• Proceedings of the Korean Vacuum Society Conference
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.188-188
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• 2011

Recently, scaling down of ULSI (Ultra Large Scale Integration) circuit of CMOS (Complementary Meta Oxide Semiconductor) based electronic devices, the electronic devices, become much faster and smaller size that are promising property of semiconductor market. However, very narrow interconnect line width has some disadvantages. Deposition of conformal and thin barrier is not easy. And metallization process needs deposition of diffusion barrier and glue layer for EP/ELP deposition. Thus, there is not enough space for copper filling process. In order to get over these negative effects, simple process of copper metallization is important. In this study, Cu-V alloy layer was deposited using of DC/RF magnetron sputter deposition system. Cu-V alloy film was deposited on the plane SiO2/Si bi-layer substrate with smooth surface. Cu-V film's thickness was about 50 nm. Cu-V alloy film deposited at $150^{\circ}C$. XRD, AFM, Hall measurement system, and AES were used to analyze this work. For the barrier formation, annealing temperature was 300, 400, $500^{\circ}C$ (1 hour). Barrier thermal stability was tested by I-V(leakage current) and XRD analysis after 300, 500, $700^{\circ}C$ (12 hour) annealing. With this research, over $500^{\circ}C$ annealed barrier has large leakage current. However vanadium-based diffusion barrier annealed at $400^{\circ}C$ has good thermal stability. Therefore thermal stability of vanadium-based diffusion barrier is desirable for copper interconnection.

• Journal of the Korean Vacuum Society
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• 제9권3호
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• pp.242-248
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• 2000

BST thin films were prepared with various deposition conditions by rf-magnetron sputtering. As substrate temperature increases and Ar/$O_2$ratio decreases, the electrical properties of the BST films improve. The conventional Schottky model and modified-Schottky model were introduced in order to investigate the leakage-current-conduction mechanisms of the deposited films. It was found that the modified-Schottky model better describes the current-conduction mechanism in the BST films than the conventional Schottky model. From the modified-Schottky model, optical dielectric constant ($\varepsilon$), electronic drift mobility ($\mu$), and barrier height $({\phi}_b)are calculated as $\varepsilon$=4.9, $\mu$=0.019 $\textrm{cm}^2$/V-s, and ${\phi}_b=0.79 eV.

• Journal of the Korean Vacuum Society
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• 제8권3A호
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• pp.231-237
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• 1999

$SrBi_{22.4}Ta_2O_9$ (SBT) thin films of 70~150 nm thickness were prepared on platinized silicon substrates by Liquid Source Misted Chemical Deposition (LSMCD) process, and their microstructure, feroelectric and leakage current characteristics were investigated. By annealing at $800^{\circ}C$ for 1 hour in oxygen ambient, SBT films were fully crystallized to the Bi layered perovskite structure without preferred orientation. The grain size of the LSMCD- derived SBT films was about 100nm, and was not varied with the film thickness. $2P_r$ and $E_c$ of the SBT films increased with decreasing the film thickness, and the 70nm-thick SBT film exhibited $2P_r$ of 17.8 $\mu$C/$\textrm{cm}^2$ and $E_c$ of 74kV/cm at applied voltage of 5V. Within the film thickness range of 70~150nm, the relative dielectric permittivity of the LSMCD-derived SBT film decreased with decreasing the film thickness. Leakage current densities lower than $10^{-7}\textrm{A/cm}^2$ at 5V were observed in the SBT films thicker than 125nm.

• Proceedings of the Korean Vacuum Society Conference
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.240.1-240.1
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• 2013

본 연구에서는 Symmetric NMOSFET의 channel length에 따른 전기적 특성 분석에 관한 연구를 진행하였다. 특성 분석에 사용된 소자의 Gate oxide 두께는 6 nm 이며, 채널 Width/Length는 각각 10/10 ${\mu}m$, 10/0.2 ${\mu}m$ 이다. Drain Avalanche Hot Carrier(DAHC) 테스트를 진행하기 위하여 각각 스트레스 조건을 추출하였고, 조건에 해당되는 스트레스를 1700초 동안 인가하였다. 스트레스 후, Channel length가 10 ${\mu}m$과 0.2 ${\mu}m$인 두 소자의 특성을 측정, 분석결과 10 ${\mu}m$의 소자의 경우 문턱전압(VT)과 Subthreshold swing (SS)의 변화가 없었지만 0.2 ${\mu}m$의 소자의 경우 0.42V의 (from 0.67V to 1.09V) 문턱전압 변화 (VTH)와 71 mV/dec (from 79 mV/dec to 150 mV/dec))의 Swing (SS)변화를 보여 스트레스 후에 Interface trap이 증가하였음을 알 수 있다. off-state leakage current를 측정 결과 0.2 ${\mu}m$ 의 경우 leakage current의 양이 증가하였음을 알 수 있고 이는 드레인 부근에 증가된 interface trap에 의한 현상으로 판단된다. 상기 결과와 같이 DAHC 스트레스에 의한 소자의 열화 현상은 Channel length가 짧을수록 더 크게 의존하는 것을 확인하였다.

• Progress in Superconductivity and Cryogenics
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• 제22권3호
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• pp.25-30
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• 2020

The diminishing of heat leak into cryogenic vessels can prolong the storage time of cryogenic liquid. With the storage of cryogenic liquid reducing, the heat leak decreases, while the actual storage time increases. Regarding to the theoretical analysis, the obtained results seems to be constructive for the cryogenic insulation system applications. This study presents a predictive assessment of heat leak occurring in non-vacuum tanks with a single layer of insulation. A Radial steady-state heat transfer, based on heat conduction equation, is taken into consideration. Graphical results show the thermal performance of the insulation used, they also allow us to choose the appropriate insulation thickness according to the shape and diameter of the storage tank.

• Proceedings of the Korean Vacuum Society Conference
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• 한국진공학회 1998년도 제14회 학술발표회 논문개요집
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• pp.23-23
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• 1998

High resolution field emission dispplay(FED) devices of 5 inch diagonal in size are fully developped for the applications of near-future flat ppanel dispplays. Under the unique gate-switching drive scheme electron trajectory pprofiles are simulated and tested by considering leakage effects of each ppixel. Uniquely-pprinted sppacer with high asppect ratio are fabricated on real ITO glass for high vacuum ppackaging. In addition new gas aging scheme of stabilizing field emitting array are extensively investigated during the sealing and exhausting pprocess in order to pprevent oxidation effects on the micro tipp. Finally fulll color images of 64 gray scale will be demonstrated.

• Proceedings of the KIEE Conference
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• 대한전기학회 2001년도 추계학술대회 논문집 전기물성,응용부문
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• pp.23-25
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• 2001

In this work, the $Ta_2O_5$ thin films were deposited on Pt/n-Si substrate by reactive magnetron sputtering and the RTA treatment at temperatures range from 650 to $750^{\circ}C$ in $O_2$ and vacuum. X-ray diffraction analysis, FE SEM, dielectric properties and leakage current density have been used to study the structural and electrical properties of the $Ta_2O_5$ thin films. XRD result showed that as- deposited films were amorphous and the annealed films crystallized (<$700^{\circ}C$) into ${\beta}-Ta_2O_5$. The crystallinity increased with temperature in terms of an increase in the intensity of the diffracted peaks(${\beta}-Ta_2O_5$) and annealing in oxygen reduced defect dang1ing Ta-O bonds. As deposited $Ta_2O_5$ films show the leakage current density $10^{-7}$ to $10^{-8}$ (A/$cm^2)$ at low electric fields (<200 kV/cm) However, it was found leakage current density of $Ta_2O_5$ thin films decreased with $O_2$ ambient annealing. The dielectric constant of the as deposited $Ta_2O_5$ thin films was ${\varepsilon}_r$ $9{\sim}11$ but the dielectric constant was increased after RTA treatment in $O_2$ ambient more then in vacuum.

• Proceedings of the Korean Vacuum Society Conference
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.409-409
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• 2013

최근, 집적 소자의 미세화에 따라 늘어난 배선 신호 지연 및 상호 간섭, 그리고 소비 전력의 증가는 초고집적 소자 성능 개선에 한계를 가져온다. 이에 따라 기존의 알루미늄(Al)/실리콘 절연 산화막은 구리(Cu)/저유전율 박막(low-k)으로 대체되고 있고, 이는 소자 성능 개선에 큰 영향을 미친다. 그러나 Cu는 Si과 low-k 내부로 확산이 빠르게 일어나 소자의 비저항을 높이고, 누설 전류를 일으키는 등 소자의 성능을 저하시킬 수 있는 문제점을 가지고 있다. 이러한 Cu의 확산을 막기 위하여 Ta, TaN 등과 같은 확산방지막에 대한 연구가 활발히 진행되어 왔으나, 배선 공정의 집적화와 low-k 대체에 따른 공정 및 신뢰성 문제로 인해 새로운 확산방지막의 개발이 필요하게 되었다. 이를 위해, 본 연구에서는 Cu-V 합금을 사용하여 low-k 기판 위에 확산방지막을 자가 형성 시키는 공정에 대한 연구를 진행하였다. 다양한 low-k 기판에서 열처리조건에 따른 Cu-V 합금의 특성을 확인하기 위해 4-point probe를 통한 비저항 평가와 XRD (X-ray diffraction) 분석이 이뤄졌다. 또한, TEM (transmission electron microscope)을 이용하여 $300^{\circ}C$에서 1 시간 동안 열처리를 거쳐 자가형성된 V-based interlayer가 low-k와 Cu의 계면에서 균일하게 형성된 것을 확인하였다. 형성된 V-based interlayer의 barrier 특성을 평가하고자 Cu-V합금/low-k/Si 구조와 Cu/low-k/Si 구조의 leakage current를 비교 분석하였다. Cu/low-k/Si 구조는 비교적 낮은 온도에서 leakage current가 급격히 증가하는 양상을 보였으나, Cu-V 합금/low-k/Si 구조는 $550^{\circ}C$의 thermal stress 에서도 leakage current의 변화가 거의 없었다. 이러한 결과를 바탕으로 열처리를 통해 자가형성된 V-based interlayer의 Cu/low-k 간 확산방지막으로서 가능성을 검증하였다.

• Journal of the Korean Vacuum Society
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• 제21권4호
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• pp.193-198
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• 2012

In this study, we have fabricated the polymer insulator and diamond-like carbon (DLC) thin films by using plasma enhanced chemical vapor deposition methods. we fabricated the DLC films with various thicknesses as the passivation layer on plasma polymer and investigated the structural, physical, and electrical properties of DLC/plasma polymer films. The plasma polymer synthesized in this work had the low leakage current and low dielectric constant. The values of hardness and elastic modulus in DLC/plasma polymer films are increased, and the value of rms surface roughness is decreased, and contact angle value is increased with increasing DLC film thickness. In the electrical properties of DLC/plasma polymer, the value of the dielectric constant is increased, however the leakage current property of the DLC/plasma polymer is improved than that of plasma polymer film with increasing DLC film thickness.

• Journal of the Korean Vacuum Society
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• 제18권1호
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• pp.49-53
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• 2009

The chemical properties of SiOC film was studied for inter-layer insulator. SiOC film was formed with non polarity due to the appropriate union by the alkyl and hydroxyl group. An amorphous structure of non polarity can induce the low dielectric constant materials. The chemical properties of thin film can define the bonding structure owing to the ionic variation, and the analysis of chemical properties was researched by the carbon content using the FTIR spectra, and induced the film with non polarity. The electrical properties is the electron flow, and is always not the same as the chemical properties. The electrical properties of SiOC film with various flow rate ratios was analyzed and researched the correlation between the chemical properties. SiOC film showed the increasing of the leakage current after annealing process, and abruptly increased the carbon content at some samples. But the sample with increasing the carbon content decreased the leakage current. It means that the chemical properties is not the same as the electrical properties, and the carbon is related with the variation of the bonding structure, and does not contribute the current flow.