• Journal of the Korean Crystal Growth and Crystal Technology
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• v.13 no.6
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• pp.297-303
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• 2003

Mn-Ni-Co type thin films were prepared at various conditions by a rf magnetron sputtering system. At the condition. or substrate temperature of $300^{\circ}C$ and $Ar/O_2$= 10/0, a cubic spinel phase was obtained. When oxygen was included in process gas, a cubic spinel phase was not formed even after the thermal annealing at $900^{\circ}C$. The thermistor thin film had no other elements except Mn, Ni and Co. The infrared reflection spectra of the thermistor thin films showed that the films had somewhat high reflectance for incoming infrared ray with some angle. The etch rate of the thermistor thin films was about 63nm/min at a condition of DI water : $HNO_3$: HCl = 60 : 30 : 10 vol%. The B constant and temperature coefficient of resistance of the thermistor thin films were 3500 K and -3.95 %/K, respectively. The voltage responsivity of the thermistor thin film infrared sensor was 108.5 V/W and its noise equivalent power and specific detectivity were $5.1\times 10^{-7}$ W/$Hz^{-1/2}$ and $0.2\times 10^6$cm $Hz^{1/2}$/W, respectively.

• Korean Journal of Materials Research
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• v.13 no.3
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• pp.155-159
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• 2003

The polypyrrole and polyaniline thin film sensors which were made by chemical polymerization were employed to detect ethanol gas. With a single sensor element we can obtain characteristic patterns of behaviour across a very wide frequency range when measuring either resistance or capacitance. Impedance spectroscopy was employed to study the gas sensing behavior of both capacitance and resistance based sensors with conducting polymer as the active sensing element.

• Journal of the Korean institute of surface engineering
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• v.40 no.6
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• pp.258-261
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• 2007

Relationships between the electrical resistivity and the growth characteristic of $SnO_2$ thin films were investigated. $SnO_2$ thin films with thickness from 64 nm to 91 nm were made by controlling the RF deposition energy from 80 to 150 W. These $SnO_2$ thin films were annealed at $200^{\circ}C{\sim}700^{\circ}C$ temperature range of $100^{\circ}C$ interval in the $O_2$ gas condition. After annealing treatments, the microstructures of the $SnO_2$ thin films were changed mixed structure(amorphous & crystalline) to lamina columnar crystalline structure. Both the film thickness and the grain size were increased with increasing the local crystallization of $SnO_2$ microstructure of thin films by annealing treatment. Their electrical resistivity increased up to the annealing temperature of $400^{\circ}C$, and then slowly decreased.

• Korean Journal of Materials Research
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• v.20 no.11
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• pp.611-616
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• 2010

A cobalt oxide - tin oxide nanocomposite based gas sensor on an $SiO_2$ substrate was fabricated. Granular thin film of tin oxide was formed by a rheotaxial growth and thermal oxidation method using dc magnetron sputtering of Sn. Nano particles of cobalt oxide were spin-coated on the tin oxide. The cobalt oxide nanoparticles were synthesized by polymer-assisted deposition method, which is a simple cost-effective versatile synthesis method for various metal oxides. The thickness of the film can be controlled over a wide range of thicknesses. The composite structures thus formed were characterized in terms of morphology and gas sensing properties for reduction gas of $H_2$. The composites showed a highest response of 240% at $250^{\circ}C$ upon exposure to 4% $H_2$. This response is higher than those observed in pure $SnO_2$ (90%) and $Co_3O_4$ (70%) thin films. The improved response with the composite structure may be related to the additional formation of electrically active defects at the interfaces. The composite sensor shows a very fast response and good reproducibility.

• Journal of the Korean Society for Heat Treatment
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• v.23 no.5
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• pp.245-248
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• 2010

Sn doped $In_2O_3$ (ITO) and ITO/Ni/ITO (INI) multilayer films were deposited on the glass substrates with a reactive magnetron sputtering system without intentional substrate heating and then the influence of the Ni interlayer on the methanol gas sensitivity of ITO and INI film sensors were investigated. Although both ITO and INI film sensors have the same thickness of 100 nm, INI sensors have a sandwich structure of ITO 50 nm/Ni 5 nm/ITO 45 nm. The changes in the gas sensitivity of the film sensors caused by methanol gas ranging from 100 to 1000 ppm were measured. It is observed that the INI film sensors show the higher sensitivity than that of the ITO single layer sensors. Finally, it can be concluded that the INI film sensor have the potential to be used as improved methanol gas sensors.

• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.1600-1604
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• 2004

As the integrated circuit device shrinks to the smaller dimension, the chemical mechanical polishing (CMP) process was required for the global planarization of inter-metal dielectric(IMD) layer with free-defect. The effect of alternative commerical slurries pads, and post-CMP cleaning alternatives are discuess, with removal rate, scratch dentisty, surface roughness, dishing, erosion and particulate density used as performance metrics. we investigated the performance of $SnO_2$-CMP process using commonly used silica slurry, ceria slurry, tungsten slurry. This study shows removal rate and nonuniformity of $SnO_2$ thin film used to gas sensor by using Ceria, Silica, W-Slurry after CMP process. This study also shows the relation between partical size and CMP with partical size analysis of used slurry.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.04b
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• pp.93-96
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• 2004

As the integrated circuit device shrinks to the smaller dimension, the chemical mechanical polishing (CMP) process was required for the global planarization of inter-metal dielectric(IMD) layer with free-defect. The effect of alternative commerical slurries pads, and post-CMP cleaning alternatives are discuess, with removal rate, scratch dentisty, surface roughness, dishing, erosion and particulate density used as performance metrics. we investigated the performance of $SnO_2$-CMP process using commonly used silica slurry, ceria slurry, tungsten slurry. This study shows removal rate and nonuniformity of $SnO_2$ thin film used to gas sensor by using Ceria, Silica, W-Slurry after CMP process. This study also shows the relation between partical size and CMP with partical size analysis of used slurry.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.389-392
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• 2004

As the integrated circuit device shrinks to the smaller dimension, the chemical mechanical polishing (CMP) process was required for the global planarization of inter-metal dielectric(IMD) layer with free-defect. The effect of alternative commerical slurries pads, and post-CMP cleaning alternatives are discuess, with removal rate, scratch dentisty, surface roughness, dishing, erosion and particulate density used as performance metrics. we investigated the performance of $SnO_2$-CMP process using commonly used silica slurry, ceria slurry, tungsten slurry. This study shows removal rate and non-uniformity of $SnO_2$ thin film used to gas sensor by using Ceria, Silica, W-Slurry after CMP process. This study also shows the relation between particle size and CMP with particle size analysis of used slurry.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.184-187
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• 2003

As the integrated circuit device shrinks to the smaller dimension, the chemical mechanical polishing (CMP) process was required for the global planarization of inter-metal dielectric(IMD) lyaer with free-defect. The effect of alternative commerical slurries pads, and post-CMP cleaning alternatives are discuess, with removal rate, scratch dentisty, surface roughness, dishing, erosion and particulate density used as performance metrics. we investigated the performance of $SnO_2-CMP$ process using commonly used silica slurry, ceria slurry, tungsten slurry. This study shows removal rate and nonuniformity of $SnO_2$ thin film used to gas sensor by using Ceria, Silica, W-Slurry after CMP process. This study also shows the relation between partical size and CMP with partical size analysis or used slurry.

• Journal of the Korean Ceramic Society
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• v.39 no.9
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• pp.840-845
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• 2002

As an ozone gas sensor, the semiconductor gas sensor which is cheap, portable and simple in use and has a high sensitivity and an excellent selectivity, has been known as an alternative. In the present study, ITO ($In_2O_3 95%,\;SnO_2$ 5%) thin films were deposited on the alumina substrate by using R.F. magnetron sputtering method. The substrate temperature was 300$^{\circ}C$ and 500$^{\circ}C$, respectively and then some specimens were annealed at 500$^{\circ}C$ for 4h in air. ITO gas-sensing films formed crystallines before and after annealing. As results of gas sensitivity measurements to an ozone gas, the sensor deposited at 300$^{\circ}C$ and then annealed has the highest sensitivity (sensible below 1 ppm). As the operating temperature increased gradually, the sensitivity decreased but the response time and stability improved.