21 results on '"Su Min Hwang"'
Search Results
2. Investigation of the Physical Properties of Plasma Enhanced Atomic Layer Deposited Silicon Nitride as Etch Stopper
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Byung Keun Hwang, Gary Goodman, Lanxia Cheng, Harrison Sejoon Kim, Aswin L. N. Kondusamy, Xin Meng, Antonio T. Lucero, Si Joon Kim, Jiyoung Kim, Alan S. Wan, Su Min Hwang, Young-Chul Byun, Telgenhoff Michael D, Joy S. Lee, and Robert M. Wallace
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010302 applied physics ,Materials science ,business.industry ,Hexachlorodisilane ,Analytical chemistry ,02 engineering and technology ,Plasma ,021001 nanoscience & nanotechnology ,01 natural sciences ,Cathode ,law.invention ,chemistry.chemical_compound ,Atomic layer deposition ,Semiconductor ,chemistry ,Silicon nitride ,Impurity ,law ,0103 physical sciences ,General Materials Science ,0210 nano-technology ,business ,Layer (electronics) - Abstract
Correlations between physical properties linking film quality with wet etch rate (WER), one of the leading figures of merit, in plasma-enhanced atomic layer deposition (PEALD) grown silicon nitride (SiNx) films remain largely unresearched. Achieving a low WER of a SiNx film is especially significant in its use as an etch stopper for technology beyond 7 nm node semiconductor processing. Herein, we explore the correlation between the hydrogen concentration, hydrogen bonding states, bulk film density, residual impurity concentration, and the WERs of PEALD SiNx using Fourier transform infrared spectrometry, X-ray reflectivity, and spectroscopic ellipsometry, etc. PEALD SiNx films for this study were deposited using hexachlorodisilane and hollow cathode plasma source under a range of process temperatures (270–360 °C) and plasma gas compositions (N2/NH3 or Ar/NH3) to understand the influence of hydrogen concentration, hydrogen bonding states, bulk film density, and residual impurity concentration on the WER. Va...
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- 2018
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3. Hollow Cathode Plasma-Enhanced Atomic Layer Deposition of Silicon Nitride Using Pentachlorodisilane
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Jiyoung Kim, Jeanette Young, Su Min Hwang, Young-Chul Byun, Telgenhoff Michael D, Xiaobing Zhou, Joy S. Lee, Byung Keun Hwang, Xin Meng, Harrison Sejoon Kim, and Antonio T. Lucero
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010302 applied physics ,Materials science ,Hexachlorodisilane ,Analytical chemistry ,02 engineering and technology ,Atmospheric temperature range ,021001 nanoscience & nanotechnology ,01 natural sciences ,Cathode ,law.invention ,chemistry.chemical_compound ,Atomic layer deposition ,chemistry ,X-ray photoelectron spectroscopy ,Silicon nitride ,law ,0103 physical sciences ,General Materials Science ,Fourier transform infrared spectroscopy ,0210 nano-technology ,Refractive index - Abstract
In this work, a novel chlorodisilane precursor, pentachlorodisilane (PCDS, HSi2Cl5), was investigated for the growth of silicon nitride (SiNx) via hollow cathode plasma-enhanced atomic layer deposition (PEALD). A well-defined self-limiting growth behavior was successfully demonstrated over the growth temperature range of 270–360 °C. At identical process conditions, PCDS not only demonstrated approximately >20% higher growth per cycle than that of a commercially available chlorodisilane precursor, hexachlorodisilane (Si2Cl6), but also delivered a better or at least comparable film quality determined by characterizing the refractive index, wet etch rate, and density of the films. The composition of the SiNx films grown at 360 °C using PCDS, as determined by X-ray photoelectron spectroscopy, showed low O content (∼2 at. %) and Cl content (
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- 2018
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4. Investigation on etching characteristics of Pd thin films using CH 3 COOH/Ar gas
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Jae Sang Choi, Doo Hyeon Cho, Chee Won Chung, Jae Yong Lee, and Su Min Hwang
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010302 applied physics ,Chemistry ,Metals and Alloys ,Analytical chemistry ,02 engineering and technology ,Surfaces and Interfaces ,021001 nanoscience & nanotechnology ,01 natural sciences ,Electron spectroscopy ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,X-ray photoelectron spectroscopy ,Etching (microfabrication) ,Sputtering ,0103 physical sciences ,Materials Chemistry ,Thin film ,Inductively coupled plasma ,Reactive-ion etching ,0210 nano-technology ,Spectroscopy - Abstract
Inductively coupled plasma reactive ion etching of Pd thin films with TiN hard masks was carried out in a CH 3 COOH/Ar gas mixture. The addition of CH 3 COOH to Ar gas decreased the etch rate but a good etch profile with a high degree of anisotropy was obtained at 50% CH 3 COOH/Ar. Variations in the etch parameters showed that high inductively coupled plasma power and dc-bias voltage improved the etch profile. X-ray photoelectron spectroscopy and optical emission spectroscopy results revealed that the Pd films in CH 3 COOH/Ar gas followed the sputtering etch mechanism assisted by the oxidation and sidewall protection provided by polymer films.
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- 2017
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5. Anisotropic etching of CoFeB magnetic thin films in C 2 H 5 OH/Ar plasma
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Adrian Adalberto Garay, Doo Hyeon Cho, Jae Sang Choi, Jae Yong Lee, Chee Won Chung, and Su Min Hwang
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010302 applied physics ,Materials science ,technology, industry, and agriculture ,Metals and Alloys ,Analytical chemistry ,02 engineering and technology ,Surfaces and Interfaces ,021001 nanoscience & nanotechnology ,01 natural sciences ,Electron spectroscopy ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,X-ray photoelectron spectroscopy ,Sputtering ,Etching (microfabrication) ,0103 physical sciences ,Materials Chemistry ,Thin film ,Reactive-ion etching ,Inductively coupled plasma ,0210 nano-technology ,Spectroscopy - Abstract
The etch characteristics of TiN hard mask-patterned CoFeB thin films were investigated by inductively coupled plasma reactive ion etching in an C2H5OH/Ar gas mixture. The effects of gas mixture concentration, rf coil power, dc bias voltage, and process pressure on the etch profile were investigated. Etch profiles with a high degree of anisotropy were achieved with C2H5OH concentrations from 25% to 50%. Further increases in the C2H5OH concentration decreased the degree of anisotropy of the etch profile. The etch profile improved as the rf coil power and dc bias increased and the process pressure decreased. Optical emission spectroscopy revealed the presence of [C], [H], [O], and [Ar] species, among others, in the plasma, while X-ray photoelectron spectroscopy analysis of the CoFeB thin film surface revealed the presence of Co, Fe, and B oxides, and the deposition of carbon-containing compounds. Results suggest that the etch mechanism is driven by physical sputtering, assisted by oxidation of the films and formation of a CxHy inhibition layer.
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- 2017
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6. Dry etching of palladium thin films in high density plasmas of CH3OH/Ar, C2H5OH/Ar, CH4/Ar, and CH4/O2/Ar gas mixtures
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Jae Sang Choi, Doo Hyun Cho, Su Min Hwang, Chee Won Chung, and Jae Yong Lee
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010302 applied physics ,Plasma etching ,Chemistry ,Metals and Alloys ,Analytical chemistry ,chemistry.chemical_element ,02 engineering and technology ,Surfaces and Interfaces ,021001 nanoscience & nanotechnology ,01 natural sciences ,Electron spectroscopy ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,X-ray photoelectron spectroscopy ,Etching (microfabrication) ,0103 physical sciences ,Materials Chemistry ,Dry etching ,Thin film ,0210 nano-technology ,Spectroscopy ,Tin - Abstract
High density plasma etching of Pd thin films masked with TiN films was performed using CH3OH/Ar, C2H5OH/Ar, CH4/Ar, and CH4/O2/Ar gas mixtures. The etch rates of the Pd films and TiN masks in all the gas mixtures decreased whereas the etch selectivities increased. The etch profiles of the Pd films etched under C2H5OH/Ar gas were better than those obtained with CH3OH/Ar gas. Addition of O2 gas to the CH4/Ar gas mixture considerably improved the etch profiles of the Pd films. CH4, Ar, and O2 were found to play a critical role in obtaining a vertical etch profile with smooth sidewalls. Energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy revealed the formation of polymeric layers and PdOx compounds on the sidewalls and the film surface. Good etch profiles with a high degree of anisotropy were achieved with the use of C2H5OH/Ar and CH4/O2/Ar gas mixtures.
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- 2017
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7. A Novel Combinatorial Approach to the Ferroelectric Properties in Hf x Zr 1− x O 2 Deposited by Atomic Layer Deposition
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Jaidah Mohan, Su Min Hwang, Jin-Hyun Kim, Dan N. Le, Jiyoung Kim, Jean François Veyan, Yong Chan Jung, Harrison Sejoon Kim, Si Joon Kim, Heber Hernandez-Arriaga, Rino Choi, Namhoon Kim, and Akshay Sahota
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Atomic layer deposition ,Materials science ,X-ray photoelectron spectroscopy ,Annealing (metallurgy) ,X-ray crystallography ,Analytical chemistry ,General Materials Science ,Dielectric ,Thin film ,Nitride ,Condensed Matter Physics ,Ferroelectricity - Published
- 2021
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8. Highly anisotropic etching of Ta thin films using high density plasmas of halogen based gases
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Adrian Adalberto Garay, Su Min Hwang, Ji Hyun Choi, Jai Yong Lee, and Chee Won Chung
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010302 applied physics ,fungi ,technology, industry, and agriculture ,Tantalum ,Analytical chemistry ,chemistry.chemical_element ,macromolecular substances ,02 engineering and technology ,Photoresist ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Surfaces, Coatings and Films ,stomatognathic system ,X-ray photoelectron spectroscopy ,chemistry ,Etch pit density ,Etching (microfabrication) ,0103 physical sciences ,Inductively coupled plasma ,Reactive-ion etching ,Thin film ,0210 nano-technology ,Instrumentation - Abstract
Inductively coupled plasma reactive ion etching of Ta thin films masked with photoresist was performed using C2F6/Ar, HBr/Ar and Cl2/Ar gases. The etch characteristics such as etch rate, etch selectivity and etch profile were investigated in different gas concentrations of each gas. The Cl2 chemistry showed high degree of anisotropy in etch profile as well as fastest etch rate and highest etch selectivity of Ta films among these gases. Optical emission spectroscopy revealed that the increase in chlorine radicals with increasing Cl2 concentration was responsible for the increase in the Ta etch rate. The etch rate of Ta films increased with increasing ICP rf power and dc-bias voltage, and decreasing process pressure. Good etch profiles were obtained at high rf power and dc-bias voltage, and low process pressure. X-ray photoelectron spectroscopy confirmed the existence of a chemical reaction of Ta with chlorine radicals by forming tantalum chlorides. These results suggested that Ta etching in Cl2/Ar follows the typical reactive ion etching mechanism. It was concluded that a high degree of anisotropy and high etch rate of Ta films were achieved using Cl2/Ar gas.
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- 2016
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9. Etch characteristics of Ru thin films using O2/Ar, CH4/Ar, and O2/CH4/Ar plasmas
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Ji Hyun Choi, Chee Won Chung, Su Min Hwang, and Adrian Adalberto Garay
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010302 applied physics ,Materials science ,Metals and Alloys ,Analytical chemistry ,chemistry.chemical_element ,02 engineering and technology ,Surfaces and Interfaces ,021001 nanoscience & nanotechnology ,01 natural sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Etch pit density ,X-ray photoelectron spectroscopy ,chemistry ,Etching (microfabrication) ,0103 physical sciences ,Materials Chemistry ,Inductively coupled plasma ,Reactive-ion etching ,Thin film ,0210 nano-technology ,Selectivity ,Tin - Abstract
The etch characteristics of Ru thin films patterned with TiN hard masks in O 2 /Ar, CH 4 /Ar and O 2 /CH 4 /Ar gas mixtures were studied using inductively coupled plasma reactive ion etching. When the Ru films were etched in O 2 /Ar gas, the etch rates of the Ru films and TiN hard masks decreased but the etch selectivity of the Ru films to the hard mask increased with increasing O 2 concentration. The etch profiles of Ru films at various O 2 concentrations were very similar, showing high etch slopes of > 80° with uneven sidewalls. In the case of CH 4 /Ar gas, as the CH 4 concentration increased, the etch rates of the Ru films and TiN hard masks and the etch selectivity of Ru films decreased. The etch profile of Ru films etched in 20% CH 4 /Ar showed the etch slope of approximately 60° and the etch slopes became worse with increasing CH 4 concentration. The addition of O 2 to the CH 4 /Ar gas resulted in a significant improvement in the etch profile, but both etch rates decreased slightly. Optical emission spectroscopy of O 2 /CH 4 /Ar plasma showed that O species could oxidize the Ru films to RuO x , and that inhibition layers containing C or CH x were formed, which protected the pattern sidewalls. X-ray photoelectron spectroscopy also identified the formation of RuO x and C or CH x compounds on the film surface. These findings indicated that Ru etching in O 2 /CH 4 /Ar gas chemistry could provide a good etch profile without redeposition or etch residues.
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- 2016
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10. Ozone based high-temperature atomic layer deposition of SiO2thin films
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Zhiyang Qin, Su Min Hwang, Jinho Ahn, Arul Vigneswar Ravichandran, Byung Keun Hwang, Yong Chan Jung, Si Joon Kim, Harrison Sejoon Kim, and Jiyoung Kim
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010302 applied physics ,Ozone ,Materials science ,Physics and Astronomy (miscellaneous) ,Thermal decomposition ,General Engineering ,Analytical chemistry ,General Physics and Astronomy ,Chemical vapor deposition ,01 natural sciences ,chemistry.chemical_compound ,Atomic layer deposition ,chemistry ,Plasma-enhanced chemical vapor deposition ,0103 physical sciences ,Thin film ,Saturation (chemistry) ,Deposition (chemistry) - Abstract
In this paper, atomic layer deposition of SiO2 thin films was investigated with Si2Cl6 and O3/O2 (400 g m−3). O3/O2 is not preferred for high-temperature (>400 °C) processes due to its lower decomposition temperature, especially in a furnace-type chamber. However, with Si oxidation test using a cold-wall chamber, we have demonstrated the reactivity of O3/O2 up to 800 °C in comparison with O2 and H2O. The ALD of SiO2 films was examined at deposition temperatures from 500 °C to 700 °C. The growth rate at 600 °C was saturated to 0.03 nm/cycle with Si2Cl6 exposure over 1.2 × 105 L. O3/O2 also showed ALD-like saturation behaviors for exposures over 2.4 × 106 L. The ALD films deposited at 600 °C exhibited relatively smooth surface roughness (
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- 2020
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11. Inductively coupled plasma reactive ion etching of CoFeB magnetic thin films in a CH3COOH/Ar gas mixture
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Su Min Hwang, Byoung-Chul Min, Chee Won Chung, Adrian Adalberto Garay, and Ji Hyun Choi
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Materials science ,fungi ,technology, industry, and agriculture ,Analytical chemistry ,chemistry.chemical_element ,macromolecular substances ,Condensed Matter Physics ,Surfaces, Coatings and Films ,stomatognathic system ,chemistry ,X-ray photoelectron spectroscopy ,Etching (microfabrication) ,Sputtering ,Inductively coupled plasma ,Thin film ,Reactive-ion etching ,Tin ,Instrumentation ,Layer (electronics) - Abstract
The etch characteristics of TiN hard mask patterned CoFeB thin films were investigated using an inductively coupled plasma reactive ion etching in a CH3COOH/Ar gas mixture. The etch characteristics of CoFeB magnetic thin film and TiN hard masks were investigated as a function of gas mixture concentration, coil rf power, dc-bias voltage and gas pressure. As CH3COOH concentration in the CH3COOH/Ar gas mixture increased, the etch rates of CoFeB films and degree of anisotropy in the etch profile decreased, while increased coil rf-power and dc bias voltage and reduced gas pressure increased the etch rate and improved the etch profile. Additionally, a thick hydrocarbon layer was formed on the film surface at a dc-bias voltage of 100 V. X-ray photoelectron spectroscopy and optical emission spectroscopy analyses of the etched films at various CH3COOH concentrations suggest that CoFeB thin films etched in a CH3COOH/Ar gas mixture follow a physical sputtering etch mechanism assisted by oxidation of the film and formation of a protective inhibition layer on the film surface. Etching of TiN patterned CoFeB films with a high degree of anisotropy was accomplished without redepositions or etch residues when conducted under high sputtering conditions.
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- 2015
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12. Inductive couple plasma reactive ion etching characteristics of TiO2 thin films
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Su Min Hwang, Chee Won Chung, and Adrian Adalberto Garay
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Scanning electron microscope ,Chemistry ,Metals and Alloys ,Analytical chemistry ,Surfaces and Interfaces ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,chemistry.chemical_compound ,X-ray photoelectron spectroscopy ,Etch pit density ,Etching (microfabrication) ,Materials Chemistry ,Hydrobromic acid ,Inductively coupled plasma ,Thin film ,Reactive-ion etching - Abstract
Changes in the inductively coupled plasma reactive ion etching characteristics of TiO 2 thin films in response to the addition of HBr, Cl 2 and C 2 F 6 to Ar gas were investigated. As the HBr, Cl 2 and C 2 F 6 concentration increased, the etch rate increased; however, the etch profile degree of anisotropy followed a different trend. As HBr concentration increased, the greatest anisotropic etch profile was obtained at 100% HBr, while the greatest anisotropic etch profile was obtained at concentrations of 25% when etching was conducted under C 2 F 6 and Cl 2 . Field emission scanning electron microscopy revealed that 25% C 2 F 6 generated the greatest vertical etch profile; hence, etch parameters were varied at this concentration. The effects of rf power, dc-bias voltage and gas pressure on the etch rate and etch profile were also investigated. The etch rate and degree of anisotropy in the etch profile increased with increasing rf power and dc-bias voltage and decreasing gas pressure. X-ray photoelectron spectroscopy analysis of the films etched under a C 2 F 6 /Ar gas mixture revealed the existence of etch byproducts containing F (i.e. TiF x ) over the film. C x F y compounds were not detected on the film surface, probably due to contamination with atmospheric carbon.
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- 2015
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13. High density plasma reactive ion etching of Ru thin films using non-corrosive gas mixture
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Su Min Hwang, Adrian Adalberto Garay, Chee Won Chung, and Wan In Lee
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Materials science ,Metals and Alloys ,Analytical chemistry ,chemistry.chemical_element ,Surfaces and Interfaces ,Electron spectroscopy ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,chemistry ,X-ray photoelectron spectroscopy ,Etching (microfabrication) ,Sputtering ,Materials Chemistry ,Thin film ,Reactive-ion etching ,Inductively coupled plasma ,Tin - Abstract
Inductively coupled plasma reactive ion etching (ICPRIE) of Ru thin films patterned with TiN hard masks was investigated using a CH3OH/Ar gas mixture. As the CH3OH concentration in CH3OH/Ar increased, the etch rates of Ru thin films and TiN hard masks decreased. However, the etch selectivity of Ru films on TiN hard masks increased and the etch slope of Ru film improved at 25% CH3OH/Ar. With increasing ICP radiofrequency power and direct current bias voltage and decreasing process pressure, the etch rates of Ru films increased, and the etch profiles were enhanced without redeposition on the sidewall. Optical emission spectroscopy and X-ray photoelectron spectroscopy were employed to analyze the plasma and surface chemistry. Based on these results, Ru thin films were oxidized to RuO2 and RuO3 compounds that were removed by sputtering of ions and the etching of Ru thin films followed a physical sputtering with the assistance of chemical reaction.
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- 2015
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14. Dry etching of Co 2 MnSi magnetic thin films using a CH 3 OH/Ar based inductively coupled plasma
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Chee Won Chung, Su Min Hwang, and Adrian Adalberto Garay
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Materials science ,fungi ,technology, industry, and agriculture ,Analytical chemistry ,chemistry.chemical_element ,macromolecular substances ,Plasma ,Condensed Matter Physics ,Surfaces, Coatings and Films ,Tunnel magnetoresistance ,stomatognathic system ,Etch pit density ,chemistry ,Etching (microfabrication) ,Dry etching ,Thin film ,Inductively coupled plasma ,Tin ,Instrumentation - Abstract
The inductively coupled plasma etching characteristics of Co2MnSi thin films patterned using a TiN hard mask were investigated by the addition of CH3OH to Ar gas. As the CH3OH concentration increased, the etch rates of Co2MnSi magnetic thin films and TiN hard mask decreased, but the etch profile improved. The effects of rf power, dc-bias voltage and gas pressure on the etch rate and etch profile were also investigated. The etch rate and etch profile degree of anisotropy increased with increasing rf power and dc-bias voltage and decreasing gas pressure. Optical emission spectroscopy analysis revealed that [H], [O], [CO], [OH], [CH3O] and [Ar] species in the CH3OH/Ar plasma played a key role in achieving a good etch profile.
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- 2015
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15. Etch characteristics of CoFeB thin films and magnetic tunnel junction stacks in a H2O/CH3OH plasma
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Chee Won Chung, Adrian Adalberto Garay, Su Min Hwang, and Il Hoon Lee
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Field electron emission ,Tunnel magnetoresistance ,Materials science ,Transmission electron microscopy ,General Chemical Engineering ,Analytical chemistry ,General Chemistry ,Plasma ,Inductively coupled plasma ,Reactive-ion etching ,Thin film ,Anisotropy - Abstract
Inductively coupled plasma reactive ion etching of CoFeB thin films and magnetic tunnel junction (MTJ) stacks with nanometer-sized patterns was performed using H2O/CH3OH gas mixture. As the CH3OH concentration in H2O/CH3OH increased, the etch rate of both the CoFeB films and MTJ stacks increased, but the etch selectivity decreased while the etch profiles of CoFeB films and MTJ stacks improved. Field emission transmission electron microscopy observation clearly revealed that the MTJ stacks etched at 75% CH3OH in H2O/CH3OH gas mixture showed a good etch profile without any redeposition and a high degree of anisotropy. These results indicate that there were some chemical reactions between CH X in H2O/CH3OH plasma and the films that comprise the MTJ stacks, such as CoFeB magnetic films. It was confirmed that H2O/CH3OH gas mixture could be a good etch gas in attaining a high etch rate and high degree of anisotropy in the etch profile.
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- 2014
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16. Etch characteristics of MgO thin films in Cl2/Ar, CH3OH/Ar and CH4/Ar plasmas
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Tea Young Lee, Su Min Hwang, Il Hoon Lee, and Chee Won Chung
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Plasma etching ,Hydrogen ,Chemistry ,Magnesium ,fungi ,technology, industry, and agriculture ,Analytical chemistry ,chemistry.chemical_element ,macromolecular substances ,Condensed Matter Physics ,Surfaces, Coatings and Films ,stomatognathic system ,X-ray photoelectron spectroscopy ,Etching (microfabrication) ,Sputtering ,Dry etching ,Thin film ,Instrumentation - Abstract
High density plasma etching of MgO thin films patterned with Ti (or TiN) hard masks was conducted using Cl2/Ar, CH3OH/Ar and CH4/Ar gases. As the concentration of each gas increased, the etch rate of MgO thin films decreased and there was no enhancement of etch profiles except for those obtained using CH4/Ar gas. The etch profiles of MgO thin films under CH4/Ar gas, which is non-corrosive and non-toxic, were improved without redeposition with increasing CH4 concentration. The enhancement of etch profiles in CH4/Ar gas was attributed to both the formation of a protective layer containing hydrogen and hydroxyl species on the sidewall of the patterns and the formation of magnesium compounds during the etching. Optical emission spectroscopy and X-ray photoelectron spectroscopy analyses showed that magnesium hydroxide was formed due to chemical reactions on the film surface under CH4/Ar gas. Additionally, the MgO thin films were found to be etched by a physical sputtering etching mechanism that was influenced by a chemical reaction.
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- 2014
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17. Effect of hydrogen derived from oxygen source on low-temperature ferroelectric TiN/Hf0.5Zr0.5O2/TiN capacitors
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Tamer San, Dushyant Narayan, Pil-Ryung Cha, Jiyoung Kim, Harrison Sejoon Kim, Su Min Hwang, Alan S. Wan, Chadwin D. Young, Gary Goodman, Jaidah Mohan, Si Joon Kim, Jae-Gil Lee, Luigi Colombo, Jaebeom Lee, and Scott R. Summerfelt
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010302 applied physics ,Materials science ,Physics and Astronomy (miscellaneous) ,Hydrogen ,Analytical chemistry ,chemistry.chemical_element ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Ferroelectricity ,Oxygen ,Atomic layer deposition ,chemistry ,0103 physical sciences ,Electrode ,Orthorhombic crystal system ,0210 nano-technology ,Tin ,Monoclinic crystal system - Abstract
The ferroelectric (FE) properties of 10-nm-thick Hf0.5Zr0.5O2 (HZO) films deposited by an atomic layer deposition technique were improved by adopting O3 as an oxygen source instead of H2O. All HZO films were annealed at 400 °C for 1 min in an N2 atmosphere after TiN top electrode deposition. Regardless of the oxygen source, the HZO films exhibited the formation of a noncentrosymmetric orthorhombic phase, which is responsible for FE behavior with the suppression of the monoclinic phase. However, compared to the O3-based HZO film, it was confirmed that the H2O-based HZO film was more incorporated with hydrogen derived from H2O, thereby degrading FE polarization and leakage behavior. The results indicate that the strategy of using O3 as the oxygen source is useful for the fabrication and integration of FE HZO films for next-generation memory applications.
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- 2019
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18. Inductively Coupled Plasma Reactive Ion Etching of Magnetic Tunnel Junction Stacks in a CH3COOH/Ar Gas
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Su Min Hwang, Adrian Adalberto Garay, Chee Won Chung, and Ji Hyun Choi
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Tunnel magnetoresistance ,Materials science ,Analytical chemistry ,Electrical and Electronic Engineering ,Inductively coupled plasma ,Reactive-ion etching ,Electronic, Optical and Magnetic Materials - Published
- 2015
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19. Photochemical Response Analysis on Drought Stress for Red Pepper (Capsiumannuum L.)
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Min-Ju Lee, Sohyun Park, Sung-Yung Yoo, Tae-Seok Ko, Yongho Lee, Kyong-mi Choi, A-Ram Kim, Su-Min Hwang, June-Young Park, and Tae Wan Kim
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Pheophytin ,Photosynthetic reaction centre ,chemistry.chemical_compound ,chemistry ,Photosystem II ,Chlorophyll ,Analytical chemistry ,Quantum yield ,Kautsky effect ,Photochemistry ,Electron transport chain ,Chlorophyll fluorescence - Abstract
The aim of this study is to determine the drought stress index through photochemical analysis in red pepper (Capsiumannuum L.). The photochemical interpretation was performed in the basis of the relation between Kautsky effect and Photosystem II (PSII) following the measurement of chlorophyll, pheophytin contents, and CO₂ assimilation in drought stressed 5-week-old red pepper plants. The CO₂ assimilation rate was severely lowered with almost 77% reduction of chlorophyll and pheophytin contents at four days after non-irrigation. It was clearly observed that the chlorophyll fluorescence intensity rose from a minimum level (the O level), in less than one second, to a maximum level (the P-level) via two intermediate steps labeled J and I (OJIP process). Drought factor index (DFI) was also calculated using measured OJIP parameters. The DFI was -0.22, meaning not only the initial inhibition of PSII but also sequential inhibition of PSI . In real, most of all photochemical parameters such as quantum yield of the electron transport flux from Quinone A (QA) to Quinone B (QB), quantum yield of the electron transport flux until the PSI electron acceptors, quantum yield of the electron transport flux until the PSI electron acceptors, average absorbed photon flux per PSII reaction center, and electron transport flux until PSI acceptors per cross section were profoundly reduced except number of QA reducing reaction centers (RCs) per PSII antenna chlorophyll (RC/ABS). It was illuminated that at least 6 parameters related with quantum yield/efficiency and specific energy fluxes (per active PSII RC) could be applied to be used as the drought stress index. Furthermore, in the combination of parameters, driving forces (DF) for photochemical activity could be deduced from the performance index (PI) for energy conservation from photons absorbed by PSII antenna until the reduction of PSI acceptors. In conclusion, photochemical responses and their related parameters can be used as physiological DFI.
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- 2013
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20. Influence of oxygen on characteristics of Zn(O,S) thin films deposited by RF magnetron sputtering
- Author
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Adrian Adalberto Garay, Ji Hyun Choi, Chee Won Chung, and Su Min Hwang
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Materials science ,Analytical chemistry ,Energy-dispersive X-ray spectroscopy ,chemistry.chemical_element ,Surfaces and Interfaces ,Sputter deposition ,Condensed Matter Physics ,Electron spectroscopy ,Oxygen ,Surfaces, Coatings and Films ,X-ray photoelectron spectroscopy ,chemistry ,Sputtering ,Limiting oxygen concentration ,Thin film - Abstract
Zn(O,S) thin films were successfully deposited by reactive sputtering using Ar and O2 gas mixtures at 473 K. X-ray diffraction patterns revealed that the well crystallized Zn(O,S) films were deposited with increasing oxygen concentration in O2/Ar, resulting in a shift of the Zn peak of 28.5° to a higher angle, closer to the ZnO peak of 34.4°. Zn(O,S) films were composed of grains agglomerated from small particles, which grew gradually with increasing oxygen concentration. The depth profiles and energy dispersive spectroscopy results of the films indicated that the O/(O+S) ratio increased from 0.04 to 0.81, and all Zn(O,S) films were Zn rich with uniform concentrations of each component. X-ray photoelectron spectroscopy revealed that, as the oxygen concentration increased to 2%, the ZnS films were transformed to Zn(O,S) films via substitution of oxygen for sulfur.
- Published
- 2015
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21. Effect of O2 on etch characteristics of Co2MnSi thin films in CH4/O2/Ar gas mixture
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Su Min Hwang, Adrian Adalberto Garay, and Chee Won Chung
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Materials science ,Passivation ,Process Chemistry and Technology ,fungi ,technology, industry, and agriculture ,Analytical chemistry ,chemistry.chemical_element ,macromolecular substances ,Plasma ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,stomatognathic system ,X-ray photoelectron spectroscopy ,chemistry ,Materials Chemistry ,Electrical and Electronic Engineering ,Inductively coupled plasma ,Thin film ,Reactive-ion etching ,Tin ,Instrumentation ,Layer (electronics) - Abstract
Co2MnSi thin films masked with TiN films were etched in CH4/Ar and CH4/O2/Ar plasmas by inductively coupled plasma reactive ion etching. The etch rates decreased with increasing CH4 concentration in CH4/Ar gas, whereas the etch selectivity increased. The addition of O2 to CH4/Ar gas resulted in significant improvement in the etch profile but a decrease in the etch rates. Optical emission spectroscopy showed that a variety of COx, OH, and H2O species were formed in the CH4/O2/Ar plasma, acting a role as a passivation layer to protect the pattern sidewalls. X-ray photoelectron spectroscopy also confirmed the formation of metal oxides on the film surface, which could be sputtered off easily by Ar ion bombardment. A high degree of anisotropy of Co2MnSi films was obtained in the CH4/O2/Ar etch gas.
- Published
- 2015
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