• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.4
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• pp.805-811
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• 2012

In this paper, movement of conduction path has been analyzed for electron distribution in the channel of double gate(DG) MOSFET. The analytical potential distribution model of Poisson equation, validated in previous researches, has been used to analyze transport characteristics. DGMOSFETs have the adventage to be able to reduce short channel effects due to improvement for controllability of current by two gate voltages. Since short channel effects have been occurred in subthreshold region including threshold region, the analysis of transport characteristics in subthreshold region is very important. Also transport characteristics have been influenced on the deviation of electron distribution and conduction path. In this study, the influence of electron distribution on conduction path has been analyzed according to intensity and distribution of doping and channel dimension.

• 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.2
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• pp.372-377
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• 2013

This paper have presented the breakdown voltage for double gate(DG) MOSFET. The analytical solution of Poisson's equation and Fulop's breakdown condition have been used to analyze for breakdown voltage. The double gate(DG) MOSFET has the advantage to reduce the short channel effects as improving the current controllability of gate. But we need the study for the breakdown voltage of DGMOSFET since the decrease of the breakdown voltage is unavoidable. To approximate with experimental values, we have used the Gaussian function as charge distribution for Poisson's equation, and the change of breakdown voltage has been observed for device geometry. Since this potential model has been verified in the previous papers, we have used this model to analyze the breakdown voltage. As a result to observe the breakdown voltage, the smaller channel length and the higher doping concentration become, the smaller the breakdown voltage becomes. Also we have observed the change of the breakdown voltage for gate oxide thickness and channel thickness.

• 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.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.704-707
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• 2013

This paper has analyzed the subthreshold swings for top and bottom gate voltages of asymmetric double gate(DG) MOSFET. The asymmetric DGMOSFET is four terminal device to be able to separately bias for top and bottom gates. The subthreshold swing, therefore, has to be analyze not only for top gate voltage, but also for bottom gate voltage. In the pursuit of this purpose, Poisson equation has been solved to obtain the analytical solution of potential distribution with Gaussian function, and the subthreshold swing model has been presented. As a result to observe the subthreshold swings for the change of top and bottom gate voltage using this subthreshold swing model, we know the subthreshold swings are greatly changed for gate voltages. Especially we know the conduction path has been changed for top and bottom gate voltage and this is expected to greatly influence on subthreshold swings.

• 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.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.9
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• pp.2183-2188
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• 2014

This paper has analyzed threshold voltage movement for channel doping concentration of asymmetric double gate(DG) MOSFET. The asymmetric DGMOSFET is generally fabricated with low doping channel and fully depleted under operation. Since impurity scattering is lessened, asymmetric DGMOSFET has the adventage that high speed operation is possible. The threshold voltage movement, one of short channel effects necessarily occurred in fine devices, is investigated for the change of channel doping concentration in asymmetric DGMOSFET. The analytical potential distribution of series form is derived from Possion's equation to obtain threshold voltage. The movement of threshold voltage is investigated for channel doping concentration with parameters of channel length, channel thickness, oxide thickness, and doping profiles. As a result, threshold voltage increases with increase of doping concentration, and that decreases with decrease of channel length. Threshold voltage increases with decrease of channel thickness and bottom gate voltage. Lastly threshold voltage increases with decrease of oxide thickness.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.2
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• pp.401-406
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• 2015

The change of subthreshold swing for channel length of asymmetric double gate(DG) MOSFET has been analyzed. The subthreshold swing is the important factor to determine digital chracteristics of transistor and is degraded with reduction of channel. The subthreshold swing for channel length of the DGMOSFET developed to solve this problem is investigated for channel thickness, oxide thickness, top and bottom gate voltage and doping concentration. Especially the subthreshold swing for asymmetric DGMOSFET to be able to be fabricated with different top and bottom gate structure is investigated in detail for bottom gate voltage and bottom oxide thickness. To obtain the analytical subthreshold swing, the analytical potential distribution is derived from Possion's equation, and Gaussian distribution function is used as doping profile. As a result, subthreshold swing is sensitively changed according to top and bottom gate voltage, channel doping concentration and channel dimension.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.741-744
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• 2014

This paper has analyzed threshold voltage roll-off for bottom gate voltages of asymmetric double gate(DG) MOSFET. Since the asymmetric DGMOSFET is four terminal device to be able to separately bias for top and bottom gates, the bottom gate voltage influences on threshold voltage. It is, therefore, investigated how the threshold voltage roll-off known as short channel effects is reduced with bottom gate voltage. In the pursuit of this purpose, off-current model is presented in the subthreshold region, and the threshold voltage roll-off is observed for channel length and thickness with a parameter of bottom gate voltage as threshold voltage is defined by top gate voltage that off-currnt is $10^{-7}A/{\mu}m$ per channel width. As a result to observe the threshold voltage roll-off for bottom gate voltage using this model, we know the bottom gate voltage greatly influences on threshold voltage roll-off voltages, especially in the region of short channel length and thickness.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.748-751
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• 2014

This paper has analyzed threshold voltage movement for channel doping concentration of asymmetric double gate(DG) MOSFET. The asymmetric DGMOSFET is generally fabricated with low doping channel and fully depleted under operation. Since impurity scattering is lessened, asymmetric DGMOSFET has the adventage that high speed operation is possible. The threshold voltage movement, one of short channel effects necessarily occurred in fine devices, is investigated for the change of channel doping concentration in asymmetric DGMOSFET. The analytical potential distribution of series form is derived from Possion's equation to obtain threshold voltage. The movement of threshold voltage is investigated for channel doping concentration with parameters of channel length, channel thickness, oxide thickness, and doping profiles. As a result, threshold voltage increases with increase of doping concentration, and that decreases with decrease of channel length. Threshold voltage increases with decrease of channel thickness and bottom gate voltage. Lastly threshold voltage increases with decrease of oxide thickness.