Piezoelectric element, method of manufacturing the same, surface acoustic wave element, and piezoelectric thin film resonance element
A piezoelectric element includes a single crystal piezoelectric film, wherein the single crystal piezoelectric film includes an aluminum nitride film and wherein a full width at half maximum at (002) diffraction peak of the aluminum nitride film is smaller than 1.00 degree.
1. A piezoelectric element comprising:
a piezoelectric film,
wherein the piezoelectric film is a laminated film including a first thin film and a highly c-axis oriented aluminum nitride film that is laminated to the first thin film,
wherein a full width at half maximum of a (002) diffraction peak of the aluminum nitride film is smaller than 1.00 degree, and
wherein the first thin film is a thin film having a negative linear expansion coefficient.
2. The piezoelectric element of claim 1 , further comprising
a base substrate,
wherein the piezoelectric film is arranged on the base substrate.
3. The piezoelectric element of claim 2 , wherein the base substrate is one selected from the group of a silicon (111) substrate, an SOI substrate in which an active layer is silicon (111), a SiC substrate, and a sapphire substrate.
4. The piezoelectric element of claim 1 , wherein the full width at half maximum at (002) diffraction peak of the aluminum nitride film is smaller than 0.36 degrees.
5. The piezoelectric element of claim 1 , wherein a film thickness of the aluminum nitride film is 70 nm or more.
6. The piezoelectric element of claim 1 , wherein a film thickness of the aluminum nitride film is 100 nm or more.
7. The piezoelectric element of claim 1 , wherein the piezoelectric film further includes a second thin film, and
wherein the second thin film is at least one selected from the group of a gallium nitride film, an aluminum gallium nitride film, and an aluminum nitride film containing scandium.
8. A surface acoustic wave element comprising the piezoelectric element of claim 1 .
9. A piezoelectric thin film resonance element comprising the piezoelectric element of claim 1 .
10. A method of manufacturing a piezoelectric element, comprising:
forming a piezoelectric film, which is a laminated film including a first thin film and a highly c-axis oriented aluminum nitride film that is laminated to the first thin film, on a base substrate,
wherein the aluminum nitride film is formed by one selected from the group of a CVD method and an MBE method,
wherein a full width at half maximum of a (002) diffraction peak of the aluminum nitride film is smaller than 1.00 degree, and
wherein the first thin film is a thin film having a negative linear expansion coefficient.
11. The method of claim 10 , wherein the base substrate is one selected from the group of a silicon (111) substrate, an SOI substrate in which an active layer is silicon (111), a SiC substrate, and a sapphire substrate.
12. The method of claim 10 , wherein the aluminum nitride film is formed by a MOCVD method.
13. The method of claim 12 , wherein the aluminum nitride film is formed by the MOCVD method in which trimethylaluminum and ammonia are used, the base substrate is set at 900 to 1,100 degrees C., and a pressure at the time of film formation is 10 to 15 kPa.
14. The method of claim 10 , wherein the full width at half maximum at (002) diffraction peak of the aluminum nitride film is smaller than 0.36 degrees.
15. The method of claim 10 , wherein a film thickness of the aluminum nitride film is 70 nm or more.
16. The method of claim 10 , wherein a film thickness of the aluminum nitride film is 100 nm or more.
17. The method of claim 10 , wherein the piezoelectric film further includes a second thin film, and
wherein the second thin film is at least one selected from the group of a gallium nitride film, an aluminum gallium nitride film, and an aluminum nitride film containing scandium.
18. The method of claim 10 , wherein the base substrate is peeled off by at least one selected from the group of etching, grinding, and polishing.