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Influence of the Microstructure on the Optical Characteristics of SrTiO3 thin films

Published online by Cambridge University Press:  03 March 2011

M. Gaidi ,
L. Stafford ,
A. Amassian ,
M. Chaker ,
J. Margot ,
L. Martinu  and
M. Kulishov
M. Gaidi*
Affiliation:
Institut National de la Recherche Scientifique Énergie, Matériaux et Télécommunications, Varennes, Québec J3X 1S2, Canada
L. Stafford
Affiliation:
Université de Montréal, Département de Physique, Montréal, Québec H3C 3J7, Canada
A. Amassian
Affiliation:
École Polytechnique de Montréal, Département de Génie Physique, Montréal, Québec H3C 3A7, Canada
M. Chaker
Affiliation:
Institut National de la Recherche Scientifique Énergie, Matériaux et Télécommunications, Varennes, Québec J3X 1S2, Canada
J. Margot
Affiliation:
Université de Montréal, Département de Physique, Montréal, Québec H3C 3J7, Canada
L. Martinu
Affiliation:
École Polytechnique de Montréal, Département de Génie Physique, Montréal, Québec H3C 3A7, Canada
M. Kulishov
Affiliation:
Adtek Photomask Inc, Montréal, Québec H4T 1J6, Canada
*
a)Address all correspondence to this author. e-mail: [email protected]
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Abstract

The influence of the microstructure of strontium-titanate-oxide (SrTiO3 or STO) thin films on their optical properties was investigated through an extensive characterization. The STO films have been deposited on silicon substrates by reactive pulsed laser deposition. The effect of the oxygen deposition pressure on the crystalline quality of the films was systematically studied by x-ray diffraction and scanning electron microscopy. Rutherford backscattering spectrometry, x-ray photoelectron spectroscopy, and secondary ion mass spectrometry were used to determine the atomic density and depth concentration profiles of the various species forming the film. The refractive index and extinction coefficient were obtained using variable angle spectroscopic ellipsometry. Based on this full characterization, it is demonstrated that the optical characteristics of the films are directly correlated to their microstructural properties. In particular, the refractive index increases with film density, while losses decrease. In addition, the interface between STO and Si is characterized by an interdiffusion layer. As the deposition pressure is enhanced, the width of this layer significantly increases, inducing localized inhomogeneity of the refractive index.

Keywords

MicrostructurePulsed laser deposition (PLD)Optical properties
Type
Articles
Information
Journal of Materials Research , Volume 20 , Issue 1 , January 2005 , pp. 68 - 74
Copyright
Copyright © Materials Research Society 2004

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