• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.11
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• pp.2511-2516
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• 2012

This paper have analyzed the change of threshold voltage for conduction path of double gate(DG) MOSFET. The threshold voltage roll-off among the short channel effects of DGMOSFET have become obstacles of precise device operation. The analytical solution of Poisson's equation have been used to analyze the threshold voltage, and Gaussian function been used as carrier distribution to analyze closely for experimental results. The threshold voltages for conduction path have been analyzed for device parameters such as channel length, channel thickness, gate oxide thickness and doping concentration. Since this potential model has been verified in the previous papers, we have used this model to analyze the threshold voltage. Resultly, we know the threshold voltage is greatly influenced on the change of conduction path for device parameters of DGMOSFET.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.6
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• pp.1422-1428
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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.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.1
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• pp.163-168
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• 2015

This paper analyzed the deviation of tunneling current for bottom gate voltage of sub-10 nm asymmetric double gate MOSFET. The asymmetric double gate MOSFET among multi gate MOSFET developed to reduce the short channel effects has the advantage to increase the facts to be able to control the channel current, compared with symmetric double gate MOSFET. The increase of off current is, however, inescapable if aymmetric double gate MOSFET has the channel length of sub-10 nm. The influence of tunneling current was investigated in this study as the portion of tunneling current for off current was calculated. The tunneling current was obtained by the WKB(Wentzel-Kramers-Brillouin) approximation and analytical potential distribution derived from Poisson equation. As a results, the tunneling current was greatly influenced by bottom gate voltage in sub-10 nm asymmetric double gate MOSFET. Especially it showed the great deviation for channel length, top and bottom gate oxide thickness, and channel thickness.

• 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.

• Proceedings of the Korean Vacuum Society Conference
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• 2009.08a
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• pp.195-195
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• 2009

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.762-765
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• 2013

This paper analyzed the change of subthreshold current for gate oxide thickness of double gate(DG) MOSFET. Poisson's equation had been used to analyze the potential distribution in channel, and Gaussian function had been used as carrier distribution. The potential distribution was obtained as the analytical function of channel dimension, using the boundary condition. The subthreshold current had been analyzed for gate oxide thickness, and projected range and standard projected deviation of Gaussian function. Since this analytical potential model was verified in the previous papers, we used this model to analyze the subthreshold current. Resultly, we know the subthreshold current was influenced on parameters of Gaussian function and gate oxide thickness for DGMOSFET.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.8
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• pp.1465-1470
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• 2017

In conventional MOSFETs, the silicon thickness is always larger than inversion layer, so that the drain induced barrier lowering (DIBL) is expressed as a function of oxide thickness and channel length regardless of silicon thickness. However, since the silicon thickness is fully depleted in the sub-10 nm low doped double gate (DG) MOSFET, the conventional SPICE model for DIBL is no longer available. Therefore, we propose a novel DIBL SPICE model for DGMOSFETs. In order to analyze this, a thermionic emission and the tunneling current was obtained by the potential and WKB approximation. As a result, it was found that the DIBL was proportional to the sum of the top and bottom oxide thicknesses and the square of the silicon thickness, and inversely proportional to the third power of the channel length. Particularly, static feedback coefficient of SPICE parameter can be used between 1 and 2 as a reasonable parameter.

• Steel and Composite Structures
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• v.50 no.5
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• pp.515-529
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• 2024

Cold-formed steel (CFS) is a popular choice for construction due to its low cost, durability, sustainability, resistance to high environmental and seismic pressures, and ease of installation. The beam-column connections in residential and medium-rise structures are formed using self-drilling screws that connect two CFS channel sections and a gusset plate. In order to increase the moment capacity of these CFS screwed beam-column connections, stiffeners are often placed on the web area of each single channel. However, there is limited literature on studying the effects of stiffeners on the moment capacity of CFS screwed beam-column connections. Hence, this paper proposes a new test approach for determining the moment capacity of CFS screwed beam-column couplings. This study describes an experimental test programme consisting of eight novel experimental tests. The effect of stiffeners, beam thickness, and gusset plate thickness on the structural behaviour of CFS screwed beam-column connections is investigated. Besides, nonlinear elasto-plastic finite element (FE) models were developed and validated against experimental test data. It found that there was reasonable agreement in terms of moment capacity and failure mode prediction. From the experimental and numerical investigation, it found that the increase in gusset plate or beam thickness and the use of stiffeners have no significant effect on the structural behaviour, moment capacity, or rotational capacity of joints exhibiting the same collapse behaviour; however, the capacity or energy absorption capacities have increased in joints whose failure behaviour varies with increasing thickness or using stiffeners. Besides, the thickness change has little impact on the initial stiffness.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• v.y2005m4
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• pp.134-138
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• 2005

The structural analysis and water pressure test of regenerative liquid rocket thrust chamber cooling channel specimens are performed at room temperature. material properties of copper alloy are obtained by uniaxial tension test at room temperature and used of elastic-plastic structural analysis. The plate type of cooling channel specimen are manufactured and performed water pressure test in order to confirm the analysis results. The differences between results of elastic-plastic analysis and that of water pressure test of cooling channel specimen are small and find that manufacturing process affect the structural stability of cooling channel very much because cooling channel thickness is small

• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.4
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• pp.77-85
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• 1999

By assuming a linearly graded depletion edge approximation in the intrinsic MOS region and by taking into account the mobility variation dependent on both lateral and vertical fields, a physics-based analytical model for a short-channel(n-channel) MOSFET is suggested. Derived expressions for the threshold voltage and the drain current of typical MOSFET is structures could be used in a unified manner for all operating range. The threshold voltage was calculated by changing following variables : channel length, drain-source voltage, source-substrate voltage, p-substrate doping level, and oxide thickness. It is shown that the threshold voltage decreases almost exponentially as the channel length decreases. In addition, the short-channel threshold voltage roll-off, the channel length modulation and the electron mobility degradation can be derived within a satisfactory accuracy.