High-sensitivity mems surface acoustic wave gyroscope chip with swiftlet sound wave enhancement

Abstract

The application relates to the technical field of acoustic surface wave gyroscopes, in particular to a high-sensitivity MEMS acoustic surface wave gyroscope chip with enhanced acoustic wave of imitated swiftlets, which comprises a silicon substrate, the upper surface of the silicon substrate is provided with a piezoelectric substrate, the upper surface of the piezoelectric substrate is provided with a delay line, the delay line comprises a metal dot array, two interdigital transducers and two reflectors, the two interdigital transducers are respectively located on the left and right sides of the metal dot array, and the two reflectors are respectively located on the front and back sides of the metal dot array. The application effectively solves the problem of low detection sensitivity of the existing acoustic surface wave gyroscope and is suitable for the fields of aerospace, navigation, robots, automobiles and the like.

Description

Technical Field

[0001] This invention relates to the field of surface acoustic wave gyroscope technology, specifically a high-sensitivity MEMS surface acoustic wave gyroscope chip that uses swiftlet-like acoustic wave enhancement. Background Technology

[0002] A surface acoustic wave (SAW) gyroscope is an angular velocity sensor based on the Coriolis effect and surface acoustic wave (SAW) technology. Its core principle is to measure angular velocity by detecting the effect of the Coriolis force caused by rotation on the propagation characteristics of SAW waves. SAW gyroscopes are widely used in aerospace, navigation, robotics, and automotive fields due to their advantages of small size, low power consumption, and low cost. However, in practical applications, existing SAW gyroscopes suffer from the following problems due to their structural limitations: First, the extremely weak Coriolis effect in existing SAW gyroscopes leads to low detection sensitivity. Second, the low conversion efficiency and high propagation loss of SAW waves further contribute to low detection sensitivity. Therefore, it is necessary to invent a high-sensitivity MEMS SAW gyroscope chip that enhances the acoustic wave effect, mimicking that of a swiftlet, to solve the problem of low detection sensitivity in existing SAW gyroscopes. Summary of the Invention

[0003] To address the problem of low detection sensitivity in existing surface acoustic wave gyroscopes, this invention provides a high-sensitivity MEMS surface acoustic wave gyroscope chip that incorporates swiftlet-like acoustic wave enhancement.

[0004] This invention is achieved using the following technical solution: A high-sensitivity MEMS surface acoustic wave gyroscope chip with swiftlet-like acoustic wave enhancement includes a silicon substrate; a piezoelectric substrate is disposed on the upper surface of the silicon substrate; a delay line is disposed on the upper surface of the piezoelectric substrate; the delay line includes a metal dot matrix, two interdigital transducers, and two reflectors; the two interdigital transducers are respectively located on the left and right sides of the metal dot matrix; the two reflectors are respectively located on the front and rear sides of the metal dot matrix.

[0005] Furthermore, a sound-absorbing adhesive is also provided on the upper surface of the silicon substrate, and the sound-absorbing adhesive is located to the right of the interdigital transducer.

[0006] Furthermore, the surface of the silicon substrate has perforated holes, and the perforated holes cover the delay lines through the piezoelectric substrate.

[0007] Furthermore, the piezoelectric substrate is a 128° YX-cut LiNbO3 piezoelectric substrate.

[0008] Furthermore, the metal dot matrix includes several rows. yA group of metal dots arranged equidistantly along the axial direction; each row of metal dots includes several along the axial direction. x Rectangular metal dots arranged at equal intervals along the axial direction; each rectangular metal dot in... x The length in the axial direction is x axial direction surface acoustic wave wavelength l x 1 / 2; each rectangular metal point in y The width in the axial direction is y axial direction surface acoustic wave wavelength l y 1 / 4; the center-to-center distance between two adjacent rectangular metal dots in each row of metal dot groups is l x The center-to-center distance between two adjacent rows of metal dots is l y / 2, and adjacent rows of metal dots in x Offset in axial direction l x / 2.

[0009] Furthermore, the rectangular metal dots are made of Au and have a thickness of 400nm~600nm.

[0010] Furthermore, the interdigital transducer adopts a fan-shaped single-phase unidirectional structure with six interdigitates, arranged equidistantly in the radial direction; wherein the widths of the first, second, fourth, and fifth interdigitates are all... x axial direction surface acoustic wave wavelength l x 1 / 8; the width of the third interdigitated finger and the width of the sixth interdigitated finger are both l x / 4; The distance between two adjacent interdigitated fingers is l x / 8.

[0011] Furthermore, the interdigital transducer is made of Al with a thickness of 1%. l x ~1.2% l x .

[0012] Furthermore, the reflector adopts a fan-shaped short-circuit grid structure with seven grid bars, which are arranged equidistantly in the radial direction; the width of each grid bar is [missing information]. y axial direction surface acoustic wave wavelength l y 1 / 8; the distance between two adjacent bars is l y / 4.

[0013] Furthermore, the reflector is made of Al with a thickness of 1%. l y ~1.2% l y .

[0014] Compared with existing surface acoustic wave (SAW) gyroscopes, the high-sensitivity MEMS SAW gyroscope chip with swiftlet-inspired acoustic enhancement described in this invention has the following advantages: First, this invention designs a metal dot array based on the SAW wavelength, thereby effectively enhancing the Coriolis effect and thus significantly improving detection sensitivity. Second, based on the SAW wavelength, this invention designs an interdigital transducer with a fan-shaped single-phase unidirectional structure, and a reflector with a fan-shaped short-circuit grid structure inspired by a swiftlet's ear. This effectively improves the conversion efficiency of SAW waves and reduces propagation loss, further enhancing detection sensitivity.

[0015] This invention effectively solves the problem of low detection sensitivity of existing surface acoustic wave gyroscopes and is applicable to aerospace, navigation, robotics, automotive and other fields. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of the present invention.

[0017] Figure 2 yes Figure 1 Rear view.

[0018] Figure 3 yes Figure 1 AA sectional view.

[0019] Figure 4 This is a schematic diagram of the structure of the metal dot matrix in this invention.

[0020] Figure 5 This is a schematic diagram of the interdigital transducer in this invention.

[0021] Figure 6 This is a schematic diagram of the reflector structure in this invention.

[0022] In the figure: 1-Silicon substrate, 2-Piezoelectric substrate, 3-Metal lattice, 4-Interdigital transducer, 5-Reflector, 6-Sound-absorbing adhesive. Detailed Implementation

[0023] A high-sensitivity MEMS surface acoustic wave gyroscope chip with swiftlet-like acoustic enhancement includes a silicon substrate 1; a piezoelectric substrate 2 is disposed on the upper surface of the silicon substrate 1; a delay line is disposed on the upper surface of the piezoelectric substrate 2; the delay line includes a metal dot matrix 3, two interdigital transducers 4, and two reflectors 5; the two interdigital transducers 4 are respectively located on the left and right sides of the metal dot matrix 3; the two reflectors 5 are respectively located on the front and rear sides of the metal dot matrix 3.

[0024] During operation, the interdigital transducer 4 located on the left is connected to the external power supply, and the interdigital transducer 4 located on the right is connected to the external detection circuit.

[0025] The specific working process is as follows: An external power supply applies an input voltage signal to the interdigital transducer 4 located on the left. This input voltage signal excites a surface acoustic wave (SAW) propagating along the upper surface of the piezoelectric substrate 2 through the inverse piezoelectric effect. During propagation, the SAW enters the metal dot array 3, is scattered by the metal dot array 3, is captured by two reflectors 5, and then reflected back to the metal dot array 3. After being scattered again by the metal dot array 3, it reaches the interdigital transducer 4 located on the right, and is then converted into an output voltage signal through the direct piezoelectric effect of the piezoelectric substrate 2. The output voltage signal is transmitted to an external detection circuit, which can calculate the frequency of the SAW based on the output voltage signal.

[0026] When there is no angular velocity input, the frequency of the surface acoustic wave remains constant. When an angular velocity input is present, the frequency of the surface acoustic wave changes due to the Coriolis effect, and this frequency change is proportional to the angular velocity. At this point, the external detection circuit can calculate the angular velocity based on the frequency change of the surface acoustic wave.

[0027] The upper surface of the silicon substrate 1 is also provided with sound-absorbing adhesive 6, and the sound-absorbing adhesive 6 is located to the right of the interdigital transducer 4. The sound-absorbing adhesive 6 can absorb excess surface acoustic waves, thereby suppressing the generation of stray echoes.

[0028] A perforated hole is formed on the surface of the silicon substrate 1, and the perforated hole covers the delay line through the piezoelectric substrate 2.

[0029] The piezoelectric substrate 2 is a LiNbO3 piezoelectric substrate with a 128° YX cut.

[0030] The metal dot matrix 3 includes several rows. y A group of metal dots arranged equidistantly along the axial direction; each row of metal dots includes several along the axial direction. x Rectangular metal dots arranged at equal intervals along the axial direction; each rectangular metal dot in... x The length in the axial direction is x axial direction surface acoustic wave wavelength l x 1 / 2; each rectangular metal point iny The width in the axial direction is y axial direction surface acoustic wave wavelength l y 1 / 4; the center-to-center distance between two adjacent rectangular metal dots in each row of metal dot groups is l x The center-to-center distance between two adjacent rows of metal dots is l y / 2, and adjacent rows of metal dots in x Offset in axial direction l x / 2. Based on this design, the metal lattice 3 effectively enhances the Coriolis effect, thereby effectively improving the detection sensitivity.

[0031] The rectangular metal dots are made of Au and have a thickness of 400nm~600nm.

[0032] The interdigitated transducer 4 adopts a fan-shaped single-phase unidirectional structure with six interdigitated fingers arranged equidistantly in the radial direction. The widths of the first, second, fourth, and fifth interdigitated fingers are all... x axial direction surface acoustic wave wavelength l x 1 / 8; the width of the third interdigitated finger and the width of the sixth interdigitated finger are both l x / 4; The distance between two adjacent interdigitated fingers is l x / 8. This design ensures single-phase, unidirectional propagation of surface acoustic waves while effectively increasing the contact area of ​​the interdigital transducer 4, thereby improving the conversion efficiency of surface acoustic waves and further enhancing detection sensitivity.

[0033] The interdigital transducer 4 is made of Al with a thickness of 1%. l x ~1.2% l x .

[0034] The reflector 5 adopts a fan-shaped short-circuit grid structure with seven grid bars, which are arranged equidistantly in the radial direction; the width of each grid bar is... y axial direction surface acoustic wave wavelength l y 1 / 8; the distance between two adjacent bars is l y / 4. This design mimics the ear of a swiftlet (swiftlets have large, flexible ears with a unique shape and folds along the edges, which effectively captures sound waves), giving it excellent surface acoustic wave (SAW) capture capabilities. This effectively reduces SAW propagation loss and further improves detection sensitivity.

[0035] The reflector 5 is made of Al and has a thickness of 1%. l y ~1.2% l y .

[0036] In practice, the perforations on the surface of the silicon substrate 1 are made using a deep reactive ion etching (DRIE) process.

[0037] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but all such changes and modifications fall within the scope of protection of the present invention.

Claims

1. A high-sensitivity MEMS surface acoustic wave gyroscope chip with swiftlet-like acoustic wave enhancement, characterized in that: The device includes a silicon substrate (1); a piezoelectric substrate (2) is disposed on the upper surface of the silicon substrate (1); a delay line is disposed on the upper surface of the piezoelectric substrate (2); the delay line includes a metal dot matrix (3), two interdigital transducers (4), and two reflectors (5); the two interdigital transducers (4) are located on the left and right sides of the metal dot matrix (3), respectively; the two reflectors (5) are located on the front and rear sides of the metal dot matrix (3), respectively.

2. The high-sensitivity MEMS surface acoustic wave gyroscope chip with swiftlet-like acoustic enhancement according to claim 1, characterized in that: The upper surface of the silicon substrate (1) is also provided with sound-absorbing adhesive (6), and the sound-absorbing adhesive (6) is located to the right of the interdigital transducer (4).

3. The high-sensitivity MEMS surface acoustic wave gyroscope chip with swiftlet-like acoustic enhancement according to claim 1, characterized in that: A perforated hole is formed on the surface of the silicon substrate (1), and the perforated hole covers the delay line through the piezoelectric substrate (2).

4. The high-sensitivity MEMS surface acoustic wave gyroscope chip with swiftlet-like acoustic enhancement according to claim 1, characterized in that: The piezoelectric substrate (2) is a 128° YX-cut LiNbO3 piezoelectric substrate.

5. The high-sensitivity MEMS surface acoustic wave gyroscope chip with swiftlet-like acoustic enhancement according to claim 1, characterized in that: The metal dot matrix (3) includes several rows. y A group of metal dots arranged equidistantly along the axial direction; each row of metal dots includes several along the axial direction. x Rectangular metal dots arranged at equal intervals along the axial direction; each rectangular metal dot in... x The length in the axial direction is x axial direction surface acoustic wave wavelength λ x 1 / 2; each rectangular metal point in y The width in the axial direction is y axial direction surface acoustic wave wavelength λ y 1 / 4; the center-to-center distance between two adjacent rectangular metal dots in each row of metal dot groups is λ x The center-to-center distance between two adjacent rows of metal dots is λ y / 2, and adjacent rows of metal dots in x Offset in axial direction λ x / 2.

6. The high-sensitivity MEMS surface acoustic wave gyroscope chip with swiftlet-like acoustic enhancement according to claim 5, characterized in that: The rectangular metal dots are made of Au and have a thickness of 400nm~600nm.

7. The high-sensitivity MEMS surface acoustic wave gyroscope chip with swiftlet-like acoustic enhancement according to claim 1, characterized in that: The interdigitated transducer (4) adopts a fan-shaped single-phase unidirectional structure with six interdigitated fingers arranged equidistantly along the radial direction; wherein the widths of the first, second, fourth, and fifth interdigitated fingers are all... x axial direction surface acoustic wave wavelength λ x 1 / 8; the width of the third interdigitated finger and the width of the sixth interdigitated finger are both λ x / 4; The distance between two adjacent interdigitated fingers is λ x / 8.

8. The high-sensitivity MEMS surface acoustic wave gyroscope chip with swiftlet-like acoustic enhancement according to claim 7, characterized in that: The interdigitated transducer (4) is made of Al with a thickness of 1%. λ x ~1.2% λ x .

9. The high-sensitivity MEMS surface acoustic wave gyroscope chip with swiftlet-like acoustic enhancement according to claim 1, characterized in that: The reflector (5) adopts a fan-shaped short-circuit grid structure with seven grid bars, which are arranged equidistantly in the radial direction; the width of each grid bar is... y axial direction surface acoustic wave wavelength λ y 1 / 8; the distance between two adjacent bars is λ y / 4.

10. The high-sensitivity MEMS surface acoustic wave gyroscope chip with swiftlet-like acoustic enhancement according to claim 9, characterized in that: The reflector (5) is made of Al with a thickness of 1%. λ y ~1.2% λ y .

Images