• Journal of the Korean Ceramic Society
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• v.41 no.4
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• pp.340-343
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• 2004

SrA1$_2$O$_4$was prepared by polymerized complex method and crystalline growth was investigated. Precursors was annealed at temperatures form 900 to 100$0^{\circ}C$, for different time(between 0 and 10 h), and that was determined by Transmittance Electron Microscopy (TEM) and X-Ray Diffractometer (XRD). Crystalline size was calculated by Scherrer's equation and its variation was studied. It increased rapidly in the primary stage and then slowly as a function of square root of time. so, It was grown to 32, 45 and 59nm after heating treatment at 900, 980, and 100$0^{\circ}C$ for 10 h respectively. Cstalline growth rates were 4.5, 9.6, and 18.6 nm/h$^{1}$2/ as a addition of heating temperature.

• Journal of Sensor Science and Technology
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• v.11 no.1
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• pp.60-65
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• 2002

$ZnGa_2O_4$ thin film phosphors have been deposited using a pulsed laser deposition method on Si(100) substrates at a substrate temperature of $550^{\circ}C$ with oxygen pressures of 100mTorr, and subsequently to investigate their photoluminescence characteristics after post-annealed at $600^{\circ}C$ and $700^{\circ}C$. As a result for X-ray diffraction, $Ga_2O_3$ shape appeared with increasing annealing temperature. The luminescent spectra show a broad band extending from 350 to 600nm peaking at 460nm. A post-annealing treatment of $ZnGa_2O_4$ thin films led to the different shape of luminescent intensity and grain size.

• Korean Journal of Metals and Materials
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• v.46 no.2
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• pp.88-96
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• 2008

Thermal evaporated 10 nm-$Ni_{50}Co_{50}$/(70 nm-poly)Si films were deposited to examine the energy saving properties of silicides formed by rapid thermal annealing at temperature ranging from 500 to $1,100^{\circ}C$ for 40 seconds. Thermal evaporated 10 nm-Ni/(70 nm-poly)Si films were also deposited as a reference using the same method for depositing the 10 nm-$Ni_{50}Co_{50}$/(70 nm-poly)Si films. A four-point probe was used to examine the sheet resistance. Transmission electron microscopy (TEM) and X-ray diffraction XRD were used to determine cross sectional microstructure and phase changes, respectively. UV-VIS-NIR and FT-IR (Fourier transform infrared spectroscopy) were used to examine the near-infrared (NIR) and middle-infrared (MIR) absorbance. TEM analysis confirmed that the uniform nickel-cobalt composite silicide layers approximately 21 to 55 nm in thickness had formed on the single and polycrystalline silicon substrates as well as on the 25 to 100 nm thick nickel silicide layers. In particular, nickel-cobalt composite silicides showed a low sheet resistance, even after rapid annealing at $1,100^{\circ}C$. Nickel-cobalt composite silicide and nickel silicide films on the single silicon substrates showed similar absorbance in the near-IR region, while those on the polycrystalline silicon substrates showed excellent absorbance until the 1,750 nm region. Silicides on polycrystalline substrates showed high absorbance in the middle IR region. Nickel-cobalt composite silicides on the poly-Si substrates annealed at $1,000^{\circ}C$ superior IR absorption on both NIR and MIR region. These results suggest that the newly proposed $Ni_{50}Co_{50}$ composite silicides may be suitable for applications of IR absorption coatings.

• Journal of Sensor Science and Technology
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• v.11 no.2
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• pp.118-123
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• 2002

$ZnGa_2O_4$ thin film phosphors have been deposited using a pulsed laser deposition technique on $Al_2O_3$(0001) substrates at a substrate temperature of $550^{\circ}C$ with various oxygen pressures 100, 200 and 300 mTorr. The films grown under different growth oxygen pressures have been characterized using microstructural and luminescent measurements. The different photoluminescence (PL) characteristics with the increase in oxygen pressures may result from the change of the crystallinity and the composition ratio of Zn and Ga in the films. The luminescent spectra show a broad band extending from 300 to 600 nm peaking at 460 nm. The PL brightness data obtained from the $ZnGa_2O_4$ films grown under optimized conditions have indicated that the sapphire is a promising substrate for the growth of high quality $ZnGa_2O_4$ thin film phosphor.

• Journal of the Korean Magnetics Society
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• v.25 no.2
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• pp.43-46
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• 2015

$Si(100){\backslash}200nm$ $SiO_2{\backslash}5nm$ $Ta{\backslash}5nm$ $MgO{\backslash}35nm$ $Fe_3O_4$ multi-layers were prepared by using RF-sputtering and ultra-high vacuum molecular beam epitaxy (UHV-MBE) techniques. After post-annealing the multi-layers at $500^{\circ}C$ for 1 hour under the high vacuum of ${\sim}1{\times}10^{-6}Torr$, we observed ferromagnetic properties at room temperature as well as the Verwey transition which is the typical features of magnetite crystals formed. We have carried out a comparative study of the effect of Ta buffered layer on the crystallinity and magnetic properties of $Fe_3O_4$ thin films prepared under different growth and annealing conditions.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.05a
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• pp.275-278
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• 2002

As the gate lengths of MOSFETs are scaled down to sub-50nm regime, there are key issues to be considered in the device design. In this paper, we have investigated the characteristics of threshold voltage for MOSFET device. We have simulated the MOSFETs with gate lengths from 100nm to 30nm using generalized scaling. Then, we have known the device scaling limits for nano structure MOSFET. We have determined the threshold voltages using LE(Linear Extraction) method.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.2
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• pp.297-302
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• 2019

In this study, we deposited ITO thin films on buffer layer of $Nb_2O_5(8nm)/SiO_2(45nm)$ using DC magnetron sputtering method and investigated its electrical and optical properties with various DC powers(100~400 W). The surface of the ITO thin film was observed by AFM. All thin films had defected free surface such as pinholes and cracks. The thin film deposited at DC power of 200 W exhibited the smallest surface roughness of 1.431nm. As a result of electrical and optical measurements, the ITO thin film deposited at DC power of 200 W which showed the lowest resistivity of $3.03{\times}10^{-4}{\Omega}-cm$. The average transmittance in the visible light region(400 to 800 nm) and the transmittance at the wavelength of 550nm were found to be 85.8% and 87.1%, respectively. The chromaticity(b*) was also a relatively good value as 2.13. The figure of merit obtained from the sheet resistance of the ITO thin film, the average transmittance in the visible light region and the transmittance at the wavelength of 550nm were the best values of $2.50{\times}10^{-3}{\Omega}^{-1}$ and $2.90{\times}10^{-3}{\Omega}^{-1}$ at a DC power of 200W, respectively.

• Journal of the Korean institute of surface engineering
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• v.54 no.2
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• pp.96-101
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• 2021

NaNbO₃:Eu³⁺ phosphor thin films were grown on quartz substrates by radio-frequency magnetron sputtering at a growth temperature of 100 ℃, with subsequent annealing at temperatures of 800, 900, and 1000 ℃. The effects of annealing temperature on the structural, morphological, and optical properties of the thin films were investigated. The NaNbO₃:Eu³⁺ sputtering target was synthesized by a solid-state reaction of raw materials Na₂CO₃, Nb₂O₅, and Eu₂O₃. The X-ray diffraction patterns exhibited that the thin films had two mixed phases of NaNbO₃ and Eu₂O₃. Surface morphologies were investigated by using field emission-scanning electron microscopy and indicated that the grains of the thin film annealed at 1000 ℃ showed irregular shapes with an average size of approximately 300 nm. The excitation spectra of Eu³⁺-doped NaNbO₃ thin film consisted of a strong charge transfer band centered at 304 nm in the range of 240-350 nm and two weak peaks at 395 and 462 nm, respectively, resulting from the ⁷F₀→⁵L₆ and ⁷F₀→⁵H₂ transitions of Eu³⁺ ions. The emission spectra under excitation at 304 nm exhibited an intense red band centered at 614 nm and two weak bands at 592 and 681 nm. As the annealing temperature increased from 800 ℃ to 1000 ℃, the intensities of all the emission bands and the band gap energies gradually increased. These results indicate that the higher annealing temperature enhance the luminescent properties of NaNbO₃:Eu³⁺ thin films.

• Proceedings of the IEEK Conference
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• 2003.07b
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• pp.707-710
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• 2003

10nm 이하의 두께를 갖는 얇은 SOI 층 위에서 우수한 동작 특성을 보이는 Fully-Depleted SOI nMOSFET 을 제작하였다. 게이트의 길이가 큰 경우에는 SOI 층이 얇지 않아도 좋은 특성을 보이지만, 게이트 길이가 100nm 이하에서는 Short Channel Effect 에 의한 특성 열화 때문에 SOI thin body 의 두께가 게이트 길이에 따라 같이 얇아져야 한다. [1] 100nm 게이트 길이 SOI-NMOSFET에서 10nm 이하 body 두께에 따라 Vth는 조금 상승했고, Subthreshold slope은 조금 개선되는 특성을 보였다. 또한, 45nm 게이트 길이와 3nm 로 추정되는 body 두께를 갖는 nMOSFET 에서 우수한 I-V 동작 특성을 얻었다.

• Korean Journal of Materials Research
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• v.23 no.1
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• pp.47-52
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• 2013

Graphene has been synthesized on 100- and 300-nm-thick Ni/$SiO_2$/Si substrates with $CH_4$ gas (1 SCCM) diluted in mixed gases of 10% $H_2$ and 90% Ar (99 SCCM) at $900^{\circ}C$ by using inductively-coupled plasma chemical vapor deposition (ICP-CVD). The film morphology of 100-nm-thick Ni changed to islands on $SiO_2$/Si substrate after heat treatment at $900^{\circ}C$ for 2 min because of grain growth, whereas 300-nm-thick Ni still maintained a film morphology. Interestingly, suspended graphene was formed among Ni islands on 100-nm-thick Ni/$SiO_2$/Si substrate for the very short growth of 1 sec. In addition, the size of the graphene domains was much larger than that of Ni grains of 300-nm-thick Ni/$SiO_2$/Si substrate. These results suggest that graphene growth is strongly governed by the direct formation of graphene on the Ni surface due to reactive carbon radicals highly activated by ICP, rather than to well-known carbon precipitation from carbon-containing Ni. The D peak intensity of the Raman spectrum of graphene on 300-nm-thick Ni/$SiO_2$/Si was negligible, suggesting that high-quality graphene was formed. The 2D to G peak intensity ratio and the full-width at half maximum of the 2D peak were approximately 2.6 and $47cm^{-1}$, respectively. The several-layer graphene showed a low sheet resistance value of $718{\Omega}/sq$ and a high light transmittance of 87% at 550 nm.