• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.10
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• pp.1815-1821
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• 2006

In this paper, the subthreshold swing has been analyzed for FinFET under channel length of 20nm. The analytical current model has been developed , including thermionic current and tunneling current models. The potential distribution by Poisson equation and carrier distribution by Maxwell-Boltzman statistics are used to calculate thermionic emission current and WKB(Wentzel-Kramers-Brillouin) approximation to tunneling current. The cutoff current is obtained by simple adding two currents since two current is independent. The subthreshold swings by this model are compared with those by two dimensional simulation and two values agree well. Since the tunneling current increases especially under channel length of 10nm, the characteristics of subthreshold swing is degraded. The channel and gate oxide thickness have to be fabricated as am as possible to decrease this short channel effects, and this process has to be developed. The subthreshold swings as a function of channel doping concentrations are obtained. Note that subthreshold swings are resultly constant at low doping concentration.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.865-868
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• 2006

In this paper, the subthreshold swing has been analyzed for double gate FinFET under channel length of 20nm. The analytical current model has been developed, including thermionic current and tunneling current models. The potential distribution by Poisson equation and carrier distribution by Maxwell-Boltzman statistics are used to calculate thermionic emission current, and WKB(Wentzel-Framers-Brillouin) approximation to tunneling current. The cutoff current is obtained by simple adding two currents since two current is independent. The subthreshold swings by this model are compared with those by two dimensional simulation and two values are good agreement. Since the tunneling current increases especially under channel length of 10nm, the characteristics of subthreshold swing is degraded. The channel and gate oxide thickness have to be fabricated as thin as possible to decrease this short channel effects and this process has to be developed. The subthreshold swings as a function of channel doping concentrations are obtained.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.3
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• pp.541-546
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• 2008

In this paper, conduction phenomena have been considered for nano structure double gate MOSFET, using the analytical model. The Possion equation is used to analytical model. The conduction mechanisms to have an influence on current conduction are thermionic emission and tunneling current, and subthreshold swings of this paper are compared with those of two dimensional simulation to verify this model. The deviation of current path and the influence of current path on subthreshold swing have been considered according to the dimensional parameters of double gate MOSFET, i.e. gate length, gate oxide thickness, channel thickness. The optimum channel doping concentration is determined as the deviation of conduction path is considered according doping concentration.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.10
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• pp.1840-1844
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• 2008

In this paper, the influence of channel doping concentration, which the most important factor is as double gate MOSFET is fabricated, on transport characteristics has been analyzed in the subthreshold region. The analytical model is used to derive transport model based on Poisson equation. The thermionic omission and tunneling current to have an influence on subthreshold current conduction are analyzed, and the relationship of doping concentration and subthreshold swings of this paper are compared with those of Medici two dimensional simulation, to verify this model. As a result, transport model presented in this paper is good agreement with two dimensional simulation model, and the transport characteristics have been considered according to the dimensional parameters of double gate MOSFET.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.709-712
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• 2008

본 연구에서는 이중게이트 MOSFET 제작시 가장 중요한 요소인 채널도핑농도가 전송특성에 미치는 영향을 분석하고자 한다. 이를 위하여 분석학적 전송모델을 사용하였으며 분석학적 모델을 유도하기 위하여 포아슨방정식을 이용하였다. 나노구조 이중게이트 MOSFET에서 문턱전압이하의 전류전도에 영향을 미치는 열 방사전류와 터널링전류에 대하여 분석하였으며 본 연구의 모델이 타당하다는 것을 입증하기 위하여 서브문턱스윙값과 채널도핑농도의 관계를 이차원 시뮬레이션 값과 비교하였다. 결과적으로 본 연구에서 제시한 전송특성모델이 이차원 시뮬레이션모델과 매우 잘 일치하였으며 이중게이트 MOSFET의 구조적 파라미터에 따라 전송특성을 분석하였다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.9
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• pp.1599-1604
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• 2008

In this paper, it has been analyzed how transport characteristics is influenced on gate oxide properties in the subthreshold region as nano structure FinFET is fabricated. The analytical model is used to derive transport model, and Possion equation is used to obtain analytical model. The thermionic emission and tunneling current to have an influence on subthreshold current conduction are analyzed for nano-structure FinFET, and subthreshold swings of this paper are compared with those of two dimensional simulation to verify this model. As a result, transport model presented in this paper is good agreement with two dimensional simulation model, and this study shows that the transport characteristics have been changed by gate oxide properties. As gate length becomes smaller, funneling characteristics, one of the most important transport mechanism, have been analyzed.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.861-864
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• 2006

In this paper conduction phenomena have been considered for nano structure double gate MOSFET, using the analytical model. The Possion equation is used to obtain the analytical model. The conduction mechanisms to have an influence on current conduction are thermionic emission and tunneling current, and subthreshold swings of this paper is compared with those of two dimensional simulation to verify this model. The deviation of current path and the influence of current path on subthreshold swing have been considered according to the dimensional parameters of double gate MOSFET, i.e. gate length, gateoxide thickness, channel thickness. The optimum channel doping concentration is determined as the deviation of conduction path is considered according to channel doping concentration.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.3
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• pp.479-485
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• 2006

The double gate(DG) MOSFET is a promising candidate to further extend the CMOS scaling and provide better control of short channel effect(SCE). DGMOSFETs, having ultra thin undoped Si channel for SCEs control, ale being validated for sub-20nm scaling. A novel analytical transport model for the subthreshold mode of DGMOSFETs is proposed in this paper. The model enables analysis of short channel effect such as the subthreshold swing(SS), the threshold voltage roil-off$({\Delta}V_{th})$ and the drain induced barrier lowering(DIBL). The proposed model includes the effects of thermionic emission and quantum tunneling of carriers through the source-drain barrier. An approximative solution of the 2D Poisson equation is used for the distribution of electric potential, and Wentzel-Kramers-Brillouin approximation is used for the tunneling probability. The new model is used to investigate the subthreshold characteristics of a double gate MOSFET having the gate length in the nanometer range $(5-20{\sim}nm)$ with ultra thin gate oxide and channel thickness. The model is verified by comparing the subthreshold swing and the threshold voltage roll-off with 2D numerical simulations. The proposed model is used to design contours for gate length, channel thickness, and gate oxide thickness.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.4
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• pp.804-810
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• 2005

An analytical subthreshold swing (SS) model has been presented for double gate MOSFET(DGMOSFET) in this study. The results calculated by this model are more precise for about 10nm channel length and thickness than those derived from the previous models. The results of this model are compared with Medici simulation to varify the validity of this model, and good agreementes have been obtained. The changes of SS have been investigated for various channel lengths, channel thicknesses and gate oxide thicknesses using this model, given that these parameters are very important in design of DGMOSFET. This demonstrates that the proposed model provides useful data for design of nano-scale DGMOSFET. It is Known that the SS is improved to smaller ratios of channel thickness vs channel length and is smaller in very thin oxides. New gate dielectric materials with high permittivity have to be developed to enable design of nano-scale DGMOSFET.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.751-754
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• 2008

본 연구에서는 나노구조 FinFET 제작시 게이트산화막 특성이 서브문턱영역에서 전송특성에 미치는 영향을 분석하고자 한다. 이를 위하여 분석학적 전송모델을 사용하였으며 분석학적 모델을 유도하기 위하여 포아슨방정식을 이용하였다. 나노구조 FinFET에서 문턱전압이하의 전류전도에 영향을 미치는 열방사전류와 터널링전류에 대하여 분석하였으며 본 연구의 모델이 타당하다는 것을 입증하기 위하여 서브문턱스윙값을 이차원 시뮬레이션값과 비교하였다. 결과적으로 본 연구에서 제시한 전송특성모델이 이차원 시뮬레이션모델과 매우 잘 일치하였으며 FinFET의 전송특성이 게이트산화막의 특성에 따라 매우 큰 변화를 보이는 것을 알 수 있었다. 특히 게이트길이가 작아지면서 전송특성에 커다란 영향을 미치는 터널링특성에 대하여 집중적으로 분석하였다.