Characterization of Inhomogeneity in Thermal Oxide SiO2 Films on 4H-SiC Epitaxial Substrates by a Combination of Fourier Transform Infrared Spectroscopy and Cathodoluminescence Spectroscopy

2018 ◽  
Vol 924 ◽  
pp. 273-276 ◽  
Author(s):  
Masanobu Yoshikawa ◽  
Keiko Inoue ◽  
Junichiro Sameshima ◽  
Hirohumi Seki
Keyword(s):  
Fourier Transform ◽  
Oxide Layer ◽  
Layer Thickness ◽  
Phonon Mode ◽  
Fourier Transform Infrared ◽  
Blue Shift ◽  
Peak Frequency ◽  
Oxide Layer Thickness ◽  
Thermal Oxide ◽  
Ft Ir

We measured Fourier transform infrared (FT-IR) and cathodoluminescence (CL) spectra of SiO2 films with a various thickness, grown on 4H-SiC substrates. The peak frequency of the transverse optical (TO) phonon mode was blue-shifted by about 5 cm−1 as the oxide-layer thickness decreased from 50-60 nm to 10 nm. The blue shift of the TO mode is considerd to be caused by interfacial compressive stresses in the oxide-layer. On the other hand, the TO phonon mode was found to dramatically decrease as the oxide-layer thickness decreased from 10 nm to 1.7 nm. The CL measurement indicates that the intensity of the CL peaks at about 460 and 490 nm attributed to oxygen vacancy centers (OVCs) for No.2 become stronger than that for No.1. From a comparison between FT-IR and CL measurements, we concluded that the red-shift of the TO phonon with decreasing the oxide-layer thickness can mainly be attributed to an increase in inhomogeneity at the SiO2/SiC interface with decreasing oxide-layer thickness.

Characterization of Inhomogeneity in SiO2 Films on 4H-SiC Epitaxial Substrate by a Combination of Fourier Transform Infrared Spectroscopy and Cathodoluminescence Spectroscopy

2015 ◽  
Vol 821-823 ◽  
pp. 460-463 ◽  
Author(s):  
Masanobu Yoshikawa ◽  
Hirohumi Seki ◽  
Keiko Inoue ◽  
Takuma Kobayashi ◽  
Tsunenobu Kimoto
Keyword(s):  
Fourier Transform ◽  
Oxide Layer ◽  
Layer Thickness ◽  
Polarized Light ◽  
Fourier Transform Infrared ◽  
Peak Frequency ◽  
Oxide Layer Thickness ◽  
Phonon Modes ◽  
Surface Polaritons ◽  
Ft Ir

We measured Fourier transform infrared (FT-IR) and cathodoluminescence (CL) spectra of SiO2 films with various thicknesses, grown on 4H-SiC substrates. The appearance of broad phonon modes at ~1150–1250 cm-1 in p-polarized light and their disappearance in s-polarized light confirmed that the phonon modes at ~1150–1250 cm-1originated from surface polaritons (SPPs). For the thin SiO2 film (8-nm thick), the peak frequency of the transverse optical (TO) phonon in the SiO2 film on the 4H-SiC substrate was observed at ~1080 cm-1and was higher than that in SiO2 films on the Si substrate (1074 cm-1). This suggested that the thin SiO2 film (8-nm thick) is under compressive stresses at the interface between the SiO2 film and SiC substrate. On the other hand, for the thick SiO2 films (85 and 130-nm thick), the TO phonon peak frequency tended to shift toward lower frequencies with increasing oxide layer thickness. The CL measurement indicated that the CL peak intensity at ~640 nm, attributed to non-bridging oxidation hole centers (NBOHCs), became stronger with increasing oxide layer thickness, relative to that of the CL peaks at ~460 and 490 nm due to oxygen vacancy centers (OVCs). By comparing the FT-IR and CL measurements, we concluded that the TO phonon red-shift with increasing oxide layer thickness can mainly be attributed to an increase in inhomogeneity with increasing oxide layer thickness for the thick SiO2 films.

Detecting the Oxidation of Zircaloy Claddings by Infrared Interference

NANO ◽  
2018 ◽  
Vol 13 (02) ◽  
pp. 1850015 ◽  
Author(s):  
Hongyi Mi ◽  
Solomon Mikael ◽  
Edward Swinnich ◽  
Todd Allen ◽  
Kumar Sridharan ◽  
...  
Keyword(s):  
Oxide Layer ◽  
Layer Thickness ◽  
Oscillation Amplitude ◽  
Oscillation Period ◽  
Oxide Layer Thickness ◽  
Optical Interference ◽  
Cross Sectional ◽  
Oxide Layers ◽  
Ft Ir ◽  
And Performance

As the expected life of dry cask storage installations increases, it becomes increasingly desirable to monitor the state and performance of the cask internals to ensure that they continue to safely contain the radioactive materials in the fuel. One aspect of this task is the monitoring of oxidation of the cladding. With this consideration in mind, Zircaloy-4 (Zr-4) cladding samples were exposed to air at 500[Formula: see text]C for various duration times to create thin corrosion oxide layers on the surface. The surfaces of the oxidized samples were then systematically scanned by Fourier Transform Infrared (FT-IR) spectroscopy to achieve the infrared (IR) interference spectra and study the relationship between the optical interference and the various thicknesses of the oxide layers. The profiles of the oxide layers were verified througth cross-sectional examination by Scanning Electron Microscopy. The IR interference patterns varied with oxide layer thickness, enabling the determination of oxide layer thickness of values, including half micron thick. Further analysis demonstrated that the interference oscillation period and the oscillation amplitude decreased with increasing oxide layer thickness. Combined with a physical model that describes the optical interference, the interference spectra were directly correlated to the oxide layer thickness quantitatively. The study provides the basis for an accurate, nondestructive and sensitive method to monitor the degree of zirconium-based cladding corrosion due to oxidation.

Characterization of Thermal Oxides on 4H-SiC Epitaxial Substrates Using Fourier-Transform Infrared Spectroscopy

2016 ◽  
Vol 71 (5) ◽  
pp. 911-918 ◽  
Author(s):  
Hirofumi Seki ◽  
Masanobu Yoshikawa ◽  
Takuma Kobayashi ◽  
Tsunenobu Kimoto ◽  
Yukihiro Ozaki
Keyword(s):  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Fourier Transform Infrared Spectroscopy ◽  
Compressive Stress ◽  
Fourier Transform Infrared ◽  
Blue Shift ◽  
Peak Frequency ◽  
Oxide Thickness ◽  
Interfacial Stress ◽  
Si Substrate

Fourier transform infrared (FT-IR) spectra were measured for thermal oxides with different electrical properties grown on 4H-SiC substrates. The peak frequency of the transverse optical (TO) phonon mode was blue-shifted by 5 cm−1 as the oxide-layer thickness decreased to 3 nm. The blue shift of the TO mode indicates interfacial compressive stress in the oxide. Comparison of data for the oxide on a SiC substrate with that for similar oxides on a Si substrate implies that the peak shift of the TO mode at the SiO2/SiC interface is larger than that of SiO2/Si, which suggests that the interfacial stress for the oxide on the SiC substrate is larger than that on the Si substrate. For the SiO2/SiC interfacial region (<3 nm oxide thickness), despite the fact that the blue shift of the TO modes becomes larger while approaching the oxide/SiC interface, the peak frequency of the TO modes red-shifts at the oxide/SiC interface. The peak-frequency shift of the TO mode for the sample without post-oxidation annealing was larger than that for the samples post-annealed in a nitric oxide atmosphere. The channel mobilities are correlated with the degree of shift of the TO mode when the oxide thickness is <3 nm. It appears that the compressive stress at the SiO2/SiC interface generates silicon suboxide components and weakens the Si-O bonds. As the result, the TO mode was red-shifted and the oxygen deficiency increased to relax the compressive stress in the oxide with <3 nm thickness. Fourier transform infrared spectroscopy measurements provide unique and useful information about stress and inhomogeneity at the oxide/SiC interface.

FR-IR Molecular Microanalysis System

1990 ◽  
Vol 48 (2) ◽  
pp. 270-271
Author(s):  
John A. Reffner ◽  
William T. Wihlborg
Keyword(s):  
Fourier Transform ◽  
Fourier Transform Infrared ◽  
Integrated System ◽  
Morphological Examination ◽  
Fully Integrated ◽  
Ir Microscopy ◽  
Normal Functions ◽  
Infrared Microspectroscopy ◽  
Infrared Spectral ◽  
Ft Ir

The IRμs™ is the first fully integrated system for Fourier transform infrared (FT-IR) microscopy. FT-IR microscopy combines light microscopy for morphological examination with infrared spectroscopy for chemical identification of microscopic samples or domains. Because the IRμs system is a new tool for molecular microanalysis, its optical, mechanical and system design are described to illustrate the state of development of molecular microanalysis. Applications of infrared microspectroscopy are reviewed by Messerschmidt and Harthcock.Infrared spectral analysis of microscopic samples is not a new idea, it dates back to 1949, with the first commercial instrument being offered by Perkin-Elmer Co. Inc. in 1953. These early efforts showed promise but failed the test of practically. It was not until the advances in computer science were applied did infrared microspectroscopy emerge as a useful technique. Microscopes designed as accessories for Fourier transform infrared spectrometers have been commercially available since 1983. These accessory microscopes provide the best means for analytical spectroscopists to analyze microscopic samples, while not interfering with the FT-IR spectrometer’s normal functions.

On-Chip Micro–Electro–Mechanical System Fourier Transform Infrared (MEMS FT-IR) Spectrometer-Based Gas Sensing

2016 ◽  
Vol 70 (5) ◽  
pp. 897-904 ◽  
Author(s):  
Mazen Erfan ◽  
Yasser M Sabry ◽  
Mohammad Sakr ◽  
Bassem Mortada ◽  
Mostafa Medhat ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Mechanical System ◽  
Gas Sensing ◽  
Fourier Transform Infrared ◽  
Micro Electro Mechanical System ◽  
Ft Ir ◽  
On Chip

Tetrachlorodibenzo-p-Dioxin Isomer Differentiation by Capillary Gas Chromatography Fourier Transform-Infrared Spectroscopy

1987 ◽  
Vol 41 (5) ◽  
pp. 809-820 ◽  
Author(s):  
James Grainger ◽  
Leslie T. Gelbaum
Keyword(s):  
Gas Chromatography ◽  
Fourier Transform ◽  
Vapor Phase ◽  
Valence Bond ◽  
Fourier Transform Infrared ◽  
Molecular Geometry ◽  
Ether Linkage ◽  
Relative Electron ◽  
Ft Ir ◽  
Infrared Frequencies

Reference infrared vapor-phase spectra of the 22 tetrachlorodibenzo-dioxin (TCDD) isomers were recorded at low microgram concentrations. These reference spectra of synthetic mixture components separated chromatographically or by spectral subtraction exhibit distinct infrared spectra for each isomer. The infrared frequencies are delineated in correlation tables and are interpreted in terms of substitution patterns which determine the strength of the ether linkage. Absorbance values in the 1330–1280 cm−1 (C-O-C asymmetric stretch) region correlate with specific substitution patterns and molecular geometry. Relative electron-withdrawing capacities for chlorinated aromatic rings in TCDD isomers were estimated on the basis of relative capacities determined for model compounds. Qualitative correlations were established between electron-withdrawing capacities and the effects of resonance and field interactions on the ether linkage absorption frequencies of individual TCDD isomers. Gas chromatography Fourier transform infrared (GC/FT-IR) isomer assignments are generally consistent with those obtained by proton Fourier transform nuclear magnetic resonance (1H FT/NMR) and flame ionization gas chromatography (GC/FID). A chromatographically independent method of assigning TCDD isomer structures on the basis of ether linkage asymmetric stretching frequencies was established by utilization of valence-bond approximations. GC/FT-IR assignments for several TCDD isomers differ from isomer assignments in previously published results. A user-generated, vapor-phase reference library, containing individual TCDD spectra and spectra of isomer pairs that are incompletely resolved on chromatographic columns, correctly identified each isomer in variety of mixtures by means of a software algorithm.

Effect of Palm Kernel Meal as Melamine Urea Formaldehyde Adhesive Extender for Plywood Application: Using a Fourier Transform Infrared Spectroscopy (FTIR) Study

2011 ◽  
Vol 121-126 ◽  
pp. 493-498 ◽  
Author(s):  
Huei Ruey Ong ◽  
Reddy Prasad ◽  
Md. Maksudur Rahman Khan ◽  
Md. Najmul Kabir Chowdhury
Keyword(s):  
Fourier Transform ◽  
Functional Groups ◽  
Chemical Interaction ◽  
Urea Formaldehyde ◽  
Palm Kernel ◽  
Fourier Transform Infrared ◽  
Blue Shift ◽  
Hot Press ◽  
Kernel Meal ◽  
Palm Kernel Meal

Increased demand for wood adhesives, environmental concerns, and the uncertainty of continuing availability of petrochemicals have led to recent attention on protein-based adhesives. This study was conducted to investigate the physico-chemical interaction of palm kernel meal (PKM) with melamine urea formaldehyde (MUF) resins in adhesive formulation by using Fourier Transform Infrared (FTIR) Spectroscopy. The effect of hot press on PKM extender has been investigated by FTIR and blue shift is observed due to the hot press indicating that the functional groups (such as C=O, -OH and NH) are become more free in the samples. In the case of PKM-MUF blend bonding interactions observed where, PKM played the role as an extender. Red shift of C=O and N-H groups stretching in PKM-MUF-Wood blend is observed which suggests the interaction of these functional groups through hydrogen bonding. The results suggest that PKM extender-based MUF adhesive resins have potential application for the production of exterior plywood.

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