Properties and structure of AlSiN and AlSiON films
Magneto-optical disks employ rare earth-transition metal amorphous alloy films (RE-TM films) as recording films, therefore improvement of the corrosion resistance of such disks is an important problem which must be resolved to enable practical application. Development of protective layers for magneto-optical disks is important to improving corrosion resistance. Such protective layers must offer excellent protective performance, and must also have a large refractive index in order that a large Kerr effect enhancement be obtained. AlSiN and AlSiON films are being developed for use as protective films meeting these requirements. However, as yet not much is known about the structure, bonding states, and relation between composition and refractive index of such films. This article reports on the refractive indices, structures, and bonding states of AlSiN and AlSiON sputtered films.
Effect of Growth Temperature on Formation of Amorphous Nitride Interlayer between AlN and Si(111)
The formation of an amorphous interlayer between AlN and Si(111), which may degrade the film quality, is studied by varying the substrate temperature from 860 to 1010 °C in metal–organic chemical vapor deposition with a preflow of trimethylaluminum. The microstructure and chemistry of the amorphous interlayer have been investigated using transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Cross-sectional TEM examinations show that AlN is directly in contact with Si for growth at 860 °C. At higher growth temperatures, an amorphous interlayer can be formed even if an AlN layer has been previously deposited on Si, and its thickness increases with growth temperature. The XPS depth profile across the amorphous interlayer formed at 1010 °C shows that both Al and N exhibit similar distribution, which gradually decreases toward the Si substrate whereas the Si concentration has the opposite distribution. The composition of the amorphous interlayer is determined to consist of Al, Si, and N.
Refinement of crystal structure parameters using convergent‐beam electron diffraction: the low‐temperature phase of SrTiO3
The method to refine crystal structure parameters (atom positions and Debye–Waller factors) using convergent-beam electron diffraction (CBED), which is applicable to crystal structure analysis of a small specimen area down to a few nm in diameter, is studied. The line profiles of higher-order Laue-zone reflections are recorded using imaging plates. Theoretical intensities are calculated based on the dynamical theory of electron diffraction with the aid of the generalized Bethe approximation to shorten calculation time. The structural parameters are determined by fitting the experimental profiles with the theoretical ones using a nonlinear least-squares method. The present method has been applied to the low-temperature phase of SrTiO3. The structural parameter or the rotation angle of the oxygen octahedron has been determined to be \varphi = 1.12 (4)°, which shows good agreement with that obtained from electron spin resonance experiments.