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Papers by youngsoo park

Research paper thumbnail of Incubation Layer-Free Nanocrystalline-Si Thin Film Fabricated by ICP-CVD at 150°C for Flexible Electronics

MRS Proceedings, 2006

ABSTRACT

Research paper thumbnail of Self-Consistent Technique for Extracting Density of States in Amorphous GaInZnO Thin Film Transistors by Combining an Optical Response of C-V Curve and Gate Voltage-Dependent Intrinsic Channel Mobility

Research paper thumbnail of 스테레오스코픽 3D 동영상을 위한 동기화 방법

Journal of Broadcast Engineering, 2013

Research paper thumbnail of Design and implementation of Mobile Trusted Module for trusted mobile computing

2010 Digest of Technical Papers International Conference on Consumer Electronics (ICCE), 2010

Research paper thumbnail of Dimethylgallium Isopropoxide as a New Volatile Source for ALD and MOCVD of Ga

ECS Transactions, 2009

ABSTRACT Dimethylgallium isopropoxide, Me2GaOiPr, is a gallium analogue of the volatile aluminum ... more ABSTRACT Dimethylgallium isopropoxide, Me2GaOiPr, is a gallium analogue of the volatile aluminum source dimethylaluminum isopropoxide, Me2AlOiPr, which was recently commercialized as a precursor for Al2O3. It is a liquid at room temperature and has a reasonably high vapor pressure, high enough for atomic layer deposition and/or metal organic chemical vapor deposition. We employed this precursor in the atomic layer deposition (ALD) and metalorganic chemical vapor deposition (MOCVD) of Ga2O3 thin films. Our ALD process, in which water was used as the oxygen source, showed an apparent ALD temperature window between 300 and 325ºC with a growth rate of ~1.5 Aå/cycle. The MOCVD was performed in the temperature range 450-625ºC with oxygen as the reacting gas. The Ga2O3 films deposited in both processes were found to be stoichiometric and amorphous.

Research paper thumbnail of Gallium Removal from Weapons-Grade Plutonium and Cerium Oxide Surrogate by a Thermal Technique

MRS Proceedings, 1999

ABSTRACT This paper describes the process of gallium removal from Ga2O3 -doped CeO2−x a surrogate... more ABSTRACT This paper describes the process of gallium removal from Ga2O3 -doped CeO2−x a surrogate for weapons-grade PuO2−x. Gallium is removed from the surrogate feedstock material using thermal techniques. An Ar-6% H, gas was used in order to reduce the oxide to gaseous Ga2O. Experimental results were shown in the temperature range of 600°C to 1200°C as a function of time and sample geometry. The results to date have shown that CeO2−x is a very good surrogate for PuO2−x.

Research paper thumbnail of Bioactivity Responses of Different Uhmwpe Particles from In-Vivo and In-Vitro Tests

MRS Proceedings, 2000

ABSTRACT This paper describes the results of bioactivity responses to different ultra high molecu... more ABSTRACT This paper describes the results of bioactivity responses to different ultra high molecular weight polyethylene (UHMWPE) particles. Particles were produced by a wear tester using two different textures of steel counters, one with cross-hatched and the other with uni-hatched grooves. These two textured surfaces produced two distinct populations of wear particles. One is larger and more elongated (fibril shapes) than the other. The mean sizes and aspect ratios of the particles are in the ranges of 5 μm to 25 μm and about 1.5 to 3, respectively. These two distinct UHMWPE particles were examined through in-vitro and in-vivo tests. Macrophages RAW 264.7 and the murine air-pouch model of inflammation were employed to characterize the effect of the particle size and shape. Preliminary in-vivo tests results showed that more elongated and larger particles enhanced bio-reactions.

Research paper thumbnail of Thin Ferroelectric Film between Double Schottky Barriers

Research paper thumbnail of An efficient inverse multiplier/divider architecture for cryptography systems

Proceedings of the 2003 International Symposium on Circuits and Systems, 2003. ISCAS '03., 2003

Research paper thumbnail of A Study on the Behavior of Water Absorption of SiOf Thin Films Deposited by Electron Cyclotron Resonance Plasma Enhanced Chemical Vapor Deposition Method

Research paper thumbnail of Highly efficient InGaN/GaN blue LED on 8-inch Si (111) substrate

Jun-Youn Kima)*, Yongjo Tak a), Jae Won Leea), Hyun-Gi Honga), Suhee Chae a), Hyoji Choia), Bokki... more Jun-Youn Kima)*, Yongjo Tak a), Jae Won Leea), Hyun-Gi Honga), Suhee Chae a), Hyoji Choia), Bokki, Mina), Youngsoo Park a), Minho Kimb), Seongsuk Leeb), Namgoo Chab),Yoonhee Shin b), Jong-Ryeol Kimc), and Jong-In Shimd) a)Photo-Electronic Device Group, ...

Research paper thumbnail of <title>A global disparity adjustment scheme using binocular energy model and image partition</title>

Three-Dimensional TV, Video, and Display VI, 2007

This paper presents a practical way of adjusting global disparity with binocular energy model and... more This paper presents a practical way of adjusting global disparity with binocular energy model and image partition for given stereoscopic images. Previous method estimated a single global disparity and then used it directly to control the convergence angle between cameras. But, the previous method might cause local disparities to be excessive in some regions since a single global disparity has been considered. Hence in this paper, we consider how to mitigate the excessive disparities in some regions. To begin with, we partition the stereoscopic images into 4 sub-images, respectively, and then calculate multiple local disparities for a pair of partitioned images. Secondly, we define a new disparity by the average value of the local disparities. Lastly, the newly defined disparity is used to adjust the global disparity of the given stereoscopic images. Through experimental results, we show that the proposed method can prevent the local disparities from being excessive in some regions.

Research paper thumbnail of High performance oxide thin film transistors with double active layers

2008 IEEE International Electron Devices Meeting, 2008

Abstract We successfully integrated the high performance oxide thin film transistors with double ... more Abstract We successfully integrated the high performance oxide thin film transistors with double active layers. The active layer is composed of IZO (or ITO) and GIZO layers. The TFT with ITO/GIZO double active layer shows a high mobility of 104cm2/V.sec, the acceptable ...

Research paper thumbnail of Future photonics convergence on Si

The 9th International Conference on Group IV Photonics (GFP), 2012

Research paper thumbnail of Comparison of Retention Characteristics of Pb(Zr,Ti)O3 (PZT) Capacitors Fabricated with Noble Metal Electrodes and Their Oxide Electrodes

Integrated Ferroelectrics, 2004

We compared retention characteristics of Pb(Zr,Ti)O3 (PZT) capacitors with either noble metal ele... more We compared retention characteristics of Pb(Zr,Ti)O3 (PZT) capacitors with either noble metal electrodes or their oxide compounds. Very thin PZT films with thickness below 100 nm were deposited by metal-organic chemical vapor deposition (MOCVD) on Ir bottom electrodes, and Pt, Ir, IrO2 were covered as top electrodes thereon. The capacitors with IrO2 top electrodes had the better opposite-state retention performance

Research paper thumbnail of Improvement in the electrical properties in Pt/Pb(Zr0.52Ti0.48)O3/Pt ferroelectric capacitors using a wet cleaning method

Journal of Applied Physics, 1999

A wet cleaning solution was designed to specifically eliminate nonferroelectric phases, such as p... more A wet cleaning solution was designed to specifically eliminate nonferroelectric phases, such as pyrochlore, PbO, and the etching damaged layer. Scanning electron microscopy pictures clearly showed that treatment with the cleaning solution completely removed these nonferroelectric phases. After removing the nonferroelectric phases, ferroelectric properties such as remnant polarization, coercive voltage, and leakage current, were remarkably improved. In addition, the wet cleaned ferroelectric capacitors yielded superior endurance against hydrogen-induced damage compared to those of the noncleaned capacitors.

Research paper thumbnail of Deposition-temperature-dependent stress of capping oxide and its effect on Pt/Pb(Zr1-xTix)O3/Pt ferroelectric capacitor

Applied Physics Letters, 1999

Two different interlayer dielectric (ILD) materials, electron cyclotron resonance chemical vapor ... more Two different interlayer dielectric (ILD) materials, electron cyclotron resonance chemical vapor deposition oxide (ECR-OXIDE) and plasma enhanced chemical vapor deposition TEOS oxide (PE-TEOS), were prepared at 400 and 200 °C respectively, on silicon substrates and Pt/Pb(Zr1-xTix)O3 (PZT)/Pt capacitors. It was found that the ILD deposition temperature is a most important parameter for minimizing the degradation of remnant polarization (Pr) during the ILD deposition. Since the stress of PZT capacitor strongly depends on the ILD deposition temperature, the PZT capacitor with PE-TEOS showed more compressive stress than that with ECR-OXIDE, which results in severe Pr degradation of PZT capacitor with PE-TEOS. This large stress effect of PE-TEOS was confirmed by x-ray diffraction (XRD) patterns in which the d spacing of (111) PZT films with PE-TEOS was much larger than that of PZT films with ECR-OXIDE. Therefore, the low ILD deposition temperature is a key parameter for achieving an ILD integration without any Pr degradation.

Research paper thumbnail of Transient-current measurement of the trap charge density at interfaces of a thin-film metal/ferroelectric/metal structure

Applied Physics Letters, 2005

A method providing estimation of the trap density at metal/ferroelectric interfaces of a depleted... more A method providing estimation of the trap density at metal/ferroelectric interfaces of a depleted ferroelectric film located between back-to-back Schottky barriers has been developed. The method is based on the recharge of interface traps induced by external bias pulse applied to the metal/ferroelectric/metal structure. It is shown that the transient current under bias pulse can be controlled by the trap

Research paper thumbnail of Fabrication of 3D trench PZT capacitors for 256Mbit FRAM device application

International Electron Devices Meeting, 2005

We fabricated trench PbZrxTi1-xO3 (PZT) capacitors that can be used in 256Mbit 1T-1C FRAM devices... more We fabricated trench PbZrxTi1-xO3 (PZT) capacitors that can be used in 256Mbit 1T-1C FRAM devices. The capacitor has 0.25μm diameter and 0.4μm depth. Three layers, Ir(20nm)/PZT(60nm )/Ir(20nm), were deposited in SiO2 trench holes by ALD and MOCVD. Both columnar and ...

Research paper thumbnail of High-Current-Density CuO x /InZnO x Thin-Film Diodes for Cross-Point Memory Applications

Advanced Materials, 2008

AbstractRoom-temperature-deposited CuOxInZnOx thin-film heterojunction diodes show a high current... more AbstractRoom-temperature-deposited CuOxInZnOx thin-film heterojunction diodes show a high current density of 3.5 × 104 A cm−2 and a high on/off current ratio of 106 (see figure). The oxide diode is a promising switch element for three-dimensional stackable memory devices, where high-temperature-prepared silicon diodes are difficult to apply.

Research paper thumbnail of Incubation Layer-Free Nanocrystalline-Si Thin Film Fabricated by ICP-CVD at 150°C for Flexible Electronics

MRS Proceedings, 2006

ABSTRACT

Research paper thumbnail of Self-Consistent Technique for Extracting Density of States in Amorphous GaInZnO Thin Film Transistors by Combining an Optical Response of C-V Curve and Gate Voltage-Dependent Intrinsic Channel Mobility

Research paper thumbnail of 스테레오스코픽 3D 동영상을 위한 동기화 방법

Journal of Broadcast Engineering, 2013

Research paper thumbnail of Design and implementation of Mobile Trusted Module for trusted mobile computing

2010 Digest of Technical Papers International Conference on Consumer Electronics (ICCE), 2010

Research paper thumbnail of Dimethylgallium Isopropoxide as a New Volatile Source for ALD and MOCVD of Ga

ECS Transactions, 2009

ABSTRACT Dimethylgallium isopropoxide, Me2GaOiPr, is a gallium analogue of the volatile aluminum ... more ABSTRACT Dimethylgallium isopropoxide, Me2GaOiPr, is a gallium analogue of the volatile aluminum source dimethylaluminum isopropoxide, Me2AlOiPr, which was recently commercialized as a precursor for Al2O3. It is a liquid at room temperature and has a reasonably high vapor pressure, high enough for atomic layer deposition and/or metal organic chemical vapor deposition. We employed this precursor in the atomic layer deposition (ALD) and metalorganic chemical vapor deposition (MOCVD) of Ga2O3 thin films. Our ALD process, in which water was used as the oxygen source, showed an apparent ALD temperature window between 300 and 325ºC with a growth rate of ~1.5 Aå/cycle. The MOCVD was performed in the temperature range 450-625ºC with oxygen as the reacting gas. The Ga2O3 films deposited in both processes were found to be stoichiometric and amorphous.

Research paper thumbnail of Gallium Removal from Weapons-Grade Plutonium and Cerium Oxide Surrogate by a Thermal Technique

MRS Proceedings, 1999

ABSTRACT This paper describes the process of gallium removal from Ga2O3 -doped CeO2−x a surrogate... more ABSTRACT This paper describes the process of gallium removal from Ga2O3 -doped CeO2−x a surrogate for weapons-grade PuO2−x. Gallium is removed from the surrogate feedstock material using thermal techniques. An Ar-6% H, gas was used in order to reduce the oxide to gaseous Ga2O. Experimental results were shown in the temperature range of 600°C to 1200°C as a function of time and sample geometry. The results to date have shown that CeO2−x is a very good surrogate for PuO2−x.

Research paper thumbnail of Bioactivity Responses of Different Uhmwpe Particles from In-Vivo and In-Vitro Tests

MRS Proceedings, 2000

ABSTRACT This paper describes the results of bioactivity responses to different ultra high molecu... more ABSTRACT This paper describes the results of bioactivity responses to different ultra high molecular weight polyethylene (UHMWPE) particles. Particles were produced by a wear tester using two different textures of steel counters, one with cross-hatched and the other with uni-hatched grooves. These two textured surfaces produced two distinct populations of wear particles. One is larger and more elongated (fibril shapes) than the other. The mean sizes and aspect ratios of the particles are in the ranges of 5 μm to 25 μm and about 1.5 to 3, respectively. These two distinct UHMWPE particles were examined through in-vitro and in-vivo tests. Macrophages RAW 264.7 and the murine air-pouch model of inflammation were employed to characterize the effect of the particle size and shape. Preliminary in-vivo tests results showed that more elongated and larger particles enhanced bio-reactions.

Research paper thumbnail of Thin Ferroelectric Film between Double Schottky Barriers

Research paper thumbnail of An efficient inverse multiplier/divider architecture for cryptography systems

Proceedings of the 2003 International Symposium on Circuits and Systems, 2003. ISCAS '03., 2003

Research paper thumbnail of A Study on the Behavior of Water Absorption of SiOf Thin Films Deposited by Electron Cyclotron Resonance Plasma Enhanced Chemical Vapor Deposition Method

Research paper thumbnail of Highly efficient InGaN/GaN blue LED on 8-inch Si (111) substrate

Jun-Youn Kima)*, Yongjo Tak a), Jae Won Leea), Hyun-Gi Honga), Suhee Chae a), Hyoji Choia), Bokki... more Jun-Youn Kima)*, Yongjo Tak a), Jae Won Leea), Hyun-Gi Honga), Suhee Chae a), Hyoji Choia), Bokki, Mina), Youngsoo Park a), Minho Kimb), Seongsuk Leeb), Namgoo Chab),Yoonhee Shin b), Jong-Ryeol Kimc), and Jong-In Shimd) a)Photo-Electronic Device Group, ...

Research paper thumbnail of <title>A global disparity adjustment scheme using binocular energy model and image partition</title>

Three-Dimensional TV, Video, and Display VI, 2007

This paper presents a practical way of adjusting global disparity with binocular energy model and... more This paper presents a practical way of adjusting global disparity with binocular energy model and image partition for given stereoscopic images. Previous method estimated a single global disparity and then used it directly to control the convergence angle between cameras. But, the previous method might cause local disparities to be excessive in some regions since a single global disparity has been considered. Hence in this paper, we consider how to mitigate the excessive disparities in some regions. To begin with, we partition the stereoscopic images into 4 sub-images, respectively, and then calculate multiple local disparities for a pair of partitioned images. Secondly, we define a new disparity by the average value of the local disparities. Lastly, the newly defined disparity is used to adjust the global disparity of the given stereoscopic images. Through experimental results, we show that the proposed method can prevent the local disparities from being excessive in some regions.

Research paper thumbnail of High performance oxide thin film transistors with double active layers

2008 IEEE International Electron Devices Meeting, 2008

Abstract We successfully integrated the high performance oxide thin film transistors with double ... more Abstract We successfully integrated the high performance oxide thin film transistors with double active layers. The active layer is composed of IZO (or ITO) and GIZO layers. The TFT with ITO/GIZO double active layer shows a high mobility of 104cm2/V.sec, the acceptable ...

Research paper thumbnail of Future photonics convergence on Si

The 9th International Conference on Group IV Photonics (GFP), 2012

Research paper thumbnail of Comparison of Retention Characteristics of Pb(Zr,Ti)O3 (PZT) Capacitors Fabricated with Noble Metal Electrodes and Their Oxide Electrodes

Integrated Ferroelectrics, 2004

We compared retention characteristics of Pb(Zr,Ti)O3 (PZT) capacitors with either noble metal ele... more We compared retention characteristics of Pb(Zr,Ti)O3 (PZT) capacitors with either noble metal electrodes or their oxide compounds. Very thin PZT films with thickness below 100 nm were deposited by metal-organic chemical vapor deposition (MOCVD) on Ir bottom electrodes, and Pt, Ir, IrO2 were covered as top electrodes thereon. The capacitors with IrO2 top electrodes had the better opposite-state retention performance

Research paper thumbnail of Improvement in the electrical properties in Pt/Pb(Zr0.52Ti0.48)O3/Pt ferroelectric capacitors using a wet cleaning method

Journal of Applied Physics, 1999

A wet cleaning solution was designed to specifically eliminate nonferroelectric phases, such as p... more A wet cleaning solution was designed to specifically eliminate nonferroelectric phases, such as pyrochlore, PbO, and the etching damaged layer. Scanning electron microscopy pictures clearly showed that treatment with the cleaning solution completely removed these nonferroelectric phases. After removing the nonferroelectric phases, ferroelectric properties such as remnant polarization, coercive voltage, and leakage current, were remarkably improved. In addition, the wet cleaned ferroelectric capacitors yielded superior endurance against hydrogen-induced damage compared to those of the noncleaned capacitors.

Research paper thumbnail of Deposition-temperature-dependent stress of capping oxide and its effect on Pt/Pb(Zr1-xTix)O3/Pt ferroelectric capacitor

Applied Physics Letters, 1999

Two different interlayer dielectric (ILD) materials, electron cyclotron resonance chemical vapor ... more Two different interlayer dielectric (ILD) materials, electron cyclotron resonance chemical vapor deposition oxide (ECR-OXIDE) and plasma enhanced chemical vapor deposition TEOS oxide (PE-TEOS), were prepared at 400 and 200 °C respectively, on silicon substrates and Pt/Pb(Zr1-xTix)O3 (PZT)/Pt capacitors. It was found that the ILD deposition temperature is a most important parameter for minimizing the degradation of remnant polarization (Pr) during the ILD deposition. Since the stress of PZT capacitor strongly depends on the ILD deposition temperature, the PZT capacitor with PE-TEOS showed more compressive stress than that with ECR-OXIDE, which results in severe Pr degradation of PZT capacitor with PE-TEOS. This large stress effect of PE-TEOS was confirmed by x-ray diffraction (XRD) patterns in which the d spacing of (111) PZT films with PE-TEOS was much larger than that of PZT films with ECR-OXIDE. Therefore, the low ILD deposition temperature is a key parameter for achieving an ILD integration without any Pr degradation.

Research paper thumbnail of Transient-current measurement of the trap charge density at interfaces of a thin-film metal/ferroelectric/metal structure

Applied Physics Letters, 2005

A method providing estimation of the trap density at metal/ferroelectric interfaces of a depleted... more A method providing estimation of the trap density at metal/ferroelectric interfaces of a depleted ferroelectric film located between back-to-back Schottky barriers has been developed. The method is based on the recharge of interface traps induced by external bias pulse applied to the metal/ferroelectric/metal structure. It is shown that the transient current under bias pulse can be controlled by the trap

Research paper thumbnail of Fabrication of 3D trench PZT capacitors for 256Mbit FRAM device application

International Electron Devices Meeting, 2005

We fabricated trench PbZrxTi1-xO3 (PZT) capacitors that can be used in 256Mbit 1T-1C FRAM devices... more We fabricated trench PbZrxTi1-xO3 (PZT) capacitors that can be used in 256Mbit 1T-1C FRAM devices. The capacitor has 0.25μm diameter and 0.4μm depth. Three layers, Ir(20nm)/PZT(60nm )/Ir(20nm), were deposited in SiO2 trench holes by ALD and MOCVD. Both columnar and ...

Research paper thumbnail of High-Current-Density CuO x /InZnO x Thin-Film Diodes for Cross-Point Memory Applications

Advanced Materials, 2008

AbstractRoom-temperature-deposited CuOxInZnOx thin-film heterojunction diodes show a high current... more AbstractRoom-temperature-deposited CuOxInZnOx thin-film heterojunction diodes show a high current density of 3.5 × 104 A cm−2 and a high on/off current ratio of 106 (see figure). The oxide diode is a promising switch element for three-dimensional stackable memory devices, where high-temperature-prepared silicon diodes are difficult to apply.