Growth of Transparent SiO2 Thin Film on Silicon at Room Temperatüre by Using I72nm Xe2* Excimer Lamp

1996 ◽  
Vol 446 ◽  
Author(s):  
T. Suzuki ◽  
M. Murahara
Keyword(s):  
Reaction Time ◽  
Chemical Reaction ◽  
Room Temperature ◽  
Specific Resistance ◽  
Relative Dielectric Constant ◽  
Si Substrate ◽  
Chain Reaction ◽  
Experimental Conditions ◽  
Excimer Lamp ◽  
Sio2 Thin Film

AbstractSiO2 insulator was fabricated by using Xe2* excimer lamp at room temperature. In this method, a mixrine of NF3 and O2 gases was employed as a reaction gas. When the NF3 and O2 gases were exposed to the Xe2* excimer lamp light NF3 and O2 gases inside the chamber where Si substrate was placed, SiFn and NO2 were produced by photo‐chemical reaction. The SiFn accumulates on the Si substrate, and SiO2 is formed by oxidation reaction between SiFn and NO2. Subsequently SiFn adheres onto the formed SiO2 and again oxidizes by NO2. These processes occur spontaneously, and on SiO2 film is grown. Experimental conditions were NF3:O2 = 10:1, the total gas pressure 330 torr, photo‐chemical reaction time 5 minutes, and chain reaction time 5 minutes. The results of the film characterization were a SiO2 film thickness of about 1500Å, a refractive index of 1.38, specific resistance of 1.67*1010 Ω cm and relative dielectric constant of 6.96.

Formation of Transparent SiO2 Thin Film at Room Temperature with Excimer Lamp Irradiation

1997 ◽  
Vol 495 ◽  
Author(s):  
T. Okamoto ◽  
H. Iizuka ◽  
S. Ito ◽  
M. Murahara
Keyword(s):  
Thin Film ◽  
Room Temperature ◽  
Molecular Layer ◽  
Surface Current ◽  
Atomic Layer ◽  
Reaction Chamber ◽  
Surface Current Density ◽  
Excimer Lamp ◽  
Sio2 Thin Film ◽  
Mixed Gases

ABSTRACTA transparent SiO2 thin film was grown with Xe2* excimer lamp and NF3, O2 mixed gases at room temperature. Unlike the conventional methods such as atomic layer epitaxy (ALE) at low temperature, this method requires only a few minutes for deposition without changing material gases. A Si substrate was placed in a reaction chamber, which was filled with NF3 and O2 gases. The gases were exposed to the Xe2* excimer lamp light, and SiF4 and NO2 were produced by photochemical reaction. The SiF4 was adsorbed on the substrate; which reacted with NO2 in gas ambient and was oxidized to form SiO2. The molecular layer was produced per reaction, and by voluntarily repeated reaction, the transparent SiO2 thin film was grown. As a result, the SiO2 film thickness of about 2200 Å was achieved for 15 minutes at room temperature. By annealing the formed SiO2 film, the surface current density of the formed SiO2 decreased; the higher the annealing temperature became, the more the surface density decreased.

Simultaneous Fabrication of Insulator and Contact Holes by Excimer Laser

1991 ◽  
Vol 236 ◽  
Author(s):  
S. Aomori ◽  
M. Murahara
Keyword(s):  
Laser Beam ◽  
Film Thickness ◽  
Excimer Laser ◽  
Chemical Reaction ◽  
Room Temperature ◽  
Excimer Lasers ◽  
Si Substrate ◽  
Krf Laser ◽  
Arf Laser ◽  
Selective Pattern

AbstractA SiO2 insulator and contact holes were simultaneously fabricated at room temperature by ArF and KrF excimer lasers. In this method, NF3 and O2 gases were employed for the reaction gas. When the ArF laser beam irradiated the NF3 and O2 gases in the presence of Si, SiFn and NO2 were produced by photo-chemical reaction. The SiFn adsorbed on the Si substrate pulled out O atoms from the NO2 to form a SiO2 layer. At the same time, the patterned KrF laser beam projected on the substrate and ablated the part exposed to fabricate contact holes. As the results, the simultaneous fabrication of SiO2 insulator with the 700 Å film thickness and selective pattern with the 10 μm width was demonstrated.

Physical Behavior of Fluorine Atoms in the Fabricated Transparent SiO2 Thin Film at Room Temperature

1998 ◽  
Vol 555 ◽  
Author(s):  
H lizuka ◽  
M Murahara
Keyword(s):  
Thin Film ◽  
Refractive Index ◽  
Photochemical Reaction ◽  
Oxidation Reaction ◽  
Room Temperature ◽  
Annealing Temperature ◽  
Reaction Chamber ◽  
Si Substrate ◽  
Physical Behavior ◽  
Sio2 Thin Film

AbstractThis paper describe the growth of a transparent SiO2 thin film performed by using Xe2• excimer lamp at room temperature. In this study, NF., and O2 mixture gases was employed as a reaction gas. A silicon substrate was placed in a reaction chamber, which was filled with NF3 and O2 mixture gases. The mixture gases were exposed to the Xe2• excimer lamplight, and SiF4 and NO2 gases were produced by photochemical reaction. Subsequently SiF4 adsorbed onto the Si substrate. SiO2 was formed by oxidation reaction between SiF4 and NO2. These processes occur spontaneously, and SiO2 film is grown. The refractive index of fabrication SiO2 thin film is 1.32. By annealing at 200°C, the refractive index of this filn was increased to 1.44. Further increase in the annealing temperature, resulted in a higher refractive index and lower density of fluorine atoms.

Synthesis and Optimum of Silver Selenide Nanopowder via Room Temperature Conversion Method

2012 ◽  
Vol 535-537 ◽  
pp. 349-352 ◽  
Author(s):  
Feng Xia Yang ◽  
Feng Xian Liu ◽  
Xiao Ling Yu
Keyword(s):  
Reaction Time ◽  
Optimum Condition ◽  
Chemical Reaction ◽  
Room Temperature ◽  
Lattice Parameter ◽  
Chemical Mechanism ◽  
Silver Selenide ◽  
Conversion Method

Silver selenide nanopowder was prepared by a room temperature conversion method, in which selenide powder(Se) and ethylenediamine (NH2CH2CH2NH2) were used as precursors. Chemical mechanism were studied by several comparative experiments. It was found that chemical reaction was taken place between Se and Ag ions through ethylenediamine. The influence of the chemical reaction time on the phase and microstructure was investigated. The results showed that the reaction was not completely if the reaction time was lower than 4h, on the contrary, some plane begin to split if the reaction time was longer than 12h. While the size and lattice parameter increase firstly with increasing time and then reduce. The results were discussed and the optimum condition was obtianed.

A crystallographic analysis of the CoSi/Si(111) interface using Transmission Electron Microscopy

1990 ◽  
Vol 48 (4) ◽  
pp. 574-575
Author(s):  
A.C. Daykin ◽  
C.J. Kiely ◽  
R.C. Pond ◽  
J.L. Batstone
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Defect Structure ◽  
Room Temperature ◽  
Theoretical Method ◽  
Crystallographic Analysis ◽  
Si Substrate ◽  
Transmission Electron ◽  
Theoretical Predictions

When CoSi2 is grown onto a Si(111) surface it can form in two distinct orientations. A-type CoSi2 has the same orientation as the Si substrate and B-type is rotated by 180° degrees about the [111] surface normal.One method of producing epitaxial CoSi2 is to deposit Co at room temperature and anneal to 650°C.If greater than 10Å of Co is deposited then both A and B-type CoSi2 form via a number of intermediate silicides .The literature suggests that the co-existence of A and B-type CoSi2 is in some way linked to these intermediate silicides analogous to the NiSi2/Si(111) system. The phase which forms prior to complete CoSi2 formation is CoSi. This paper is a crystallographic analysis of the CoSi2/Si(l11) bicrystal using a theoretical method developed by Pond. Transmission electron microscopy (TEM) has been used to verify the theoretical predictions and to characterise the defect structure at the interface.

Tyrosine-Selective Bioconjugation with Iminoxyl Radicals

2020 ◽  
Author(s):  
Katsuya Maruyama ◽  
Takashi Ishiyama ◽  
Yohei Seki ◽  
Kounosuke Oisaki ◽  
Motomu Kanai
Keyword(s):  
Reaction Time ◽  
Steric Hindrance ◽  
Room Temperature ◽  
Water Soluble ◽  
Light Irradiation ◽  
Sodium Ascorbate ◽  
Iminoxyl Radical ◽  
Short Reaction Time ◽  
Modified Peptides ◽  
The Stability

A novel Tyr-selective protein bioconjugation using the water-soluble persistent iminoxyl radical is described. The conjugation proceeded with high Tyr-selectivity and short reaction time under biocompatible conditions (room temperature in buffered media under air). The stability of the conjugates was tunable depending on the steric hindrance of iminoxyl. The presence of sodium ascorbate and/or light irradiation promoted traceless deconjugation, restoring the native Tyr structure. The method is applied to the synthesis of a protein-dye conjugate and further derivatization to azobenzene-modified peptides.

A Reinvestigation of the Deceptively Simple Reaction of Toluene with ●OH, and the Fate of the Benzyl Radical. I. a Combined Thermodynamic and Kinetic Study on the Competition Between ●OH Addition and Hydrogen Abstraction Reactions.

2019 ◽  
Author(s):  
Zoi Salta ◽  
Agnie M. Kosmas ◽  
Marc E. Segovia ◽  
Martina Kieninger ◽  
Oscar Ventura ◽  
...  
Keyword(s):  
Density Functional ◽  
Room Temperature ◽  
Hydrogen Abstraction ◽  
Reaction Rates ◽  
Composite Model ◽  
Alternative Mechanism ◽  
Radical Intermediate ◽  
Experimental Conditions ◽  
Methyl Group ◽  
Benzyl Radical

This work reports density functional and composite model chemistry calculations performed on the reactions of toluene with the hydroxyl radical. Both experimentally observed H-abstraction from the methyl group and possible additions to the phenyl ring were investigated. Reaction enthalpies and heights of the barriers suggest that H-abstraction is more favorable than ●OH addition to the ring. The calculated reaction rates at room temperature and the radical-intermediate product fractions support this view. This is somehow contradictory with the fact that, under most experimental conditions, cresols are observed in a larger concentration than benzaldehyde. Since the accepted mechanism for benzaldehyde formation involves H-abstraction, a contradiction arises that begs for an explanation. In this first part of our work we give the evidences that support the preference of hydrogen abstraction over ●OH addition and suggest an alternative mechanism which shows that cresols can actually arise also from the former reaction and not only from the latter.

A Reinvestigation of the Deceptively Simple Reaction of Toluene with ●OH, and the Fate of the Benzyl Radical. I. a Combined Thermodynamic and Kinetic Study on the Competition Between ●OH Addition and Hydrogen Abstraction Reactions.

2019 ◽  
Author(s):  
Zoi Salta ◽  
Agnie M. Kosmas ◽  
Marc E. Segovia ◽  
Martina Kieninger ◽  
Oscar Ventura ◽  
...  
Keyword(s):  
Density Functional ◽  
Room Temperature ◽  
Hydrogen Abstraction ◽  
Reaction Rates ◽  
Composite Model ◽  
Alternative Mechanism ◽  
Radical Intermediate ◽  
Experimental Conditions ◽  
Methyl Group ◽  
Benzyl Radical

This work reports density functional and composite model chemistry calculations performed on the reactions of toluene with the hydroxyl radical. Both experimentally observed H-abstraction from the methyl group and possible additions to the phenyl ring were investigated. Reaction enthalpies and heights of the barriers suggest that H-abstraction is more favorable than ●OH addition to the ring. The calculated reaction rates at room temperature and the radical-intermediate product fractions support this view. This is somehow contradictory with the fact that, under most experimental conditions, cresols are observed in a larger concentration than benzaldehyde. Since the accepted mechanism for benzaldehyde formation involves H-abstraction, a contradiction arises that begs for an explanation. In this first part of our work we give the evidences that support the preference of hydrogen abstraction over ●OH addition and suggest an alternative mechanism which shows that cresols can actually arise also from the former reaction and not only from the latter.

Ultrafiltration of silica sols

1989 ◽  
Vol 54 (1) ◽  
pp. 91-101 ◽  
Author(s):  
Milan Stakić ◽  
Slobodan Milonjić ◽  
Vladeta Pavasović ◽  
Zoja Ilić
Keyword(s):  
Particle Size ◽  
Silica Particle ◽  
Specific Resistance ◽  
Membrane Surface ◽  
Membrane Resistance ◽  
Experimental Conditions ◽  
Surface Unit ◽  
Silica Sols ◽  
Filtration Flux ◽  
Batch Cell

Ultrafiltration of three laboratory made silica and two commercial silica sols was studied using Amicon YC membrane in a 200 ml capacity batch-cell. The effect of silica particle size, stirring conditions, pressure, pH and silica contents on ultrafiltration was investigated. The results obtained indicate that the smaller particles have, disregarding the stirring conditions, lower filtration flux. The differences observed in filtration flux are more pronounced in the conditions without stirring. The obtained value of the membrane resistance is independent of the conditions investigated (stirring, pressure, pH, silica contents and particle size). The values of the resistance of polarized solids, specific resistance, and the mass of gel per membrane surface unit were calculated for all experimental conditions.

scholarly journals Study on Chromaticity Removal from Mineral Processing Wastewater with Salicylic Hydroxamic Acid by Granular Activated Carbon Catalyzed Ozonation

Minerals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 359
Author(s):  
Liping Zhang ◽  
Shengnian Wu ◽  
Nan Zhang ◽  
Ruihan Yao ◽  
Eryong Wu
Keyword(s):  
Activated Carbon ◽  
Reaction Time ◽  
Hydroxamic Acid ◽  
Ph Value ◽  
Oxygen Demand ◽  
Granular Activated Carbon ◽  
Mineral Processing ◽  
Ultraviolet Absorption Spectrum ◽  
Experimental Conditions ◽  
Removal Ratio

Salicylic hydroxamic acid is a novel flotation reagent used in mineral processing. However, it impacts the flotation wastewater leaving behind high chromaticity which limits its reuse and affects discharge for mining enterprises. This study researched ozonation catalyzed by the granular activated carbon (GAC) method to treat the chromaticity of the simulated mineral processing wastewater with salicylic hydroxamic acid. The effects of pH value, ozone (O3) concentration, GAC dosage, and reaction time on chromaticity and chemical oxygen demand (CODCr) removal were discussed. The results of individual ozonation experiments showed that the chromaticity removal ratio reached 79% and the effluent chromaticity exceeded the requirement of reuse and discharge when the optimal experimental conditions were pH value 3, ozone concentration 6 mg/L, and reaction time 40 min. The orthogonal experimental results of catalytic ozonation with GAC on chromaticity removal explained that the chromaticity removal ratio could reach 96.36% and the chromaticity of effluent was only 20 when the optimal level of experimental parameters was pH value 2.87, O3 concentration 6 mg/L, GAC dosage 0.06 g/L, reaction time 60 min respectively. The degradation pathway of salicylic hydroxamic acid by ozonation was also considered based on an analysis with ultraviolet absorption spectrum and high-performance liquid chromatography (HPLC).

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