• Journal of information and communication convergence engineering
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• v.4 no.1
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• pp.18-22
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• 2006

A small-sized gas identification system has been fabricated and characterized using an integrated gas sensor array and artificial neural-network. The sensor array consists of four thick-film oxide semiconductor gas sensors whose sensing layers are $In_{2}O_{3}-Sb_{2}O_{5}-Pd-doped\;SnO_2$ + Pd-coated layer, $La_{2}O_{5}-PdCl_{2}-doped\;SnO_2,\;WO_{3}-doped\;SnO_{2}$ + Pt-coated layer and $ThO_{2}-V_{2}O_{5}-PdCl_{2}\;doped\;SnO_{2}$. The small-sized gas identification instrument is composed of a GMS 81504 containing an internal ROM (4k bytes), a RAM (128 bytes) and four-channel AD converter as MPU, LEDs for displaying alarm conditions for three gases (liquefied petroleum gas: LPG, liquefied natural gas: LNG and carbon monoxide: CO) and interface circuits for them. The instrument has been used to identify alarm conditions for three gases among the real circumstances and the identification has been successfully demonstrated.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.12 no.6
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• pp.283-287
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• 2002

We have studied Zr(Si)N film as a diffusion barrier between Cu metal and Si substrate for application of interconnection metal in ULSI circuits. Zr(Si)N film was deposited with reactive DC magnetron sputtering system using $Ar/N_2$mixed gas. The value of the resistivity was the lowest for the ZrN film using 29 : 1 of Ar : $N_2$reactant gas ratio at room temperature and decreased with increasing of Si substrate temperature. As the value of ZrN film resistivity was decreased, the direction of crystal growth was toward to (002) plane. The barrier property of ZrN film added with Si was improved. But Si was added too much in ZrN film, the barrier property was degraded. The adhesive property was improved with increasing of Si in ZrN. For the analysis of the film, XRD, Optical microscopy, Scretch tester, so on were used.

• Applied Chemistry for Engineering
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• v.34 no.4
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• pp.383-387
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• 2023

The quartz crystal microbalance (QCM), commonly used in high vacuum deposition, becomes difficult to use when a thick film is deposited on the quartz, affecting the crystal's inherent vibration. In this study, a non-destructive optical measurement method was developed to measure the film's deposition rate during the in-situ film deposition process. By measuring the scattered laser intensity caused by the dimer in the parylene gas passing through the gas flow path, it was successfully confirmed that the ratio of the dimer in the parylene gas increases as the pyrolysis temperature decreases. Additionally, it was noted that the film's thickness and haze increase as the pyrolysis temperature decreases by confirming the characteristics of the visible parylene films. Through the research results, we aim to utilize the stable in-situ film deposition rate measurement system to control the precise film deposition rate of parylene films.

• Journal of Sensor Science and Technology
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• v.16 no.2
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• pp.91-96
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• 2007

The characteristic of tellurium thin films was studied for detecting nitrogen dioxide gas at room temperature. The film was deposited on $Al_{2}O_{3}$ substrate by using thermal evaporator. The subsequent process was heat treatment by several conditions. (temperature, flowed gases) Surface and grain boundary was investigated using SEM. The results showed that resistance of the tellurium film decreases reversibly in the presence of nitrogen dioxide. The sensitivity of this device depends on the gas concentration and detect lower concentrations less than 10 ppm.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.154-159
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• 2005

Low RF power density was used for preparing transparent conducting AI-doped ZnO (AZO) thin films by RF Magnetron Sputtering on Corning 1737 glass. The dependence of films' structural, optical and electrical properties on sputtering gas, film's thickness and substrate temperature were investigated. Low percent of incorporated H2 in Ar sputtering gas has proven to reduce film's resistivity and sheet resistance as low as $4.1\times10^{-3}{\Omega}.cm$. It also formed new preferred peaks orientation of (101) and (100) which indicated that the c-axis of AZO films was parallel to the substrate. From UN-VIS-NIR Spectrophotometer analysis, it further showed high optical transmittance at about $\~ 90\%$ at visible light spectra (400-700nm).

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1995.11a
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• pp.97-101
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• 1995

GaN films were prepared on Si(111) substrates by hydride vapor phase epitaxy (HVPE) on HCl-NH$_3$-N$_2$gas system. Effects of HCl gas flow rate on the film investigate under deposition conditions of flow time of 10min, 20min, 30min. The deposition rate increased with increasing HCl gas flow rate in the range of 10cc/min to 40cc/min and deposition time. Strung (00.2) oriented GaN film was obtained at a lower HCl flow rate and improved of the surface morphology.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1995.11a
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• pp.179-182
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• 1995

The NO$_2$gas-detection characteristics were investigated using the functional organic Langmuir-Blodgett(LB) films of Copper-tetra-tert-butylphthalocyanine(CuTBP). The optimum conditions for a film deposition were obtained through a study of $\pi$-A isotherms, and the deposited film status was confirmed by the ellipsometry measurements. It was found that at room temperature there are increments of electrical conductivities by 40 times, 25 seconds of response time and 40 seconds of response time when the films were exposed to the 200ppm NO$_2$gases. We hale observed an increase of the electrical conductivities as the density of NO2 gas increases.

• Journal of the Korean Ceramic Society
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• v.37 no.12
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• pp.1135-1139
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• 2000

본 연구에서는 Pt/Sn $O_2$박막의 CO 감지특성을 향상시키기 위하여 표면 형상을 제어하였다. Pt/Sn $O_2$계 박막센서의 최적 동작온도는 175$^{\circ}C$이었다. Pt가 12초 동안 증착된 Sn $O_2$가 200ppm의 CO 가스에 대하여 1.23의 최대감도를 나타내었고, 그 이상의 Pt 증착시간 증가에 따라 Sn $O_2$위의 Pt의 coverage가 증가하여 센서의 감도를 감소시켰다. 다층박막(multi-layer thin film)의 단층의 Pt/Sn $O_2$복합체 위에 다시 Sn $O_2$및 Pt의 cluster 층들을 연속적으로 증착함으로서 제작되었다. 단지 하나의 Pt 층만을 증착한 Sn $O_2$막보다 다층의 Pt/Sn $O_2$막이 더욱 우수한 감도( $R_{air}$/ $R_{co}$=1.72, CO: 200 ppm)를 나타내었다. Pt/Sn $O_2$다층박막의 우수한 감도의 원인은 Pt와 Sn $O_2$사이의 계면적 증대 때문인 것으로 생각되어 진다.다.

• Korean Journal of Materials Research
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• v.14 no.4
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• pp.276-280
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• 2004

Carbon nanotubes(CNT) were synthesized by arc-discharge method. To fabricate CNT sensor, CNT powder was dispersed in $\alpha$-Terpinol($C_{10}$ $H_{17}$OH) solution. The CNT films were fabricated by screen printing on the interdigitated Pt/Pd alloy electrode. The microstructure of CNT film were observed by scanning electron microscopy (SEM). In order to investigate the gas sensing characteristics of the film, the CNT film was experimented to measure NH$_3$ response and recovery time. And this sensor shows better reproductibility and faster recovery time than another CNT sensors. We suggest the possibility to utilize a CNT as new sensing materials for environmental monitoring.

• Journal of Welding and Joining
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• v.29 no.5
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• pp.58-62
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• 2011

Stainless steels are alloy steels with a nominal chromium content of at least 11 percent, with other alloy additions. The stainlessness and corrosion resistance of these alloy steels are attributed to the presence of a passive oxide film on the surface. When exposed to conditions like Resistance Spot Welding (RSW) process that remove the passive oxide film, stainless steels are subject to corrosive attack. And exposure to elevated temperatures causes oxidation (discoloration) of areas around indentation in Spot welding. In this paper, deal with the effect of shielding gas (Ar) preventing the corrosion, oxidation of stainless steel. And find the optimal shielding gas flow rate. In addition, suggest effective purging method for direct/indirect spot welding process.