• Korean Journal of Materials Research
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• v.27 no.6
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• pp.295-300
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• 2017

Aluminum-oxide($Al_2O_3$) thin films were deposited by electron cyclotron resonance plasma-enhanced atomic layer deposition at room temperature using trimethylaluminum(TMA) as the Al source and $O_2$ plasma as the oxidant. In order to compare our results with those obtained using the conventional thermal ALD method, $Al_2O_3$ films were also deposited with TMA and $H_2O$ as reactants at $280^{\circ}C$. The chemical composition and microstructure of the as-deposited $Al_2O_3$ films were characterized by X-ray diffraction(XRD), X-ray photo-electric spectroscopy(XPS), atomic force microscopy(AFM) and transmission electron microscopy(TEM). Optical properties of the $Al_2O_3$ films were characterized using UV-vis and ellipsometry measurements. Electrical properties were characterized by capacitance-frequency and current-voltage measurements. Using the ECR method, a growth rate of 0.18 nm/cycle was achieved, which is much higher than the growth rate of 0.14 nm/cycle obtained using thermal ALD. Excellent dielectric and insulating properties were demonstrated for both $Al_2O_3$ films.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1999.06a
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• pp.67-72
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• 1999

Scanning probe Microscope(SPM) such as Scanning Tunneling Microscope(STM) and Atomic Force Microscope(AFM) was shown to be the powerful tool for nano-scale characterization of material surfaces Using this technique, surface morphology of the cyclically deformed Cu or Cu-Al single crystal was observed. The surface became proportionately rough as the number of cycles increased, but after some number of cycles no further change was observed. Slip steps with the heights of 100 to 200 nm and the widths of 1000 to 2000 nm were prevailing at the stage. The slipped distance of one slip system at the surface was not uniform. and formation of the extrusions or intrusions was assumed to occur such place. By comparing the morphological change caused by crystallographic orientation, strain amplitude, number of cycles or stacking fault energy, some interesting results which help to clarify the basic mechanism of fatigue damage were obtained. Furthermore, applicability of the scanning tunneling microscopy to fatigue damage is discussed.

• Journal of Electrical Engineering and Technology
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• v.7 no.4
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• pp.596-600
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• 2012

ZnO-$SnO_2$ films were deposited by rf magnetron sputtering using a ZnO-$SnO_2$ (2:1 molar ratio) target. The target was made from a mixture of ZnO and $SnO_2$ powders calcined at $800^{\circ}C$. The working pressure was 1 mTorr, and the rf power was 120 W. The ratio of oxygen to argon ($O_2$:Ar) was varied from 0% to 10%, and the substrate temperature was varied from $27^{\circ}C$ to $300^{\circ}C$. The crystallographic properties and the surface morphologies of the films were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), and atomic force spectroscopy (AFM). The ZnO-$SnO_2$ films deposited in $O_2$:Ar = 10% exhibited resistivity higher than $10^6{\Omega}cm$ and transmittance of more than 80% in the visible range.

• Membrane Journal
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• v.23 no.6
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• pp.439-449
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• 2013

This study investigated the aromatic polyamide reverse osmosis membrane was modified with diphenylamine (DPA) for enhanced chlorine and fouling resistance and how to optimize. DPA has high reactivity and thermo chemical stability. The performance of a modified membranes was investigated and its surface analyzed using atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and contact angle measurement. The experiment was conducted while changing the conditions of temperature and DPA solution concentration.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.184-184
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• 2009

This paper introduces the characteristics of SnO2 inorganic film deposited by radio-frequency magnetron sputtering as an alternative alignment layer for liquid crystal display (LCD) applications. The pretilt angle of the SnO2 layer was shown to be a function of the ion beam(IB) incident angle, a planer alignment of nematic liquid crystal was achieved. The about $1.8^{\circ}$ of stable pretilt angle was achieved at the range from 1500 ~ 2500eV of incident energy. To characterize the film shows atomic force microscopy (AFM) on the IB irradiated SnO2 surfaceand the X-ray phtoelectron spectroscopy analysis showed that the liquid crystal(LC) alignment on the IB irradiated $SnO_2$ surface was due to the reformation of Sn-O bonds. Also, Figure 1 shows that The alignment capability of the IB irradiated SnO2 layers is maintained until annealing temperature of $200^{\circ}C$. Comparable electro-optical characteristics to rubbed polyimide were also achieved.

• Journal of the Korean Society for Nondestructive Testing
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• v.31 no.2
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• pp.174-180
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• 2011

Nondestructive surface imaging of elastic characteristic and mechanical property has been studied on nanoscale surface with ultrasonic AFM. Resonance frequency variation of cantilever is theoretically analyzed with respect to contact mechanics as well as experimentally measured. The contact resonance frequency is calculated theoretically using the spring-mass and Herzian model in accordance with the resonance frequency of UAFM cantilever measured experimentally. Consequently, the topography and amplitude images could be obtained successfully and the elastic characteristic at the nanoscale surface was evaluated qualitatively by amplitude signals.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.12
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• pp.1032-1038
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• 2000

Ni$_{81}$$Fe_{19}$(200 nm) thin films have been deposited by RF-magnetron sputtering on Si(001) substrates, Atomic force microscopy(AFM), X-ray diffraction(XRD) and magnetoresistance(MR) measurements of the thin films for investigating electromagnetic properties and microstructures were employed. During field annelaing for 1hr, there was no big difference n XRD patterns of Ni$_{81}$$Fe_{19}$ thin films. However, there was a significant change in XRD patterns of Ni$_{81}$$Fe_{19}$ thin films deposited at 40$0^{\circ}C$ during in-situ magnetic field deposition. The degree of surface roughness increased with increasing annealing and deposition temperature. With variation of surface roughness, there was no significant difference in MR Characteristics of Ni$_{18}$ $Fe_{19}$ thin films in 1hr-annealed case. High MR ratio was observed in the case of in-situ field deposited Ni$_{81}$$Fe_{19}$ films. 19/ films.

• Electrical & Electronic Materials
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• v.11 no.10
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• pp.60-65
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• 1998

Deposition conditions, surface morphology, and electrical properties of polyamic acid alkylamine salts (PAAS) Langmuir-Blodgett(LB) films have been investigated through a study of surface pressure-area $\pi$-A isotherms, AFM (atomic force microscopy), and current-voltage characteristics. To obtain the optimum conditions of film deposition, the $\pi$-A isotherms were examined by varying temperature, barrier moving speed, dipping speed, spreading amount of solution etc. The Z-type LB films were made at the surface pressure of 5 mN m-1 and 25 mN m-1 for the AFM study; the former surface pressure forms the gas phase and the latter one forms the solid phase. The LB film made in the gas phase show domains with a size of about 200 A diameter and 70 A height. However, the LB films made in the solid phase show a very smooth surface with 2 A surface roughness. In the current-voltage characteristics measured along the perpendicular direction of the films, ohmic conduction has been observed below 105 V cm-1 and the calculated electrical conductivity is about 10-13 S cm-1. Nonohmic conduction has been observed above = 10-11 V cm and the conduction mechanism can be explained by the Schottky effect.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.11
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• pp.953-957
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• 2002

Single crystal 3C-SiC (cubic silicon carbide) thin-films were deposited on Si(100) wafer up to the thickness of 4.3 ${\mu}{\textrm}{m}$ by APCVD (atmospheric pressure chemical vapor deposition) method using HMDS (hexamethyildisilane; ｛CH$_{3}$｝$_{6}$ Si$_{2}$) at 135$0^{\circ}C$. 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 film was 4.3 ${\mu}{\textrm}{m}$/hr. The 3C-SiC epitaxial film grown on Si(100) wafer was characterized by XRD (X-ray diffraction), AFM (atomic force microscopy), RHEED (reflection high energy electron diffraction), XPS (X-ray photoelecron spectroscopy), and Raman scattering, respectively. Two distinct phonon modes of TO (transverse optical) near 796 $cm^{-1}$ / and LO (longitudinal optical) near 974$\pm$1 $cm^{-1}$ / of 3C-SiC were observed by Raman scattering measurement. The heteroepitaxially grown film was identified as the single crystal 3C-SiC phase by XRD spectra (2$\theta$=41.5。).).

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.10
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• pp.883-888
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• 2002

SiC direct bonding technology is very attractive for both SiCOI(SiC-on-insulator) electric devices and SiC-MEMS(micro electro mechanical system) fields because of its application possibility in harsh environments. This paper presents pre-bonding techniques with variation of HF pre-treatment conditions for SiC wafer direct bonding using PECVD(plasma enhanced chemical vapor deposition) oxide. The PECYD oxide was characterized by XPS(X-ray photoelectron spectrometer) and AFM(atomic force microscopy). The characteristics of the bonded sample were measured under different bonding conditions of HF concentration and an applied pressure. The bonding strength was evaluated by the tensile strength method. The bonded interface was analyzed by using SEM(scanning electron microscope). Components existed in the interlayer were analyzed by using FT-IR(fourier transform infrared spectroscopy). The bonding strength was varied with HF pre-treatment conditions before the pre-bonding in the range of 5.3 kgf/cm$^2$to 15.5 kgf/cm$^2$.