• Current Photovoltaic Research
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• 제10권1호
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• pp.28-32
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• 2022

We investigated the optical and electrical characteristics of ITO/Ag/ITO (IAI) 3-layer thin films prepared by using RF/DC sputtering. To measure the thickness of all thin film samples, we used scanning electron microscopy. As a function of Ag thickness we characterized the optical transmittance and sheet resistance of the IAI samples by using UV-Visible spectroscopy and Hall measurement system, respectively. While the thickness of both ITO thin films in the 3-layered IAI samples were fixed at 50 nm, we varied Ag layer thickness in the range of 0 nm to 11 nm. The optical transmittance and sheet resistance of the 3-layered IAI thin films were found to vary strongly with the thickness of Ag film in the ITO (50 nm)/Ag(t₀)/ITO (50 nm) thin film. For the best transparent conducting oxide (TCO) electrode, we obtained a 3-layered ITO (50 nm)/Ag (t₀ = 8.5 nm)/ITO (50 nm) that showed an avrage optical transmittance, AVT = 90.12% in the visible light region of 380 nm to 780 nm and the sheet resistance, R_□ = 7.24 Ω/□.

• 대한금속재료학회지
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• 제46권2호
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• pp.88-96
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• 2008

Thermal evaporated 10 nm-$Ni_{50}Co_{50}$/(70 nm-poly)Si films were deposited to examine the energy saving properties of silicides formed by rapid thermal annealing at temperature ranging from 500 to $1,100^{\circ}C$ for 40 seconds. Thermal evaporated 10 nm-Ni/(70 nm-poly)Si films were also deposited as a reference using the same method for depositing the 10 nm-$Ni_{50}Co_{50}$/(70 nm-poly)Si films. A four-point probe was used to examine the sheet resistance. Transmission electron microscopy (TEM) and X-ray diffraction XRD were used to determine cross sectional microstructure and phase changes, respectively. UV-VIS-NIR and FT-IR (Fourier transform infrared spectroscopy) were used to examine the near-infrared (NIR) and middle-infrared (MIR) absorbance. TEM analysis confirmed that the uniform nickel-cobalt composite silicide layers approximately 21 to 55 nm in thickness had formed on the single and polycrystalline silicon substrates as well as on the 25 to 100 nm thick nickel silicide layers. In particular, nickel-cobalt composite silicides showed a low sheet resistance, even after rapid annealing at $1,100^{\circ}C$. Nickel-cobalt composite silicide and nickel silicide films on the single silicon substrates showed similar absorbance in the near-IR region, while those on the polycrystalline silicon substrates showed excellent absorbance until the 1,750 nm region. Silicides on polycrystalline substrates showed high absorbance in the middle IR region. Nickel-cobalt composite silicides on the poly-Si substrates annealed at $1,000^{\circ}C$ superior IR absorption on both NIR and MIR region. These results suggest that the newly proposed $Ni_{50}Co_{50}$ composite silicides may be suitable for applications of IR absorption coatings.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.562-565
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• 2001

In this paper, novel device structures in order to realize ultra fast and ultra small silicon devices are investigated using ultra-high vacuum chemical vapor deposition(UHVCVD) and Excimer Laser Annealing (ELA). Based on these fundamental technologies for the deep sub-micron device, high speed and low power devices can be fabricated. These junction formation technologies based on damage-free process for replacing of low energy ion implantation involve solid phase diffusion and vapor phase diffusion. As a result, ultra shallow junction depths by ELA are analyzed to 10~20nm for arsenic dosage(2${\times}$10$\_$14//$\textrm{cm}^2$), exciter laser source(λ=248nm) is KrF, and sheet resistances are measured to 1k$\Omega$/$\square$ at junction depth of 15nm and realized sub-50nm n-MOSFET.

• 한국세라믹학회지
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• 제41권3호
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• pp.202-209
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• 2004

침전법 및 솔젤법에 의하여 10- l5 nm 및 500 nm 크기의 구형 TiO$_2$ 분말을 제조하고 수열합성법으로 50-70 nm 및 120-250 nm 크기의 침상 hydroxyapatite(이하 HA라 표기) 입자를 각각 제조한 다음, 두 분말의 조성비를 달리한 세 종류(HA/TiO$_2$비; 75/25, 50/50, 25/75wt%)의 HA/TiO$_2$ 복합분말을 planetary 볼밀로 혼합하여 각각 제조하였다. 복합분말을 탄소몰드에 넣고 hot-press를 사용하여 가압소결로 치밀체를 제조하였는데, 가압도중 대부분의 HA가 tricalcium phosphate(이하 TCP라 표기)로 분해되면서 $\beta$-TCP/TiO$_2$ 복합체가 제조되었다. 제조된 복합체의 미세구조와 소결밀도는 복합분말의 형태와 조성에 따라 변화하였는데, 입자가 균질하게 분산되어 있는 미세구조를 갖는 복합분말을 소결한 경우, 치밀한 소결체를 얻을 수 있었으며, 소결온도가 증가할수록 균질한 미세구조를 나타내었다. 또한 복합분말 내 HA 함량이 증가하면서 소결체의 입자크기가 증가한 반면, 소결밀도가 감소하고, 미세구조는 불균질하였다. 반대로 HA분말에 비하여 TiO$_2$분말의 함량이 큰 시편은 전체적으로 작은 입자크기와 균질한 미세구조를 나타냈으며, 소결밀도 또한 증가하였다.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2002년도 추계종합학술대회
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• pp.486-489
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• 2002

본 논문에서는 50nm 이하의 double gate MOSFET의 특성을 조사하였다. 1.5V의 main gate 전압과 3V의 side gate 전압이 인가될 때 I-V 특성으로부터 IDsat=510$\mu$A/$\mu\textrm{m}$을 얻을 수 있었다. 이때, 전달 컨덕턴스는 111$\mu$A/V, subthreshold slope는 86mV/dec, DIBL값은 51.3mV이다. 그밖에 TCAD tool이 소자 시뮬레이터로서 적합함을 나타내었다.

• 한국전자통신학회논문지
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• 제17권6호
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• pp.1069-1074
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• 2022

본 연구에서는 Nb₂O₅/SiO₂ 이중 버퍼층위에 ITO박막을 증착하여, SiO₂버퍼층 두께 변화 (40~50 nm)에 따른 전기적 및 광학적 특성을 조사하였다. Nb₂O₅/SiO₂ 이중 버퍼층을 도입한 ITO박막의 표면 거칠기는 0.815에서 1.181 nm 범위의 작은 값을 가지는 매끄러운 형상을 보였고, 면저항은 99.3~134.0 Ω/sq. 범위로 정전용량식 터치스크린 패널에 적용하는데 문제가 없는 것으로 나타났다. 특히 Nb₂O₅ (10 nm) / SiO₂ (40 nm) 이중 버퍼층을 삽입한 ITO박막의 단파장(400~500 nm) 영역에서의 평균 투과도와 색도(b^*)는 83.58 % 와 0.05로 이중버퍼층이 삽입되지 않은 ITO박막의 74.46 % 와 4.28에 비해 상당히 향상된 결과를 나타내었다. 이를 통해 Nb₂O₅/SiO₂ 이중 버퍼층을 도입한 ITO박막에서 인덱스 매칭 효과로 인해 단파장 영역의 투과도 및 색도와 같은 광학적 특성이 현저히 향상되었음을 확인할 수 있었다.

• 한국재료학회지
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• 제33권3호
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• pp.101-105
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• 2023

A mixture of elemental Co₅₀Si₅₀ powders was subjected to mechanical alloying (MA) at room temperature to prepare a CoSi thermoelectric compound. Consolidation of the Co₅₀Si₅₀ mechanically alloyed powders was performed in a spark plasma sintering (SPS) machine using graphite dies up to 800 ℃ and 1,000 ℃ under 50 MPa. We have revealed that a nanocrystalline CoSi thermoelectric compound can be produced from a mixture of elemental Co₅₀Si₅₀ powders by mechanical alloying after 20 hours. The average grain size estimated from a Hall plot of the CoSi intermetallic compound prepared after 40 hours of MA was 65 nm. The degree of shrinkage of the consolidated samples during SPS became significant at about 450 ℃. All of the compact bodies had a high relative density of more than 94 % with a metallic glare on the surface. X-ray diffraction data showed that the SPS compact produced by sintering mechanically alloyed powders for 40-hours up to 800 ℃ consisted of only nanocrystalline CoSi with a grain size of 110 nm.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2002년도 춘계종합학술대회
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• pp.275-278
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• 2002

MOSFET의 게이트 길이가 50nm이하로 작아지면 소자를 설계함에 있어 고려해야 하는 많은 문제점들이 존재하게 된다. 본 논문에서는 MOSFET 소자에 대한 문턱 전압 특성을 조사하였다. 소자에 대한 스케일링은 generalized scaling을 사용하였고 게이트 길이 100nm에서 30nm까지 시뮬레이션 하였다. 이때 나노 구조 MOSFET에 대한 스케일링의 한계를 볼 수 있었다. 문턱 전압을 구하는 방법으로는 선형 추출 방법을 사용하였다.

• 한국전기전자재료학회논문지
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• 제25권1호
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• pp.33-36
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• 2012

In this study, the thickness effects of $Al_2O_3$ layer on the sensing properties of $SiO_2/Al_2O_3$ (OA) stacked membrane were investigated using electrolyte-insulator-semiconductor (EIS) structure for high quality pH sensor. The $Al_2O_3$ layers with a respective thickness of 5 nm, 15 nm, 23 nm, 50 nm, and 100 nm were deposited on the 5-nm-thick $SiO_2$ layers. The electrical characteristics and sensing properties of each OA membranes were investigated using metal-insulator-semiconductor (MIS) and EIS devices, respectively. As a result, the OA stacked membrane with 23-nm-thick $Al_2O_3$ layer shows the excellent characteristics as a sensing membrane of EIS sensor, which can enhance the signal to noise ratio.

• Current Optics and Photonics
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• 제7권6호
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• pp.673-682
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• 2023

In this paper, a three-key triple data encryption algorithm (TDEA) of a digital cryptosystem based on phase-shifting interferometry is proposed. The encryption for plaintext and the decryption for the ciphertext of a complex digital hologram are performed by three independent keys called a wavelength key k₁(λ), a reference distance key k₂(d_r) and a holographic encryption key k₃(x, y), which are represented in the reference beam path of phase-shifting interferometry. The results of numerical simulations show that the minimum wavelength spacing between the neighboring independent wavelength keys is about δλ = 0.007 nm, and the minimum distance between the neighboring reference distance keys is about δd_r = 50 nm. For the proposed three-key TDEA, choosing the deviation of the key k₁(λ) as δλ = 0.4 nm and the deviation of the key k₂(d_r) as δd_r = 500 nm allows the number of independent keys k₁(λ) and k₂(d_r) to be calculated as N(k₁) = 80 for a range of 1,530-1,562 nm and N(d_r) = 20,000 for a range of 35-45 mm, respectively. The proposed method provides the feasibility of independent keys with many degrees of freedom, and then these flexible independent keys can provide the cryptosystem with very high security.