Optical dielectric functions for amorphous Al2O3 and γ-Al2O3

Abstract

Using the classical oscillator model, the optical dielectric functions for amorphous alumina (a-Al2O3) and gamma alumina (γ-Al2O3) thin films prepared by ion implantation and subsequent annealing of sapphire (α-Al2O3) substrates were determined for the first time from analysis of infrared reflection spectra. Two transverse optical modes at 422 and 721 cm−1 were obtained for the a-Al2O3 film while four modes at 357, 536, 744, and 807 cm−1 were identified for the γ-Al2O3 film. Also, the problems involving the analysis of modes with large damping are discussed.

Quantitative chemical composition of thin films with infrared spectroscopic ellipsometry: application to hydrated oxide films on aluminium

“…The barrier layer sample shows an intense peak at 960 cm 1 , which has been assigned to the longitudinal optical mode corresponding to the Al-O-Al stretch. 20,28,29 No hydration of the barrier layer is observed within the precision of the apparatus. Only some contamination by carbonate from reaction of the oxide film with CO 2 in the air is observed.…”

Berreman effect in infrared absorption spectroscopy of ionic oxide coatings formed by atomic layer deposition on three-dimensional structures

“…13 A dielectric function ͑͒ in the zero-and-pole ͑or factorized͒ form 14 is selected for the ␥-Al 2 O 3 layers, and the parameters needed for the simulations are taken from Ref. 15. In the calculations the ionic oxide layers are always assumed to be freestanding.…”

Morphological effects on IR band profiles

“…Barker 1963;Loewenstein et al 1973;Querry 1985;Gervais 1991) as well as γ-Al 2 O 3 (e.g. Chu et al 1988;Koike et al 1995), δ-and θ-Al 2 O 3 (Kurumada et al 2005), and amorphous Al 2 O 3 (e.g. Chu et al 1988;Begemann et al 1997 ions surrounded by 32 O 2− ions in a unit cell of the spinel.…”

“…Chu et al 1988;Koike et al 1995), δ-and θ-Al 2 O 3 (Kurumada et al 2005), and amorphous Al 2 O 3 (e.g. Chu et al 1988;Begemann et al 1997 ions surrounded by 32 O 2− ions in a unit cell of the spinel. In consequence, spinel has 56 ions per unit cell (see details in Klein & Hurlbut 1993;Fabian et al 2001).…”