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High Temperature Raman Studies of Phase Transitions in Thin Film Dielectrics

Published online by Cambridge University Press:  22 February 2011

Gregory J. Exarhos*
Affiliation:
Pacific Northwest Laboratory, Richland, Washington 99352
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Abstract

Rapid and unambiguous characterization of crystalline phases in submicron sputter deposited TiO2 films on silica substrates can be inferred from measured Raman spictra. Pure anatase and rutile, mixed phase, and amorphous films to thicknesses of several hundred Angstroms and greater yield Raman spectra exhibiting little interference from the substrate when the appropriate component of the scattered light is analyzed. In situ Raman spectra were acquired as a function of temperature to 900°C using conventional radiant heating techniques and to temperatures near 2000°C using 10.6μ radiation from a CW CO2 laser as a localized heating source. Pulsed Raman excitation/gated deiection techniques were used to minimize blackbody radiation interference at these high temperatures. Anatase and amorphous TiO2 films transform irreversibly to the rutile phase at temperatures below 900°C while rutile appears to be stable at much higher temperatures. Measurements performed on uncoated silica substrates at temperatures where the glass becomes fluid suggest that the strongly crosslinked glass has partially transformed into a chain-like structure.

Type
Research Article
Copyright
Copyright © Materials Research Society 1985

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References

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