scholarly journals Subthreshold swing model using scale length for sub-10 nm junction-based double-gate MOSFETs

2020 ◽  
Vol 10 (2) ◽  
pp. 1747
Author(s):  
Hakkee Jung
Keyword(s):  
Analytical Model ◽  
Potential Distribution ◽  
Geometric Mean ◽  
Oxide Thickness ◽  
Channel Length ◽  
Subthreshold Swing ◽  
Double Gate ◽  
Silicon Thickness ◽  
The Relationship ◽  
Scale Length

We propose an analytical model for subthreshold swing using scale length for sub-10 nm double gate (DG) MOSFETs. When the order of the calculation for the series type potential distribution is increased it is possible to obtain accuracy, but there is a problem that the calculation becomes large. Using only the first order calculation of potential distribution, we derive the scale length λ1 and use it to obtain an analytical model of subthreshold swing. The findings show this subthreshold swing model is in concordance with a 2D simulation. The relationship between the channel length and silicon thickness, which can analyze the subthreshold swing using λ1, is derived by the relationship between the scale length and the geometric mean of the silicon and oxide thickness. If the silicon thickness and oxide film thickness satisfy the condition of (Lg-0.215)/6.38 > tsi(=tox), it is found that the result of this model agrees with the results using higher order calculations, within a 4% error range.

scholarly journals Analysis of subthreshold swing in junctionless double gate MOSFET using stacked high-k gate oxide

2021 ◽  
Vol 11 (1) ◽  
pp. 240
Author(s):  
Hakkee Jung
Keyword(s):  
Dielectric Constant ◽  
Oxide Film ◽  
Gate Voltage ◽  
Gate Oxide ◽  
Oxide Thickness ◽  
Channel Length ◽  
Subthreshold Swing ◽  
Asymmetric Structure ◽  
Double Gate ◽  
High K

In this paper, the subthreshold swing was observed when the stacked high-k gate oxide was used for a junctionless double gate (JLDG) MOSFET. For this purpose, a subthreshold swing model was presented using the series-type potential model derived from the Poisson equation. The results of the model presented in this paper were in good agreement with the two-dimensional numerical values and those from other papers. Using this model, the variation of the subthreshold swing for the channel length, silicon thickness, gate oxide thickness, and dielectric constant of the stacked high-k material was observed using the dielectric constant as a parameter. As a result, the subthreshold swing was reduced when the high-k materials were used as the stacked gate oxide film. In the case of the asymmetric structure, the subthreshold swing can be reduced than that of the symmetric JLDG MOSFET when the dielectric constant of the bottom stacked oxide film was greater than that of the top stacked oxide film. In the case of the asymmetric structure, the subthreshold swing could be also reduced by applying the bottom gate voltage lower than the top gate voltage.

scholarly journals The Impact of Tunneling on the Subthreshold Swing in Sub-20 nm Asymmetric Double Gate MOSFETs

2016 ◽  
Vol 6 (6) ◽  
pp. 2730
Author(s):  
Hak Kee Jung ◽  
Sima Dimitrijev
Keyword(s):  
Carrier Transport ◽  
Thermionic Emission ◽  
Tunneling Current ◽  
Channel Length ◽  
Subthreshold Swing ◽  
Double Gate ◽  
Subthreshold Region ◽  
Channel Thickness ◽  
20 Nm ◽  
The Impact

<p>This paper analyzes the subthreshold swing in asymmetric double gate MOSFETs with sub-20 nm channel lengths. The analysis of the carrier transport in the subthreshold region of these nano scaled MOSFET includes tunneling as an important additional mechanism to the thermionic emission. It is found that the subthreshold swing is increasing due to tunneling current and that the performance of nano scaled MOSFETs is degraded. The degradation of the subthreshold swing due to tunneling is quantified using analytical potential distribution and Wentzel–Kramers–Brillouin (WKB) approximation in this paper. This analytical approach is verified by two dimensional simulation. It is shown that the degradation of subthreshold swing increases with both reduction of channel length and increase of channel thickness. We also show that the subthreshold swing is increasing in case of different top and bottom gate oxide thicknesses.</p>

scholarly journals Threshold voltage roll-off for sub-10 nm asymmetric double gate MOSFET

2019 ◽  
Vol 9 (1) ◽  
pp. 163
Author(s):  
Hakkee Jung
Keyword(s):  
Threshold Voltage ◽  
Tunneling Current ◽  
Gate Oxide ◽  
Oxide Thickness ◽  
Channel Length ◽  
Double Gate ◽  
Short Channel ◽  
Double Gate Mosfet ◽  
Channel Effects ◽  
Channel Thickness

Threshold voltage roll-off is analyzed for sub-10 nm asymmetric double gate (DG) MOSFET. Even asymmetric DGMOSFET will increase threshold voltage roll-off in sub-10 nm channel length because of short channel effects due to the increase of tunneling current, and this is an obstacle against the miniaturization of asymmetric DGMOSFET. Since asymmetric DGMOSFET can be produced differently in top and bottom oxide thickness, top and bottom oxide thicknesses will affect the threshold voltage roll-off. To analyze this, <em>thermal</em><em> </em>emission current and tunneling current have been calculated, and threshold voltage roll-off by the reduction of channel length has been analyzed by using channel thickness and top/bottom oxide thickness as parameters. As a result, it is found that, in short channel asymmetric double gate MOSFET, threshold voltage roll-off is changed greatly according to top/bottom gate oxide thickness, and that threshold voltage roll-off is more influenced by silicon thickness. In addition, it is found that top and bottom oxide thickness have a relation of inverse proportion mutually for maintaining identical threshold voltage. Therefore, it is possible to reduce the leakage current of the top gate related with threshold voltage by increasing the thickness of the top gate oxide while maintaining the same threshold voltage.

The Impact of Tunneling on the Subthreshold Swing in Sub-20 nm Asymmetric Double Gate MOSFETs

2016 ◽  
Vol 6 (6) ◽  
pp. 2730
Author(s):  
Hak Kee Jung ◽  
Sima Dimitrijev
Keyword(s):  
Carrier Transport ◽  
Thermionic Emission ◽  
Tunneling Current ◽  
Channel Length ◽  
Subthreshold Swing ◽  
Double Gate ◽  
Subthreshold Region ◽  
Channel Thickness ◽  
20 Nm ◽  
The Impact

<p>This paper analyzes the subthreshold swing in asymmetric double gate MOSFETs with sub-20 nm channel lengths. The analysis of the carrier transport in the subthreshold region of these nano scaled MOSFET includes tunneling as an important additional mechanism to the thermionic emission. It is found that the subthreshold swing is increasing due to tunneling current and that the performance of nano scaled MOSFETs is degraded. The degradation of the subthreshold swing due to tunneling is quantified using analytical potential distribution and Wentzel–Kramers–Brillouin (WKB) approximation in this paper. This analytical approach is verified by two dimensional simulation. It is shown that the degradation of subthreshold swing increases with both reduction of channel length and increase of channel thickness. We also show that the subthreshold swing is increasing in case of different top and bottom gate oxide thicknesses.</p>

Projected Range Dependent Tunneling Current of Asymmetric Double Gate MOSFET

2016 ◽  
Vol 6 (1) ◽  
pp. 113
Author(s):  
Hak Kee Jung
Keyword(s):  
Distribution Function ◽  
Gaussian Distribution ◽  
Potential Distribution ◽  
Gaussian Function ◽  
Tunneling Current ◽  
Channel Length ◽  
Double Gate ◽  
Accurate Analysis ◽  
Projected Range ◽  
Gaussian Distribution Function

This study is to analyze the changes of tunneling current according to projected range, a variable of Gaussian function of channel doping function of Asymmetric Double Gate; ADG MOSFET. In MOSFET with channel length below 10 nm, tunneling current occupies a large percentage among off-currents. The increase of tunneling current has a large effect on the characteristics of subthreshold such as threshold voltage movement and the decline of subthreshold swing value, so the accurate analysis of this is being required. To analyze this, potential distribution of series form was obtained using Gaussian distribution function, and using this hermeneutic potential distribution, thermionic emission current and tunneling current making up off-current were obtained. At this point, the effect that the changes of projected range, a variable of Gaussian distribution function, have on the ratio of tunneling current among off-currents was analyzed. As a result, the smaller projected range was, the lower the ratio of tunneling current was. When projected range increased, tunneling current increased largely. Also, it was observed that the value of projected range which the ratio of tunneling current increased changed according to maximum channel doping value, channel length, and channel width.

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