Grain boundaries in barium strontium titanate thin films: structure, chemistry and influence on electronic properties

S. Stemmer; S. K. Streiffer; N. D. Browning; C. Basceri; A. I. Kingon

doi:10.1023/a:1008794520909

Grain boundaries in barium strontium titanate thin films: structure, chemistry and influence on electronic properties

S. Stemmer, S. K. Streiffer, N. D. Browning, C. Basceri, A. I. Kingon

Research output: Contribution to journal › Article › peer-review

26 Scopus citations

Abstract

In this paper, we investigate the role of grain boundaries in polycrystalline (Ba_xSr_1-x)Ti_1+yO_3+z films, grown by metal organic vapor deposition, in the accomodation of nonstoichiometry, as well as their role in the strong composition dependence of the electric and dielectric behavior observed in these films. High-spatial resolution electron energy-loss spectroscopy is used for the analysis of composition and structural changes at grain boundaries, as a function of film composition. The existence of amorphous, titanium rich, TiO₂-like phases at the grain boundaries of films with large amounts of excess Ti (y ≥ 0.08) may explain the non-monotonic resistance degradation behavior of the films as a function of Ti content. However, we show that a grain boundary phase model fails to explain the strong composition dependence of the dielectric behavior. Electron energy-loss spectra indicate a distortion of the Ti-O octahedra in the grain interiors in samples with increasing Ti excess. The decrease of the dielectric constant with increasing amounts of excess Ti is therefore more likely due to Ti accommodation in the grain interiors.

Original language	English
Pages (from-to)	209-221
Number of pages	13
Journal	Interface Science
Volume	8
Issue number	2
DOIs	https://doi.org/10.1023/a:1008794520909
State	Published - 2000
Externally published	Yes

Funding

S.S. would like to acknowledge the use of the microscopy facilities at the RRC at the University of Illinois at Chicago (NSF contract DMR-9601792). We also acknowledge funding by the U.S. Department of Energy, Basic Energy Sciences—Materials Science through contract no. DE-FG02-96ER45610 and contract #W-31-109-ENG-38, U.S. DOE—Office of Transportation Technology, and by DARPA, contract #8C392. BST samples were provided by Advanced Technology Materials, Inc., through the DARPA Ultradense Capacitor Materials Processing Partnership, NCSU contract ATM93-734-05.

Funders	Funder number
Basic Energy Sciences—Materials Science	DE-FG02-96ER45610, -31-109-ENG-38
DARPA Ultradense Capacitor Materials Processing Partnership
Office of Transportation Technology
U.S. Department of Energy
Defense Advanced Research Projects Agency	8C392
Defense Advanced Research Projects Agency
North Carolina State University	ATM93-734-05
North Carolina State University

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title = "Grain boundaries in barium strontium titanate thin films: structure, chemistry and influence on electronic properties",

abstract = "In this paper, we investigate the role of grain boundaries in polycrystalline (BaxSr1-x)Ti1+yO3+z films, grown by metal organic vapor deposition, in the accomodation of nonstoichiometry, as well as their role in the strong composition dependence of the electric and dielectric behavior observed in these films. High-spatial resolution electron energy-loss spectroscopy is used for the analysis of composition and structural changes at grain boundaries, as a function of film composition. The existence of amorphous, titanium rich, TiO2-like phases at the grain boundaries of films with large amounts of excess Ti (y ≥ 0.08) may explain the non-monotonic resistance degradation behavior of the films as a function of Ti content. However, we show that a grain boundary phase model fails to explain the strong composition dependence of the dielectric behavior. Electron energy-loss spectra indicate a distortion of the Ti-O octahedra in the grain interiors in samples with increasing Ti excess. The decrease of the dielectric constant with increasing amounts of excess Ti is therefore more likely due to Ti accommodation in the grain interiors.",

author = "S. Stemmer and Streiffer, {S. K.} and Browning, {N. D.} and C. Basceri and Kingon, {A. I.}",

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AU - Streiffer, S. K.

AU - Browning, N. D.

AU - Basceri, C.

AU - Kingon, A. I.

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Y1 - 2000

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Grain boundaries in barium strontium titanate thin films: structure, chemistry and influence on electronic properties

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