• 한국재료학회지
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• 제18권6호
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• pp.294-297
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• 2008

In this paper, a novel non-vacuum technique is described for the fabrication of a $CuInSe_2$ (CIS) absorber layer for thin film solar cells using a low-cost precursor solution. A solution containing Cu- and Inrelated chemicals was coated onto a Mo/glass substrate using the Doctor blade method and the precursor layer was then selenized in an evaporation chamber. The precursor layer was found to be composed of CuCl crystals and amorphous In compound, which were completely converted to chalcopyrite CIS phase by the selenization process. Morphological, crystallographic and compositional analyses were performed at each step of the fabrication process by SEM, XRD and EDS, respectively.

• 한국정밀공학회지
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• 제16권3호통권96호
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• pp.62-71
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• 1999

Integrating micro-machined sensors and actuators on the conventional devices with the copper power lines was incompatible to fabricate the mass produced micro electromechanical system (MEMS) devices. To achieve the compatibility of the wiring method between MEMS parts and devices, we developed the three-dimensional sputter-evaporation system that coats micropatterned thin copper films on the surface of the MEMS element. The system consists of a process chamber, two branch chambers, the substrate holder, and a linear-rotary motion feedthrough. Thin copper film was sputtered and evaporated on the biocompatible polymer, Pellethane$^{circed{R}}$ and silicone, catheter that is 2 mm in diameter and 700 mm in length. The metal film coating technique with three-dimensional thin film sputter-evaporation system was developed to apply the power and signal lines on the micro active endoscope. In this paper, we developed the three-dimensional metal film sputter-evaporation system operated on the low temperature for the biopolymeric substrates used in the medical MEMS devices.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 추계학술대회 논문집 학회본부
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• pp.688-691
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• 1997

Good quality superconducting $YBa_2Cu_30_{7-{\delta}}$(YBCO) thin films were grown on Hastelloy (Ni-Cr-Mo alloys) with yttria-stabilized zirconia(YSZ) buffer layers by in situ pulsed laser deposition in a multi-target processing chamber. Generally, Hastelloy exhibits excellent resistance to corrosion, fatigue, thermal shock, impact, and erosion. However, it is difficult to make films on flexible metallic substrates due to interdiffusion problems between metallic substrates and superconducting overlayers. To overcome this difficulty, it is necessary to use YSZ buffer layer since it will not only limit the interdiffusion process but also minimize the surface microcrack formation due to smaller mismatch between the film and the substrate. In order to enhance the crystallinity of YBCO films on metallic substrates, YSZ buffer layers were grown at various temperatures different from the deposition temperature of YBCO films. On YSZ buffer layer grown at higher temperature than that for depositing YBCO film, the YBCO thin film was found to be textured with c-axis orientation by x-ray diffraction and had a zero-resistance critical temperature of about 85K.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 추계학술대회 논문집
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• pp.41-43
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• 1999

Among the feffoelectric thin films that have been widely investigated for ferroelectric random access memory (FRAM) applications, SrBi$_2$Ta$_2$$O_{9}$ thin film is appropriate to memory capacitor materials for its excellent fatigue endurance. However, very few studies on etch properties of SBT thin film have been reported although dry etching is an area that demands a great deal of attention in the very large scale integrations. In this study, the a SrBi$_2$Ta$_2$$O_{9}$ thin films were etched by using magnetically enhanced inductively coupled Ar/CHF$_3$ plasma. Etch properties, such as etch rate, selectivity, and etched profile, were measured according to gas mixing ratio of CHF$_3$(Ar$_{7}$+CHF$_3$) and the other process conditions were fixed at RF power of 600 W, dc bias voltage of 150 V, chamber pressure of 10 mTorr. Maximum etch rate of SBT thin films was 1750 A77in, under CHF$_3$(Ar+CHF$_3$) of 0.1. The selectivities of SBT to Pt and PR were 1.35 and 0.94 respectively. The chemical reaction of etched surface were investigated by X-ray photoelectron spectroscopy (XPS) analysis. The Sr and Ta atoms of SBT film react with fluorine and then Sr-F and Ta-F were removed by the physical sputtering of Ar ion. The surface of etched SBT film with CHF$_3$(Ar+CHF$_3$) of 0.1 was analyzed by secondary ion mass spectrometer (SIMS). Scanning electron microscopy (SEM) was used for examination of etched profile of SBT film under CHF$_3$(Ar+CHF$_3$) of 0.1 was about 85˚.85˚.˚.

• International Journal of Automotive Technology
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• 제2권3호
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• pp.85-91
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• 2001

Characteristics of methane direct-injection spark-ignition stratified combustion in lean hydrogen mixture were analyzed both in a single cylinder engine and in a constant volume combustion chamber. Combustion pressure and Instantaneous combustion chamber wall temperature during the combustion process were measured with a thin-film thermocouple and used in analyses of combustion and cooling loss. Results in this research show that the premixed hydrogen increases cooling loss to combustion chamber wall while achieving combustion promotion, and the combustion system is effective especially in lean mixture conditions. Analysis of flame propagation was also done with Schlieren photography in the constant volume combustion chamber.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 춘계학술대회 논문집
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• pp.17-17
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• 2010

Polycrystalline $CuInS_2$ thin films were performed from S/In/Cu Stacked elemental layer(SEL) method with post annealing. In thin method, the thin films were annealed in Vacuum of $10^{-3}$ torr or in S ambient. $CuInS_2$ thin films were manufctured by using the evaporation and the annealing with vacuum quartz furnace of sulfurization process was used in the vacuum chamber to the substrate temperature on the glass substrate the annealing temperature and characteristics thereof were investigated. The physical properties of the thin film were investigated under various fabrication conditions including the substrate temperature annealing time by XRD, FE-SEM, and Hall measurement system.

• Journal of Information Display
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• 제2권3호
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• pp.72-77
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• 2001

Amorphous silicon thin-film transistors (a-Si TFTs) were incorporated into Mo-tip-based triode-type field emitters and diode-type ones of carbon nanotubes for an active-matrix cathode (AMC) plate of field emission displays. Also, we developed a novel surface-treatment process for the Mo-tip fabrication, which gleatly enhanced in the stability of field emission. The field emission currents of AMC plates on glass substrate were well controlled by the gate bias of a-Si TFTs. Active-matrix field emission displays (AMFEDs) with these AMC plates were demonstrated in a vacuum chamber, showing low-voltage matrix addressing, good stability and reliability of field emission, and highly uniform light emissions from the anode plate with phosphors. The optimum design of AMFEDs including a-Si TFTs and a new light shield/focusing grid is discussed.

• 한국초전도ㆍ저온공학회논문지
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• 제8권3호
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• pp.18-22
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• 2006

We obtained in-situ $MgB_2$ thin films in an one-step process using ESSD (Evaporation Sputtering Simultaneous Deposition) method. In our approach. the Ma evaporator is designed specially Mg and B are simultaneously evaporated and sputtered, respectively, in the specially designed ESSD chamber. The background pressure was less than $1{\times}10^{-6}$ Torr. The substrate temperature was kept at 623 K. The film properties were investigated by both electrical resistivity and PPMS. As a result, typical $T_c$ of films was 11 K.

• 센서학회지
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• 제13권2호
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• pp.128-132
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• 2004

Short wave infrared (SWIR) photovoltaic devices have been fabricated from metal organic vapour phase epitaxy (MOVPE) grown n- on p- HgCdTe films on GaAs substrates. The MOVPE grown films were processed into mesa type discrete devices with wet chemical etching employed for meas delineation and ZnS surface passivatlon. ZnS was thermally evaporated from effusion cell in an ultra high vacuum (UHV) chamber. The main features of the ZnS deposited from effusion cell in UHV chamber are low fixed surface charge density, and small hysteresis. It was found that a negative flat band voltage with -0.6 V has been obtained for Metal Insulator Semiconductor (MIS) capacitor which was evaporated at $910^{\circ}C$ for 90 min. Current-Voltage (I-V) and temperature dependence of the I-V characteristics were measured in the temperature range 80 - 300 K. The Zero bias dynamic resistance-area product ($R_{0}A$) was about $7500{\Omega}-cm^{2}$ at room temperature. The physical mechanisms that dominate dark current properties in the HgCdTe photodiodes are examined by the dependence of the $R_{0}A$ product upon reciprocal temperature. From theoretical considerations and known current expressions for thermal and tunnelling process, the device is shown to be diffusion limited up to 180 K and g-r limited at temperature below this.

• JSTS:Journal of Semiconductor Technology and Science
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• 제13권4호
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• pp.395-401
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• 2013

In-situ optical emission spectroscopy (OES) is employed for leak detection in plasma etching system. A misprocessing is reported for significantly reduced silicon etch rate with chlorine gas, and OES is used as a supplementary sensor to analyze the gas phase species that reside in the process chamber. Potential cause of misprocessing reaches to chamber O-ring wear out, MFC leaks, and/or leak at gas delivery line, and experiments are performed to funnel down the potential of the cause. While monitoring the plasma chemistry of the process chamber using OES, the emission trace for nitrogen species is observed at the chlorine gas supply. No trace of nitrogen species is found in other than chlorine gas supply, and we found that the amount of chlorine gas is slightly fluctuating. We successfully found the root cause of the reported misprocessing which may jeopardize the quality of thin film processing. Based on a quantitative analysis of the amount of nitrogen observed in the chamber, we conclude that the source of the leak is the fitting of the chlorine mass flow controller with the amount of around 2-5 sccm.