Ferroelectric film and method of producing same

Patent metadata

Field	Value
Publication number	US-2016279906-A1
Application number	US-201615080728-A
Country	US
Kind code	A1
Filing date	Mar 25, 2016
Priority date	Mar 26, 2015
Publication date	Sep 29, 2016
Grant date	—

Abstract

A ferroelectric film a plurality of fired films is provided. Each of the plurality of fired films is made of metal oxide in a perovskite structure including Pb, Zr, and Ti, a total content of Li, Na, and K in the each of the plurality of fired films is 3 mass ppm or less, and the total content of Li, Na, and K on one surface of each of the plurality of fired films is 5 times or more of the total concentration of Li, Na, and K on other surface of each of the plurality of fired films.

First claim

1 . A ferroelectric film made of a plurality of fired films, wherein
the ferroelectric film is made of metal oxide in a perovskite structure inclining Pb, Zr, and Ti, a total content of Li, Na, and K in the ferroelectric film is 3 mass ppm or less, and the total content of Li, Na, Na, and K on one surface of each of the plurality of fired films is 5 times or more of the total concentration of Li, Na, and K on other surface of each of the plurality of fired films.

2 . The ferroelectric film according to claim 1 , wherein a constant concentration gradient of the total content of Li, Na, and K is formed in a film thickness direction between the one surface and the other surface in each of the plurality of fired films.

3 . The ferroelectric film according to claim 2 , wherein the other surface of a first fired film is adjacent to the one surface of a second fired film, the first fired film and the second fired film being each of a pair of adjacent fired films among the plurality of the fired films.

4 . The ferroelectric film according to claim 3 , wherein the total content of Li, Na and K on the one surface of the second fired film is 5 times or more of the total content of Li, Na, and K on the other surface of the first fired film.

5 . A method of producing a ferroelectric film comprising the steps of:
applying a liquid composition for forming the ferroelectric film containing Pb, Zr and Ti on a substrate to form a precursor film at least once; calcining the precursor film in order to convert thereof to complex oxide to form a calcined film at least once; and firing the calcined film in order to crystallize thereof to form a fired film at least once, wherein the liquid composition for forming the ferroelectric film contains 3 mass % or more and 10 mass % or less of Li, Na and K as a total, and a wind speed of a carrier gas is 0.1 m/sec or more and 1.0 m/sec or less at a position 10 mm above from an upper surface of the substrate in the step of calcining.

6 . An electric part including the ferroelectric film according to claim 1 .

Assignees

• Mitsubishi Materials Corp

Inventors

• Sakurai Hideaki
• Fujii Jun
• Soyama Nobuyuki

Classifications

• H01G4/1245

  containing also titanates · CPC title

• C04B2235/6562

  Heating rate · CPC title

• C04B2235/768

  Perovskite structure ABO3 · CPC title

• C04B35/62218

  obtaining ceramic films, e.g. by using temporary supports · CPC title

• C04B2235/3203

  Lithium oxide or oxide-forming salts thereof · CPC title