• Journal of the Korean institute of surface engineering
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• v.34 no.5
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• pp.503-509
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• 2001

Thin films of hydrogenated amorphous silicon (a-Si : H) and hydrogenated amorphous silicon carbide (a-SiC:H) of different compositions were deposited on Si(100) wafer and glass by RF plasma-enhanced chemical vapor deposition (RF-PECVD). In the present work, we have investigated the effects of the RF power on the properties, such as optical band gap, transmittance and crystallinity. The Raman data show that the a-Si:H material consists of an amorphous and crystalline phase for the co-presence of two peaks centered at 480 and $520 cm^{-1}$ . The UV-VIS data suggested that the optical energy band gap ($E_{g}$ ) is not changed effectively with RF power and the obtained $E_{g}$(1.80eV) of the $\mu$c-Si:H thin film has almost the same value of a-Si:H thin film (1.75eV), indicating that the crystallity of hydrogenated amorphous silicon thin film can mainly not affected to their optical properties. However, the experimental results have shown that$ E_{g}$ of the a-SiC:H thin films changed little on the annealing temperature while $E_{g}$ increased with the RF power. The Raman spectrum of the a-SiC:H thin films annealed at high temperatures showed that graphitization of carbon clusters and microcrystalline silicon occurs.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07b
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• pp.857-860
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• 2004

Cubic CdS thin film with the strongest XRD peak (111) at diffraction angle $(\theta)$ of 26.5 was well made at substrate temperature of $150^{\circ}C$. At that time, lattice constant a of the thin film was $5.79{\AA}$, grain size of that was more over ${\mu}m$ and it's resistivity was over $10^3{\Omega}cm$. And the peak of diffraction intensityat miller index (111) of CdS:In thin film with dopant In of 1 atom% was shown higher about 20 % than undoped CdS thin film. Also, CdS:In thin film had in part hexagonal structure among cubic structure as secondary phase. Lattice constant of a and grain size of secondary phase of the film with dopant In of 1 atom% was $5.81{\AA}$ and around $1{\mu}m$ respectively The lowest resistivity of $5.1{\times}10^{-3}{\Omega}cm$ was appeared on dopant In of 1.5 atom%. Optical band gap of undoped CdS thin film was 2.43 eV and CdS:In thin film with dopant In of 0.5 atom% had the largest band gap 2.49 eV.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.8
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• pp.714-719
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• 2005

NiCr thin film was deposited by DC magnetron sputtering on $A;_2O_3$/Si substrate with NiCr (80:20) alloy target. NiCr thin films were annealed at $300^{\circ}C,\;400^{\circ}C,\;500^{\circ}C,\;600^{\circ}C,\;and\;700^{\circ}C$ for 6 hr in $H_2$ after annealing at $500^{\circ}C$ for 6hr in air atmosphere, respectively. To analyze NiCr thin film properties, the changes of its micro structure were Investigated through field emission scanning electron microscope (FESEM). X-ray photoelectron spectroscopy (XPS) was used to analyze a surface of NiCr thin film. Resistance of NiCr thin film was measured by 4-point probe technique. The generated heats were measured by infrared thermometer through the application of DC voltage (5 V/l2 V). NiCr thin film treated by gradational double annealing process had uniform and small grains. Maximum temperature generated heat by NiCr micro heater was $173^{\circ}C$. We expect that our results will be a useful reference in the realization of NiCr micro heater.

• Journal of Satellite, Information and Communications
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• v.10 no.2
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• pp.75-79
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• 2015

In this study, we investigated the electro-optical (EO) characteristic of fringe-field switching (FFS) mode cell by the ion beam alignment method on the a-C:H thin film. The suitable inorganic thin films for FFS cell and the aligning capabilities of nematic liquid crystal (NLC) using the new alignment material of a-C:H thin film were studied. An excellent voltage-transmittance (V-T) and response time curve of the ion beam aligned FFS-LCD was observed with oblique ion beam exposure on the a-C:H thin films. Also, the V-T hysteresis characteristics of the ion beam-aligned FFS-LCD with IB exposure on the a-C:H thin films is almost the same as that of the rubbing-aligned FFS cell on a polyimide surface.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.443-446
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• 2001

MI(Magneto-Impedance) sensor which is made by thin films has significantly high detecting sensitivity in weak magnetic field. It also has a merit to be able to build in low power system. Its structure is simple, which makes it easier to prepare a miniature. In this study, its magnetic permeability and anisotropy field(H$\sub$k/) as a function of a thickness of sputtered amorphous CoZrNb thin film with high saturation magnetostriction and excellent soft magnetic property are investigated. In order to make a uniaxial anisotropy, thin film was subjected to post annealing with a static magnetic field with 1KOe intensity at 250, 300, and 320$^{\circ}C$ for 2 hour. Anisotropy field(H$\sub$k/)of thin film is measured by using MH loop tracer. Its magnetic permeability of thin film is measured over the frequency range from 1 MHz to 750MHz. It has shown that the magnetic permeability of amorphous CoZrNb thin film is decreased due to the skin effect with increasing a thickness of CoZrNb thin film, and hence its driving frequency is lowered.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.653-655
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• 1997

In this paper, a monoblock dielectric filter for 900MHz band CT-1 is designed by using CAD(Computer Aided Design). Equivalent circuit for monoblock dielectric filter represented by parallel coupled stripline is simulated by using SuperCompact software tool. A Designed filter structure is simulated by using HFSS to optimize result.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1211-1214
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• 2003

The film is prepared by electron cyclotron resonance chemical vapor deposition (ECRCVD) employing CH$_4$ and H$_2$ gases. It is deposited by the control of microwave plasma power, gas flow ratio, deposition pressure, and In-situ thermal treatment temperature. The structure of a-C:H (hydrogenated amorphous carbon) thin film is analysed by FT-IR spectroscopy. The fraction sp$^3$ versus sp$^2$ bonding is very important to clear up the surface and interrace of a-C:H film properties such as nano-scale friction behavior. The sp$^3$ versus sp$^2$ bonding of a-C:H thin film is dependent on the deposition conditions, therefore. nano-scale friction behavior is dependent on the deposition conditions.

• Proceedings of the KIEE Conference
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• 2003.07c
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• pp.1595-1597
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• 2003

This paper presents the deposition of ${\mu}c$-Si:H thin-film and fabrication of a solar cell by VHF-PECVD method. The ${\mu}c$-Si:H thin films and pin-type solar cells are fabricated using multi-chamber cluster tool system. A 7.4% conversion efficiency was achieved from ${\mu}c$-Si:H thin film solar cells with total thickness less than $5{\mu}m$. The physical characteristic was measured by Raman spectroscopy, Solar cell characteristic was measured under AM1.5 illumination.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.165-168
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• 2004

In this study, AZO(ZnO:Al) thin film were prepared by FTS(Facing Target Sputtering) system. The electrical, optical and crystallographic properties of AZO thin film with $O_2$ gas flow ratio have been investigated. The thickness, transmittance, crystal structure and resistivity of AZO thin film were measured by a-step, UV-VIS spectrometer, XRD and four-point probe, respectively. As a result AZO thin film deposited with the transmittance over 80% and the resistivity about $10^{-1}\Omega-cm$.

• Current Photovoltaic Research
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• v.8 no.3
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• pp.94-101
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• 2020

This study was trying to focus on achieving high efficiency of multi junction solar cell with thin film silicon solar cells. The proposed thin film Si-Ge/c-Si tandem junction solar cell concept with a combination of low-cost thin-film silicon solar cell technology and high-efficiency c-Si cells in a monolithically stacked configuration. The tandem junction solar cells using amorphous silicon germanium (a-SiGe:H) as an absorption layer of upper sub-cell were simulated through ASA (Advanced Semiconductor Analysis) simulator for acquiring the optimum structure. Graded Ge composition - effect of E_g profiling and inserted buffer layer between absorption layer and doped layer showed the improved current density (J_sc) and conversion efficiency (η). 13.11% conversion efficiency of the tandem junction solar cell was observed, which is a result of showing the possibility of thin film Si-Ge/c-Si tandem junction solar cell.