title: Abnormal behavior of longitudinal optical phonon in silicon dioxide films on 4H-SiC bulk epitaxial substrate using Fourier transform infrared (FT-IR) spectroscopy.
abstract: We report the abnormal behavior of longitudinal optical (LO) phonon in a silicon dioxide (SiO2) film on a 4H-SiC bulk epitaxial substrate using an attenuated total reflection (ATR) technique. The peak frequency of the LO phonon in the ATR spectrum was observed at around 1165 cm(-1) and red-shifted by approximately 92 cm(-1) relative to that at the grazing incidence (40°), whereas the peak frequency of the transverse optical (TO) phonon in the ATR spectrum agreed well with that at the grazing incidence. Furthermore, the peak frequency of the TO phonon hardly depends on change in the incident angle and thickness, suggesting that the microstructure of the sample is homogeneous within a thickness of 100 nm. On the other hand, we found that the microstructure of the sample was inhomogeneous within a thickness less than 5 nm. Fourier transform infrared (FT-IR) spectroscopy provides us with a large amount of data on microstructures in the SiO2 films on a 4H-SiC substrate.
authors: Toray Research Center Inc., 3-3-7 Sonoyama, Otsu, Shiga 520-8567, Japan. masanobu_yoshikawa@trc.toray.co.jp
authors: Masanobu
authors: M
authors: Yoshikawa
authors: Hirohumi
authors: H
authors: Seki
authors: Tsuneyuki
authors: T
authors: Yamane
authors: Yuichiro
authors: Y
authors: Nanen
authors: Muneharu
authors: M
authors: Kato
authors: Tsunenobu
authors: T
authors: Kimoto