• Bulletin of the Korean Chemical Society
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• v.25 no.4
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• pp.480-484
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• 2004

$LiGaO_2$ films have been grown on Si (100) substrates using a new single precursor $[Li(OCH_2CH_2OCH_3)_2-Ga(CH_3)_2]_2$ under high vacuum conditions $(5{\times}10^{-6}Torr)$. The $[Li(OCH_2CH_2OCH_3)_2Ga(CH_3)_2]_2$ was synthe-sized and characterized by using spectroscopic methods and single-crystal X-ray diffraction analysis. The chemical composition, crystalline structure, and morphology of the deposited films were investigated by X-ray photoelectron spectroscopy, X-ray diffraction, and scanning electron microscopy. The results show that polycrystalline $LiGaO_2$ films preferentially oriented in the [010] direction can be deposited on Si (100) at 500-550$^{\circ}C$ by metal organic chemical vapor deposition (MOCVD). The single precursor $[LiOCH_2CH_2OCH_3)_2-Ga(CH_3)_2]_2$ has been found suitable for chemical vapor deposition of $LiGaO_2$ thin films on Si substrates.

• Journal of Sensor Science and Technology
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• v.16 no.2
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• pp.85-90
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• 2007

This paper presents the growth conditions and characteristics of polycrystalline 3C-SiC (silicon carbide) thin films for M/NEMS applications related to harsh environments. The growth of the 3C-SiC thin film on the oxided Si wafers was carried out by APCVD using HMDS (hexamethyildisilane: $Si_{2}(CH_{3})_{6})$ precursor. Each samples were analyzed by XRD (X-ray diffraction), FT-IR (fourier transformation infrared spectroscopy), RHEED (reflection high energy electron diffraction), GDS (glow discharge spectrometer), XPS (X-ray photoelectron spectroscopy), SEM (scanning electron microscope) and TEM (tunneling electro microscope). Moreover, the electrical properties of the grown 3C-SiC thin film were evaluated by Hall effect. From these results, the grown 3C-SiC thin film is very good crystalline quality, surface like mirror and low defect. Therefore, the 3C-SiC thin film is suitable for extreme environment, Bio and RF M/NEMS applications in conjunction with Si fabrication technology.

• Journal of the Korean Vacuum Society
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• v.8 no.3B
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• pp.269-275
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• 1999

The phase transition on the surface which several adsorbates (K, Mg, etc.) are deposited was observed by Low Energy Electron Diffraction (LEED) and Reflection High Energy Electron Diffraction (RGEED). We took the photoelectron spectra from the valence and core level at several oxygen exposure. For oxygen adsorption, the surface state in valence spectra diminished concurrently with S1, S2 peaks in core level spectra and surface periodicity turned to 3$\times$2 by post-annealing. These results suggest that the phase transition from 3$\times$2 to 3$\times$ on the Si(113) at initial stage is induced by a rearrangement of atoms on the substrate, not by the formation of overlayer.

• Journal of Adhesion and Interface
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• v.7 no.3
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• pp.26-33
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• 2006

Nylon fabrics were corona treated with different current intensity (5, 10, 15, 20 A) and feeding speed (5, 10, 15 m/min). We confirmed the change of nylon fabrics surface using X-ray diffraction apparatus, scanning electron microscopy (SEM) and X-ray photoelectron spectrometer (ESCALAB). And the change of physical properties through measuring the tensile strength, tear strength, bonding and wet bonding strength. Thermosetting reactive polyurethane hot melt adhesive was used in the adhesion of nylon fabrics. Functional groups were introduced on nylon fabric surface by treating the fabrics in air atmosphere with corona discharge, and the result adhesion was improved. Bonding strength of the nylon fabric treated with corona was increased with increasing current intensity and decreasing feeding speed.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.29-29
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• 1999

The synthesis of layered structures on the nanometer scale has become essential for continued improvements in the operation of various electronic and magnetic devices. Abrupt metal-metal interfaces are desired for applications ranging from metallization in semiconductor devices to fabrication of magnetoresistive tunnel junctions for read heads on magnetic disk drives. In particular, characterizing the interface structure between various transition metals (TM) and aluminum is desirable. We have used the techniques of MeV ion backscattering and channeling (HEIS), x-ray photoemission (ZPS), x-ray photoelectron diffraction(XPD), low-energy ion scattering (LEIS), and low-energy electron diffraction(LEED), together with computer simulations using embedded atom potentials, to study solid-solid interface structure for thin films of Ni, Fe, Co, Pd, Ti, and Ag on Al(001), Al(110) and Al(111) surfaces. Considerations of lattice matching, surface energies, or compound formation energies alone do not adequately predict our result, We find that those metals with metallic radii smaller than Al(e.g. Ni, Fe, Co, Pd) tend to form alloys at the TM-Al interface, while those atoms with larger atomic radii(e.g. Ti, Ag) form epitaxial overlayers. Thus we are led to consider models in which the strain energy associated with alloy formation becomes a kinetic barrier to alloying. Furthermore, we observe the formation of metastable fcc Ti up to a critical thickness of 5 monolayers on Al(001) and Al(110). For Ag films we observe arbitrarily thick epitaxial growth exceeding 30 monolayers with some Al alloying at the interface, possible driven by interface strain relief. Typical examples of these interface structures will be discussed.

• Bulletin of the Korean Chemical Society
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• v.28 no.4
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• pp.533-537
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• 2007

This paper describes the heteroepitaxial growth of single-crystalline 3C-SiC (cubic silicon carbide) thin films on Si (100) wafers by atmospheric pressure chemical vapor deposition (APCVD) at 1350 oC for micro/nanoelectromechanical system (M/NEMS) applications, in which hexamethyldisilane (HMDS, Si2(CH3)6) was used as a safe organosilane single-source precursor. The HMDS flow rate was 0.5 sccm and the H2 carrier gas flow rate was 2.5 slm. The HMDS flow rate was important in obtaing a mirror-like crystalline surface. The growth rate of the 3C-SiC film in this work was 4.3 μm/h. A 3C-SiC epitaxial film grown on the Si (100) substrate was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), reflection high energy electron diffraction (RHEED), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and Raman scattering, respectively. These results show that the main chemical components of the grown film were single-crystalline 3C-SiC layers. The 3C-SiC film had a very good crystal quality without twins, defects or dislocations, and a very low residual stress.

• Journal of the Korean Vacuum Society
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• v.7 no.s1
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• pp.140-148
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• 1998

We prepared $C_3N_4$ films by rf plasma enhanced chemical vapor deposition(PCVD) and alternating $C_3N_4$/TiN composite films by dc magnetron sputtering. X-ray diffraction (XRD) and transmission electron diffraction (TED) revealed that the structure of the films is amorphous or polycrystalline, depending on deposition conditions and heat treatment. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectroscopy confirmed the presence of $sp_3\; and sp _2$ hybridized C atoms bonded with N atoms in the tetrahedral and hexagonal configurations, respectively. Graphite-free $C_3N_4$ films were obtained by PCVD under optimal conditions. To prepare well crystallized $C_3N_4$ films by magnetron sputtering, we introduced negatively biased gratings in the sputtering system. CN films deposited at grating voltages (Vg) lower than 400V are amorphous. Crystallites of cubic and $\beta$-$C_3N_4$ were formed at increased voltages.

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.122-122
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• 2000

Magnesium oxide is thermodynamically very stable, has a low dielectric constant and a low refractive index, and has been widely used as substrate for growing various thin film materials, particulary oxides of the perovskite structure. There has been a considerable interest in integrating the physical properties of these oxides with semiconductor materials such as GaAs and Si. In this regard, it is considered very important to be able to grow MgO buffer layers epitaxially on the semiconductors. Various oxide films can then be grown on such buffer layers eliminating the need for using MgO single crystal substrates. Vapor phase epitaxy of magnesium oxide has been accomplished on Si(001) substrates in a high vacuum chamber using the single precursor methylmagnesium tert-butoxide in the temperature range 750-80$0^{\circ}C$. For the epitaxy of the MgO films, SiC buffer layers had to be grown on Si(001). The films were characterized by reflection high energy electron diffraction (RHEED) in situ in the growth chamber, and x-ray diffraction (XRD), x-ray pole figure analysis, scanning electron microscopy (SEM), and x-ray photoelectron spectroscopy (XPS) after the growth.

• Korean Journal of Materials Research
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• v.21 no.12
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• pp.703-707
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• 2011

The electrochromic properties of tungsten oxide films grown by RF sputtering were investigated. Among the sputter parameters, first the $Ar:O_2$ ratios were controlled with division into only an $O_2$ environment, 1:1 and 4:1. The structure of each film prepared by these conditions was studied by X-ray diffraction, X-ray photoelectron spectroscopy and Rutherford backscattering spectroscopy. The sputter-deposited tungsten oxide films had an amorphous structure regardless of the $Ar:O_2$ ratios. The chemical compositions, however, were different from each other. The stoichiometric structure and low-density film was obtained at higher $O_2$ contents. Electrochemical tests were performed by cyclic voltammetry and chronoamperometry at 0.05 M $H_2SO_4$ solutions. The current density and charge ratio was estimated during the continuous potential and pulse potential cycling at -0.5 V and 1.8 V, respectively. The film grown in a higher oxygen environment had a higher current density and a reversible charge reaction during intercalation and deintercalation. The in-situ transmittance tests were performed by He-Ne laser (633 nm). At higher oxygen contents, a big transmittance difference was observed but the response speed was too slow. This was likely caused by higher film resistivity. Furthermore, the effect of sputtering pressure was also investigated. The structure and surface morphology of each film was observed by X-ray diffraction and scanning electron microscopy. A rough surface was observed at higher sputtering pressure, and this affected the higher transmittance difference and coloration efficiency.

• Journal of the Korean Ceramic Society
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• v.54 no.6
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• pp.511-517
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• 2017

With different working pressures and substrate biases, Cr-Al-N coatings were deposited by hybrid physical vapor deposition (PVD) method, consisting of unbalanced magnetron (UBM) sputtering and arc ion plating (AIP) processes. Cr and Al targets were used for the arc ion plating and the sputtering process, respectively. Phase analysis, and composition, binding energy, and microstructural analyses were performed using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and field emission scanning electron microscopy (FESEM), respectively. Surface droplet size of Cr-Al-N coatings was found to decrease with increasing substrate bias. A decrease of the deposition rate of Cr-Al-N films was expected due to the increase of substrate bias. The coatings were grown with textured CrN phase and (111), (200), and (220) planes. X-ray diffraction data show that all Cr-Al-N coatings shifted to lower diffraction angles due to the addition of Al. The XPS results were used to determine the $Cr_2N$, CrN, and (Cr,Al)N binding energies. The compositions of the Cr-Al-N films were measured by XPS to be Cr 23.2~36.9 at%, Al 30.1~40.3 at%, and N 31.3~38.6 at%.