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Determination of thickness and optical properties of tantalum oxide thin films by spectroscopic ellipsometry
Author(s)
Chananonnawathorn, Chanunthorn
Srichaiyaperk, Thanat
Samransuksamer, Benjarong
Horprathum, Mati
Eiamchai, Pitak
Limwichean, Saksorn
Aiempanakit, Kamon
Chindaudom, Pongpan
Date Issued
January 1, 2014
Type
Conference Paper
Abstract
Tantalum oxide (Ta2O5) thin films were prepared, at different deposition time, by a DC reactive magnetron sputtering. During the deposition, a high-quality tantalum target was sputtered under argon and oxygen ambience on to silicon (100) and glass substrates. The prepared thin films were systematically characterized for both physical and optical properties based on spectroscopic ellipsometry (SE), and consequently confirmed by several methods. With the SE physical models, we could determine the thin film thickness as well as their inhomogeneity. The films thickness results were directly confirmed by field-emission scanning electron microscopy (FE-SEM) used to observe cross-sections, and surface profiler used to measure the physical thickness of the films. With the SE optical models, we applied both the Cauchy and Tauc-Lorentz dispersions in order to obtain the optical constants, to be directly compared with those from the Swanepoel method (SM). Our result showed that from the SE analyses, the SE physical model was obtained as the multi-layer configurations. The obtained Ta2O5 thin film thickness was closely related with the measured result from the FE-SEM cross-sectional micrographs and the surface profiler. For the optical characteristic, the double layer physical model was best optimized with the Tauc Lorentz dispersion model for the most accurate results. In comparison, the SM technique also demonstrated a capability to determine both the film thickness and its refractive index only from some samples. Therefore, this study proved that the SE technique successfully and accurately determine both the physical and optical properties of the Ta2O5 thin films. © (2014) Trans Tech Publications, Switzerland.
Citation
Advanced Materials Research, 979, 244-247, 2014