• Journal of Magnetics
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• v.4 no.4
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• pp.111-114
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• 1999

Numerical calculation for temperature dependence of galvanomagnetic properties of thin bismuth films is pursued. The quasi-two dimensional system is treated in the perturbation formalism of previous study, where realistic screened potential due to impurity is assumed to be the only scattering channel. The potential is separated into pure two dimensional part and the remaining presumed perturbation part. Relaxation time and mobilities for both electron and hole are evaluated, then temperature dependence of the Hall coefficient and magnetoresistance is obtained. The broad minimum of magnetoresistnace is manifested, and the interpretation under the kinetic theory is made. Thickness dependence of the quantities are also shown, which are in good agreement with the expected quantum size effect.

• Proceeding of EDISON Challenge
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• 2016.03a
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• pp.339-343
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• 2016

본 연구에서는 양자역학적 전하수송 모델링을 바탕으로 channel length ($L_{ch}$), equivalent oxide thickness (EOT), supply voltage ($V_{DS}$) 등의 소자 파라미터들에 초점을 맞춰 저전력 소자를 구현하였다. 본 연구에서 나타낸 최적의 소자 특성으로부터 ITRS에서 제시하고 있는 2021년 예측되는 소자 특성에 비하여 더 낮은 $V_{DS}$에서 동작을 하면서 더 높은 $I_{on}$과 낮은 SS 로서 구동하는 것이 가능할 것으로 기대된다. 뿐만 아니라 inverter 동작에 있어서 ideal inverter에 가까운 동작을 할 것으로 기대된다.

• Journal of the Korean Magnetics Society
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• v.22 no.1
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• pp.6-10
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• 2012

We have observed the change in the film resistance of thin nickel film up to 13 nm, which is deposited on a porous anodic alumina substrate, prepared by two-step anodization technique under phosphoric acid. The resulting film grows as a porous film, following the pore structure on the surface of the alumina substrate, and the value of the resistance lies above $150k{\Omega}$ within the range of thickness studied here, decreasing very slowly with the film thickness. The observed resistance value is much higher than the reported value of a uniform film at the same thickness. Since the observed value of the surface coverage with the pores is smaller than the critical value, expected from the percolation theory, the pore structure limits the formation of conduction channel across the film. In addition, by comparing to the typical model of thickness-dependent resistivity, we expect that the scattering at the pore edge further increases the film resistance.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.907-909
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• 2009

In this paper, the dependence of threshold voltage on the gate oxide thickness, which it mostly influenced on short channel effects in fabrication of FinFET, has been investigated. The transport model based on three dimensional Possion's equation has been used to analyze influence on gate oxide thickness. The gate oxide thickness is the most important factor to influence on the threshold voltage in nano structure FinFET. The potential distributions of this model are compared with those of three dimensional numerical simulation to verify this model. As a result, since potential model presented in this paper is good agreement with hree dimensional numerical model, the threshold voltage characteristics have been considered according to the gate oxide thickness of FinFET.

• Korean Journal of Agricultural Science
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• v.45 no.4
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• pp.707-713
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• 2018

This study was done to search for positional candidate genes associated with the back fat thickness trait using a Genome-Wide Association Study (GWAS) in purebred Yorkshires (N = 1755). Genotype and phenotype analyses were done for 1,642 samples. As a result of the associations with back fat thickness using the Gemma program (ver. 0.93), when the genome-wide suggestive threshold was determined using the Bonferroni method ($p=1.61{\times}10^{-5}$), the single nucleotide polymorphism (SNP) markers with suggestive significance were identified in 1 SNP marker on chromosome 2 (MARC0053928; $p=3.65{\times}10^{-6}$), 2 SNP markers on chromosome 14 (ALGA0083078; $p=7.85{\times}10^{-6}$, INRA0048453; $p=1.27{\times}10^{-5}$), and 1 SNP marker on chromosome 18 (ALGA0120564; $p=1.44{\times}10^{-5}$). We could select positional candidate genes (KCNQ1, DOCK1, LOC106506151, and LOC110257583), located close to the SNP markers. Among these, we identified a potassium voltage-gated channel subfamily Q member gene (KCNQ1) and the dedicator of cytokinesis 1 (DOCK1) gene associated with obesity and Type-2 diabetes. The SNPs and haplotypes of the KCNQ1 and DOCK1 genes can contribute to understanding the genetic structure of back fat thickness. Additionally, it may provide basic data regarding marker assisted selection for a meat quality trait in pigs.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.11
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• pp.767-773
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• 2017

Printed Circuit Heat Exchanger (PCHE) has an advantage for exchanging thermal energy between high-pressure and high-temperature fluids because its core is made by diffusion bonding method of accumulated metal thin-plates which are engraved of flow channel. Moreover, because it is possible that the flow channel can be micro-size hydraulic diameter, the heat transfer area per unit volume can be made larger than traditional heat exchanger. Therefore, PCHE can have higher efficiency of heat transfer. The smaller channel size can make the larger heat transfer area per unit volume. But if high pressure fluid flows inside the channel, the channel wall can be deformed, the structure and shape of flow channel and header have to be designed appropriately. In this study, the design methodology of PCHE channel in high pressure environment based on pressure vessel codes was investigated. And this methodology was validated by computational analysis.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.137-137
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• 2009

Thin-film transistors (TFTs) that can be prepared at low temperatures have attracted much attention due to the great potential for flexible electronics. One of the mainstreams in this field is the use of organic semiconductors such as pentacene. But device performance of the organic TFTs is still limited by low field effect mobility or rapidly degraded after exposing to air in many cases. Another approach is amorphous oxide semiconductors. Amorphous oxide semiconductors (AOSs) have exactly attracted considerable attention because AOSs were fabricated at room temperature and used lots of application such as flexible display, electronic paper, large solar cells. Among the various AOSs, a-IGZO was considerable material because it has high mobility and uniform surface and good transparent. The high mobility is attributed to the result of the overlap of spherical s-orbital of the heavy pest-transition metal cations. This study is demonstrated the effect of thickness channel layer from 30nm to 200nm. when the thickness was increased, turn on voltage and subthreshold swing were decreased. a-IGZO TFTs have used a shadow mask to deposit channel and source/drain(S/D). a-IGZO were deposited on SiO2 wafer by rf magnetron sputtering. using power is 150W, working pressure is 3m Torr, and an O2/Ar(2/28 SCCM) atmosphere at room temperature. The electrodes were formed with Electron-beam evaporated Ti(30nm) and Au(70nm) structure. Finally, Al(150nm) as a gate metal was evaporated. TFT devices were heat treated in a furnace at $250^{\circ}C$ in nitrogen atmosphere for an hour. The electrical properties of the TFTs were measured using a probe-station to measure I-V characteristic. TFT whose thickness was 150nm exhibits a good subthreshold swing(S) of 0.72 V/decade and high on-off ratio of 1E+08. Field effect mobility, saturation effect mobility, and threshold voltage were evaluated 7.2, 5.8, 8V respectively.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.615-618
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• 2005

In this work, the effects of corner transistors in SOI MOSFETs were investigated. We fabricated SOI MOSFETs with various widths and a fixed length and characterized them. The SOI thickness was $4000{\AA}$ and the buried oxide(BOX) thickness was $4000{\AA}$. The isolation of active region was simply done by silicon etching and TEOS sidewall formation. Several undesirable characteristics have been reported for LOCOS isolation in fabrication on SOI wafers so far. Although we used an STI-like process instead of LOCOS, there were still a couple of abnormal phenomena such as kinks and double humps in drain current. Above all, we investigated the location of the parasitic transistors and found that they were at the corners of the SOI in width direction by high-resolution SEM inspection. It turned out that their characteristics are strongly dependent on the channel width. We made a contact pad through which we can control the body potential and figured out the dependency of operation on the body potential. The double humps became more prominent as the body bias went more negative until the full depletion of the channel where the threshold voltage shift did not occur any more. Through these works, we could get insights on the process that can reduce the effects of corner transistors in SOI MOSFETs, and several possible solutions are suggested at the end.

• Journal of electromagnetic engineering and science
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• v.12 no.1
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• pp.101-106
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• 2012

In this study, we investigated the effect of groove pattern and gap-fill with lossy materials at 15 GHz frequency of Ku-band. We used Epoxy/MWCNT composite materials as gap-fill materials. Although epoxy does not have an absorbance capability, epoxy added conductive fillers, which are multi-walled carbon nanotubes (MWCNT), can function as radar absorbing material. Specimens were fabricated with different MWCNT mass fractions (0, 0.5, 1.0, 2.0 wt%) and their permittivity in the Ku-band was measured using the waveguide technique. We investigated the effect of gap-fill on monostatic RCS by calculating RCS with and without gap-fill. For arbitrarily chosen thickness and experimentally obtained relative permittivity, we chose the relative permittivity of MWCNT at 2 wt% (${\varepsilon}_r$=8.8-j2.4), which was the lowest reflection coefficient for given thickness of 3.3 mm at V-pol. and $80^{\circ}$ incident angle. We also checked the monostatic RCS and the field intensity inside the groove channel. In the case of H-pol, gap-fill was not affected by the monostatic RCS and magnitude was similar with or without gap-fill. However, in the case of V-pol, gap-fill effectively reduced the monostatic RCS. The field intensity inside the groove channel reveals that different RCS behaviors depend on the wave polarizations.

• Journal of the Korean Institute of Telematics and Electronics
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• v.25 no.11
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• pp.1373-1379
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• 1988

This paper describes a two-dimensional analysis of the potential distribution and electron concentration of the MODFET at channel using FDM. More exact analysis can be obtained by two-dimensional analysis which considers parasitic effects ignored in one-dimensional analysis. Using Poisson and Shrodinger equations, the potential distribution and the wave function are calculated within a constant error bound. As a result, the relations between the thickness of spacer, doping concentration of (n) AlGaAs layer, and the sheet density of the 2DEG (2 Dimensional Electron Gas) of MODFET at channel are suggested quantitively. The sheet density of the 2DEG is increased as the thickness of the spacer is decreased of the doping concentration of the (n)AlGaAs layer is lowered.