• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.04b
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• pp.137-140
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• 2004

We treated $O_2$ plasma on ITO thin film using RIE (Reactive Ion Etching) system, and analyzed the ingredient of ITO thin film according to change of processing conditions. The ingredient analysis of ITO thin film was used by EDS (Energy Dispersive Spectroscopy) and XPS (X-ray Photoelectron Spectroscopy) to compare and analyze the ingredient of bulk and surface. We measured electrical resistivity using Four-Point-Probe and calculated sheet resistance, and ITO surface roughness was measured by using AFM (Atomic Force Microscope). Finally, we fabricated OLEDs (Organic Light-Emitting Diodes) device using substrate that was treated optimum ITO surface. The result of the study for electrical and optical properties using I V L System (Flat Panel Display Analysis System), we confirmed that electrical properties (I-V) and optical properties (L-V) were improved.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.04b
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• pp.57-57
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• 2009

In this work, we carried out the variation of surface characteristics of organic polymer films by O2 plasma. The plasma diagnostics were performed by DLP(Double Langmuir Probe) and OES(Optical Emission Spectroscopy) measurements. Moreover, variation of surface characteristics were measured by AFM(Atomic Force Microscope), XPS(X-ray Photoelectron Spectroscopy), and contact angle goniometer. It was found that the etch rate of organic films was controlled by O radicals flux and dc bias voltage. And O radical density and dc bias voltage increased with increasing bias power. So, it was changed surface energy as a function of surface roughness and O/C ratio in organic films.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.1
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• pp.39-44
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• 2014

Silicon nitride thin film deposited with Plasma Enhanced Chemical Vapor Deposition was treated by a nitrogen plasma generated by Inductively Coupled Plasma at room temperature. The treatment was investigated by Fourier Transform Infrared Spectroscopy and Atomic Force Microscopy on the surface at various RF source powers at two RF bias powers. The amount of hydrogen was reduced and the surface roughness of the films was decreased remarkably after the plasma treatment. In order to understand the causes, we analyzed the plasma diagnostics by Optical Emission Spectroscopy and Double Langmuir Probe. Based on these analysis results, we show that the nitrogen plasma treatment was effective in the improving of the properties silicon nitride thin film for flexible display.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.378.2-378.2
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• 2014

We have investigated optical characteristics of $p-Ge_{0.99}Sn_{0.01}$ and Ge films grown on Si substrates using photoreflectance (PR) spectroscopy. The $Ge_{0.99}Sn_{0.01}$ and Ge films were grown by using an ultra-high vacuum chemical vapor deposition and molecular beam epitaxy methods, respectively. PR spectra were measured at 25 K and an extended InGaAs detector was used. By comparing $Ge_{0.99}Sn_{0.01}/Si$ and Ge/Si spectra, we observed the signals related to direct transition and split-off band of $Ge_{0.99}Sn_{0.01}$. The transition energies of $Ge_{0.99}Sn_{0.01}$ and Ge films were approximately 0.74 and 0.84 eV, respectively. Considering the shift of split-off band transition of $Ge_{0.99}Sn_{0.01}$, we suppose that the transition at 0.74 eV is attributed to direct transition between ${\Gamma}$ band and valence band. The temperature- and excitation power-dependent PR spectra were also measured.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.384.2-384.2
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• 2014

We investigated the electrical and structural properties of chemical vapor deposition (CVD)-grown graphene and post treated by O2 plasma. For the patterning of graphene, the plasma technology is generally used and essential for etching of graphene. But, the cautious O2 plasma treatments are required to avoid the damage in graphene edge which can be the harmful effects on the device performance. To analyze the effects of plasma treatment on structural properties of graphene, the change of surface morphology of graphene are measured by scanning electron microscope and atomic force microscope before and after plasma treatment. In addition, the binding energy of carbon and oxygen are measured through to X-ray photoelectron spectroscopy. After plasma treatment, the severe changes of surface morphology and binding energy of carbon and oxygen were observed which effects on the change of sheet resistance. Finally, to analyze of graphene characteristics, we measured the Raman spectroscopy. The measured results showed that the plasma treatment makes the upward of D-peak and downward of G'-peak by elevated power of plasma.

• Journal of the Korean Society for Heat Treatment
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• v.14 no.5
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• pp.292-296
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• 2001

In this work, an ultra-high vacuum activated reactive evaporation equipment was built. With reaction of Al and oxygen plasma, $Al_2O_3$ was deposited on the surface of etched Al foil. The chamber was evacuated down to $2{\times}10^{-7}$ torr initially. The Ar and $O_2$ gas introduced into the chamber to maintain $5{\times}10^{-5}$ torr during deposition. Ar gas prevents recombining of the ionized oxygen. Evaporation was maintained by electron beam evaporator continuously. Heating filament and electrode were used in order to generate plasma. The substrate bias of -300V was introduced to accelerate deposition of evaporated Al atoms. The composition and morphology of deposited $Al_2O_3$ films were analyzed by x-ray photoelectron spectroscopy(XPS) and atomic force microscopy (AFM), respectively. The Al oxide was formed on the surface of etched Al foil. According to AFM results, the surface morphology of $Al_2O_3$ film indicates uniform feature. Dielectric characteristic was measured as a function of frequency. Measured withstanding voltage and capacitance were 52V and $24{\mu}F/cm^2$, respectively. The obtained $Al_2O_3$ film shows clean condition without contaminants, which could be adapted to capacitor production.

• KSTLE International Journal
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• v.1 no.1
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• pp.12-20
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• 2000

Nano-wear and friction of carbon overcoated laser-textured and mechanically-textured computer hard disk were characterised after contact start/stop (CSS) wear test. Various analytical and mechanical testing techniques were employed to study the changes in topography, roughness, chemical elements, mechanical properties and friction characteristics of the coating arising from the contact start/stop wear test These techniques include: the atomic force microscopy (AFM), the continuous nano-indentation test, the nano-scratch test, the time-of-flight secondary ion mass spectroscopy (TOF-SIMS) and the auger electron spectroscopy (AES). It was shown that the surface roughness of the laser-textured (LT) bump and mechanically textured (MT) Bone was reduced approximately am and 7nm, respectively, after the CSS wear test. The elastic modulus and hardness values increased after the CSS test, indicating straining hardening of the top coating layer, A critical load was also identified fer adhesion failure between the magnetic layer and the Ni-P layer, The TOF-SIMS analysis also revealed some reduction in the intensity of C and $C_2$$F_59$, confirming the wear of lubricant elements on the coating surface.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.561-561
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• 2012

Graphene, two dimensional single layer of carbon atoms, has tremendous attention due to its superior property such as fast electron mobility, high thermal conductivity and optical transparency, and also found many applications such as field-effect transistors (FET), energy storage and conversion, optoelectronic device, electromechanical resonators and chemical sensors. Several techniques have been developed to form the graphene. Especially chemical vapor deposition (CVD) is a promising process for the large area graphene. For the electrically isolated devices, the graphene should be transfer to insulated substrate from Cu or Ni. However, transferred graphene has serious drawback due to remaining polymeric residue during transfer process which induces the poor device characteristics by impurity scattering and it interrupts the surface functionalization for the sensor application. In this study, we demonstrate the characteristics of solution-gated FET depending on the removal of polymeric residues. The solution-gated FET is operated by the modulation of the channel conductance by applying a gate potential from a reference electrode via the electrolyte, and it can be used as a chemical sensor. The removal process was achieved by several solvents during the transfer of CVD graphene from a copper foil to a substrate and additional annealing process with H2/Ar environments was carried out. We compare the properties of graphene by Raman spectroscopy, atomic force microscopy(AFM), and X-ray Photoelectron Spectroscopy (XPS) measurements. Effects of residual polymeric materials on the device performance of graphene FET will be discussed in detail.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.52 no.8
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• pp.325-329
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• 2003

Effects of thermal treatment on the structural properties of diamond-like carbon (DU) films were examined. The DLC films were deposited by using a modified filtered cathodic vacuum arc (FCVA) deposition system and by varying the negative substrate bias voltage, deposition time, and nitrogen flow rate. Thermal treatment on DLC films was performed using a rapid thermal annealing (RTA) process at $600^{\circ}C$ for 2min. Raman spectroscopy, x-ray photoemission spectroscopy (XPS), atomic force microscope (AFM), and surface profiler were used to characterize the I$_{D}$I$_{G}$ intensity ratio, sp$^3$ hybrid carbon fraction, internal stress, and surface roughness. It was found for all the deposited DLC films that the RTA-treatment results in the release of internal compressive stress, while at the same time it leds to the decrease of sp$^3$ fraction and the increase of I$_{D}$I$_{G}$ intensity ratio. It was also suggested that the thermal treatment effect on the structural property of DLC films strongly depends on the diamond-like nature (i.e., sp$^3$ fraction) of as-deposited film.ed film.

• Proceedings of the KIEE Conference
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• 1994.11a
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• pp.219-221
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• 1994

Oil-soluble poly(p-phenylene(1-methoxyethylene)), as a precursor of poly(p-phenylenevinylene) (PPV), was synthesized add identified with NMR and FT-IR spectroscopy. The PPV films were prepared by PPV precursor films with a thermal treatment at $250^{\circ}C$ under vacuum, where the PPV precursor films wets formed on various substrates by using Langmuir-Blodgett(LB) method. The characterization of these films was carried out by FT-IR spectroscopy, UV-VIS absorption spectroscopym, and photoluminescence (PL). Atomic Force Microscopy (AFM) has been used to investigate He surface morphology of PPV films.