X-ray absorption spectroscopy study on SiC-side interface structure of SiO₂–SiC formed by thermal oxidation in dry oxygen

Abstract

Extended X-ray absorption fine structure (EXAFS) spectroscopy is demonstrated to measure the fine atomic structure of SiO 2 -SiC interfaces. The SiC-side of the interface can be measured by fabricating thin SiO 2 films and using SiC-selective EXAFS measurements. Fourier transforms of the oscillations of the EXAFS spectra correspond to radial-structure functions and reveal a new peak of the first nearest neighbor of Si for m-face SiC, which does not appear in measurements of the Si-face. This finding suggests that the m-face interface could include a structure with shorter Si-C distances. Numerical calculations provide additional support for this finding.

Local atomic structure analysis of GaN surfaces via X-ray absorption spectroscopy by detecting Auger electrons with low energies

“…We studied surface-sensitive techniques of EXAFS by detecting Auger electrons escaping from sample surfaces (Isomura et al, 2016(Isomura et al, , 2017(Isomura et al, , 2018. EXAFS spectra are obtained during the energy sweep of the incident X-ray by monitoring the intensity of Auger electrons using the electron monochromator.…”

X-ray Absorption Fine Structural Study of Atomic Structures and Chemical States of Dopants in 4H-SiC(0001)

“…From the fitting, the coordination number and the Al–C distance were estimated to be 4.0 and 2.13 Å, respectively. Since the undoped SiC exhibits a coordination number of 4.0 and a Si–C bond length of 1.89 Å, the Al dopant atom increases the bond length around the dopant. , This may be due to the difference in atom size between the Al atom (radius: 0.125 nm) and the Si atom (radius: 0.111 nm) . The derivation of the bond length may be attributed to the relaxation of the local structure around the dopant Al atom.…”

Non-destructive depth analysis of acidic phosphate ester boundary layers by hard X-ray photoelectron spectroscopy

“…Therefore, in general, HAXPES analysis uses X-rays from synchrotron radiation, which have high brightness. We used the Aichi Synchrotron Radiation Center (Aichi SR) BL6N1 (Yamamoto et al, 2014;Isomura et al, 2018) as our source for 3 keV radiation, the Super Photon Ring 8 GeV (SPring-8) BL16XU (Hirai et al, 2004;Isomura et al, 2019a) for 6 keV radiation, and SPring-8 BL46XU (Isomura et al, 2019b) for 10 keV radiation. Each light source consisted of quasi-monochromatic light, monochromatized using a double-crystal monochromator.…”