• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.371-372
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• 2012

We have studied lead-based gapless semiconductors, $PbPdO_2$, which is very sensitive to external parameters such as temperature, pressure, electric field, etc[1]. We have fabricated pure $PbPdO_2$, Co- and Mn-doped $PbPdO_2$ thin films using the pulsed laser deposition. Because of the volatile element of Pb, it is very difficult to grow the films. Note that in case of $MgB_2$, Mg is also volatile element. So in order to enhance the quality of $MgB_2$, some experiments are carried out in annealing with Mg-rich atmosphere [2]. This annealing process with volatile element plays an important role in making smooth surface. Thus, we applied such process to our studies of $PbPdO_2$ thin films. As a result, we found the optimal condition of ex-situ annealing temperature ${\sim}650^{\circ}C$ and time ~12 hrs. The ex-situ annealing brought the extreme change of surface morphology of thin films. After ex-situ annealing with PbO-rich atmosphere, the grain size of thin film was almost 100 times enlarged for all the thin films and also the PbO impurity phase was smeared out. And from X-ray diffraction measurements, we determined highly crystallized phases after annealing. So, we measured electrical and magnetic properties. Because of reduced grain boundary, the resistivity of ex-situ annealed samples changed smaller than no ex-situ sample. And the carrier densities of thin films were decreased with ex-situ annealing time. In this case, oxygen vacancies were removed by ex-situ annealing. Furthermore, we will discuss the transport and magnetic properties in pure $PbPdO_2$, Co- and Mn-doped $PbPdO_2$ thin films in detail.

• Journal of the Microelectronics and Packaging Society
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• v.12 no.1 s.34
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• pp.1-7
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• 2005

The effect of trimming process to adjust accurate resistance of a thin-film resistor was studied with respect to low temperature coefficient of resistance(TCR) and high precision. The characteristics of a thin-film resistor fabricated by sputtering were investigated depending on trimming condition and annealing temperature. Measured results showed that the characteristic of a thin-film resistor was degraded with increased trimming speed. However, an average resistance deviation and a TCR were improved to $0.26\%$ and 52.77[ppm/K], respectively, through annealing treatment. Also, thin-film resistors with 1 k$\Omega$ and 10k$\Omega$ showed better performance compared to a resistor with 100k$\Omega$. The Optimal trimming speed and annealing temperature were 20mm/sec and 539K, respectively, and under this optimal condition, a thin-film resistor with an average resistance deviation of $0.31\%$ and a TCR of below 10[ppm/K] was obtained.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.233-233
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• 2010

CdS thin films were deposited on glass substrates by R.F. magnetron sputtering method and some of the samples were treated by rapid thermal annealing (RTA) process. Effects of thermal annealing on structural and optical properties were investigated at different temperatures ranging from 100 to $600^{\circ}C$. The crystallographic structure of the films and the size of the crystallites in the films were studied by X-ray diffraction. The crystallite sizes were found to increase, and the X-ray diffraction patterns were seen to sharpen by annealing. Optical properties of the films were calculated using the envelope method and the photoluminescence measurements. The optical properties of the films were seen to be dependent on the film thicknesses. The energy gap of the films was found to decrease by annealing. The band edge sharpness of the optical absorption was seen to oscillate by thermal annealing. Annealing over $400^{\circ}C$ was seen to degrade the optical properties of the film. The best annealing temperature for the films was found to be $400^{\circ}C$ from the optical properties. It is observed that the CdS film annealed at $400^{\circ}C$ reveals the strongest UV emission intensity and narrowest full width at half maximum among the temperature ranges studied. The enhanced UV emission from the film annealed at $400^{\circ}C$ is attributed to the improved crystalline quality of CdS thin film due to the effective relaxation of residual compressive stress and achieving maximum grain size. The results show that heat treatments under optimal annealing condition can provide significant improvements in the properties of CdS thin films.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.423-423
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• 2007

In this study, the effects of annealing conditions on the structural and optical properties of ZnO films were investigated. ZnO oxide (ZnO) films were deposited onto $SiO_2$/Si substrates by RF magnetron sputtering from a ZnO target. The substrate was not heated during deposition. ZnO films were annealed in temperature ranges of $500{\sim}650^{\circ}C$ in the $O_2$ flow for 5 ~ 20 min. The film average thicknesses were in the range of 291 nm. The surface morphologies and structures of the samples were characterized by SEM and XRD, respectively. The optical properties were evaluated by PL measurement at room temperature using a He-Cd 325 nm laser. According to the results, the optimal annealing conditions for the best photoluminescence (PL) characteristics were found to be oxygen fraction, ($O_2/O_2+Ar$) of 20%, RF power of 240W, substrate temperature of RT (room temperature), annealing condition of $600^{\circ}C$ for 20 min, and sputtering pressure of 20 mTorr. The obtained wavelength of light emission was found at 379 nm (ultraviolet-UV region). However, the optimal parameters for the best PL characteristics of ZnO thin films were not consistent with those obtained from the (002) intensities of XRD analyses. As a result, XRD pattern was not considered as the key issue concerning the intensity of PL of ZnO thin film. The intensity of the emitted UV light will correspond to the grain size of ZnO film.

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.59-59
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• 2000

Recently low resistance of bus line is required for large screen size TFT-LCD panels. As a result, lower resistance Al-alloy is currently reviewed extensively. The resistivity is required smaller than 10 $\mu$$\Omega$cm. In this paper, Al-Nd thin film were deposited on glass substrates by D.C. magnetron sputtering system under various condition. Its properties were characterized by SEM, AFM, XRD, 4-ping-probe. The optimal condition of Al-Nd was 12$0^{\circ}C$, 125W, 0.4Pa, 30sccm(Ar) and 35$0^{\circ}C$, 20min. annealing. At that condition the resistivity of Al-Nd(2wt.%) was about 4 $\mu$$\Omega$cm. The minimum contact resistance of ITO/Nd was about 110$\mu$$\Omega$cm in the condition of 30$0^{\circ}C$, Ar 30 sccm. O2.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.45 no.3
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• pp.131-138
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• 2022

The demand for chiller equipment that keeps each machine at a constant temperature to maintain the best possible condition is growing rapidly. PID (Proportional Integral Derivation) control is a popular temperature control method. The error, which is the difference between the desired target value and the current system output value, is calculated and used as an input to the system using a proportional, integrator, and differentiator. Through such a closed-loop configuration, a desired final output value of the system can be reached using only the target value and the feedback signal. Furthermore, various temperature control methods have been devised as the control performance of various high-performance equipment becomes important. Therefore, it is necessary to design for accurate data-driven temperature control for chiller equipment. In this research, support vector regression is applied to the classic PID control for accurate temperature control. Simulated annealing is applied to find optimal PID parameters. The results of the proposed control method show fast and effective control performance for chiller equipment.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2001.04a
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• pp.281-286
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• 2001

Titanium alloy conducted in this experimental study has superior corrosive resistant and is mainly used in aerospace, automotive and petro-chemical industries. It is also treated with important materials of domestic goods due to improvement of the standard of living. In this study specimens were processed in the wire EDM after annealing, solution treatment and aging. Results were obtained through repeated experments of main rough process and finish process with the change of process parameters. Processing characteristics such as surface hardness, surfaces roughness, shape of processed surface and components were measured. The results confirmed that the above mentioned elements were improved in accordance with the number of process. Therefore, the optimal wire EDM condition in accord with processing characteristics is proposed in this experiment.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.149-149
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• 2011

CdS films were deposited on glass substrates by R.F. magnetron sputtering method and the films were annealed at various substrate temperatures ranging from room temperature to $300^{\circ}C$. Structural properties of the films were studied by X-ray diffraction analysis. The structural parameters as crystallite size have been evaluated. The crystallite sizes were found to increase, and the X-ray diffraction patterns were seen to sharpen by increasing substrate temperatures. X-ray diffraction patterns of these films indicated that they contain both cubic (zincblende) and hexagonal (wurtzite) structures as a mixture. Optical properties of the films were measured at room temperature by using UV/VIS spectrometer in the wavelength range of 190 to 1100nm and optical absorption coefficients were calculated using these data. The energy gap of the films was found to decrease, and the band edge sharpness of the optical absorption was seen to oscillate by annealing. The results show that heat treatments under optimal annealing condition can provide significant improvements in the properties of CdS thin films.

• Korean Journal of Materials Research
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• v.28 no.4
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• pp.195-200
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• 2018

This study investigated the effects of the post annealing temperatures on the electrical and interfacial properties of a metal-semiconductor-metal photodetector(MSM-PD) device. The interdigitate type MSM-PD devices had the structure Al(500 nm) / Ti(200 nm) / poly-Si(500 nm). Structural analyses of the MSM-PD devices were performed by employing X-ray diffraction(XRD), scanning electron microscopy(SEM) and transmission electron microscope(TEM). Electrical characteristics of the MSM-PD were also examined using current-voltage(I-V) measurements. The optimal post annealing condition for the Schottky contact of MSM-PD devices are $350^{\circ}C$-30minutes. However, as the annealing temperature and time are increased, electrical characteristics of MSM-PD device are degraded. Especially, for the annealing conditions of $400^{\circ}C$-180minutes and $500^{\circ}C$-30minutes, the I-V measurement itself was impossible. These results are closely related to the solid phase reactions at the interface of MSM-PD device, which result in the formation of intermetallic compounds such as $Al_3Ti$ and $Ti_7Al_5Si_{12}$.

• Journal of the Korean Society for Heat Treatment
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• v.11 no.3
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• pp.216-226
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• 1998

Heat treatment conditions and the formation of microstructures were studied for improving the transformation-induced plasticity(TRIP) effect of retained austenite and mechanical properties of Fe-0.2%C-1.5%Si-1.5%Mn sheet steel. An excellent combination of elongation about 30% and high strength over 760MPa was achieved by processing of intercritical annealing and isothermal holding Intercritical annealing the sheet steel produced fine particles($1{\sim}2{\mu}m$) of retained austenite which were stabilized due to C enrichment by subsequent holding in bainite transformation range. Heat treatment conditions were depended on the shape and distribution of second phases as well as the volume fraction and stability of retained austenrte. In this work, the heat treatment condition of optimal strength-elongation balance was obtained by holding the steel at $400^{\circ}C$ for 200sec, after intercritical annealing at $790^{\circ}C$ for 300sec.