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US 9,793,464 B2Granted
Ferroelectric film and method for manufacturing the same
AssigneeYoutec Co., Ltd.
InventorsTakeshi Kijima, Yuuji Honda
Life of this patent
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Abstract
To produce a ferroelectric film formed of a lead-free material. The ferroelectric film according to an aspect of the present invention includes a (K1-XNaX)NbO3 film or a BiFeO3 film having a perovskite structure and a crystalline oxide preferentially oriented to (001) formed on at least one of the upper side and lower side of the (K1-XNaX)NbO3 film or BiFeO3 film, and X satisfies the formula below 0.3≦X≦0.7.
Claims12
A method for manufacturing a ferroelectric film, comprising the steps of:
- forming, by coating a sol-gel solution containing K, Na and Nb on a substrate by a spin-coating method, a coated film on said substrate;
- forming, by calcining said coated film, a ferroelectric material film on said substrate;
- forming a first material film for forming a crystalline oxide in an island shape or in a film shape directly on said ferroelectric material film;
- and
- forming, by heat-treating said ferroelectric material film and said first material film for forming a crystalline oxide in an oxygen atmosphere, a ferroelectric film obtained by crystallizing said ferroelectric material film and said first material film for forming a crystalline oxide,
- wherein a first crystalline oxide obtained by crystallizing said first material film for forming a crystalline oxide is preferentially oriented to (001);
- wherein said first crystalline oxide is a bismuth layered-structure ferroelectric substance having a pseudo-perovskite structure or is a tungsten-bronze type ferroelectric substance;
- and
- wherein the resulting crystallized ferroelectric material film is a (K1-xNax)NbO3 film having a perovskite structure, and X satisfies the formula of 0<X<1.
6 more elements
A method for forming a ferroelectric film, comprising the steps of:
- forming a first material film for forming a crystalline oxide in an island shape or in a film shape on a substrate;
- forming, by coating a sol-gel solution containing K, Na and Nb on said first material film for forming a crystalline oxide by a spin-coating method, a coated film on said first material film for forming a crystalline oxide;
- forming, by calcining said coated film, a ferroelectric material film on said first material film for forming a crystalline oxide;
- forming a blocking film on said ferroelectric material film;
- and
- forming, by suppressing separation of K and Na from said ferroelectric material film by said blocking film while heat-treating said ferroelectric material film and said first material film for forming a crystalline oxide in an oxygen atmosphere, a ferroelectric film obtained by crystallizing said ferroelectric material film and said first material film for forming a crystalline oxide,
- wherein a first crystalline oxide obtained by crystallizing said first material film for forming a crystalline oxide is preferentially oriented to (001).
4 more elements
Dependencies are inferred from the claim text.