• Proceedings of the Materials Research Society of Korea Conference
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• 1998.11a
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• pp.36-36
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• 1998

• Electrical & Electronic Materials
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• v.8 no.1
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• pp.90-94
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• 1995

Reactive Ion Etching(RIE) of Si$_{3}$N$_{4}$ in a CF$_{4}$/O$_{2}$ gas plasma exhibits such good anisotropic etching properties that it is widely employed in current VLSI technology. However, the RIE process can cause serious damage to the silicon surface under the Si$_{3}$N$_{4}$ layer. When an atmospheric pressure chemical vapor deposited(APCVD) SiO$_{2}$ layer is used as a etch-stop material for Si$_{3}$N$_{4}$, it seems inevitable to get a good etch selectivity of Si$_{3}$N$_{4}$ with respect to SiO$_{2}$. Therefore, we have undertaken thorough study of the dependence of the etch rate of Si$_{3}$N$_{4}$ plasmas on $O_{2}$ dilution, RF power, and chamber pressure. The etch selectivity of Si$_{3}$N$_{4}$ with respect to SiO$_{2}$ has been obtained its value of 2.13 at the RF power of 150 W and the pressure of 110 mTorr in CF$_{4}$ gas plasma diluted with 25% $O_{2}$ by flow rate.

• Korean Chemical Engineering Research
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• v.44 no.6
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• pp.588-596
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• 2006

The surface of polystyrene membrane treated by Ar, $O_2$ plasma, and the effects were observed before and after the treatment and permeability of $CO_2$, $N_2$ and selectivity of $CO_2$ relative to $N_2$ was measured using continuous flow gas permeation analyzer (GPA). The mole ratio of O over C in the surface was increased from 0 to 0.179 with Ar plasma treatment and route mean square of surface was increased from $15.86{\AA}$ to $71.64{\AA}$. Therefore the contact angle was decreased from $89.16^{\circ}$ to $18.1^{\circ}$. Thus Plasma treatments made surface of membrane tend to be highly hydrophilic. The optimum condition for the $CO_2$ permeability and ideal selectivity of the plasma treated membrane was as follows: the measurement of Ar (60 W, 2 min, $70^{\circ}C$) plasma treatment was $1.14{\times}10^{-12}[m^3(STP){\cdot}m/m^2{\cdot}sec{\cdot}atm]$ and 4.22. In the case of $O_2$ plasma treatment, the contact angle was decreased at $13.56^{\circ}$ with increase of O/C ratio ($0.189{\AA}$) and route mean square of surface ($57.10{\AA}$). The optimum condition for the $CO_2$ permeability and ideal selectivity of the plasma treated membrane was as follows: the measurement of $O_2$ (90 W, 2 min, $70^{\circ}C$) plasma treatment was $7.1{\times}10^{-12}[m^3(STP){\cdot}m/m^2{\cdot}sec{\cdot}atm]$ and 11.5. After plasma treatment, the changes of membrane surface were all subtly linked with both cross-linking and etching effects. Finally, it was confirmed that the gas permeation capacity and selectivity of the modified membrane with plasma could be improved by an appropriate control of the plasma conditions such as treatment time, the power input and sort of plasma gas.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.690-693
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• 2003

An Si substrate (100) was oxidized at $400^{\circ}C$ in inductively coupled oxygen plasma. Interstitial oxygen was found in the Si substrate at the initial stage of oxidation by IR measurements. An x-ray rocking curve of Si substrates showed a lower peak intensity due to lattice distortion by the interstitial oxygen. The refractive index of thin oxides, below which interstitial oxygen existed in the Si substrate, was smaller than the refractive index of thick oxides, below which no interstitial oxygen existed. The interstitial oxygen was found by plasma oxidation using $O_{2}$ gas and $N_{2}O$ gas. The inductively coupled plasma oxidation using $N_{2}O$ gas was performed by atomic oxygen, not by molecular oxygen, indicating that atomic oxygen in plasma is responsible for the incorporation of interstitial oxygen.

• Proceedings of the Korean Magnestics Society Conference
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• 2000.09a
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• pp.268-272
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• 2000

Oxygen-plasma effects of single crystal and thin film samples of L $a_{0.7}$C $a_{0.3}$Mn $O_{3-}$$\delta$/ have been studied. Our resistivity measurements indicate that oxygen plasma treatment gives rise to oxygen diffusion into bulk regions, which results in a decrease of M $n^{3+}$ concentration in oxygen nonstoichiometric L $a_{0.7}$C $a_{0.3}$Mn $O_{3-}$$\delta$/ and in the activation energies of Holstein's small polarons in the paramagnetic region.n.egion.n.n.

• Proceedings of the KIEE Conference
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• 1998.11c
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• pp.895-897
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• 1998

The optical spectra of microwave plasma by four kinds of gases($N_2$, $N_2-CH_4$, $H_{2}-CH_{4}$ and Air-$CH_4$) have been measured for investigating 388.4[nm] peak which has the same intensity as $H_{\alpha}$(656.4[nm]) peak. A 388.4[nm] peak by $N_2$ plasma, $N_{2}-CH_{4}$ plasma and Air-$CH_4$ plasma may be CN peak because it is with 337.1, 357.8 and 316.0[nm] peaks by $N_2$. And a 388.4[nm] peak by $H_{2}-CH_{4}$ plasma without by $N_2$ 337.1, 357.8 and 316.0[nm] peaks may be CH peak. In the investigation results for optical spectra by $H_{2}-CH_{4}$ plasma and $H_{2}-CH_{4}-O_{2}$ plasma, the density of hydrogen atom was increased because oxygen decompose hydrogen molecules in $H_{2}-CH_{4}$ plasma with oxygen. These hydrogen atom decompose $CH_4$ and increase CH radical. And the crystalline of deposited diamond was good and the growth rate increased.

• Applied Chemistry for Engineering
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• v.9 no.3
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• pp.383-387
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• 1998

The effect of hydrophilic surface modification of low density polyethylene(LDPE) byt the plasma gas($O_2$, $N_2$, and $O_2/N_2$) was investigated from the point of view of the functionalities of the generated LDPE surfaces and the contact angle. By virtue of x-ray photoelectron spectra(XPS) and attenuated total reflectance(FT-IR ATR) analysis, the LDPE surfaces treated with plasma were generated with oxygen functionalities of carbonyl, carboxyl, and the like, nitrogen functionalities by nitrogen plasma and mixing of nitrogen and oxygen plasma treatment were identified with. It was found that nitrogen plasma treatment showed with minimum value at contact angle for rf-power and treatment time, we had obtained optimum condition for hydrophilic surface modification at composite parameter, [(W/FM)t] 520~550GJs/kg.

• Journal of the Korean Ceramic Society
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• v.46 no.5
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• pp.467-471
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• 2009

Effects of boron and carbon on the densification and thermal decomposition of an AlN-SiC-$TiB_2$ system were investigated. $SiO_2$ was mostly removed by the addition of carbon, while $Al_2O_3$ formed $Al_4O_4C$ and promoted the densification of the systems above $1850^{\circ}C$. Rather porous specimens were obtained without the additives after hot pressing at $2100^{\circ}C$, while densification was mostly completed at $2000^{\circ}C$ by using the additives. The sintering temperature decreased further to $1950^{\circ}C$ by applying spark plasma sintering. The additives promoted the shrinkage of AlN by forming a liquid phase which was originated from the carbo- and boro-thermal reduction of $Al_2O_3$ and AlN.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2000.11a
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• pp.116-119
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• 2000

The advantage of plasma-sprayed coating is their good resistance against thermal shock due to the porous state of the coated layer with a consequently low Youngs modulus. However, the existence of many pores with a bimodal distribution and a laminar structure in the coating reduces coating strength and oxidation protection of the base metals. In order to counteract these problems, there have been many efforts to obtain dense coatings by spraying under low pressure or vacuum and by controlling particle size and morphology of the spraying materials. The aim of the present study is to survey the effects of the HIP treatment between 1100 and 130$0^{\circ}C$ on plasma-sprayed oxide coating of A1$_2$O$_3$, A1$_2$O$_3$-SiO$_2$on the metal substrate (type C18N10T stainless steel). These effects were characterized by phase identification, Vickers hardness measurement, and tensile test before and after HIPing. These results show that high-pressure treatment has an advantage for improving adhesive strength and Vickers hardness of plasma-sprayed coatings.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.116-119
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• 2000

The advantage of plasma-sprayed coating is their good resistance against thermal shock due to the porous state of the coated layer with a consequently low Youngs modules. However, the existence of many pores with a bimodal distribution and a laminar structure in the coating reduces coating strength and oxidation protection of the base metals. In order to counteract these problems, there have been many efforts to obtain dense coatings by spraying under low pressure or vacuum and by controlling particle size and morphology of the spraying materials. The aim of the present study is to survey the effects of the HIP treatment between 1100 and 130$0^{\circ}C$ on plasma-sprayed oxide coating of A1$_2$O$_3$, A1$_2$O$_3$-SiO$_2$ on the metal substrate (type C18N10T stainless steel). These effects were characterized by phase identification, Vickers hardness measurement, and tensile test before and after HIPing, These results show that high-pressure treatment has an advantage for improving adhesive strength and Vickers hardness of plasma- sprayed coatings.