• Transactions on Electrical and Electronic Materials
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• 제12권3호
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• pp.106-109
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• 2011

We investigated the etching characteristics of titanium nitride (TiN) thin film in $BCl_3$/Ar inductively coupled plasma. The etching parameters were the gas mixing ratio, radio frequency (RF) power, direct current (DC)-bias voltages and process pressures. The standard conditions were as follows: total flow rate = 20 sccm, RF power = 500 W, DC-bias voltage = -100 V, substrate temperature = $40^{\circ}C$, and process pressure = 15 mTorr. The maximum etch rate of TiN thin film and the selectivity of TiN to $Al_2O_3$ thin film were 54 nm/min and 0.79. The results of X-ray photoelectron spectroscopy showed no accumulation of etch byproducts from the etched surface of TiN thin film. The TiN film etch was dominated by the chemical etching with assistance by Ar sputtering in reactive ion etching mechanism, based on the experimental results.

• 한국전기전자재료학회논문지
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• 제13권1호
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• pp.6-12
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• 2000

In this study, molybdenum thin films were etched with Cl\ulcorner/(Cl\ulcorner+SF\ulcorner) gas mixing ratio in an magneti-cally enhanced reactive ion etching(MERIE) by the etching parameters such as rf power of 250 watts, chamber pressure of 100 mTorr and B-field of 30 gauss. The etch rate was 150nm/min under Cl\ulcorner/(Cl\ulcorner+SF\ulcorner) gas mixing ratio of 0.25. At this time, the selectivity of Mo to SiO\ulcorner, photoresist were respectively 0.94, 0.05. The surface reaction of the etched Mo thin films was investigated with X-ray photoelectron spectroscopy(XPS). It was analyzed that Mo peaks was mainly observed in Mo-O bonds formed MoO\ulcorner compounds and F was detected in Mo-F and O-F bonds. Cl peaks were detected by the peak of Cl 2p\ulcorner in Cl-Mo bonds of MoCl\ulcorner or MoO\ulcornerCl\ulcorner formulas. Almost all of both Cl and S atoms had been com-bined with Mo, respectively.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2010년도 제39회 하계학술대회 초록집
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• pp.70-70
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• 2010

Cerium oxide nanofibers have been of great interest in fundamental level study. We fabricated polyvinylpyrollidone (PVP) and cerium nitrate nanofibers composite applying a mixed solution of PVP and cerium nitrate hydrate (Ce(NO3)3) with various cerium concentration from 8.87 to 35.5wt% by electrospinning process. Electrospinning method is a simple and cost-effective process to make nanoand submicro nanofiber fabrication. We applied 0.69 kV/cm of electric field between the capillary and a drum collector covered with aluminum foil. Cerium oxide nanofibers were obtained after calcination of PVP/Ce(NO3)3 nanofibers composite at 573, 873 and 1273K, which were chosen by thermal gravimetry analysis. The obtained nanofibers were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS). When the viscosity of the electrospinning solution was high named over 60 cP, only nano and submicro-sized cerium oxide fibers were collected. X-ray photoelectron spectroscopy (XPS) was performed for investigation of the chemical nature of the obtained ceria nanofibers. After we calcined the PVP/ceria nanocomposites, metallic cerium was oxidized to cerium oxide including ceria.

• 열처리공학회지
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• 제14권5호
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• pp.292-296
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• 2001

In this work, an ultra-high vacuum activated reactive evaporation equipment was built. With reaction of Al and oxygen plasma, $Al_2O_3$ was deposited on the surface of etched Al foil. The chamber was evacuated down to $2{\times}10^{-7}$ torr initially. The Ar and $O_2$ gas introduced into the chamber to maintain $5{\times}10^{-5}$ torr during deposition. Ar gas prevents recombining of the ionized oxygen. Evaporation was maintained by electron beam evaporator continuously. Heating filament and electrode were used in order to generate plasma. The substrate bias of -300V was introduced to accelerate deposition of evaporated Al atoms. The composition and morphology of deposited $Al_2O_3$ films were analyzed by x-ray photoelectron spectroscopy(XPS) and atomic force microscopy (AFM), respectively. The Al oxide was formed on the surface of etched Al foil. According to AFM results, the surface morphology of $Al_2O_3$ film indicates uniform feature. Dielectric characteristic was measured as a function of frequency. Measured withstanding voltage and capacitance were 52V and $24{\mu}F/cm^2$, respectively. The obtained $Al_2O_3$ film shows clean condition without contaminants, which could be adapted to capacitor production.

• Transactions on Electrical and Electronic Materials
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• 제11권4호
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• pp.166-169
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• 2010

In this study, we changed the etch parameters (gas mixing ratio, radio frequency [RF] power, direct current [DC]-bias voltage, and process pressure) and then monitored the effect on the $HfAlO_3$ thin film etch rate and the selectivity with $SiO_2$. A maximum etch rate of 108.7 nm/min was obtained in $Cl_2$ (3 sccm)/$BCl_3$ (4 sccm)/Ar (16 sccm) plasma. The etch selectivity of $HfAlO_3$ to $SiO_2$ reached 1.11. As the RF power and the DC-bias voltage increased, the etch rate of the $HfAlO_3$ thin film increased. As the process pressure increased, the etch rate of the $HfAlO_3$ thin films increased. The chemical state of the etched surfaces was investigated with X-ray photoelectron spectroscopy. According to the results, the etching of $HfAlO_3$ thin film follows the ion-assisted chemical etching.

• Bulletin of the Korean Chemical Society
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• 제30권2호
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• pp.441-444
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• 2009

The formation and structure of self-assembled monolayers (SAMs) by the adsorption of acetyl-protected octylthioacetate (OTA) on Au(111) in a catalytic tetrabutylammonium cyanide (TBACN) solution were examined by means of scanning tunneling microscopy (STM), X-ray photoelectron spectroscopy (XPS), and cyclic voltammetry (CV). Molecular-scale STM imaging revealed that OTA molecules on Au(111) in a pure solvent form disordered SAMs, whereas they form well-ordered SAMs showing a c(4 × 2) structure in a catalytic TBACN solution. XPS and CV measurements also revealed that OTA SAMs on Au(111) formed in a TBACN solution have a stronger chemisorbed peak in the S 2p region at 162 eV and a higher blocking effect compared to OTA SAMs formed in a pure solvent. In this study, we clearly demonstrate that TBACN can be used as an effective deprotecting reagent for obtaining well-ordered SAMs of thioacetyl-protected molecules on gold.

• Carbon letters
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• 제8권2호
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• pp.120-126
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• 2007

The effect of cobalt precursor on the structure of Co supported multi-walled carbon nanotubes (MWCNTs) were studied by using X-ray photoelectron spectroscopy (XPS). MWCNTs were treated with a mixture of nitric and sulfuric acids and decorated with cobalt and/or cobalt oxides via aqueous impregnation solutions of cobalt nitrate or cobalt acetate followed by reduction in hydrogen. XPS was mainly used to investigate the phase of cobalt on MWCNTs after reduction with $H_2$ flow at $400^{\circ}C$ for 2 h. Higher cobalt-nanoparticle dispersion was found in the MWCNTS prepared via cobalt nitrate decomposition. A typical XPS spectrum of Co 2p showed the peaks at binding energy (BE) values equal to 781 and 797 eV, respectively. It is found that cobalt nitrate supported MWCNTs is more dispersive and have catalytic activity than that of cobalt acetate supported MWCNTs at same preparation condition such as concentration of precursor solution and reduction environment.

• Transactions on Electrical and Electronic Materials
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• 제12권4호
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• pp.144-147
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• 2011

In this work, we present a study regarding the etching characteristics on titanium nitride (TiN) thin films using an inductively coupled plasma system. The TiN thin film was etched using a $N_2/BCl_3$/Ar plasma. The studied etching parameters were the gas mixing ratio, the radio frequency (RF) power, the direct current (DC)-bias voltages, and the process pressures. The baseline conditions were as follows: RF power = 500 W, DC-bias voltage = -150 V, substrate temperature = $40^{\circ}C$, and process pressure = 15 mTorr. The maximum etch rate and the selectivity of the TiN to the $SiO_2$ thin film were 62.38 nm/min and 5.7, respectively. The X-ray photoelectron spectroscopy results showed no accumulation of etching byproducts from the etched surface of the TiN thin film. Based on the experimental results, the etched TiN thin film was obtained by the chemical etching found in the reactive ion etching mechanism.

• Bulletin of the Korean Chemical Society
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• 제27권11호
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• pp.1851-1853
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• 2006

We herein report a new analytical application of XPS to the identification of organic molecules in room temperature ionic liquid for the first time. An organic compound, propargylamine (1), produced in 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][$PF_6$]), which is one of the room temperature ionic liquids (RTILs), via $A^3$ coupling reaction, is characterized by means of x-ray photoelectron spectroscopy (XPS) rather than using conventional organic compound analysis techniques. There are four non-equivalent carbons in RTILs and 1 each. The ratios of normalized integrated areas of the deconvoluted binding energy of core electron of carbon (C1s) peaks are well matched to the number of carbons in those compounds. The binding energies of C1s of the featured carbons in 1, C4 (sp carbons in acetylene group) and C5 ($sp^2$ carbons in benzene ring), are assigned 286.2 and 285.4 eV, respectively. These results will be able to provide an important tool and a new strategy for the analysis of organic molecules

• Advances in materials Research
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• 제4권2호
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• pp.113-132
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• 2015

The phenomena of high-voltage polarization and conductivity in oriented vinylidenefluoride and tetrafluoroethylene copolymer films have been investigated. It was shown that under certain electric fields, injection of carriers from the material of electrodes appears The barrier for holes injection in the copolymer was found to be lower than that for electrons. It results in more effective screening of the external field near the anode than near cathode. Electrones, ejected from cathode, creating negative charge by trapping on the surface. It is shown that the electrons injected from cathodes create a negative homocharge on the copolymer surface and then become captured on the surface shallow traps. Their nature has been studied by the x-ray photoelectron spectroscopy. It was shown that these traps may consist of chemical defects in the form of new functional groups formed by reactions of surface macromolecules with sputtered atoms of aluminum. The asymmetric shape of hysteresis curves was explained by the difference in mobility of injected holes and electrons. These factors caused appearance of "non-closed" hysteresis curves for fluorine-containing polymer ferroelectrics. Hysteresis phenomena observed at low electric fields (below coercive ones) are to associate with the behavior of the domains localized in the ordered regions formed during secondary crystallization of copolymers.