• Journal of the Korean Ceramic Society
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• v.41 no.3
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• pp.197-201
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• 2004

SiO$_2$ and SiON thick films were deposited by Plasma Enhanced Chemical Vapor Deposition (PECVD) technique on silicon wafer (100) using SiH$_4$ and $N_2$O as precursor gases. In this work, the influence of rf power, and rf bias power on the optical and physical properties of SiO$_2$ and SiON thick films is presented. The refractive index decreases with increasing rf power, and rf bias power. The refractive index of the films varied from 1.4493 to 1.4952 at wavelength at 1552 nm, with increasing rf power, the nitrogen content decreases while the oxygen content increases, in a manner that the O/N ratio increases approximately linearly.

• Progress in Superconductivity and Cryogenics
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• v.15 no.2
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• pp.12-15
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• 2013

The pure and carbon (C)-doped $MgB_2$ thin films were fabricated on $Al_2O_3$ (0001) substrates at a temperature of $650^{\circ}C$ by using hot-filament-assisted hybrid physical-chemical vapor deposition technique. The $T_c$ value for pure $MgB_2$ film is 38.5 K, while it is between 30 and 35 K for carbon-doped $MgB_2$ films. Expansion in c-axis lattice parameter was observed with increase in carbon doping concentration which is in contrast to carbon-doped $MgB_2$ single crystals. Significant enhancement in the critical current density was obtained for C-doped $MgB_2$ films as compared to the undoped $MgB_2$ film. This enhancement is most probably due to the incorporation of C into $MgB_2$ and the high density of grain boundaries, both help in the pinning of vortices and result in improved superconducting performance.

• Proceedings of the KSME Conference
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• 2001.06a
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• pp.567-572
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• 2001

In order to investigate the fracture behaviors(penetration modes) and resistance to penetration during ballistic impact of Titanium alloy laminates and nitrified Titanium alloy laminates which were treated by PVD(Physical Vapor Deposition) method, ballistic tests were conducted. Evaporation, sputtering, and ion plating are three kinds of PVD method. In this research, Ion plating was used to achieve higher surface hardness and surface hardness test were conducted using a Micro vicker's hardness tester. Resistance to penetration is determined by the protection ballistic limit($V_{50}$), a statistical velocity with 50% probability for complete penetration. Fracture behaviors and ballistic tolerance, described by penetration modes, are respectfully observed at and above ballistic limit velocities, as a result of $V_{50}$ test and Projectile Through Plates (PTP) test methods. PTP tests were conducted with $0^{\circ}$ obliquity at room temperature using 5.56mm ball projectile. $V_{50}$ test with $0^{\circ}$ obliquity at room temperature were conducted with projectiles that were able to achieve near or complete penetration during PTP tests. Surface hardness, resistance to penetration, and penetration modes of Titanium alloy laminates are compared to those of nitrified Titanium alloy laminates.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.369.2-369.2
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• 2014

Diamond-like Carbon(DLC) films doping Si were deposited by linear ion source(LIS)-physical vapor deposition method on Si wafer. We have studied the effects of Si content on friction and wear properties of DLC films and the characteristics of the films were investigated using Nano-indentation, Micro raman spectroscopy, Field Emission-Scanning Electron Microscope (FM-SEM) and X-ray Photoelectron Spectroscopy (XPS). The films has been various low-friction and low-stress by varying the flow rates of silane gas. Under the about 2% of Si doping is very suitable for improving the adhesion of films and reducing internal stress while maintaining the surfaces hardness of DLC films. Linear ion source (LIS)를 사용하여 Si wafer위에 Si 이온이 첨가된 DLC 박막을 증착하였다. 참가된Si 이온의 양에 따라 DLC 박막에 미치는 영향을 분석하기 위하여 마찰 계수 및 경도를 비교하였고, Micro raman spectroscopy, Field Emission-Scanning Electron Microscope (FM-SEM) and X-ray Photoelectron Spectroscopy (XPS)를 통하여 표면 상태를 분석하였다. 천체 주입된 가스량의 약 2%까지 Si 이온 주입이 늘어날수록 DLC 박막의 마찰계수는 낮아졌고, 경도는 Si 이온이 주입되지 않았을 경우와 비슷한 값(약 20~23 GPa)을 가졌다. 2% 이상의 주입량에서는 마찰계수는 주입량이 늘어날수록 높아졌으며 경도는 떨어지는 경향을 보였다. 이는 Si이온이 2%이하로 첨가되었을 경우, DLC 박막의 생성시 탄소 이온들의 결합 Stress를 줄여 마찰계수가 줄어든다고 볼 수 있으며, 그 양이 2%이상이 되면 오히려 불순물로 작용하여 DLC 박막의 Stress는 급격히 증가하고 마찰계수도 높아짐을 알 수 있다.

• Proceedings of the KIPE Conference
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• 2006.06a
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• pp.56-58
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• 2006

본 논문은 PVD(Physical Vapor Deposition)의 마그네트론 스퍼터(Magnetron sputter) 박막코팅(Thin film coating) 공정에서 플라즈마(Plasma)를 발생시키고 제어하는 DC 전원공급 장치에 관한 것이다. 이 논문에서는 임피던스의 변화가 심하고 아크(Arc)가 빈번히 발생하는 플라즈마 부하의 특성에 대해, 과도상태(Transient state)의 출력제어 성능을 향상시키고 아크 발생 시 부하로 전가되는 아크에너지를 저감시키기 위한 직류 전원 공급 장치에 대해 소개한다. 전원장치는 수하특성을 가지며 플라즈마 부하에 적합한 출력 제어성을 확보하고 아크 에너지를 최소화하기 위해 고주파 L-C 직렬공진회로 기법을 적용한다. 개발된 DC 20kW급 전원 장치는 인버터와 고주파 절연변압기, 정류기로 구성된다. 인버터는 $100{\sim}200kHz$의 제어주파수로 PFM 및 PWM 제어를 하며, 단위용량 5kW급 컨버터 4개를 직, 병렬 연결하여 출력리플을 최소화 하였다. 개발된 장치의 우수한 제어성능은 실제 플라즈마 공정에서 시험 평가한 결과를 통해 검증할 수 있었다.

• Journal of the Korean institute of surface engineering
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• v.44 no.6
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• pp.269-276
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• 2011

Phase evolution and tribological behavior of Cr-Mo-N multi compositional films with different interlayer were investigated. The films were deposited by hybrid PVD (Physical Vapor Deposition) system consisted of dc unbalanced magnetron (UBM) sputtering and arc ion plating (AIP) sources. A pure molybdenum (Mo) was used as sputtering target and also a pure Cr was used as AIP target to form the Cr-Mo-N films. Various growth planes were found, no textured surface, in all of the multi composition films. Maximum value of microhardness was measured in Cr-Mo-N film with Mo interlayer as 29 GPa. Composition film was mainly showed the aspect of the adhesive wear than CrN film. The friction coefficient was decreased from 0.6 for pure CrN coating to 0.35 for Cr-Mo-N film with Mo interlayer. This result may come from the formation of metal oxide tribo-layer which is known as solid lubricant during the wear test.

• Progress in Superconductivity
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• v.10 no.1
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• pp.35-39
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• 2008

By using the hybrid physical-chemical vapor deposition (HPCVD) technique, we have fabricated $MgB_2$ thick films on $Al_{2}O_3$ substrates with various impurity layers of Ni, Ti, and SiC. We have found a significant enhancement of the critical current density ($J_c$) for $MgB_2$ films grown on impurity layered substrates, indicating that additional impurity layers were provided as possible pinning sites by chemical doping in $MgB_2$ films. All samples doped by Ni, Ti, and SiC were observed to have high superconducting transition temperatures of 39 - 41 K. The $J_c$ of $MgB_2$ films grown on SiC impurity layered substrates showed three times higher than that of undoped films at high magnetic fields above 1 T.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.378-380
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• 2009

$MgF_2$ is a current material for the optical applications in the UV and deep UV range. Process variables for manufacturing the $MgF_2$ thin film were established in order to clarify optimum conditions for growth of the thin film depending upon process conditions, and then by changing a number of vapor deposition conditions and substrate temperature, Annealing conditions variously, structural and Optical characteristics were measured. Thereby, optimum process variables were derived. Nevertheless, modern applications still require improvement of the optical and structural quality of the deposited layers. In the present work, the composition and microstructure of $MgF_2$ single layers grown on slide glass substrate by Electro beam Evaporator(KV-660) processes, were analyzed and compared. The surface Substrate temperature having an effect on the quality of the thin film was changed from $200[^{\circ}C]$ to $350[^{\circ}C]$ at intervals of $50[^{\circ}C]$. and annealing temperature an effect on the thin film was changed from $200[^{\circ}C]$ to $400[^{\circ}C]$ at intervals of $50[^{\circ}C]$. Physical properties of the thin film were investigated at various fabrication conditions substrate temperature, annealing and temperature, annealing time by XRD, FE-SEM.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.12
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• pp.126-134
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• 2003

In order to investigate the effect of surface treatment in Aluminium alloy and Titanium alloy which are used to armor material during ballistic impact, a ballistic testing was conducted. Anodizing was used to achieve higher surface hardness of Aluminium alloy and Iron plating in PVD(Physical Vapor Deposition) method was used to achieve higher surface hardness of Titanium alloy. Surface hardness test were conducted using a Micro victor's hardness tester. Ballistic resistance of these materials was measured by protection ballistic limit(V-50), a statical velocity with 50% probability penetration. Fracture behaviors and ballistic tolerance, described by penetration modes, are respectfully observed from the results of V-50 test and Projectile Through Plates (PTP) test at velocities greater than V-50. PTP tests were conducted with 0$^{\circ}$obliquity at room temperature using 5.56mm ball projectile. V-50 tests were conducted with 0$^{\circ}$obliquity at room temperature with projectiles that were able to achieve near or complete penetration during PTP tests. Surface hardness, resistance to penetration. and penetration modes of surface treated alloy laminates are compared to those of surface non-treated alloy laminates. A high speed photography was used to analyze the dynamic perforation phenomena of the test materials.

• Progress in Superconductivity
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• v.9 no.2
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• pp.173-176
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• 2008

[ $MgB_2$ ] films grown by hybrid physical chemical vapor deposition under appropriate growth conditions commonly exhibit columnar grain structure. The grain boundaries between adjacent columnar grains have been reported to be good flux pinning centers. In this work, we measured the angular dependence of critical current density ($J_c$) and observed the enhanced flux pinning when an external magnetic field was aligned parallel to the columnar direction. This $J_c$ was almost comparable to the $J_c$ for intrinsic pinning case up to 1 T at low temperatures, indicating that grain boundary pinning is very effective. At high fields, however, $J_c$ decreased rapidly resulting from the fact that the density of flux pinning centers provided by grain boundaries was outnumbered by the flux density.