KR-20260065793-A - Surface acoustic wave devices, radio frequency front-end modules, and electronic devices

Abstract

The present application relates to a surface acoustic wave element, a radio frequency front-end module, and an electronic device. The surface acoustic wave element comprises a piezoelectric layer and an interdigital electrode installed on a first surface of the piezoelectric layer, the interdigital electrode comprises a plurality of electrode fingers, the sound waves when the surface acoustic wave element operates comprise surface acoustic waves and bulk waves, the direction in which the surface acoustic waves propagate is the X direction, the first characteristic thickness of the surface acoustic wave element is T y , the thickness of the piezoelectric layer is D y , and the thickness of the piezoelectric layer and the first characteristic thickness are The conditions are satisfied, and the piezoelectric layer includes a piezoelectric crystal, and the size of the first characteristic thickness is determined according to the centerline spacing of two adjacent electrode fingers, the bulk wave sound speed along the X direction of the piezoelectric crystal, and the operating frequency. By limiting the thickness of the piezoelectric layer through the first characteristic thickness, the piezoelectric layer is prevented from becoming excessively thick and affecting the acoustic function of the rest of the structure, thereby improving the operating performance of the surface acoustic wave element.

Inventors

• 리 양
• 두 보
• 리우 민쥔
• 왕 화레이
• 니 지엔싱

Assignees

• 라드록 (충칭) 마이크로일렉트로닉스 컴퍼니 리미티드

Dates

Publication Date

20260511

Application Date

20250918

Priority Date

20241028

Claims (20)

1. In a surface acoustic wave device, It includes a piezoelectric layer and an interdigital electrode installed on a first surface of the piezoelectric layer, wherein the interdigital electrode includes a plurality of electrode fingers. When the above surface acoustic wave element is operating, the sound waves include surface acoustic waves and bulk waves, and the direction in which the surface acoustic waves propagate is the X direction, and The first characteristic thickness of the surface acoustic wave element is T y , the thickness of the piezoelectric layer is D y , and the thickness of the piezoelectric layer and the first characteristic thickness are Satisfying the conditions, A surface acoustic wave device characterized in that the piezoelectric layer comprises a piezoelectric crystal, and the size of the first characteristic thickness is determined according to the centerline spacing of two adjacent electrode fingers, the bulk wave sound speed along the X direction of the piezoelectric crystal, and the operating frequency.
2. In paragraph 1, The above first characteristic thickness is and, the centerline spacing of the two adjacent electrode fingers is P, the bulk wave sound speed along the X direction of the piezoelectric crystal is V b1 , and the operating frequency is A surface acoustic wave element characterized in that, at the above operating frequency, the bulk wave wavelength following the X direction of the piezoelectric crystal is λ1 .
3. In paragraph 2, When the frequency of the surface acoustic wave that excites the above interdigital electrode is the surface acoustic wave resonance frequency or the surface acoustic wave anti-resonance frequency, the thickness of the piezoelectric layer and the first characteristic thickness are A surface acoustic wave device characterized by satisfying conditions.
4. In paragraph 2, A surface acoustic wave device characterized in that when the frequency of the surface acoustic wave excited by the above interdigital electrode is the surface acoustic wave resonance frequency or the surface acoustic wave anti-resonance frequency, the thickness of the piezoelectric layer is smaller than the first characteristic thickness.
5. In paragraph 2, When the frequency of the surface acoustic wave that excites the above interdigital electrode is the surface acoustic wave resonance frequency or the surface acoustic wave anti-resonance frequency, the thickness of the piezoelectric layer and the first characteristic thickness are A surface acoustic wave device characterized by satisfying conditions.
6. In paragraph 2, The surface acoustic wave element further comprises a temperature compensation layer, and is characterized in that, along the thickness direction of the piezoelectric layer, the temperature compensation layer is installed on one side facing away from the interdigital electrode of the piezoelectric layer.
7. In paragraph 6, When the frequency of the surface acoustic wave that excites the above interdigital electrode is the surface acoustic wave resonance frequency or the surface acoustic wave anti-resonance frequency, the sum of the thickness of the temperature compensation layer and the thickness of the piezoelectric layer is H, and the sum of the first characteristic thickness, the thickness of the temperature compensation layer and the thickness of the piezoelectric layer is A surface acoustic wave device characterized by satisfying conditions.
8. In Paragraph 7, When the frequency of the surface acoustic wave that excites the above interdigital electrode is the surface acoustic wave resonance frequency or the surface acoustic wave anti-resonance frequency, the sum of the first characteristic thickness, the thickness of the temperature compensation layer, and the thickness of the piezoelectric layer is A surface acoustic wave device characterized by satisfying conditions.
9. In paragraph 6, When the narrow angle between the propagation direction of the bulk wave that the inter-digital electrode excites into the piezoelectric layer and the first surface is equal to the first enhancement angle θ, the bulk wave in the piezoelectric layer and the temperature compensation layer is in an enhanced state, the propagation speed of the bulk wave that the inter-digital electrode excites into the piezoelectric layer and the temperature compensation layer is V0 , and the first enhancement angle and the propagation speed of the bulk wave in the piezoelectric layer and the temperature compensation layer are Satisfying the equation, the surface acoustic wave frequency of the surface acoustic wave element is And, the sum of the thickness of the temperature compensation layer and the thickness of the piezoelectric layer is Satisfying the conditions, and the above surface acoustic wave frequency A surface acoustic wave device characterized by being a surface acoustic wave resonance frequency or a surface acoustic wave anti-resonance frequency.
10. In Paragraph 9, The thickness of the temperature compensation layer is D w , and the thickness of the temperature compensation layer and the thickness of the piezoelectric layer are A surface acoustic wave device characterized by satisfying conditions.
11. In any one of paragraphs 1 through 10, A surface elastic wave device characterized in that when the narrow angle between the propagation direction of the bulk wave that the inter-digital electrode excites into the piezoelectric layer and the first surface is equal to the first enhancement angle θ, the bulk wave in the piezoelectric layer is in an enhanced state, and the bulk wave wavelength λ B1 that the inter-digital electrode excites into the piezoelectric layer is a bulk wave wavelength that is in an enhanced state in the piezoelectric layer.
12. In Paragraph 11, The centerline spacing of the two adjacent electrode fingers is P, the first reinforcement angle is θ, and the first reinforcement angle is Satisfying the equation, V B1 is the bulk wave sound speed within the piezoelectric layer, and A surface acoustic wave device characterized in that is an operating frequency, λ B1 is a bulk wave wavelength that excites the interdigital electrode within the piezoelectric layer, and the range of the first enhancement angle θ satisfies 0° < θ < 180°.
13. In any one of paragraphs 1 through 10, The above surface acoustic wave element includes a functional layer, and along the thickness direction of the piezoelectric layer, the functional layer is installed on one side facing away from the interdigital electrode of the piezoelectric layer, and The second characteristic thickness of the surface acoustic wave element is Td , the thickness of the functional layer is Dd , and the thickness of the functional layer and the second characteristic thickness are Satisfying the conditions, A surface acoustic wave element characterized by determining the magnitude of the second characteristic thickness according to the bulk wave sound speed and operating frequency along the X direction of the material of the above functional layer.
14. In Paragraph 13, The above second characteristic thickness is Satisfying the equation, the centerline spacing of the two adjacent electrode fingers is P, the bulk wave sound speed along the X direction of the material of the functional layer is Vb2 , and the operating frequency is A surface acoustic wave element characterized in that λ2 is a wavelength corresponding to the bulk wave sound speed along the X direction of the material of the functional layer at the above operating frequency.
15. In Paragraph 14, When the frequency of the surface acoustic wave that excites the above interdigital electrode is greater than or equal to the surface acoustic wave resonance frequency or the surface acoustic wave anti-resonance frequency, the thickness of the functional layer and the second characteristic thickness are A surface acoustic wave device characterized by satisfying conditions.
16. In Paragraph 14, A surface acoustic wave device characterized in that when the frequency of the surface acoustic wave that excites the interdigital electrode is greater than or equal to the surface acoustic wave resonance frequency or the surface acoustic wave anti-resonance frequency, the thickness of the functional layer is smaller than the second characteristic thickness.
17. In Paragraph 14, When the frequency of the surface acoustic wave that excites the above interdigital electrode is greater than or equal to the surface acoustic wave resonance frequency or the surface acoustic wave anti-resonance frequency, the thickness of the functional layer and the second characteristic thickness are A surface acoustic wave device characterized by satisfying conditions.
18. In Paragraph 13, The surface acoustic wave element comprises a single-crystal silicon layer, wherein, along the thickness direction of the piezoelectric layer, the single-crystal silicon layer is installed on a surface facing away from the piezoelectric layer of the functional layer, and the spatial angle between the <110> crystal aromatics of the single-crystal silicon layer and the propagation direction of the surface acoustic wave that excites the plurality of interdigital electrodes on the first surface is 10° or less.
19. In Paragraph 18, A surface acoustic wave device characterized in that the propagation direction of the surface acoustic wave excited by the <110> crystal aromatics of the single-crystal silicon layer and the plurality of interdigital electrodes on the first surface is parallel.
20. In Paragraph 13, A surface acoustic wave device characterized in that the material of the functional layer has anisotropy or isotropy.

Description

Surface acoustic wave devices, radio frequency front-end modules, and electronic devices The present application relates to the field of radio frequency, and more specifically to a surface acoustic wave element, a radio frequency front-end module including said surface acoustic wave element, and an electronic device including said radio frequency front-end module. The present application claims priority based on the Chinese patent application filed on October 29, 2024, with application number 202411514619.4 and title "Surface acoustic wave element, radio frequency front-end module and electronic device", and the Chinese patent application filed on October 28, 2024, with application number 202411513291.4 and title "Surface acoustic wave element, radio frequency front-end module and electronic device". In the field of radio frequency, surface acoustic wave devices typically consist of a piezoelectric substrate and interdigital electrodes. Interconversion between electrical signals and acoustic signals is achieved through the alignment of the interdigital electrodes on the piezoelectric substrate with the piezoelectric substrate itself. In conventional technology, different functional layers are installed beneath a piezoelectric substrate to control the performance of inter-digital electrodes and enable characteristics such as a high quality factor (Q value) and a low temperature coefficient of frequency (TCF). However, the development efficiency of conventional technology is relatively low because the theory regarding the installation of functional layers is not yet perfect. When the installation of functional layers is not rational, it becomes difficult for the inter-digital electrode to achieve the intended effects. FIG. 1 is a structural diagram of an electronic device provided in one embodiment of the present application. FIG. 2 is a structural diagram of a radio frequency front-end module provided in one embodiment of the present application. FIG. 3 is a structural diagram of a filter provided in one embodiment of the present application. FIG. 4 is another structural diagram of a filter provided in one embodiment of the present application. FIG. 5 is a structural diagram of a surface acoustic wave element provided in one embodiment of the present application. FIG. 6 is a cross-sectional structural diagram of a surface acoustic wave element provided in one embodiment of the present application. FIG. 7 is an enlarged cross-sectional view of a surface acoustic wave element provided in one embodiment of the present application. FIG. 8 is a contrast diagram of the admittance curve of a surface acoustic wave element provided in one embodiment of the present application. FIG. 9 is a local cross-sectional structure diagram of a surface acoustic wave element provided in one embodiment of the present application. FIG. 10 is a different local cross-sectional structure of a surface acoustic wave element provided in one embodiment of the present application. FIG. 11 is a local curve diagram of the relationship between the first reinforcement angle of the piezoelectric layer of a surface acoustic wave element and the bulk wave sound speed provided in one embodiment of the present application. FIG. 12 is another structural diagram of a surface acoustic wave element provided in one embodiment of the present application. FIG. 13 is another cross-sectional structural diagram of a surface acoustic wave element provided in one embodiment of the present application. FIG. 14 is another enlarged cross-sectional view of a surface acoustic wave element provided in one embodiment of the present application. FIG. 15 is a schematic diagram of the conduction curve of a surface acoustic wave element provided in one embodiment of the present application. FIG. 16 is another local cross-sectional structure of a surface acoustic wave element provided in one embodiment of the present application. FIG. 17 is a structural diagram of a surface acoustic wave element presented in an embodiment of the present application. FIG. 18 is a schematic diagram of the bulk wave excitation of a surface acoustic wave element presented in an embodiment of the present application. FIG. 19 is a schematic diagram showing the sound waves of a surface elastic wave element presented in the embodiment of the present application penetrating into a sound velocity layer. FIG. 20 is a structural diagram of the deformation method of a surface acoustic wave element presented in the embodiment of the present application. FIG. 21 is a curve showing how the surface wave sound velocity of an embodiment of the present application changes according to the thickness of the piezoelectric layer. FIG. 22 is a curve diagram showing how the surface wave sound velocity of an embodiment of the present application changes according to the thickness of the sound velocity layer. To facilitate understanding of the present application, the application is described more comprehensively be