymmetric Double Gate MOSFET (비대칭 이중게이트 MOSFET에서 상단과 하단 산화막 두께비가 문턱전압이하 스윙에 미치는 영향)

  • Jung, Hakkee
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.20 no.3
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    • pp.571-576
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    • 2016
  • Asymmetric double gate(DG) MOSFET has the different top and bottom gate oxides thicknesses. It is analyzed the deviation of subthreshold swing(SS) and conduction path for the ratio of top and bottom gate oxide thickness of asymmetric DGMOSFET. SS varied along with conduction path, and conduction path varied with top and bottom gate oxide thickness. The asymmetric DGMOSFET became valuable device to reduce the short channel effects like degradation of SS. SSs were obtained from analytical potential distribution by Poisson's equation, and it was analyzed how the ratio of top and bottom oxide thickness influenced on conduction path and SS. SSs and conduction path were greatly influenced by the ratio of top and bottom gate oxide thickness. Bottom gate voltage cause significant influence on SS, and SS are changed with a range of 200 mV/dec for $0<t_{ox2}/t_{ox1}<5$ under bottom voltage of 0.7 V.

Analysis of Subthreshold Swing for Channel Doping of Asymmetric Double Gate MOSFET (비대칭 이중게이트 MOSFET의 채널도핑에 따른 문턱전압이하 스윙 분석)

  • Jung, Hakkee
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.18 no.3
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    • pp.651-656
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    • 2014
  • This paper analyzed the change of subthreshold swing for channel doping of asymmetric double gate(DG) MOSFET. The subthreshold swing is the factor to describe the decreasing rate of off current in the subthreshold region, and plays a very important role in application of digital circuits. Poisson's equation was used to analyze the subthreshold swing for asymmetric DGMOSFET. Asymmetric DGMOSFET could be fabricated with the different top and bottom gate oxide thickness and bias voltage unlike symmetric DGMOSFET. It is investigated in this paper how the doping in channel, gate oxide thickness and gate bias voltages for asymmetric DGMOSFET influenced on subthreshold swing. Gaussian function had been used as doping distribution in solving the Poisson's equation, and the change of subthreshold swing was observed for projected range and standard projected deviation used as parameters of Gaussian distribution. Resultly, the subthreshold swing was greatly changed for doping concentration and profiles, and gate oxide thickness and bias voltage had a big impact on subthreshold swing.