Volume 107, Number 2, July 2014
|Number of page(s)||6|
|Section||Condensed Matter: Structural, Mechanical and Thermal Properties|
|Published online||23 July 2014|
High-temperature phase transitions in SrHfO3: A Raman scattering study
1 Centre of Material Sciences, Institute of Interdisciplinary Studies (IIDS), University of Allahabad Allahabad 221002, India
2 Division of Materials Science, University of Tsukuba - Ibaraki 305-8573, Japan
3 Department of Physics and Institute of Functional Nano Materials, University of Puerto Rico San Juan, PR 00931-3343, USA
4 Department of Physics, Cavendish Laboratory - J. J. Thomson Avenue, Cambridge CB3 0HE, UK
Received: 25 April 2014
Accepted: 28 June 2014
SrHfO3 (SHO) is probably the leading gate oxide for the Si chip industry. The material is processed at and annealed at high temperature . Unfortunately there are two phase transitions in SrHfO3 in this temperature range, which can affect the quality of the final films processed, especially their channel mobility in SHO-based n-FET. To clarify these transitions and their impact on SrHfO3 processing, we report the temperature dependence of soft phonon modes by Raman spectroscopy. The 1023 K transition is found to be displacive (no disorder) and nearly second order. Significant effects are also seen in the orthorhombic-orthorhombic transition at 670 K.
PACS: 63.20.-e – Phonons in crystal lattices / 77.80.-e – Ferroelectricity and antiferroelectricity / 78.30.-j – Infrared and Raman spectra
© EPLA, 2014
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