• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.04a
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• pp.265-268
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• 1997

Electroluminescent(EL) devices are constructed using multilayer organic thin film. A cell structure of glass substrate/Indium-Tinoxide/TPD as a hole transporting layer/Alq3+Rhodamine 101 perchrolate(Red3) as an emitting layer/Alq3 as an electrron transporting layer/Al as an electrode was employed. Optimal thickness of emitting layer in EL cell was performed from the viewpoint of the electronics properties of emitting layers. The general vapor-deposition method was used to control the thickness of omitting layer in EL devices and electro-optical characteristics were measured. It is clarified that controlling thickness of emitting layer in vapor-deposition film had an effect on the change of carrier injection and EL spectrum. The intensity of red omission with luminance of 81cd/$m^2$ was achived at 11V driving voltage. The surface morphology of emitting layer in EL devices was investigated.

• Korean Journal of Materials Research
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• v.4 no.7
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• pp.767-774
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• 1994

The TbFeCo thin films were prepared by the magnetron sputtering system to investigate the effect of the base pressure, film thickness and pre sputtering on the oxidation of the films by analyzing the change of matneto optical properties and by AES depth profile. The films prepared by the facing targets sputtering system represented almost constant magneto optical properties independent of the base pressure resulting from the short flight distance of the sputtered particles. Also, the thin TbFeCo films represented better perpendicular anisotropy as the films thickness increased with pre sputtering. However, it was still needed a deposition rate higher than a certain critical deposition rate to obtain a perfect perpendicular anisotropy even at a very high film thickness.

• Journal of Surface Science and Engineering
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• v.54 no.1
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• pp.25-29
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• 2021

The fabrication of nanopore membrane by deposition of Al2O3 film using electron-beam evaporation, which is fast, cost-effective, and negligible dependency on substance material, is investigated for potential applications in water purification and sensors. The decreased nanopore diameter owing to increased wall thickness is observed when Al2O3 film is deposited on anodic aluminum oxide membrane at higher deposition rate, although the evaporation process is generally known to induce a directional film deposition leading to the negligible change of pore diameter and wall thickness. This behavior can be attributed to the collision of evaporated Al2O3 particles by the decreased mean free path at higher deposition rate condition, resulting in the accumulation of Al2O3 materials on both the surface and the edge of the wall. The reduction of nanopore diameter by Al2O3 film deposition can be applied to the nanopore membrane fabrication with sub-100 nm pore diameter.

• Progress in Superconductivity and Cryogenics
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• v.6 no.3
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• pp.6-11
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• 2004

YBa$_2$Cu$_3$$O_{7-x}$ (YBCO) films were deposited on MgO(100) and SrTiO$_3$(100) single crystal substrates by cold-wall type MOCVD method using continuous source supplying system. Under the deposition temperature of 740∼76$0^{\circ}C$, c-axis oriented YBCO films were obtained. In case of the YBCO films deposited on MgO (100) single crystal substrate, the critical temperature (T$_{c}$) was under 81 K regardless of the deposition conditions, whereas T$_{c}$ of the YBCO films deposited on SrTiO$_3$(100) single crystal substrate was 83∼84 K. The critical current (I$_{c}$) of the YBCO film deposited on SrTiO$_3$(100) single crystal substrate for 30 min was 49 A/cm-width and the critical current density (J$_{c}$) was 0.82 MA/$\textrm{cm}^2$ to film thickness of 0.6 ${\mu}{\textrm}{m}$. I$_{c}$ increased to 84.4 A/cm-width as the deposition time increased to 50 min, but J$_{c}$ decreased to 0.53 MA/$\textrm{cm}^2$ to film thickness of 1.8 ${\mu}{\textrm}{m}$.rm}{m}$.

• Journal of Electrical Engineering and Technology
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• v.1 no.1
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• pp.110-113
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• 2006

A high rate deposition sputtering process of magnesium oxide thin film in oxide mode has been developed using a 20 kW unipolar pulsed power supply. The power supply was operated at a maximum constant voltage of 500 V and a constant current of 40 A. The pulse repetition rate and the duty were changed in the ranges of $10\sim50$ kHz and $10\sim60%$, respectively. The deposition rate increased with rising incident power to the target. Maximum incident power to the magnesium target was obtained by the control of frequency, duty and current. The deposition rate of a moving state was 9 nm m/min at the average power of 1.5 kW. This result shows higher deposition rate than any other previous work involving reactive sputtering in oxide mode. The thickness uniformities over the entire substrate area of $982mm{\times}563mm$ were observed at the processing pressure of $2.8\sim9.5$ mTorr. The thickness distribution was improved at lower pressure. This technique is proposed for application to a high through-put sputtering system for plasma display panels.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.20 no.5
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• pp.1624-1638
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• 1996

A study of thermophoretic particle deposition has been carried out for a particle laden stagnation flow considering the effect of radiative heat transfer. Energy, concentration and radiative transfer equations are all coupled and have been solved iteratively assuming that absorption and scattering coefficients were proportional to the local concentration of particles. Radiative heat transfer was shown to strongly affect the profiles of temperature and particle concentration. e. g., radiation increases the thickness of thermal boundary layer and wall temperature gradients significantly. As the wall temperature gradients increase, the particle concentration at the wall decreases due to thermophoretic particle transport. The deposition rate that is thermophoretic velocity times particle concentration at the wall decreases as the effects of radiation increases. The effects of optical thickness, conduction to radiation parameter and wall emissivity have been determined. The effects of anisotropic scattering are shown as insignificant.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.52 no.8
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• pp.319-324
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• 2003

AIN thin films are deposited on Si (100) and $SiO_2$/Si substrates by using an RF magnetron sputtering method and by changing the conditions of deposition variables, such as RF power, $N_2$/Ar flow ratio, and substrate temperature ($T_sub$). For all the deposited AIN films, XRD Peak patterns are monitored to examine the effect of deposition condition on the crystal orientation. Highly (002)-oriented AIN films are obtained at following nominal deposition conditions; RF Power : 350W, $N_2$/Ar ratio = 10/20, T$_{sub}$ : $250^{\circ}C$, and working pressure = 5mTorr, respectively. AIN-based SAW devices are fabricated using a lift-off method by varying the thickness of AIN layer. Insertion losses and side-lobe rejection levels of fabricated SAW devices are extracted from their frequency response characteristics, which are also compared in terms of AIN thickness and substrate. Relationships between the film properties of AIN films and the frequency responses of SAW devices are discussed. It is concluded from the experimental results that the (002)-preferred orientation as well as the surface roughness of AIN film may play a crucial role of determining the device performances of AIN-SAW devices.s.

• Korean Journal of Materials Research
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• v.29 no.11
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• pp.715-719
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• 2019

Molybdenum is a low-resistivity transition metal that can be applied to silicon devices using Si-metal electrode structures and thin film solar cell electrodes. We investigate the deposition of metal Mo thin film by plasma-enhanced atomic layer deposition (PE-ALD). $Mo(CO)_6$ and $H_2$ plasma are used as precursor. $H_2$ plasma is induced between ALD cycles for reduction of $Mo(CO)_6$ and Mo film is deposited on Si substrate at $300^{\circ}C$. Through variation of PE-ALD conditions such as precursor pulse time, plasma pulse time and plasma power, we find that these conditions result in low resistivity. The resistivity is affected by Mo pulse time. We can find the reason through analyzing XPS data according to Mo pulse time. The thickness uniformity is affected by plasma power. The lowest resistivity is $176{\mu}{\Omega}{\cdot}cm$ at $Mo(CO)_6$ pulse time 3s. The thickness uniformity of metal Mo thin film deposited by PE-ALD shows a value of less than 3% below the plasma power of 200 W.

• Journal of Powder Materials
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• v.29 no.1
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• pp.8-13
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• 2022

In this study, we have prepared a Ti-6Al-4V/V/17-4 PH composite structure via a direct energy deposition process, and analyzed the interfaces using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The joint interfaces comprise two zones, one being a mixed zone in which V and 17-4PH are partially mixed and another being a fusion zone in the 17-4PH region which consists of Fe+FeV. It is observed that the power of the laser used in the deposition process affects the thickness of the mixed zone. When a 210 W laser is used, the thickness of the mixed zone is wider than that obtained using a 150 W laser, and the interface resembles a serrated shape. Moreover, irrespective of the laser power used, the expected σ phase is found to be absent in the V/17-4 PH stainless steel joint; however, many VN precipitates are observed.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.419-419
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• 2012

We fabricated the Polyamide 4,6 (PA46) thin film using Adipoyl chloride and 1,4-butadiamine. PA46 film was grown at $70^{\circ}C$ by Molecular Layer Deposition (MLD) method. MLD is sequential and self-terminating fabrication method for organic thin film. The growth rate of PA46 is $3.5{\acute{\AA}}$ cycle. The thickness of PA46 film was measured by Ellipsometer. Surface morphology of this film was investigated by Atomic Force Microscopy (AFM) and roughness is directly proportional to number of growing cycles.