• Proceedings of the Korean Vacuum Society Conference
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• 2004.08a
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• pp.189-189
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• 2004

• Proceedings of the Korean Ceranic Society Conference
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• 2003.10a
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• pp.19.2-19
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• 2003

• 한국전자현미경학회:학술대회논문집
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• 2001.11a
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• pp.100-101
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• 2001

• Korean Journal of Materials Research
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• v.26 no.9
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• pp.486-492
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• 2016

Tungsten (W) thin film was deposited at $400^{\circ}C$ using pulsed chemical vapor deposition (pulsed CVD); film was then evaluated as a nucleation layer for W-plug deposition at the contact, with an ultrahigh aspect ratio of about 14~15 (top opening diameter: 240~250 nm, bottom diameter: 98~100 nm) for dynamic random access memory. The deposition stage of pulsed CVD has four steps resulting in one deposition cycle: (1) Reaction of $WF_6$ with $SiH_4$. (2) Inert gas purge. (3) $SiH_4$ exposure without $WF_6$ supply. (4) Inert gas purge while conventional CVD consists of the continuous reaction of $WF_6$ and $SiH_4$. The pulsed CVD-W film showed better conformality at contacts compared to that of conventional CVD-W nucleation layer. It was found that resistivities of films deposited by pulsed CVD were closely related with the phases formed and with the microstructure, as characterized by the grain size. A lower contact resistance was obtained by using pulsed CVD-W film as a nucleation layer compared to that of the conventional CVD-W nucleation layer, even though the former has a higher resistivity (${\sim}100{\mu}{\Omega}-cm$) than that of the latter (${\sim}25{\mu}{\Omega}-cm$). The plan-view scanning electron microscopy images after focused ion beam milling showed that the lower contact resistance of the pulsed CVD-W based W-plug fill scheme was mainly due to its better plug filling capability.

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.128-128
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• 2000

박막의 탄성 특성을 평가하는 방법으로 nano-indentation, Brillouin light scattering measurement, ultrasonic surface wave measurement, bulge test, vibration membrane method 등 여러 가지가 제시되어 왔다. 이러한 방법들은 필름의 두께가 일정 두께 이상이 되어야 정확한 측정이 가능한 방법으로 매우 얇은 박막에서도 탄성특성을 평가할 수 있는 freehang, bridge 방법이 제시되었으며, 이 방법은 간단한 식각 공정을 통해 매우 얇은 박막에도 적용시킬 수 있다는 장점을 가지고 있다. 본 연구에서는 아주 얇은 박막에서도 탄성특성을 평가할 수 있는 freehang 방법을 이용하여 순수한 Diamond-like carbon (DLC) 필름과 Sidl 첨가된 DLC 필름의 탄성 특성을 평가하고자 한다. 실험에서 사용한 필름은 rf-PACVD 장비를 이용하여 증착하였다. 이때 전극과 플라즈마 사이의 바이어스 음전압은 -400 Vb로 합성압력은 10mTorr로 고정하였다. 사용한 반응 가스는 벤젠(C6H6), 그리고 벤젠과 희석된 실렌(SiH4 : H2 = 10 : 90)이며, 희석된 실렌의 첨가량을 조절하여 필름 내에 일정량의 Si을 함유시켰다. 각각의 조건에서 증착시간을 조절하여 필름의 두께를 변화시켰으며, KOH(5.6mol) 용액을 이용하여 습식 식각을 함으로써 freehang을 제작하였다. 이때 식각액에 의한 DLC 필름의 손상은 관찰되지 않았다. 필름의 잔류 응력을 측정하기 위해 200$\pm$10 혹은 100$\pm$5$\mu\textrm{m}$ 두께의 얇은 (100) Si wafer를 5$\times$50 mm2의 strip 형태로 절단하여 사용하였다. 필름의 압축 잔류 응력에 의해 발생한 필름/기판 복합체의 곡률은 laser 반사법과 $\alpha$-step profiler를 이용하여 측정하였으며, 이 결과를 Brenner 등에 유도된 식을 이용하여 잔류 응력을 계산하였다. 또한 제작된 frddhang은 광학 현미경과 전자주사현미경에 의해 관찰되었다. 이렇게 제작된 freehang을 이용하여 필름이 기판에 부착되기 위해 필요한 변형률을 측정하고, 독립적으로 측정된 필름의 잔류 응력을 박막의 응력-변형률 관계식에 적용하여 biaxial elastic modulus, E/(1-v)를 구할 수 있었다. 측정 결과 필름의 잔류 응력과 biaxial elastic modulus는 필름의 두께가 감소함에 따라 감소하는 경향을 나타냈으며, 같은 두께의 필름인 경우, 식각 깊이에 따른 biaxial elastic modulus 의 변화를 통해 최적의 식각 깊이를 알 수 있었다.

• Korean Journal of Materials Research
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• v.10 no.9
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• pp.648-655
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• 2000

Synthesis of the crystalline film was investigated under the diamond growth condition with altering the addition of the nitrogen from 0% to 95%. With increasing the nitrogen concentration, surface morphology of the film was changed from the diamond film with {100} growth plane to the non-faceted diamond film with nano-scale grains. It also showed that the deposition of the diamond film could be synthesized using only methane and nitrogen gases without hydrogen gas. Separated particles with diamond structure showed an octahedral shaped I the nitrogen ranges between 30% and 80%, and newly formed hexagonal crystals are observed when substrate temperature with diamond structure, however, also identify that the hexagonal crystal was SiCN composite composed of Si, C and N atoms.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.29A no.1
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• pp.33-40
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• 1992

Several etching phenomena were observed and analyzed in diaphragm process performed on 4-inch (100) Si wafers for sensor application. In case of deep etching to above 300$\mu$m depth, the etch-defects appeared at etched surface could be classified into three categories such as hillocks, reaction products, and white residues. It was known that the hillock had a pyramidal shape or trapizoidal hexahedron structure depending on the density and size of the reaction products. The IR spectra showed that the white residue, which was due to the local over-saturation of Si dissolved in solution, was mostly Si-N-O compounds mixed with a small amount of H and C etc. Also, the difference in both the existence of etch-defects and etch rate distribution over a whole wafer was investigated when the etched surfaces were downward, upward horizontally and erective in etching solutions. The obtained data were analyzed through flow pattern in the etching bath. As the results, the downward and erective postures were favorable in the etch rate uniformity and the etch-defect removal, respectively.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.381-381
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• 2010

$(ZrO_2)_{0.66}(HfO_2)_{0.34}$ thin films as gate dielectrics have been proposed to overcome the problems of tunneling current and degradation mobility inachieving a thin equivalent oxide thickness. An extremely thin $SiO_2$ layer is used in order to separate the carrier in MOSFET channel from the dielectric field fluctuation caused by phonons in the dielectric which decreases the carrier mobility. The electronic and optical properties influenced the device performance to a great extent. $(ZrO_2)_{0.66}(HfO_2)_{0.34}$ dielectric films on p-Si (100) were grown by atomic layer deposition method, for which the conduction band offsets, valence band offsets and band gapswere obtained by using X-ray photoelectron spectroscopy and reflection electron energy loss spectroscopy. The band gap, valence and conduction band offset values for $(ZrO_2)_{0.66}(HfO_2)_{0.34}$ dielectric thin film, grown on Si substrate were about 5.34, 2.35 and 1.87 eV respectively. This band alignment was similar to that of $ZrO_2$. In addition, The dielectric function (k, $\omega$), index of refraction n and the extinction coefficient k for the $(ZrO_2)_{0.66}(HfO_2)_{0.34}$ thin films were obtained from a quantitative analysis of REELS data by comparison to detailed dielectric response model calculations using the QUEELS-$\varepsilon$(k, $\omega$)-REELS software package. These optical properties are similar with $ZrO_2$ dielectric thin films.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.2
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• pp.101-105
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• 2007

We have synthesized silicon nanowires by using RFCVD(Radio Frequency Chemical Vapor Deposition) system on Au deposited p-type Si(100) wafers, and investigated their physical and electrical properties. The silicon nanowires had been grown in the atmospheres of $H_{2},\;N_{2}\;and\;SiH_{4}$ at 10 Torr at the substrate temperatures of $700{\pm}5^{\circ}C\;and\;810{\pm}5^{\circ}C$ respectively. FE-SEM analysis revealed that diameters of the silicon nanowires are $50{\sim}60nm$ with the length of several ${\mu}m$. XRD analysis showed that the growth direction of the nanowires is Si[111]. Field emission characteristics showed that the turn-of voltages at the current of $0.01\;mA/cm^{2}$ are $10\;V/{\mu}m\;and\;8.5\;V/{\mu}m$ for the wires grown at $700{\pm}5^{\circ}C\;and\;810{\pm}5^{\circ}C$, respectively.

• Journal of Magnetics
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• v.6 no.1
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• pp.23-26
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• 2001

Nano-crystalline hexaferrite $BaFe_{12}O_{19}$(BaM) thin films have been prepared by the sol-gel method. A solution of Ba-nitrate and Fe-nitrates was dissolved in solvent with the stoichiometric ratio Ba/Fe=1/10. Films were spin-coated onto $SiO_2$Si substrates, dried and then heated in air at various temperatures. In films prepared at a drying temperature $T_d=250^{\circ}C$ and a crystallizing temperature 650${\circ}C$, single-phase BaM was obtained. High coercivities were obtained in these nano-crystalline thin films, 4~5.5 kOe for hexaferrite. Polycrystalline BaM/$SiO_2$/Si(100) thin films were characterized by Rutherford backscattering (RBS), thermogravimetry (TGA), differential thermal analysis (DTA), x-ray diffraction (XRD), and vibrating sample magnetometry (VSM), as well as Fourier transform infrared spectroscopy (FTIR). The perpendicular coercivity $H_{C\bot}$ and in-plane coercivity $H_{CII}$ after annealing at 650${\circ}C$ for 2 hours were 4766 Oe and 4480 Oe, respectively, at room temperature, under a maximum applied field of 10 kOe.