• 한국전기전자재료학회논문지
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• 제15권10호
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• pp.838-843
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• 2002

Chemical mechanical polishing(CMP) process has been widely used to planarize dielectric layers, which can be applied to the integrated circuits for deep sub-micron technology. The reverse moat etch process has been used for the shallow trench isolation(STI)-chemical mechanical polishing(CMP) process with conventional low selectivity slurries. Thus, the process became more complex, and the defects were seriously increased. In this paper, we studied the direct STI-CMP process without reverse moat etch step using high selectivity slurry(HSS). As our experimental results show, it was possible to achieve a global planarization without the complicated reverse moat process, the STI-CMP process could be dramatically simplified, and the defect level was reduced. Therefore the throughput, yield, and stability in the ULSI semiconductor device fabrication could be greatly improved.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 D
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• pp.1337-1339
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• 1998

The trench termination scheme is introduced for high voltage devices. The curvature of the depletion region at field limiting ring is critical factor to determine the breakdown voltage. The smooth curvature of the depletion junction alleviate the electric field crowding effect around this region. In the trench field limiting ring, the radius of the depletion region is smaller than conventional field limiting ring, but the distance between every trench is spaced small enough to punchthrough before initiation of local breakdown. The trench field limiting ring on silicon can ne formed by RIE followed by oxidation on side wall surface of the trench, and polysilicon filling. The combined termination of this trench floating field ring and field plate have been designed and analyzed. The breakdown simulation by 2-dimensional TCAD shows that the cylindrical junction breakdown voltage for substrate doping might be 99 percent of the ideal breakdwon voltage for substrate doping concentration of $3\times10^{14}cm^{-3}$ with about $100{\mu}m$ of lateral termination width.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 추계학술대회 논문집
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• pp.194-199
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• 1996

Grinding burn formed on the ground surface is related to the maximum temperature of workpiece surface and wheel temperature in the grinding process. The thermal characteristics of workpiece and grinding conditions on the surface temperature of the oxidation growing layer after get out of contact with the grinding wheel. The assumption used in grinding power signatures leads to the local temperature distribution between grinding wheel and workpiece, i.e., a single curve determines temperatures anywhere within the grinding wheel at anytime. This information is useful in the study of the grinding bum penetration into the wheel and thus provides an presentation of grinding trouble monitoring for the burning. On the basis of grinding power signatures in the wheel, thermally optimum conditions are defined and controlled. To cope with grinding burn, the use of grinding power signatures is an effective monitoring systems when occurring the grinding process. In this paper, the identified parameters suggested in this study which are derived from the grinding power signatures are presented.

• 한국수소및신에너지학회논문집
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• 제11권4호
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• pp.179-188
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• 2000

The anodic reaction of hydrogen/oxygen gas mixture at platinum or palladium electrode interfacing with a solid polymer electrolyte was investigated using AC impedance method. The impedance spectrum of the electrode reactions of the mixture depends on the gas composition, electrode roughness, the mode of electrochemical operation and the cell potential. For electrolysis mode of operation, the spectrum taken for the reaction on a rough platinum electrode for the gas mixture revealed clearly that the local anodic reduction of oxygen gas takes place concurrently with the anodic oxidation of hydrogen gas.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1987년도 전기.전자공학 학술대회 논문집(I)
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• pp.429-432
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• 1987

A new LOCOS (Local Oxidation of Silicon) process using a thin nitride film directly deposited on the silicon substrate by LPCVD has been developed in order to reduce the bird's beak length. SEM studies showed that nitride thickness of 50nm can decrease the bird's beak length down to 0.2um with 450nm field oxide. No crystalline defects are observed around the bird's beak after the Wright etch. A 30% improvement in current density was obtained when this new method was applied to MOS transistors (W/L*2.9/20.4) compared to conventional LOCOS process (bird's beak length=0.7um). Other various electrical parameters improved by this new simple LOCOS process are reported in this paper.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.140.1-140.1
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• 2013

The native silicon-oxide (SiOx) layer at the metal/Silicon interface acts as an electrical resistance to the metal contact of devices. Various methods are proposed for removing this layer, such as sputtering before metal contact formation or high temperature annealing. We studied the chemical evolution of the Au/SiOx/Si system during the annealing at $500^{\circ}C$ using a spatially resolved photoelectron emission method. Scanning photoelectron emission microscopy (SPEM) and core level spectra from local area of the sample show the inhomogeneous oxidation and formation of silicide of Au, as well as valence band spectra reveals the role of Au atoms during the dissociation process of SiOx.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 추계학술대회 논문집
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• pp.330-333
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• 2005

The fabrication of mold fur nano imprint lithography (NIL) is experimentally reported using the scanning probe lithography (SPL) technique, instead of the conventional I-beam lithography technique. The nanometer scale patterning structure is fabricated by the localized generation of oxide patterning on the silicon (100) wafer surface with a thin oxide layer, The fabrication method is based on the contact mode of scanning probe microscope (SPM) in air, The precision cleaning process is also performed to reach the low roughness value of $R_{rms}=0.084 nm$, which is important to increase the reproducibility of patterning. The height and width of the oxide dot are generated to be 15.667 nm and 209.5 nm, respectively, by applying 17 V during 350 ms.

• Bulletin of the Korean Chemical Society
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• 제16권10호
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• pp.981-984
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• 1995

New diamineplatinum(Ⅱ) complexes of cyclohexylidenemalonate (chm) ligand, A2Pt(OOC)2C=C(CH2)4CH2 (1, A2=ethylenediamine (en); 2, A2=propylenediamine (pn); 3, A=NH3; 4, A=isopropylamine (ipa)) have been prepared. Their oxidation with H2O2 has led to the corresponding dihydroxoplatinum(Ⅳ) complexes: cis, cis, trans-A2Pt((OOC)2C=C(CH2)4CH2)(OH)2 (5, A2=en; 6, A2=pn; 7, A=NH3; 8, A=ipa). The title complexes have been characterized by means of various spectroscopies and X-ray crystallography. 5 crystallizes in the monoclinic space group P21/a (Z=4) with a=12.098(7) Å, b=9.552(2) Å, c=16.258(4) Å, β=98.03(5)° and V=1860(1) Å3. The structure was refined to R=0.074. The local geometry around platinum atom is approximately octahedral with each hydroxide group in trans position. These platinum complexes are stable in aqueous solution. Pt(Ⅳ) complexes are readily reduced to the corresponding Pt(Ⅱ) complexes by ascorbic acid.

• 대한전자공학회논문지
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• 제23권6호
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• pp.929-935
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• 1986

In this paper, we describe the physical modelling and numerical aspects of a program called PRECISE(Program for Efficient Calculation of Impurity Profile in Semiconductor by Elimination) which calcualtes a two-dimensional impurity profile in silicon due to diffusion and ion implantation steps. The PRECISE enables rapid prediction of the two-dimensional impurity profile near the mask edge-or the bird's beak during the local oxidation process. This has been developed by modifying the existing one-dimentional simulator, DIFSIM(DIFfusion SIMulator to include models for arsenic diffusion and emitter dip effect which were found out to agree fairly well with the xperimental data.

• 한국입자에어로졸학회지
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• 제15권3호
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• pp.91-104
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• 2019

In this study, hourly measurements of $PM_{2.5}$ and its major chemical constituents such as organic and elemental carbon (OC and EC), and ionic species were made between January 15 and February 10, 2018 at the air pollution intensive monitering station in Gwangju. In addition, 24-hr integrated $PM_{2.5}$ samples were collected at the same site and analyzed for OC, EC, water-soluble OC (WSOC), humic-like substance (HULIS), and ionic species. Over the whole study period, the organic aerosols (=$1.6{\times}OC$) and $NO_3{^-}$ concentrations contributed 26.6% and 21.0% to $PM_{2.5}$, respectively. OC and EC concentrations were mainly attributed to traffic emissions with some contribution from biomass burning emissions. Moreover, strong correlations of OC with WSOC, HULIS, and $NO_3{^-}$ suggest that some of the organic aerosols were likely formed through atmospheric oxidation processes of hydrocarbon compounds from traffic emissions. For the period between January 18 and 22 when $PM_{2.5}$ pollution episode occurred, concentrations of three secondary ionic species ($=SO{_4}^{2-}+NO_3{^-}+NH_4{^+}$) and organic matter contributed on average 50.8 and 20.1% of $PM_{2.5}$, respectively, with the highest contribution from $NO_3{^-}$. Synoptic charts, air mass backward trajectories, and local meteorological conditions supported that high $PM_{2.5}$ pollution was resulted from long-range transport of haze particles lingering over northeastern China, accumulation of local emissions, and local production of secondary aerosols. During the $PM_{2.5}$ pollution episode, enhanced $SO{_4}^{2-}$ was more due to the long-range transport of aerosol particles from China rather than local secondary production from $SO_2$. Increasing rate in $NO_3{^-}$ was substantially greater than $NO_2$ and $SO{_4}^{2-}$ increasing rates, suggesting that the increased concentration of $NO_3{^-}$ during the pollution episode was attributed to enhanced formation of local $NO_3{^-}$ through heterogenous reactions of $NO_2$, rather than impact by long-range transportation from China.