• Title, Summary, Keyword: drain induced barrier lowering

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A New Two-Dimensional Model for the Drain-Induced Barrier Lowering of Fully Depleted Short-Channel SOI-MESFET's

  • Jit, S.;Pandey, Prashant;Pal, B.B.
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.3 no.4
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    • pp.217-222
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    • 2003
  • A new two-dimensional analytical model for the potential distribution and drain-induced barrier lowering (DIBL) effect of fully depleted short-channel Silicon-on-insulator (SOI)-MESFET's has been presented in this paper. The two dimensional potential distribution functions in the active layer of the device is approximated as a simple parabolic function and the two-dimensional Poisson's equation has been solved with suitable boundary conditions to obtain the bottom potential at the Si/oxide layer interface. It is observed that for the SOI-MESFET's, as the gate-length is decreased below a certain limit, the bottom potential is increased and thus the channel barrier between the drain and source is reduced. The similar effect may also be observed by increasing the drain-source voltage if the device is operated in the near threshold or sub-threshold region. This is an electrostatic effect known as the drain-induced barrier lowering (DIBL) in the short-gate SOI-MESFET's. The model has been verified by comparing the results with that of the simulated one obtained by solving the 2-D Poisson's equation numerically by using the pde toolbox of the widely used software MATLAB.

Drain induced barrier lowering and impact ionization effects in short channel polysilicon TFTs

  • Fortunato, G.;Valletta, A.;Gaucci, P.;Mariucci, L.;Cuscuna, M.;Maiolo, L.;Pecora, A.
    • 한국정보디스플레이학회:학술대회논문집
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    • pp.907-910
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    • 2008
  • The effect of channel length reduction on the electrical characteristics of self-aligned polysilicon TFTs has been investigated by combining experimental characteristics and 2-D numerical simulations. The role of drain induced barrier lowering and floating body effects has been carefully analized using numerical simulations.

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Impact of Energy Relaxation of Channel Electrons on Drain-Induced Barrier Lowering in Nano-Scale Si-Based MOSFETs

  • Mao, Ling-Feng
    • ETRI Journal
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    • v.39 no.2
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    • pp.284-291
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    • 2017
  • Drain-induced barrier lowering (DIBL) is one of the main parameters employed to indicate the short-channel effect for nano metal-oxide semiconductor field-effect transistors (MOSFETs). We propose a new physical model of the DIBL effect under two-dimensional approximations based on the energy-conservation equation for channel electrons in FETs, which is different from the former field-penetration model. The DIBL is caused by lowering of the effective potential barrier height seen by the channel electrons because a lateral channel electric field results in an increase in the average kinetic energy of the channel electrons. The channel length, temperature, and doping concentration-dependent DIBL effects predicted by the proposed physical model agree well with the experimental data and simulation results reported in Nature and other journals.

Comparison of Drain-Induced-Barrier-Lowering (DIBL) Effect by Different Drain Engineering

  • Choi, Byoung-Seon;Choi, Pyung-Ho;Choi, Byoung-Deog
    • Proceedings of the Korean Vacuum Society Conference
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    • pp.342-343
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    • 2012
  • We studied the Drain-Induced-Barrier-Lowering (DIBL) effect by different drain engineering. One other drain engineering is symmetric source-drain n-channel MOSFETs (SSD NMOSs), the other drain engineering is asymmetric source-drain n-channel MOSFETs (ASD NMOSs). Devices were fabricated using state of art 40 nm dynamic-random-access-memory (DRAM) technology. These devices have different modes which are deep drain junction mode in SSD NMOSs and shallow drain junction mode in ASD NMOSs. The shallow drain junction mode means that drain is only Lightly-Doped-Drain (LDD). The deep drain junction mode means that drain have same process with source. The threshold voltage gap between low drain voltage ($V_D$=0.05V) and high drain voltage ($V_D$=3V) is 0.088V in shallow drain junction mode and 0.615V in deep drain junction mode at $0.16{\mu}m$ of gate length. The DIBL coefficients are 26.5 mV/V in shallow drain junction mode and 205.7 mV/V in deep drain junction mode. These experimental results present that DIBL effect is higher in deep drain junction mode than shallow drain junction mode. These results are caused that ASD NMOSs have low drain doping level and low lateral electric field.

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Drain Induced Barrier Lowering of Asymmetric Double Gate MOSFET for Channel Doping Profile (비대칭 DGMOSFET의 도핑분포함수에 따른 DIBL)

  • Jung, Hakkee
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.19 no.11
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    • pp.2643-2648
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    • 2015
  • This paper analyzes the phenomenon of drain induced barrier lowering(DIBL) for doping profiles in channel of asymmetric double gate(DG) MOSFET. The DIBL, the important short channel effect, is described as lowering of source barrier height by drain voltage. The analytical potential distribution is derived from Poisson's equation to analyze the DIBL, and the DIBL is observed according to the change of doping profile to influence on potential distribution. As a results, the DIBL is significantly influenced by projected range and standard projected deviation, the variables of channel doping profiles. The change of DIBL shows greatly in the range of high doping concentration such as $10^{18}/cm^3$. The DIBL increases with decrease of channel length and increase of channel thickness, and with increase of bottom gate voltage and top/bottom gate oxide film thickness.

Analysis of Drain Induced Barrier Lowering for Double Gate MOSFET According to Channel Doping Intensity (채널도핑강도에 대한 DGMOSFET의 DIBL분석)

  • Jung, Hak-Kee
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • pp.888-891
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    • 2011
  • In this paper, drain induced barrier lowering(DIBL) has been analyzed as one of short channel effects occurred in double gate(DG) MOSFET. The DIBL is very important short channel effects as phenomenon that barrier height becomes lower since drain voltage influences on potential barrier of source in short channel. The analytical potential distribution of Poisson equation, validated in previous papers, has been used to analyze DIBL. Since Gaussian function been used as carrier distribution for solving Poisson's equation to obtain analytical solution of potential distribution, we expect our results using this model agree with experimental results. The change of DIBL has been investigated for device parameters such as channel thickness, oxide thickness and channel doping intensity.

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Analysis of Drain Induced Barrier Lowering for Double Gate MOSFET According to Channel Doping Concentration (채널도핑강도에 대한 이중게이트 MOSFET의 DIBL분석)

  • Jung, Hak-Kee
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.16 no.3
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    • pp.579-584
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    • 2012
  • In this paper, drain induced barrier lowering(DIBL) has been analyzed as one of short channel effects occurred in double gate(DG) MOSFET. The DIBL is very important short channel effects as phenomenon that barrier height becomes lower since drain voltage influences on potential barrier of source in short channel. The analytical potential distribution of Poisson equation, validated in previous papers, has been used to analyze DIBL. Since Gaussian function been used as carrier distribution for solving Poisson's equation to obtain analytical solution of potential distribution, we expect our results using this model agree with experimental results. The change of DIBL has been investigated for device parameters such as channel thickness, oxide thickness and channel doping concentration.

Analysis of Short Channel Effects Using Analytical Transport Model For Double Gate MOSFET

  • Jung, Hak-Kee
    • Journal of information and communication convergence engineering
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    • v.5 no.1
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    • pp.45-49
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    • 2007
  • The analytical transport model in subthreshold regime for double gate MOSFET has been presented to analyze the short channel effects such as subthreshold swing, threshold voltage roll-off and drain induced barrier lowering. The present approach includes the quantum tunneling of carriers through the source-drain barrier. Poisson equation is used for modeling thermionic emission current, and Wentzel-Kramers-Brillouin approximations are applied for modeling quantum tunneling current. This model has been used to investigate the subthreshold operations of double gate MOSFET having the gate length of the nanometer range with ultra thin gate oxide and channel thickness under sub-20nm. Compared with results of two dimensional numerical simulations, the results in this study show good agreements with those for subthreshold swing and threshold voltage roll-off. Note the short channel effects degrade due to quantum tunneling, especially in the gate length of below 10nm, and DGMOSFETs have to be very strictly designed in the regime of below 10nm gate length since quantum tunneling becomes the main transport mechanism in the subthreshold region.

Dependence of Channel Doping Concentration on Drain Induced Barrier Lowering for Asymmetric Double Gate MOSFET (비대칭 이중게이트 MOSFET에 대한 DIBL의 채널도핑농도 의존성)

  • 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.805-810
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    • 2016
  • The dependence of drain induced barrier lowering(DIBL) is analyzed for doping concentration in channel of asymmetric double gate(DG) MOSFET. The DIBL, the important short channel effect, is described as lowering of source barrier height by drain voltage. The analytical potential distribution is derived from Poisson's equation to analyze the DIBL, and the DIBL is observed according to top/bottom gate oxide thickness and bottom gate voltage as well as channel doping concentration. As a results, the DIBL is significantly influenced by channel doping concentration. DIBL is significantly increased by doping concentration if channel length becomes under 25 nm. The deviation of DIBL is increasing with increase of oxide thickness. Top and bottom gate oxide thicknesses have relation of an inverse proportion to sustain constant DIBL regardless channel doping concentration. We also know the deviation of DIBL for doping concentration is changed according to bottom gate voltage.

Dependence of Drain Induced Barrier Lowering for Ratio of Channel Length vs. Thickness of Asymmetric Double Gate MOSFET (비대칭 DGMOSFET에서 채널길이와 두께 비에 따른 DIBL 의존성 분석)

  • Jung, Hakkee
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.19 no.6
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    • pp.1399-1404
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    • 2015
  • This paper analyzed the phenomenon of drain induced barrier lowering(DIBL) for the ratio of channel length vs. thickness of asymmetric double gate(DG) MOSFET. DIBL, the important secondary effect, is occurred for short channel MOSFET in which drain voltage influences on potential barrier height of source, and significantly affects on transistor characteristics such as threshold voltage movement. The series potential distribution is derived from Poisson's equation to analyze DIBL, and threshold voltage is defined by top gate voltage of asymmetric DGMOSFET in case the off current is 10-7 A/m. Since asymmetric DGMOSFET has the advantage that channel length and channel thickness can significantly minimize, and short channel effects reduce, DIBL is investigated for the ratio of channel length vs. thickness in this study. As a results, DIBL is greatly influenced by the ratio of channel length vs. thickness. We also know DIBL is greatly changed for bottom gate voltage, top/bottom gate oxide thickness and channel doping concentration.