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Self-Poling of Thin BaTiO3 Films by Contact Potential Difference

Published online by Cambridge University Press:  10 February 2011

Igor Lubomirsky
Affiliation:
Dept. of Electrical Engineering, University of California at Los Angeles, CA, 90024
David T. Chang
Affiliation:
Dept. of Electrical Engineering, University of California at Los Angeles, CA, 90024
Oscar M. Stafsudd
Affiliation:
Dept. of Electrical Engineering, University of California at Los Angeles, CA, 90024
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Abstract

The substrate dependence of the ferroelectric properties of sol-gel derived BaTiO3 thin films was investigated. Thin (0.35 µm) films were deposited on Si substrates of various orientations and doping. Films deposited on p+ Si (1020 cm−3 B, 2% Ge) (110) were self-poled. The poling direction is self-restoring even after being reversed by an external bias or heated above the Curie temperature. The pyroelectric coefficient was not zero above the Curie point, which indicated that the films were permanently subjected to an electric field, which originates from the contact potential between the film and the substrate. Thisconclusion was confirmed by surface photo voltage spectroscopy. The possibility of a paraelectric to ferroelectric transition driven by an electric field due to the contact potential difference must be taken into account for dynamic random access memory (DRAM) applications.

Type
Research Article
Copyright
Copyright © Materials Research Society 1999

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References

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