• Journal of the Korean Society for Heat Treatment
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• v.22 no.5
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• pp.307-311
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• 2009

In this study, TiCrN films were deposited on STS 316 Land Si (100) wafer by inductively coupled plasma (ICP) assisted D.C. magnetron sputtering. The effect R.F. power for ICP discharge on the mechanical properties of TiCrN films was investigated. XRD, XPS and FE-SEM were used for the structure analysis. Also the Micro-Knoop hardness tester and profilometer were used for measuring hardness of coatings and film stress respectively. As increasing the R.F. power for ICP discharge, thickness of coating was decreased from 1633 nm to 1288 nm but hardness was increased about $Hk_{5g}$ 4200 at 400 W. All of the XRD patterns showed (111), (200) and (220) peaks of TiCrN films. Surface morphology was studied using the profilometer. FE-SEM was used to know morphology and cross-section of the films. Structure of the films was changed dense as increased ICP power.

• Journal of Satellite, Information and Communications
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• v.6 no.1
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• pp.28-31
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• 2011

In this paper, a new set of structural and sacrificial material that is diamond like carbon (DLC)/photoresist for high performance piezoelectric RF-MEMS switches which are actuated in d33 mode is suggested. To avoid curing problem of photoresist sacrificial layer, DLC structure layer is deposited at room temperature by radio frequency plasma enhanced chemical vapor deposition (RF-PECVD) method. And lead zirconate titanate (PZT) piezoelectric layer is deposited on structure layer directly at room temperature by rf magnetron sputtering system and crystallized by rapid thermal annealing (RTA) equipment. Particular attention is paid to the annealing of PZT film in order to crystallize into perovskite and the variation of mechanical properties of DLC layer as a function of annealing temperature. The DLC layer shows good performance for structure layer in aspect to Young's modulus and hardness. The fabrication becomes much simpler and cheaper with use of a photoresist.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.9
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• pp.681-684
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• 2010

The $TiO_2$/ZnS/Ag/ZnS/$TiO_2$ multilayered structure for the transparent electrodes in plasma display panel was designed by essential macleod program (EMP) and the multilayered film was deposited on a glass substrate by direct-current (DC)/radio-frequency (RF) magnetron sputtering system. During film deposition process, the Ag layer in $TiO_2$/Ag/$TiO_2$ structure became oxidized and the filter characteristic was degraded easily. In this study, ZnS layer was adopted as a diffusion blocking layer between $TiO_2$ and Ag to prevent the oxidation of Ag layer efficiently in $TiO_2$/ZnS/Ag/ZnS/$TiO_2$ structure. Based on the AES depth profiling analysis, the Ag layer was effectively protected by the ZnS layer as compared with the $TiO_2$/Ag/$TiO_2$ multilayered films without ZnS as an antioxidant layer. The 3 times stacked $TiO_2$/ZnS/Ag/ZnS/$TiO_2$ films have low sheet resistance of $1.22{\Omega}/{\square}$ and luminous transmittance was as high as 62% in the visible ranges.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.572-572
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• 2013

본 연구에서는 Plasma damage-free 선형 대향 타겟 스퍼터(Linear Facing Target sputtering: LFTS) 시스템을 이용하여 성막시킨 GaN-LED의 투명전극용 Ga-doped ZnO (GZO) 박막의 특성을 연구하였다. LFTS 시스템을 이용한 GZO 성막 공정 중 LED소자의 플라즈마 노출에 의한 데미지를 최소화 하기 위해 일정한 타겟간 거리(Target-to-Target distance: 65 mm)에서 타겟과 기판간 거리(Target-to-Substrate distance)를 50 mm에서 120 mm로 변화시키며 GZO 투명 전극을 성막해 박막의 특성과 소자의 특성을 동시에 분석하였다. LFTS에서 플라즈마는 GZO 타겟 사이에 형성된 일방향의 자장에 의해 효과적으로 구속되기 때문에 기판과 타겟 거리를 최적화 할 경우 플라즈마 데미지를 최소화하며 GaN-LED의 제작이 가능하다. 기판과 타겟 사이의 거리가 120 mm에서 최적화된 200 nm 두께의 GZO 투명 전극은 DC 파워 250 W, 공정 압력 0.3 mTorr, Ar 20 sccm 실험 조건하에서 LED 소자 위해 성막되었으며, 이후 $600^{\circ}C$ 수소 분위기에서 1분간 급속 열처리하였고 면저항(37 Ohm/sq.)과 450 nm 파장에서의 투과도(83%)를 나타냄을 확인할 수 있었다. LED 소자와 타겟 사이의 거리가 50 mm에서 120 mm로 증가할수록 성막공정 중 LED 소자에 미치는 플라즈마 데미지의 감소로 인해 GaN-LED 소자의 turn on voltage가 8.2 V에서 3.4 V로 감소한 것을 확인하였으며, 또한 radiant intensity는 20 mA의 전류를 인가하였을 시 0.02 mW/sr에서 8 mW/sr로 400배 향상되었다. 이러한 소자 특성은 대향 타겟 스퍼터 시스템으로 성장시킨 GZO 투명전극이 LED 소자의 투명 전극 층(Transparent Conductive Layer: TCL)에 적용될 수 있음을 말해준다.

• Journal of the Semiconductor & Display Technology
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• v.9 no.1
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• pp.41-47
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• 2010

The effects of thermal treatment on CNTs, which were coated with a-$CN_x$ thin film, were investigated and related to variations of chemical bonding and morphologies of CNTs and also properties of field emission induced by thermal treatment. CNTs were directly grown on nano-sized conical-type tungsten tips via the inductively coupled plasma-chemical vapor deposition (ICP-CVD) system, and a-$CN_x$ films were coated on the CNTs using an RF magnetron sputtering system. Thermal treatment on a-$CN_x$ coated CNT-emitters was performed using a rapid thermal annealing (RTA) system by varying temperature ($300-700^{\circ}C$). Morphologies and microstructures of a-$CN_x$/CNTs hetero-structured emitters were analyzed by FESEM and HRTEM. Chemical composition and atomic bonding structures were analyzed by EDX, Raman spectroscopy, and XPS. The field emission properties of the a-$CN_x$/CNTs hetero-structured emitters were measured using a high vacuum (below $10^{-7}$ Torr) field-emission measurement system. For characterization of emission stability, the fluctuation and degradation of the emission current were monitored in terms of operation time. The results were compared with a-$CN_x$ coated CNT-emitters that were not thermally heated as well as with the conventional non-coated CNT-emitters.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.1
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• pp.44-47
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• 2012

The $TiO_2/Si_3N_4/Ag/Si_3N_4/TiO_2$ multi layered structure was designed for the possible application of transparent electrodes in PDP (Plasma Display Panel). Multi layered film was deposited on a glass substrate at room temperature by DC/RF magnetron sputtering system and EMP (Essential Macleod Program) was adopted to optimize the optical characteristics of film. During the deposition process, the Ag layer in $TiO_2/Ag/TiO_2$ became heavily oxidized and the filter characteristic was degraded easily. In thus study, Si3N4 layer was used as a diffusion buffer layer between $TiO_2$ and Ag. in order to prevent the oxidation of Ag layer in $TiO_2/Si_3N_4/Ag/Si_3N_4/TiO_2$ structure. It was confirmed that $Si_3N_4$ layer is one of candidate materials acting as diffusin barrier between $TiO_2/Ag/TiO_2$.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.12
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• pp.2446-2452
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• 2009

A Ceramic Metal-halide lamp is achieved by adding multiple metals to a basic mercury discharge. Because the vapor pressure of most metals is very much lower than mercury itself, metal-halide salts of the desired metals, having higher vapor pressures, are used to introduce the material into the basic discharge. The metal compounds are usually polyatomic iodides, which vaporize and subsequently dissociate as they diffuse into the bulk plasma. Metals with multiple visible transitions are necessary to achieve high photometric efficiency and good color. Compounds of Sc, Dy, Ho, Tm, Ce, Pr, Yb and Nd are commonly used. The maximum visible efficacy of a Ceramic Metal Halide lamp, under the constant of a white light source, is predicted to be about 450lm/W. This is controlled principally by the chemical fill chosen for a particular lamp. Current these lamps achieve 130lm/W and these life time are the maximum 16,000[hr]. So factors of performance lower are necessary to improve lamp performance. In this paper, we analyzed factors of performance lower by accelerated deterioration test. The lamp was operated with short duration turn-on/turn-off procedure to enhance the effect due to electrode sputtering during lamp ignition. The tested lamp that was operated with a longer turn-on/off(20/20 minutes) showed blackening, changed distance between electrodes and lowered color rendering & color temperature by losses of Dy at 421.18nm, I at 511nm, T1 at 535nm and Na at 588nm compared with the new lamp.

• Proceedings of the KIEE Conference
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• 1999.11d
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• pp.863-866
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• 1999

(Ba,Sr)$TiO_3$ thin films have attracted groat interest as new dielectric materials of capacitors for ultra-large-scale integrated dynamic random access memories (ULSI-DRAMs) such as 1 Gbit or 4 Gbit. In this study, inductively coupled $BCl_3/Cl_2$/Ar plasmas was used to etch (Ba,Sr)$TiO_3$ thin films. RF power/dc bias voltage = 600 W/-250 V and chamber pressure was 10 mTorr. The $Cl_2/(Cl_2+Ar)$ was fixed at 0.2, the (Ba,Sr)$TiO_3$ thin films were etched adding $BCl_3$. The highest (Ba,Sr)$TiO_3$ etch rate is 480$\AA/min$ at 10 % $BCl_3$ adding to $Cl_2$/Ar. The characteristics of the plasmas were estimated using optical emission spectroscopy (OES). The change of Cl, B radical density measured by OES as a function of $BCl_3$ percentage in $Cl_2$/Ar. The highest Cl radical density was shown at the addition of 10% $BCl_3$ to $Cl_2$/Ar. To study on the surface reaction of (Ba,Sr)$TiO_3$ thin films was investigated by XPS analysis. Ion enhancement etching is necessary to break Ba-O bond and to remove $BaCl_2$. There is a little chemical reaction between Sr and Cl, but Sr is removed by physical sputtering. There is a chemical reaction between Ti and Cl, and Tic14 is removed with ease. The cross-sectional of (Ba,Sr)$TiO_3$ thin film was investigated by scanning electron microscopy (SEM), the etch slope is about $65\;{\sim}\;70$.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.305-305
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• 2010

It is known that a pulse of electrons of high kinetic energy (1-3 eV) in metals can be generated with the deposition of external energy to the surface such as in the absorption of light or in exothermic chemical processes. These energetic electrons are not in thermal equilibrium with the metal atoms and are called "hot electrons" The concept of photon energy conversion to hot electron flow was suggested by Eric McFarland and Tang who directly measured the photocurrent on gold thin film of metal-semiconductor ($TiO_2$) Schottky diodes [1]. In order to utilize this scheme, we have fabricated metal-semiconductor Schottky diodes that are made of Pt or Au as a metallic layer, Si or $TiO_2$ as a semiconducting substrate. The Pt/$TiO_2$ and Pt/Si Schottky diodes are made by PECVD (Plasma Enhanced Chemical Vapor Deposition) for $SiO_2$, magnetron sputtering process for $TiO_2$, e-beam evaporation for metallic layers. Metal shadow mask is made for device alignment in device fabrication process. We measured photocurrent on Pt/n-Si diodes under AM1.5G. The incident photon to current conversion efficiency (IPCE) at different wavelengths was measured on the diodes. We also show that the steady-state flow of hot electrons generated from photon absorption can be directly probed with $Pt/TiO_2$ Schottky diodes [2]. We will discuss possible approaches to improve the efficiency of photon energy conversion.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.286-286
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• 2011

최근 폴리머를 기판으로 하는 Flexible TFT (thin film transistor)나 3D-ULSI (three dimensional ultra large-scale integrated circuit)에서 높은 에너지 소비효율과, 빠른 반응 속도를 실현 시키기 위해 낮은 비저항(resistivity)을 가지며, 높은 홀 속도(carrier hall mobility)를 가지는 다결정 반도체 박막(poly-crystalline thin film)을 만들고자 하고 있다. 이를 실현 시키기 위해서는 높은 온도에서 장시간의 열처리가 필요하며, 이는 폴리머 기판의 문제점을 야기시킬 뿐 아니라 공정시간이 길다는 단점이 있었다. 이에 반도체 박막의 재결정화 온도를 낮춰주는 metal (Al, Ni, Co, Cu, Ag, Pd etc.,)을 이용하여 결정화 시키는 방법이 많이 연구 되어지고 있지만, 이 또한 재결정화가 이루어진 반도체 박막 안에 잔여 금속(residual metal)이 존재하게 되어 비저항을 높이고, 홀 속도를 감소시키는 단점이 있다. 이에 본 실험은 HiPIMS (High power impulse magnetron sputtering)와 PIII and D (plasma immersion ion implantation and deposition) 공정을 복합시킨 프로세스로 적은양의 금속이온주입을 통하여 재결정화 온도를 낮췄을 뿐 아니라, 잔여 하는 금속의 양도 매우 적은 다결정 반도체 박막을 만들 수 있었다. 분석 장비로는 박막의 결정화도를 측정하기 위해 GAXRD (glancing angle X-ray diffractometer)를 사용하였고, 잔여 하는 금속의 양과 화학적 결합 상태를 알아보기 위해 XPS를 통해 분석을 하였다. 마지막으로 홀 속도와 비저항을 측정하기 위해 Hall measurement와 Four-point prove를 사용하였다.