• Transactions on Electrical and Electronic Materials
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• v.17 no.2
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• pp.104-108
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• 2016

To research the correlation between oxygen vacancy and the electrical characteristics of ZTO, which is made by using a target mixed ZnO:SnO₂=1:1, the ZnO, SnO₂ and ZTO were analyzed by PL, XPS, XRD patterns and electrical properties. It was compared with the electron orbital spectra of O 1s in accordance with the electrical characteristics of ZnO, SnO₂ and ZTO. The electrical characteristics of ZTO were improved by increasing the annealing temperatures, due to the high degree of crystal structures at a high temperature, and the physical properties of ZTO was similar to that of ZnO. The amorphous structure of SnO₂ was increased with increasing the temperature. The Schottky contact of oxide semiconductors was formed using the depletion region, which is increased by the electron-hole combination due to the annealing processes. ZnO showed the Ohmic contact in spite of a high annealing temperature, but SnO₂ and ZTO had Schottky contact. As such, it was confirmed that the electrical properties of ZTO are affected by the molecules of SnO₂.

• Journal of Integrative Natural Science
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• v.13 no.3
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• pp.87-91
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• 2020

Molybdenum carbide (MoC_x) thin films (TFs) were deposited by reactive radio frequency (rf) magnetron co-sputtering in high vacuum chamber. We compared the properties of MoC_x thin films as the rf power changed on C target. The result of alpha step measurement showed that the thickness of the MoC_x TFs varied from163.3 to 194.86 nm as C power was increased from 160 to 200 W. The crystallinity of MoC_x such as b-Mo₂C, Mo₂C, and diamond like carbon (DLC) structures were observed by XRD. The oxidation states of Mo and C were determined using high resolution XPS spectra of Mo 3d and C 1s were deconvoluted. Molybdenum was consisted of Mo, Mo⁴⁺, and Mo⁶⁺ species. And C was deconvoluted to C-Mo, C, C-O, and C=O species.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.59-59
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• 1999

DLC(diamond-like carbon)필름은 다이아몬드와 유사한 강도, 낮은 마차계수, 높은 Optical band gap, NEA(negative electron affinity)등의 우수한 특성을 가지고 있어, 내마모 코팅이나 정보저장 매체의 윤활 코팅, FED(field emission display)의 전계방출소자등 다양한 분야에의 응용이 연구되고 있다. DLC 필름은 PECVD(plasma enhanced chemical vapor deposition), IBAD(ion beam assisted deposition), Laser ablation, Cathodic vacuum arc등의 process를 이용하여 증착되고 있다. 특히 이러한 필름의 물성은 입사되는 이온의 에너지에 의해 좌우되는데, Lifshitz 등의 연구에 의하여 hyperthermal species를 이용한 DLC 필름의 성장은 초기에 subsurface로의 shallow implantation이 일어난 후 높은 sp3 fraction을 갖는 필름이 연속적으로 성장한다는 subplantation model이 제시 되었다. 본 연구에서는 기판과 subplantation 영역이 이후 계속하여 증착되는 순수 DLC 필름의 특성 변호에 미치는 영향에 대하여 관심을 가지고 실험을 행하였다. 본 실험에서는 상기 제시되어 있는 방법보다도 더욱 정확하고도 독립적으로 탄소 음이온의 에너지와 flux를 조절할 수 있는 Cs+ ion beam sputtering system을 이용하여 탄소 음이온의 에너지를 40eV에서 200eV까지 변화시키며 필름을 증착하였다. Si(100) 웨이퍼를 기판으로 사용하였고 증착 압력은 5$\times$10-7torr 였으며 인위적인 기판의 가열은 하지 않았다. 또한 Ion beam deposited DLC film의 growth process를 연구하기 위하여 200eV의 탄소 음이온을 시간(증착두께)을 변수로 하여 증착하였고, 이 때에는 Kaufman type의 gas ion beam을 이용하여 500eV의 Ar+ ion으로 pre-sputering을 행하였다. 탄소 음이온의 에너지와 증착두께에 따라 증착된 film 내의 sp3/sp2 ratio 의 변화를 XPS plasmon loss 와 Raman spectra를 이용하여 분석하였다. 또한 증착두께에 따른 interlayer의 결합상태를 관찰하기 위하여 AES와 XPS 분석을 보조로 행하였다.

• Journal of the Korean institute of surface engineering
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• v.35 no.6
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• pp.383-390
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• 2002

To investigate behaviors of Ti and O elements and microstructures of anodic titanium oxide films, the films were prepared by anodizing pure titanium in $H_2$S $O_4$, $H_3$P $O_4$, and $H_2O$$_2$ mixed solution at 180V. The microstructures and chemical states of the elements were analyzed using SEM, X-ray mapping, AFM, XRD, XPS (depth profile). The films formed on a titanium substrate showed porous layers which were composed of pore and wall, And with increasing anodizing time a hexagonal shape of cell structures were dominant and solace roughness increased. From the XRD result the structure of the Ti $O_2$ layer was anatase type of crystal on the whole. In the XPS spectra it was found that Ti and O were chemically binded in forms of Ti $O_2$, TiOH, $Ti_2$ $O_3$ at Ti 2p, and Ti $O_2$, $Ti_2$ $O_3$, $P_2$ $O_{5}$, S $O_4^{2-}$ at O ls respectively. Concentration of Ti $O_2$ decreased as the depth increased from the surface of the oxide film towards the substrate, but to the contrary concentrations of TiOH and $Ti_2$ $O_3$ increased.d.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.54-54
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• 2011

The demand for low-friction, wear and corrosion resistant components, which operate under severe conditions, has directed attentions to advanced surface engineering technologies. The Filtered Vacuum Arc Cathode Deposition (FVACD) process has demonstrated atomically smooth surface at relatively high deposition rates over large surface areas. Preparation of Ti-Si-C-N nanocomposite coatings on (100) Si and stainless steel substrates with tetramethylsilane (TMS) gas pressures to optimize the film preparation conditions. Ti-S-C-N coatings were characterized using X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, nanoindentation, Rockwell C indentation and ball-on-disk wear tests. The XRD results have confirmed phase formation information of TiSiCN coatings, which shows mixing of TiN and TiC structure, corresponding to (111), (200) and (220) planes of TiCN. The chemical composition of the film was investigated by XPS core level spectra. The binding energy of the elements present in the films was estimated using XPS measurements and it shows present of elemental information corresponding to Ti2p, N1s, Si 2p and C1. Film hardness and elastic modulus were measured with a nano-indenter, and film hardness reached 40 GPa. Tribological behaviors of the films were evaluated using a ball-on-disk tribometer, and the films demonstrated properties of low-friction and good wear resistance.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.8
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• pp.769-774
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• 2006

In this paper the ZnO thin films, which has used spotlight of next generation short wavelength LEDs and semiconductor laser were deposited based on RF magnetron sputtering is described. The temperature at substrate and work pressure, which has implemented in sputtering process of ZnO thin films were settle down at $100^{\circ}C$ and 15 mTorr respectively. The ZnO 5N has used target. The thickness of ZnO thin films was about $1.6{\mu}m$ which was measured by SEM analysis after the sputtering process. Structural properties of ZnO thin films by in-situ and atmosphere annealing were analyzed by XRD. Transformation of grain size and surface roughness were observed by AFM. XPS spectra showed that ZnO thin film had a peak positions corresponding to the $Zn_{2p}$ and the $O_{1s}$. As form above XPS, we confirmed that post-annealing condition changed the atom ratio of Zn/O and microstructure in ZnO thin films.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.11a
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• pp.452-455
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• 2002

Single crystal 3C-SiC(cubic silicon carbide) thin-films were deposited on Si(100) substrate up to a thickness of $4.3{\mu}m$ by APCVD method using HMDS(hexamethyildisilane) at $1350^{\circ}C$. The HMDS flow rate was 0.5 sccm and the carrier gas flow rate was 2.5 slm. The HMDS flow rate was important to get a mirror-like crystal surface. The growth rate of the 3C-SiC films was $4.3{\mu}m/hr$. The 3C-SiC epitaxical films grown on Si(100) were characterized by XRD, AFM, RHEED, XPS and raman scattering, respectively. The 3C-SiC distinct phonons of TO(transverse optical) near $796cm^{-1}$ and LO(longitudinal optical) near $974{\pm}1cm^{-1}$ were recorded by raman scattering measurement. The heteroepitaxially grown films were identified as the single crystal 3C-SiC phase by XRD spectra$(2{\theta}=41.5^{\circ})$.

• Bulletin of the Korean Chemical Society
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• v.33 no.7
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• pp.2255-2259
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• 2012

Aggregation of titania nanotubes (TNTs) fabricated by hydrothermal method were calcined in air and dry nitrogen; Changes in morphology and crystallinity of the nanotubes were studied by means of TEM, EDX, and XPS. EDX patterns and XPS spectra proved that there were a certain densities of oxygen vacancies in TNTs annealed in $N_2$. The photocatalysis experiments revealed TNTs/$N_2$ possesses significantly higher photocatalytic efficiency than TNTs annealed in dry air to degrade methylene blue. The correlation between oxygen vacancies and photocatalytic property may be attributed to: 1) oxygen vacancies might have affected results on water molecules adsorption and increase of the hydroxyl concentration; and 2) oxygen vacancies resulted in some changes in electronic structure of TNTs/$N_2$ aggregation and Fermi level extends into the conducting band.

• Journal of the Korean Vacuum Society
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• v.5 no.1
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• pp.54-61
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• 1996

Indium-tin oxide (ITO) films were deposited on the glass substrate by the reactive -ionized cluster beam deposition(ICBD) method. In the oxygen atmosphere, indium cluster formed through the nozzle is ionized by the electron bombardment and is accelerated to be deposited on the substrate. And tin is simultaneoulsy evaporated from the boron-nitride crucible. The chracteristics of films were examined by the X-ray photoelectron spectroscopy(XPS), glancing angle X-ray diffractrion(GXRD) and the electrical properties. were measured by 4-point-probe and Hall effect measurement system . From the XPS spectrum , it was found that indium and tin atoms combined with the oxygen to form oxide$(In_2O_3, SnO_2)$. In the case of films with high tin-concentration, the GXRD spectra show that the main $In_2O_3$ peak of (222) plane, but also sub peaks((440) peak etc.) and $SnO_2$ peaks were detected. From that results, itis concluded that the heavily dopped tin component (more than 14 at. %) disturbs to form $In_2O_3$(222) phase. Four-point-probe and Hall effect measurement show that, in the most desirable case, the transmittance of the films is more then 90% in visible range and its resistivity is $$\rho$=3.55 \times10^{-4}\Omega$cm and its mobility is $\mu$=42.8 $\textrm{cm}^2$/Vsec.

• Journal of the Korean institute of surface engineering
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• v.29 no.5
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• pp.563-569
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• 1996

Degradation of $Zn_3N_2$ films is studied by using several analytical techniques. Polycrystalline $Zn_3N_2$ films prepared by reactie rf magnetron sputtering are kept in the air. Electrical and optical properties are measured by using van der Pauw technique and double-beam spectrometry. Structure and chemical bonding states are studied by X-ray diffraction(XRD), Fourier transfer infrared ray spectroscopy(FT-IR) and X-ray photoelectron specroscopy (XPS). Significant differences are observed in optical properties between the degraded film and the ZnO film. XRD analysis reveals that the degraded film contains very small ZnO grains because very weak and broad ZnO peaks are observed. XPS and FT-IR measurements reveal the formation of $Zn(OH)_2$ in the degraded film. The existence of N-H bonds in degraded films is exhibited from the N 1s spectra. $Zn_3N_2$ change into the mixture of ZnO, $Zn(OH)_2$ and an ammonium salt.