Film structure body and method for manufacturing the same
A film structure body has: a substrate that is a silicon substrate including an upper surface composed of a (100) plane; an orientation film including a zirconium oxide film that is cubic crystal (100)-oriented on the upper surface; and a conductive film including a platinum film that is cubic crystal (100)-oriented on the orientation film.
1. A film structure body, comprising:
a silicon substrate including a principal surface composed of a (100) plane;
a zirconium oxide film that is on the principal surface of the silicon substrate, has a cubic crystal structure, and is (100)-oriented; and
a conductive film that is on the zirconium oxide film, and includes a platinum film having a cubic crystal structure and being (100)-oriented,
wherein a <100> direction of the platinum film is along a <110> direction of the silicon substrate in the principal surface of the silicon substrate.
2. The film structure body according to claim 1 , further comprising:
a piezoelectric film that is on the conductive film, and includes a lead zirconate titanate film having a tetragonal crystal structure and being (001)-oriented.
3. The film structure body according to claim 2 , wherein, in an X-ray diffraction pattern of the piezoelectric film, by a θ-2θ method using a CuKα ray:
a diffraction angle of a diffraction peak of a (004) plane of lead zirconate titanate is 2θ 004 ;
relative permittivity of the piezoelectric film is ε r ;
2θ 004 ≤96.5°; and
ε r ≤450.
4. The film structure body according to claim 3 , wherein:
a residual polarization value of the piezoelectric film is P r ; and
P r ≥28 μC/cm 2 .
5. The film structure body according to claim 3 , wherein:
the conductive film is a first conductive film;
the film structure body further comprises a second conductive film on the piezoelectric film; and
the relative permittivity of the piezoelectric film is measured by applying an alternating voltage having a frequency of 1 kHz between the first conductive film and the second conductive film.
6. The film structure body according to claim 2 , wherein:
the zirconium oxide film is a first film;
the film structure body further comprises a second film that is on the conductive film and contains a composite oxide represented by Sr(Ti 1-z Ru z )O 3 and (100)-oriented in a pseudo-cubic representation;
the second film is in between the piezoelectric film and the conductive film; and
0≤z≤1.
7. A film structure body, comprising:
a silicon substrate including a principal surface composed of a (100) plane;
a zirconium oxide film that is on the principal surface of the silicon substrate, has a cubic crystal structure, and is (100)-oriented;
a conductive film that is on the zirconium oxide film and contains platinum having a cubic crystal structure and being (100)-oriented; and
a piezoelectric film that is on the conductive film and contains lead zirconate titanate having a tetragonal crystal structure and being (001)-oriented,
wherein:
a <100> direction of the platinum is along a <110> direction of the silicon substrate in the principal surface of the silicon substrate;
in an X-ray diffraction pattern of the piezoelectric film by a θ-2θ method using a CuKα ray:
a diffraction angle of a diffraction peak of a (004) plane of lead zirconate titanate is 2θ 004 ; and
relative permittivity of the piezoelectric film is ε r ;
2θ 004 ≤96.5°; and
ε r ≤450.
8. The film structure body according to claim 7 , wherein:
a residual polarization value of the piezoelectric film is P r ; and
P r ≥28 μC/cm 2 .
9. The film structure body according to claim 7 , wherein:
the conductive film is a first conductive film;
the film structure body further comprises a second conductive film on the piezoelectric film; and
the relative permittivity of the piezoelectric film is measured by applying an alternating voltage having a frequency of 1 kHz between the first conductive film and the second conductive film.
10. The film structure body according to claim 7 , wherein:
the zirconium oxide film is a first film;
the film structure body further comprises a second film that is on the conductive film and contains a composite oxide represented by Sr(Ti 1-z Ru z )O 3 and (100)-oriented in a pseudo-cubic representation;
the second film is in between the piezoelectric film and the conductive film; and
0≤z≤1.
11. The film structure body according to claim 7 , wherein:
the zirconium oxide film is epitaxially grown on the principal surface of the silicon substrate;
the conductive film is epitaxially grown on the zirconium oxide film; and
the piezoelectric film is epitaxially grown on the conductive film.