• Corrosion Science and Technology
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• v.11 no.4
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• pp.141-150
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• 2012

Stress corrosion cracks in Alloy 600 compact tension specimens tested at $325^{\circ}C$ in a simulated primary water environment of pressurized water reactor were analyzed by analytical transmission electron microscopy and secondary ion mass spectroscopy (SIMS). From a fine-probe chemical analysis, oxygen was found on the grain boundary just ahead of the crack tip, and chromium oxides were precipitated on the crack tip and the grain boundary attacked by the oxygen diffusion, leaving a Cr/Fe depletion (or Ni enrichment) zone. The oxide layer inside the crack was revealed to consist of a double (inner and outer) layer. Chromium oxides existed in the inner layer, with NiO and (Ni,Cr) spinels in the outer layer. From the nano-SIMS analysis, oxygen was detected at the locations of intergranular chromium carbides ahead of the crack tip, which means that oxygen diffused into the grain boundary and oxidized the surfaces of the chromium carbides. The intergranular chromium carbide blunted the crack tip, thereby suppressing the crack propagation.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.9
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• pp.714-719
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• 2001

SrBi$_2$Ta$_2$$O_{9}$ thn films were etched in inductively coupled Cl$_2$/CF$_4$/Ar plasma. THe maximum etch rate was 1060 $\AA$/min at a Cl$_2$/(Cl$_2$+CF$_4$+Ar)=0.2. The 20% additive Cl$_2$ into CF$_4$/Ar plasma decreased carbon and fluorine radicals, but increased Cl radicals. Sr was effectively removed by reacting with Cl radical because the boiling point of SrCl$_2$(125$0^{\circ}C$) is lower than that of SrF$_2$(246$0^{\circ}C$). The chemical reactions on the etched surface were studied with x-ray photoelectron spectroscopy and secondary ion mass spectrometry. The etching profile was evaluated by using scanning electron microscopy.y.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.468-470
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• 1999

One of the most critical problem in etching of platinum was generally known that the etch slope was gradual. therefore, the addition of $N_2$ gas into the Ar/C1$_2$ gas mixture, which has been proposed the optimized etching gas combination for etching of platinum in our previous article, was performed. The selectivity of platinum film to oxide film as an etch mask increased with the addition of N2 gas, and the steeper etch slope over 75 $^{\circ}$ could be obtained. These phenomena were interpreted the results the results of a blocking layer such as Si-N or Si-O-N on the oxide mask. Compostional analysis was carried out by X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS). Moreover, it could be obtained the higher etch rate of Pt film and steeper profile without residues such as p.-Cl and Pt-Pt ant the addition N\ulcorner of 20 % gas in Ar(90)/Cl$_2$(10) Plasma. The Plasma characteristic was extracted from optical emissionspectroscopy (OES).

• Journal of the Korean Ceramic Society
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• v.49 no.6
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• pp.637-641
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• 2012

Due to its high production cost and relatively high energy consumption during the Siemens process, poly-silicon makers have been continuously and eagerly sought another silicon route for decades. One candidate that consumes less energy and has a simpler acidic and metallurgical purification procedure is upgraded metallurgical-grade (UMG) silicon. Owing to its low purity, UMG silicon often requires special steps to minimize the impurity effects and to remove or segregate the metal atoms in the bulk and to remove interfacial defects such as precipitates and grain boundaries. A process often called the 'gettering process' is used with phosphorus diffusion in this experiment in an effort to improve the performance of silicon solar cells using UMG silicon. The phosphorous gettering processes were optimized and compared to the standard POCl process so as to increase the minority carrier lifetime(MCLT) with the duration time and temperature as variables. In order to analyze the metal impurity concentration and distribution, secondary ion mass spectroscopy (SIMS) was utilized before and after the phosphorous gettering process.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.50 no.5
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• pp.211-215
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• 2001

SBT thin films were etched at different content of $Cl_2$ in $Cl_2$/Ar or $Cl_2/N_2$(80%). As $Cl_2$ gas increased in $Cl_2$/Ar or $Cl_2/N_2$ gas plasma. the etch rate decreased. The result indicates that physical puttering of charged particles is dominant to chemical reaction in etching SBT thin films. To evaluate the etching mechanism of SBT thin films, x-ray photoelectron to chemical reaction in etching SBT thin films. To evaluate the etching mechanism of SBT thin films, x-ray photoelectron spectroscopy (XPS), secondary ion mass spectrometry (SIMS) and atomic force microscopy (AFM) were carried out. From the result of AFM, the rms values of etched samples in Ar only or $Cl_2$ only plasma were higher than that of as-deposited, $Cl_2$/Ar and $Cl_2/N_2$ plasma. This can be illustrated by a decrease of Bi content of nonvolatile etching products (Sr-Cl and Ta-Cl), which are revealed by XPS and SIMS.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.363-366
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• 2000

In this study, SrBi$_2$Ta$_2$$O_{9}$ (SBT) thin films were etched at different Cl$_2$gas mixing ratio in Cl$_2$/Ar. The maximum etch rate of SBT was 883 $\AA$/min in Cl$_2$(20%)/Ar(80%). The result indicates that physical sputtering of charged particles is dominant to chemical reaction in etching SBT thin films. To evaluate the changes of morphology and crystallinity on the near surface of etched SBT, atomic force microscopy (AFM) and x-ray diffraction (XRD) were used. The rms values of etched samples in Ar only or Cl$_2$ only plasma were higher than that of as-deposited, Cl$_2$/Ar Plasma. The SBT (105) crystalinity of the etched samples decreased in Af only or Cla only plasma, but maintain constant in ClyAr plasma. This can be illustrated by a decrease of Bi content or nonvolatile etching products (Sr-Cl and Ta-Cl), resulting in the changes of stoichiometry on the etched surface of the SBT thin films. The decrease of Bi content and nonvolatile etch products were revealed by x-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS).).

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.299.2-299.2
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• 2013

We investigated the potassium remaining on a crystalline silicon solar cell after potassium hydroxide (KOH) etching and its effect on the lifetime of the solar cell. KOH etching is generally used to remove the saw damage caused by cutting a Si ingot; it can also be used to etch the rear side of a textured crystalline silicon solar cell before atomic layer-deposited Al2O3 growth. However, the potassium remaining after KOH etching is known to be detrimental to the efficiency of Si solar cells. In this study, we etched a crystalline silicon solar cell in three ways in order to determine the effect of the potassium remnant on the efficiency of Si solar cells. After KOH etching, KOH and tetramethylammonium hydroxide (TMAH) were used to etch the rear side of a crystalline silicon solar cell. To passivate the rear side, an Al2O3 layer was deposited by atomic layer deposition (ALD). After ALD Al2O3 growth on the KOH-etched Si surface, we measured the lifetime of the solar cell by quasi steady-state photoconductance (QSSPC, Sinton WCT-120) to analyze how effectively the Al2O3 layer passivated the interface of the Al2O3 layer and the Si surface. Secondary ion mass spectroscopy (SIMS) was also used to measure how much potassium remained on the surface of the Si wafer and at the interface of the Al2O3 layer and the Si surface after KOH etching and wet cleaning.

• Proceedings of the IEEK Conference
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• 2000.06b
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• pp.32-35
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• 2000

Oxide-nitride-oxide(ONO) structures were formed by sequential radio frequency reactive magnetron sputtering method. The chemical composition and structure of these films were studied by using of secondary ion mass spectroscopy(SIMS) and Auger electron spectroscopy(AES) SIMS and AES experiments show the existence of nitridation at the SiO$_2$/Si substrate. The electrical characteristics of ONO films were evaluated by I-V and high frequency C-V measurements When the ONO films were annealed at 90$0^{\circ}C$ for 30 sec in $N_2$ ambient, the breakdown voltage increased and flat-band voltage decreased under high electric field.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.289.2-289.2
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• 2016

In-Ga-Zn-O(IGZO) receive great attention as a channel material for thin film transistors(TFTs) as next-generation display panel backplanes due to its superior electrical and physical properties such as a high mobility, low off-current, high sub-threshold slope, flexibility, and optical transparency. For the purpose of fabricating high performance IGZO TFTs, a thermal recovery process above a temperature of $300^{\circ}C$ is required for recovery or rearrangement of the ionic bonding structure. However diffused metal atoms from source/drain(S/D) electrodes increase the channel conductivity through the oxidation of diffused atoms and reduction of $In_2O_3$ during the thermal recovery process. Threshold voltage ($V_{TH}$) shift, one of the electrical instability, restricts actual applications of IGZO TFTs. Therefore, additional investigation of the electrical stability of IGZO TFTs is required. In this paper, we demonstrate the effect of Ti diffusion and modulation of interface traps by carrying out an annealing process on IGZO. In order to investigate the effect of diffused Ti atoms from the S/D electrode, we use secondary ion mass spectroscopy (SIMS), X-ray photoelectron spectroscopy, HSC chemistry simulation, and electrical measurements. By thermal annealing process, we demonstrate VTH shift as a function of the channel length and the gate stress. Furthermore, we enhance the electrical stability of the IGZO TFTs through a second thermal annealing process performed at temperature $50^{\circ}C$ lower than the first annealing step to diffuse Ti atoms in the lateral direction with minimal effects on the channel conductivity.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.2
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• pp.93-98
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• 2001

YMnO$_3$ films are excellent gate dielectric materials of ferroelectric random access memories (FRAMs) with MFSFET (metal -ferroelectric-semiconductor field effect transistor) structure because YMnO$_3$ films can be deposited directly on Si substrate and have a relatively low permittivity. Although the patterning of YMnO$_3$ thin films is the requisite for the fabrication of FRAMs, the etch mechanism of YMnO$_3$ thin films has not been reported. In this study, YMnO$_3$thin films were etched with Cl$_2$/Ar gas chemistries in inductively coupled plasma (ICP). The maximum etch rate of YMnO$_3$ film is 285$\AA$/min under Cl$_2$/(Cl$_2$+Ar) of 1.0, RF power of 600 W, dc-bias voltage of -200V, chamber pressure of 15 mTorr and substrate temperature of $25^{\circ}C$. The selectivities of YMnO$_3$ over CeO$_2$ and $Y_2$O$_3$ are 2.85, 1.72, respectively. The selectivities of YMnO$_3$ over PR and Pt are quite low. Chemical reaction in surface of the etched YMnO$_3$ thin films was investigated with X-ray photoelectron spectroscopy (XPS) surface of the selected YMnO$_3$ thin films was investigated with X-ray photoelectron spectroscopy(XPS) and secondary ion mass spectrometry (SIMS). The etch profile was also investigated by scaning electron microscopy(SEM)