• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.5
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• pp.21-28
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• 1999

A new method of making high speed self-aligned ESD (Elevated Source/Drain) MOSFET is proposed. Different from the conventional LDD (Lightly-Doped Drain) structure, the proposed ESD structure needs only one ion implantation step for the source/drain junctions, and makes it possible to modify the depth of the recessed channel by use of dry etching process. This structure alleviates hot-carrier stress by use of removable nitride sidewall spacers. Furthermore, the inverted sidewall spacers are used as a self-aligning mask to solve the self-align problem. Simulation results show that the impact ionization rate ($I_{SUB}/I_{D}$) is reduced and DIBL (Drain Induced Barrier Lowering) characteristics are improved by proper design of the structure parameters such as channel depth and sidewall spacer width. In addition, the use of removable nitride sidewall spacers also enhances hot-carrier characteristics by reducing the peak lateral electric field in the channel.

• Transactions on Electrical and Electronic Materials
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• v.5 no.5
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• pp.173-179
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• 2004

The influence of heavily Si impurity doping in the GaN barrier of InGaN/GaN multi-quantum well structures of blue light emitting diodes were investigated by growing samples in metal-organic chemical vapor deposition. The delta-doped sample was compared to the sample with the undoped barrier. The delta-doped sample shows the tunneling behavior and forms the energy level of 0.32 eV for tunneling and the photoemission of the 450-nm band. The photo-luminescence shows the blue-shifted broad band of the radiative transition due to the inclusion of Si delta-doped layer indicating that the delta doping effect acts to form the higher energy level than that of quantum well. The dislocation may provide the carrier tunneling channel and plays as a source of acceptor. During the tunneling of hot carrier, there was no light emission.

• Journal of the Korean Institute of Telematics and Electronics
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• v.14 no.3
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• pp.6-11
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• 1977

The noise behavior of the Schottky Barrier Gate FET has been investigated by the use of noise equivalent circuit. It has been found that an additional noise source has to be taken into account in the GaAs SBGFET's biased in the pinch-off region; the intervalley scattering noise and the hot electron noise. In this paper, a noise equivalent circuit has been used to determine the noise parameter which was taken into account influence of the saturation velocity of carrier and parasitic resistance.

• ETRI Journal
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• v.38 no.2
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• pp.244-251
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• 2016

In this paper, we investigate the electrical characteristics of two trench-gate-type super-barrier rectifiers (TSBRs) under different p-body implantation conditions (low and high). Also, design considerations for the TSBRs are discussed in this paper. The TSBRs' electrical properties depend strongly on their respective p-body implantation conditions. In the case of the TSBR with a low p-body implantation condition, it exhibits MOSFET-like properties, such as a low forward voltage ($V_F$) drop, high reverse leakage current, and a low peak reverse recovery current owing to a majority carrier operation. However, in the case of the TSBR with a high p-body implantation condition, it exhibits pn junction diode.like properties, such as a high $V_F$, low reverse leakage current, and high peak reverse recovery current owing to a minority carrier operation. As a result, the TSBR with a low p-body implantation condition is capable of operating as a MOSFET, and the TSBR with a high p-body implantation condition is capable of operating as either a pn junction diode or a MOSFET, but not both at the same time.

• Korean Membrane Journal
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• v.4 no.1
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• pp.36-40
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• 2002

The diffusion coefficients of ions in the reverse transport system using the carrier mediated membrane were estimated from the diffusional membrane permeabilities and the ion activity in membrane system. In the aqueous alkali metal ions-membrane system diffusional flux of alkali metal ions driven by coupled proton was analyzed. The aqueous phase I contained NaOH solution and the aqueous phase II also contained NaCl and HCl mixed solution. The concentration of Na ions of both phases were $10^{0},\;10^{-1},\;10^{-2},\;5{\times}10^{-1}\;and\;5{\times}10^{-2}\;mol{\cdot}dm^{-3}$ and the concentration of HCI in aqueous phase II was always kept at $1{\times}10^{-1}\;mol{\cdot}dm^{-3}$. Moreover, the carrier concentration in liquid membrane was $10^{-2}\;mol{\cdot}dm^{-3}$. The results indicated that the diffusion coefficients depend strongly on the concentration of both phases electrolyte solution equilibriated with the membrane. The points were interpreted in terms of the energy barrier theory. Furthermore, eliminating the potential terms from the membrane equation was derived.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.524-524
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• 2012

Thermal Barrier Coating (TBC)은 미사일, 로켓발사체와 같이 고온에 노출되는 장비를 열로부터 보호하기 위한 코팅이다. 일반적인 Thermal Barrier Coating (TBC)은 모재와 코팅층간의 낮은 접합력과 높은 열충격으로 인한 박리가 많이 나타난다. 그래서 접합력을 높이고, 열충격을 줄이기 위해 모재와 코팅층 사이에 본드코팅층을 만든 Duplex - Thermal Barrier Coating (Duplex-TBC)이 개발되었다. 그러나 Duplex - Thermal Barrier Coating (Duplex-TBC)은 금속재료인 본드코팅층과 세라믹재료인 탑코팅층 사이에서 박리가 많이 발생한다. 이러한 문제점을 해결하기 위해 두 가지 분말을 동시에 코팅하여 본드코팅과 탑코팅의 경계가 없는 Functional Gradient Material - Thermal Barrier Coating (FGM-TBC)의 연구가 필요하다. 본 연구에서는 Functional Gradient Material - Thermal Barrier Coating (FGM-TBC)의 열충격 특성에 미치는 진공 플라즈마 용사 조건의 영향을 조사하였다. Functional Gradient Material - Thermal Barrier Coating (FGM-TBC)는 진공 플라즈마 용사장치를 사용하여 Cu-Cr 합금위에 코팅하였다. 거리, Carrier gas flow, 그리고 챔버 내부의 압력을 달리하여 제조하였다. 사용한 분말은 본드코팅용으로 Amdry 962와 내열 세라믹코팅을 위해 204NS를 사용하였고, 각각 분말 공급조건을 조절하여 두 분말의 비율을 달리하였다. 제조한 Functional Gradient Material - Thermal Barrier Coating (FGM-TBC) 코팅은 전기로에서 50분간 가열한 후, 수조에서 10분간 냉각하는 열충격 실험을 통해 열차폐 성능을 평가 하였다. 이러한 과정에서 진공 플라즈마 용사 조건 및 FGM 조성과 비율이 내열충격 특성에 미치는 영향을 미세조직학적 관점에서 고찰하였다.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1986.04a
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• pp.206-210
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• 1986

Double Ion Implantation methods are used to improve the stiffness os carrier profiles, and then the analytical solutions to Poisson`s equation are derived with summation of each carrier profile. Numerical analyses are done using profer boudary conditions and the results show that the improvement of voltage-dependent-capacitance ratio (C(!)/C(25)) is obtained up to B.6. The third ion implantation is for the enhancement of the Schottky barrier height.

• Journal of Information Display
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• v.10 no.4
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• pp.143-148
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• 2009

The theoretical current density equations for organic semiconductors was derived according to the internal carrier emission equation based on the diffusion model at the Schottky barrier contact and the mobility equation based on the field dependence model, the so-called "Poole-Frenkel mobility model." The electric field becomes constant because of the absence of a space charge effect in the case of a higher injection barrier height and a lower sample thickness, but there is distribution in the electric field because of the space charge effect in the case of a lower injection barrier height and a higher sample thickness. The transition between the injection- and bulk-limited currents was presented according to the Schottky barrier height and the sample thickness change.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.209.2-209.2
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• 2015

Two dimensional layered materials, such as transition metal dichalcogenides (TMDs) family have been attracted significant attention due to novel physical and chemical properties. Among them, molybdenum disulfide ($MoS_2$) has novel physical phenomena such as absence of dangling bonds, lack of inversion symmetry, valley degrees of freedom. Previous studies have shown that the interface of metal/$MoS_2$ contacts significantly affects device performance due to presence of a scalable Schottky barrier height at their interface, resulting voltage drops and restricting carrier injection. In this study, we report a new device structure by using few-layer graphene as the bottom interconnections, in order to offer Schottky barrier free contact to bi-layer $MoS_2$. The fabrication of process start with mechanically exfoliates bulk graphite that served as the source/drain electrodes. The semiconducting $MoS_2$ flake was deposited onto a $SiO_2$ (280 nm-thick)/Si substrate in which graphene electrodes were pre-deposited. To evaluate the barrier height of contact, we employed thermionic-emission theory to describe our experimental findings. We demonstrate that, the Schottky barrier height dramatically decreases from 300 to 0 meV as function of gate voltages, and further becomes negative values. Our findings suggested that, few-layer graphene could be able to realize ohmic contact and to provide new opportunities in ohmic formations.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.3
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• pp.499-507
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• 2023

The core of the liquefied natural gas (LNG) carrier cargo containment system (CCS) is to store and transport LNG safely under temperatures below -163 degrees Celsius. The secondary barrier of the LNG CCS is adopted to prevent LNG leakage from CCS to the ship's hull structure. Recently, as the size of the LNG CCS increases, various studies have been conducted on the applied temperature and load ranges. The present study investigates the working condition-dependent bonding strength of the PU15 adhesives of the secondary barrier. In addition, the mechanical performance is analyzed at a cryogenic temperature of -170 degrees Celsius, and the failure surface and failure mode are investigated depending on the working condition of the bonded process. Even though the RSB and FSB-based fracture mode was confirmed, the results showed that all the tested scenarios satisfied the minimum requirement of the regulation.