Comparison of High-Purity-Ozone Oxidation on Si(111) and Si(100)

1997 ◽  
Vol 477 ◽  
Author(s):  
A. Kurokawa ◽  
S. Ichimura ◽  
D. W. Moon
Keyword(s):  
Temperature Dependence ◽  
High Purity ◽  
Photoelectron Spectroscopy ◽  
Surface Ozone ◽  
Experimental Chamber ◽  
Oxide Formation ◽  
Ozone Oxidation ◽  
X Ray ◽  
Temperature Range ◽  
Thin Oxide

ABSTRACTThe oxidation of Si(111) and Si(100) surfaces with the high-purity ozone(more than 98 mole %) was investigated with X-ray photoelectron spectroscopy (XPS). Thin oxide less than 3nm thickens was formed in an experimental chamber and the results showed that ozone oxidizes the (111) surface faster than (100) surface. Ozone does not show the temperature dependence on oxidation within the temperature range of 250–500 degree C for both (111) and (100) surfaces. Ozone proceeds the oxide formation at 700 degree C where oxygen does not proceed oxide formation rapidly.

Low Temperature Oxidation Processing with High Purity Ozone

1996 ◽  
Vol 429 ◽  
Author(s):  
A. Kurokawa ◽  
S. Ichimura ◽  
H. J. Kang ◽  
D. W. Moon
Keyword(s):  
Low Temperature ◽  
Thermal Oxidation ◽  
High Purity ◽  
Photoelectron Spectroscopy ◽  
Oxide Formation ◽  
Low Temperature Oxidation ◽  
Temperature Oxidation ◽  
X Ray

AbstractTo lower the temperature of oxide-passivation processing the high- purity ozone (more than 98 mole %) was used instead of usual thermal oxidation. Initial oxide formation on a Si(111) surface with high-purity ozone is investigated by X-ray photoelectron spectroscopy (XPS). From the comparison of the suboxides formed with ozone and oxygen exposures, it is clear that ozone forms less suboxide than oxygen. The oxidation with ozone also proceeds on the hydrogen passivated surface which oxygen molecules do not oxidize.

Study of Ta as a Diffusion Barrier in Cu/SiO2 Structure

2000 ◽  
Vol 612 ◽  
Author(s):  
J. S. Pan ◽  
A. T. S. Wee ◽  
C. H. A. Huan ◽  
J. W. Chai ◽  
J. H. Zhang
Keyword(s):  
Photoelectron Spectroscopy ◽  
Electron Spectroscopy ◽  
Auger Electron ◽  
Room Temperature ◽  
Depth Profiling ◽  
Oxide Formation ◽  
X Ray ◽  
Chemical States ◽  
The Stability

AbstractTantalum (Ta) thin films of 35 nm thickness were investigated as diffusion barriers as well as adhesion-promoting layers between Cu and SiO2 using X-ray diffractometry (XRD), Scanning electron microscopy (SEM), Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS). After annealing at 600°C for 1h in vacuum, no evidence of interdiffusion was observed. However, XPS depth profiling indicates that elemental Si appears at the Ta/SiO2 interface after annealing. In-situ XPS studies show that the Ta/SiO2 interface was stable until 500°C, but about 32% of the interfacial SiO2 was reduced to elemental Si at 600°C. Upon cooling to room temperature, some elemental Si recombined to form SiO2 again, leaving only 6.5% elemental Si. Comparative studies on the interface chemical states of Cu/SiO2 and Ta/SiO2 indicate that the stability of the Cu/Ta/SiO2/Si system may be ascribed to the strong bonding of Ta and SiO2, due to the reduction of SiO2 through Ta oxide formation.

Study of Thermal Oxide Solid-State Reaction on GaAs Surfaces

1991 ◽  
Vol 238 ◽  
Author(s):  
Z. Lu ◽  
D. Chen ◽  
R. M. Osgood ◽  
D. V. Podlesnik
Keyword(s):  
Solid State ◽  
Solid State Reaction ◽  
Photoelectron Spectroscopy ◽  
Interface Reaction ◽  
Decomposition Reaction ◽  
Thermal Reaction ◽  
Native Oxide ◽  
X Ray ◽  
Temperature Range ◽  
Thermal Oxide

ABSTRACTIn this paper, we will present a study of the thermal reaction of AsjOs with GaAs at temperatures below 550°C using monochromatic X-ray photoelectron spectroscopy (MXPS). A solid-state interface reaction of 4GaAs + 3AS2O5 → 2Ga2O3 + 3AS2O3 + 4As, which includes the usual native oxide thermal reaction: 2GaAs + AS2O3 → Ga2O3 + 4As, as well as a decomposition reaction AS2O5 → AS2O3 + O2 is responsible for the thermal reaction in this temperature range.

scholarly journals Effect of Copper Precursors on the Activity and Hydrothermal Stability of CuII−SSZ−13 NH3−SCR Catalysts

Catalysts ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 781
Author(s):  
Meixin Wang ◽  
Zhaoliang Peng ◽  
Changming Zhang ◽  
Mengmeng Liu ◽  
Lina Han ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Adsorption Capacity ◽  
Photoelectron Spectroscopy ◽  
Hydrothermal Stability ◽  
Vehicle Exhaust ◽  
No Conversion ◽  
X Ray ◽  
Temperature Range ◽  
Scr Catalysts ◽  
Temperature Programmed

A series of CuII−SSZ−13 catalysts are prepared by in-situ hydrothermal method using different copper precursors (CuII(NO3)2, CuIISO4, CuIICl2) for selective catalytic reduction of NO by NH3 in a simulated diesel vehicle exhaust. The catalysts were characterized by X−ray diffraction (XRD), scanning electron microscope (SEM), X−ray photoelectron spectroscopy (XPS), N2 adsorption-desorption, hydrogen-temperature-programmed reduction (H2−TPR), ammonia temperature-programmed desorption (NH3−TPD), and 27Al and 29Si solid state Nuclear Magnetic Resonance (NMR). The CuII−SSZ−13 catalyst prepared by CuII(NO3)2 shows excellent catalytic activity and hydrothermal stability. The NO conversion of CuII−SSZ−13 catalyst prepared by CuII(NO3)2 reaches 90% at 180 °C and can remain above 90% at a wide temperature range of 180–700 °C. After aging treatment at 800 °C for 20 h, the CuII−SSZ−13 catalyst prepared by CuII(NO3)2 still exhibits above 90% NO conversion under a temperature range of 240–600 °C. The distribution of Cu species and the Si/Al ratios in the framework of the synthesized CuII−SSZ−13 catalysts, which determine the catalytic activity and the hydrothermal stability of the catalysts, are dependent on the adsorption capacity of anions to the cation during the crystallization process due to the so called Hofmeister anion effects, the NO3− ion has the strongest adsorption capacity among the three kinds of anions (NO3−, Cl−, and SO42−), followed by Cl– and SO42– ions. Therefore, the CuII−SSZ−13 catalyst prepared by CuII(NO3)2 possess the best catalytic ability and hydrothermal stability.

scholarly journals In-flight Synthesis of Nanosized ZrC Particles from Various Precursors in RF Thermal Plasma

2021 ◽  
Author(s):  
Alejandro Martiz ◽  
Zoltán Károly ◽  
Eszter Bódis ◽  
Péter Fazekas ◽  
Miklós Mohai ◽  
...  
Keyword(s):  
Thermal Plasma ◽  
Photoelectron Spectroscopy ◽  
Average Particle Size ◽  
Reaction System ◽  
Spherical Shape ◽  
Molar Ratio ◽  
Average Particle ◽  
X Ray ◽  
Temperature Range ◽  
Rf Thermal Plasma

Synthesis of zirconium carbide (ZrC) powder was investigated applying a non-conventional atmospheric radiofrequency (RF) thermal plasma process. In one case, zirconium dioxide (ZrO2) was reacted with solid carbon or with methane with varying molar ratio. In the other, zirconium-propoxide (NZP), containing both constituents, was thermally decomposed in the Ar plasma. Temperature-dependent thermodynamic analysis was performed in the 500-5500 K temperature range to estimate the formation of possible equilibrium products for each reaction stoichiometry. Broad temperature range exists for the stability of solid ZrC for each explored reaction system. In accordance with this prediction, X-ray diffraction studies detected the ZrC as the major phase in all the prepared powders. The yield of particular runs ranged from 39 % to 98 %. Practically, full conversion was typical for the case of NZP precursor, however only partial conversion could be detected in ZrO2 reactions. The average particle size of the powders falls between 10 nm and 100 nm depending on the type of the reaction systems (either calculated from the specific surface area or derived from broadening the XRD reflections). The transmission electron micrographs indicated mostly globular shape of the nanosize particles. Quantitative analysis of the surface of the powders by X-ray photoelectron spectroscopy revealed the presence of oxygen and carbon. Evaluating the spectra of the powders prepared from NZP, and taking in the account its spherical shape, a ZrC core covered by a very thin (≈1.0 nm) ZrO2 layer may be accounted for the measured oxygen and a thicker carbonaceous layer.

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