Abstract
The temperature- and field-dependent permittivities of fiber-textured Ba0.7Sr0.3TiO3 thin films grown by liquid-source metalorganic chemical vapor deposition were investigated as a function of film thickness. These films display a nonlinear dielectric response under conditions representative of those encountered in dynamic random access memories or other integrated capacitor applications. This behavior has the exact form expected for a classical nonlinear, nonhysteretic dielectric, as described in terms of a power series expansion of the free energy in the polarization as in the Landau-Ginzburg-Devonshire approach. Curie-Weiss-like behavior is exhibited above the bulk Curie point (∼300 K), although the ferroelectric phase transition appears frustrated. Small-signal capacitance measurements of films with different thicknesses (24-160 nm) indicate that only the first term in the power series expansion varies significantly with film thickness or temperature. Possible origins for this thickness dependence are discussed.
Original language | English |
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Pages (from-to) | 2497-2504 |
Number of pages | 8 |
Journal | Journal of Applied Physics |
Volume | 82 |
Issue number | 5 |
DOIs | |
State | Published - Sep 1 1997 |
Externally published | Yes |