• Applied Chemistry for Engineering
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• v.16 no.6
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• pp.853-856
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• 2005

Inductively coupled plasma reactive ion etching of magnetic tunnel junction (MTJ) stack, which is one of the key elements in magnetic random access memory, was studied. The MTJ stacks were patterned in nanometer size by electron(e)-beam lithography, and TiN thin films were employed as a hard mask. The etch process of TiN hard mask was examined using Ar, $Cl_2/Ar$, and $SF_6/Ar$. The TiN hard mask patterned by e-beam lithography was first etched and then the etching of MTJ stack was performed. The MTJ stacks were etched using Ar, $Cl_2/Ar$, and $BCl_3/Ar$ gases by varying gas concentration and pressure.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.11
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• pp.4468-4472
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• 2010

SiOC films made by the inductively coupled plasma chemical vapor deposition were researched the relationship between the dielectric constant and the chemical shift. SiOC film obtained by plasma method had the main Si-O-C bond with the molecule vibration mode in the range of $930{\sim}1230\;cm^{-1}$ which consists of C-O and Si-O bonds related to the cross link formation according to the dissociation and recombination. The C-O bond originated from the elongation effect by the neighboring highly electron negative oxygen atoms at terminal C-H bond in Si-$CH_3$ of $1270cm^{-1}$. However, the Si-O bond was formed from the second ionic sites recombined after the dissociation of Si-$CH_3$ of $1270cm^{-1}$. The increase of the Si-O bond induced the redshift as the shift of peak in FTIR spectra because of the increase of right shoulder in main bond. These results mean that SiOC films become more stable and stronger than SiOC film with dominant C-O bond. So it was researched that the roughness was also decreased due to the high degree of amorphous structure at SiOC film with the redshift after annealing.

• Korean Journal of Metals and Materials
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• v.49 no.11
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• pp.845-852
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• 2011

The Spark Plasma Sintering(SPS) method offers a means of fabricating a sintered-body having high density without grain growth through short sintering time and a one-step process. A titanium compact having high density and purity was fabricated by the SPS process. It can be used to fabricate a Ti sputtering target with controlled parameters such as sintering temperature, heating rate, and pressure to establish the optimized processing conditions. The compact/target(?) has a diameter of ${\Phi}150{\times}6.35mm$. The density, purity, phase transformation, and microstructure of the Ti compact were analyzed by Archimedes, ICP, XRD and FE-SEM. A Ti thin-film fabricated on a $Si/SiO_2$ substrate by a sputtering device (SRN-100) was analyzed by XRD, TEM, and SIMS. Density and grain size were up to 99% and below $40{\mu}m$, respectively. The specific resistivity of the optimized Ti target was $8.63{\times}10^{-6}{\Omega}{\cdot}cm$.

• The Journal of the Petrological Society of Korea
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• v.3 no.1
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• pp.41-48
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• 1994

Three USGS rock standards (G-2, W-2, and BHVO-1) are decomposed by three different methods, such as open beaker, microwave oven, and alkali fusion method, to compare the effect of decomposition methods for trace elememt analysis in the rock samples. Solubilized trace elements are measured with inductively coupled plasma mass spectrometer (ICP-MS). Generally the analytical results of trace elements between open beaker and microwave digestion method are not different. In case of alkali fusion method, some volatile elements such as Pb, Cu, and Rb are considerably lost. Using acid digestion method, Zr and Hf concentrations are lowered in case that these elements are concentrated in refractory minerals. The concentrations of rare earth elements are generally consistent with the recommended values, but due to large dilution factor, there are some analytical problems in alkali fusion method.

• Journal of the Mineralogical Society of Korea
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• v.32 no.2
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• pp.103-111
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• 2019

In this study, characteristics of sediments and suspended solids flowing into Andong and Imha Dam was analyzed by color, X-ray diffraction and ICP/MS analysis. The minerals of sediments and suspended solid consist mainly of quartz, albite, chlorite, illite and small amounts of montmorillonite and kaolinite. Unlike the Andong Dam, the Imha Dam sediments contain large amounts of calcite. Color of sediments and suspended solids varies from grayish brown to dark orange. The concentrations of major heavy metals of sediments and suspended solids in the Andong and the Imha Dam are higher than the US National Oceanic and Atmospheric Administration standard values. The concentration of heavy metals in sediments of Andong is higher than that of Imha Dam because concentration of heavy metals in the suspended solid flowing into Andong is higher than that of Imha Dam.

• Journal of the Semiconductor & Display Technology
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• v.21 no.3
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• pp.57-62
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• 2022

The plasma resistance of multi-component glasses containing La, Gd, Ti, Zn, Y, Zr, Nb, and Ta was analyzed in this study. The plasma etching was performed via inductively coupled plasma-reactive ion etching (ICP-RIE) using CF₄/O₂/Ar mixed gas. After the reaction, the glass with a low fluoride sublimation temperature and high content of P, Si, and Ti elements showed a high etching rate. On the other hand, the glass containing a high fluoride sublimation temperature component such as Ca, La, Gd, Y, and Zr exhibited high plasma resistance because the etch rate was lower than that of sapphire. Glass with low plasma resistance increased surface roughness after etching or nanoholes were formed on the surface, but glass with high plasma resistance showed little change in surface microstructure. Thus, the results of this study demonstrate the potential for the development of plasma-resistant glasses (PRGs) with other compositions besides alumino-silicate glasses, which are conventionally referred to as plasma-resistant glasses.

• Analytical Science and Technology
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• v.27 no.2
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• pp.92-99
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• 2014

Interferences were removed using anion exchange solid phase extraction (AE SPE) in quantification of selenoproteins in Korean human blood serum with affinity high performance liquid chromatography (AF HPLC)-inductively coupled plasma/mass spectrometry (ICP/MS). The average selenium level obtained for healthy Koreans was $94.3{\pm}2.3ngg^{-1}$ using isotope dilution method. AE SPE was coupled to AF column to separate 3 selenoproteins, glutathione peroxidase GPx, selenoprotein SelP, and selenoalbumin SeAlb. Post column isotope dilution was employed to quantify the proteins. The certified reference material of human blood serum BCR-637 was analyzed to give total selenoprotein concentration of $85.4{\pm}3.4ngg^{-1}$, which agreed well with the reference value of $81{\pm}7ngg^{-1}$. The pooled concentration of GPx, SelP, and SeAlb from healthy Koreans (n=20) was $12.1{\pm}1.4ngg^{-1}$, $57.2{\pm}2.0ngg^{-1}$, and $20.0{\pm}1.9ngg^{-1}$, respectively. The sum of selenoproteins is $89.3ngg^{-1}$, which is about the same as the total selenium concentration of $94.3ngg^{-1}$. The fact suggests that selenium in blood serum is mostly consisted of selenoproteins. After the removal of interference, GPx showed a significant decrease (more than 50%) from $25.0ngg^{-1}$ to $12.1ngg^{-1}$. It was identified that the interference in blood serum was mostly from GPx and the use of AE SPE was proven to be efficient in eliminating Cl and Br that cause interference to GPx.

• Korean Journal of Materials Research
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• v.15 no.3
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• pp.161-165
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• 2005

We investigated selective dry etching of GaAs over AlGaAs and InGaP in high density planar inductively coupled $BCl_3/SF_6$ plasmas. The process parameters were ICP source power (0-500 W), RE chuck power (0-30W) and gas composition $(60-100\%\;BCl_3\;in\;BCl_3/SF_6)$. The process results were characterized in terms of etch rate, selectivities of GaAs over AlGaAs and InGaP, surface morphology, surface roughness and residues after etching. $BCl_3/SF_6$ selective etching of GaAs showed quite good results in this study. Selectivities of GaAs $(GaAs:AlGaAs\~36:1,\;GaAs:InGaP\~45:1)$ were superior at $18BCl_3/2SF_6$, 20 W RF chuck power, 300 W ICP source power and 7.5 mTorr. Addition of $(5-15\%)SF_6\;to\;BCl_3$ produced relatively high selectivities of GaAs over AlGaAs and InGaP during etching due to decrease of etch rates of AlGaAs and InGaP (boiling points of etch products: $AlF_3\~1300^{\circ}C,\;InF_3>1200^{\circ}C$ at atmosphere) at the condition. SEM and AFM data showed slightly sloped sidewall and somewhat rough surface$(RMS\~9nm)$. XPS study on the surface of processed GaAs proved a very clean surface after dry etching. It shows that planar inductively coupled $BCl_3/SF_6$ plasmas could be a good candidate for selective dry etching of GaAs over AlGaAs and InGaP.

• Journal of Food Hygiene and Safety
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• v.25 no.4
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• pp.402-409
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• 2010

The study was conducted to estimate the contents of heavy metal in commercial herbal medicines (1047 samples of 132 species) which were collected from markets in Seoul and to analyze the contents of heavy metals of herbal medicines by classifying them by parts. The samples were digested using microwave method. The contents of heavy metal (Pb, Cd, and As) and Hg were determined using Inductively coupled plasma-Mass spectrometer (ICP/MS). And the contents of Hg were obtained by Mercury analyzer. The average values of heavy metal in herbal medicines were as follows [mean (minimum-maximum), mg/kg]; Pb 0.870 (ND-69.200), As 0.148 (ND-2.965), Cd 0.092 (ND-2.010), and Hg 0.007 (ND-0.B7). And the average values of heavy metal by parts in herbal medicines were as follows [mean (minimum-maximum), mg/kg]; Ramulus 2.046 (0.065-4.474), Herba 1.886 (0.048-10.404), Flos 1.874 (0.052-5.393), Cortex 1.377 (0.011-4.837), Radix 1.165 (0.012-70.111), Rhizoma 1.116 (0.016-5.490, Fructus 0.838 (0.017-4.527), Perithecium 0.729 (0.013-4.953), Semen 0.646 (0.006-4.416). The average values of heavy metal of imported herbal medicines except Radix were higher than domestic ones. By decoction of herbal medicines exceeding the tolerances, average intake rates of Pb, As, Cd and Hg were obtained as 6.1%, 40.3%, 4.7%, and 2.2%, respectively.

• Restorative Dentistry and Endodontics
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• v.33 no.4
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• pp.369-376
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• 2008

The aim of this study was to compare the compositions and cytotoxicity of white ProRoot MTA (white mineral trioxide aggregate) and 3 kinds of Portland cements. The elements, simple oxides and phase compositions of white MTA (WMTA), gray Portland cement (GPC), white Portland cement (WPC) and fast setting cement (FSC) were measured by inductively coupled plasma atomic emission spectrometry (ICP-AES), X-ray fluorescence spectrometry (XRF) and X-ray diffractometry (XRD). Agar diffusion test was carried out to evaluate the cytotoxicity of WMTA and 3 kinds of Portland cements. The results showed that WMTA and WPC contained far less magnesium (Mg), iron (Fe), manganese (Mn), and zinc (Zn) than GPC and FSC. FSC contained far more aluminum oxide ($Al_2O_3$) than WMTA, GPC, and WPC. WMTA, GPC, WPC and FSC were composed of main phases. such as tricalcicium silicate ($3CaO{\cdot}SiO_2$), dicalcium silicate ($2CaO{\cdot}SiO_2$), tricalcium aluminate ($3CaO{\cdot}Al_2O_3$), and tetracalcium aluminoferrite ($4CaO{\cdot}Al_2O_3{\cdot}Fe_2O_3$). The significance of the differences in cellular response between WMTA, GPC, WPC and FSC was statistically analyzed by Kruskal-Wallis Exact test with Bonferroni' s correction. The result showed no statistically significant difference (p > 0.05). WMTA, GPC, WPC and FSC showed similar compositions. However there were notable differences in the content of minor elements. such as aluminum (Al), magnesium, iron, manganese, and zinc. These differences might influence the physical properties of cements.