• Proceeding of EDISON Challenge
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• 2013.04a
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• pp.266-268
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• 2013

In this paper, we study the channel doping concentration characteristics of junctionless nanowire transistors (JLT) using Edison nanowire FET device simulation. JLT has no junctions by very simple fabrication process. And this device has less variability and better electrical properties than classical inversion-mode transistors with PN junctions at the source and drain. In this simulation we use tri-gate structure. Source and drain doping concentration is $10^{20}atoms/cm^3$. The simulation results show that I-V characteristics of JLT change due to the variation of channel doping concentration.

• Journal of the Korean Institute of Telematics and Electronics
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• v.22 no.6
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• pp.58-62
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• 1985

Analytical threshold voltage model of small size ion-implanted MOSFET's is proposed. Yau's model which is only applicable to MOSFET's with constant doping concentration was modified to handle the MOSFET's with nonuniform channel doping concentration and bird's beak, whereby the short and narrow-channel effect was quantitively described. Threshold voltage model for short-channel MOSFET's was derived by approximating the SUPREM result of channel impurity profile to a 2-step profile, and the narrow width be-haviour was successfully described using thr'weighting factor'to accommodate the doping profile in the bird's beak region.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.10
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• pp.2403-2408
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• 2013

This paper has analyzed the change of forward and backward current for channel doping concentration to analyze off-current of double gate(DG) MOSFET. The Gaussian function as channel doping distribution has been used to compare with experimental ones, and the two dimensional analytical potential distribution model derived from Poisson's equation has been used to analyze the off-current. The off-current has been analyzed for the change of projected range and standard projected range of Gaussian function with device parameters such as channel length, channel thickness, gate oxide thickness and channel doping concentration. As a result, this research shows the off-current has greatly influenced on forward and backward current for device parameters, especially for the shape of Gaussian function for channel doping concentration.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.4
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• pp.793-798
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• 2012

In this paper, dependence of subthreshold current has been analyzed for doping distribution and channel structure of double gate(DG) MOSFET. The charge distribution of Gaussian function validated in previous researches has been used to obtain potential distribution in Poisson equation. Since DGMOSFETs have reduced short channel effects with improvement of current controllability by gate voltages, subthreshold characteristics have been enhanced. The control of current in subthreshold region is very important factor related with power consumption for ultra large scaled integration. The deviation of threshold voltage has been qualitatively analyzed using the changes of subthreshold current for gate voltages. Subthreshold current has been influenced by doping distribution and channel dimension. In this study, the influence of channel length and thickness on current has been analyzed according to intensity and distribution of doping.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.5
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• pp.1196-1202
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• 2013

This paper have analyzed the change of breakdown voltage for channel doping concentration and device parameters of double gate(DG) MOSFET using two dimensional potential model. The low breakdown voltage becomes the obstacle of power device operation, and breakdown voltage decreases seriously by the short channel effects derived from scaled down device in the case of DGMOSFET. The two dimensional analytical potential distribution derived from Poisson's equation have been used to analyze the breakdown voltage for device parameters such as channel length, channel thickness, gate oxide thickness and channel doping concentration. Resultly, we could observe the breakdown voltage has greatly influenced on device dimensional parameters as well as channel doping concentration, especially the shape of Gaussian function used as channel doping concentration.

• 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.

• 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.

• JSTS:Journal of Semiconductor Technology and Science
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• v.7 no.2
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• pp.120-131
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• 2007

A comprehensive short channel analytical model has been proposed for High Electron Mobility Transistor (HEMT) to obtain higher cut-off frequency maintaining the reliability of the device. The model has been proposed to consider generalized doping variation in the directions perpendicular to and along the channel. The effect of field plates and different gate-insulator geometry (T-gate, etc) have been considered by dividing the area between gate and the high band gap semiconductor into different regions along the channel having different insulator and metal combinations of different thicknesses and work function with the possibility that metal is in direct contact with the high band gap semiconductor. The variation obtained by gate-insulator geometry and field plates in the field and channel potential can be produced by varying doping concentration, metal work-function and gate-stack structures along the channel. The results so obtained for normal device structure have been compared with previous proposed model and numerical method (finite difference method) to prove the validity of the model.

• Journal of information and communication convergence engineering
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• v.9 no.6
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• pp.738-742
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• 2011

This paper has studied drain induced barrier lowering(DIBL) for Double Gate MOSFET(DGMOSFET) using analytical potential model. Two dimensional analytical potential model has been presented for symmetrical DGMOSFETs with process parameters. DIBL is very important short channel effects(SCEs) for nano structures since drain voltage has influenced on source potential distribution due to reduction of channel length. DIBL has to be small with decrease of channel length, but it increases with decrease of channel length due to SCEs. This potential model is used to obtain the change of DIBL for DGMOSFET correlated to channel doping profiles. Also device parameters including channel length, channel thickness, gate oxide thickness and doping intensity have been used to analyze DIBL.

• JSTS:Journal of Semiconductor Technology and Science
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• v.8 no.2
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• pp.170-177
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• 2008

In the present work a methodology to minimize short channel effects (SCEs) by modulating the effective channel length is proposed to design 25 nm single and double gate-source/drain underlap MOSFETs. The analysis is based on the evaluation of the ratio of effective channel length to natural/ characteristic length. Our results show that for this ratio to be greater than 2, steeper source/drain doping gradients along with wider source/drain roll-off widths will be required for both devices. In order to enhance short channel immunity, the ratio of source/drain roll-off width to lateral straggle should be greater than 2 for a wide range of source/drain doping gradients.