Surface acoustic wave gyroscope chip structure based on acoustoelectric effect of graphene

Abstract

The invention provides a surface acoustic wave gyroscope chip structure based on a graphene acoustoelectric effect, and relates to the technical field of semiconductor sensor chips, the surface acoustic wave gyroscope chip structure comprises a piezoelectric substrate, and a surface acoustic wave resonator and a surface acoustic wave detector which are arranged on the surface of the piezoelectric substrate, the surface acoustic wave resonator comprises two oppositely arranged driving interdigital transducers, a wave energy modulation area is arranged between the two driving interdigital transducers, a first surface acoustic wave reflecting grating is arranged on the outer side of each driving interdigital transducer, and the surface acoustic wave resonators are used for generating primary surface acoustic waves on the piezoelectric substrate through the driving interdigital transducers. Standing waves corresponding to the primary surface acoustic wave reflecting grating are generated on the first surface acoustic wave reflecting grating; the surface acoustic wave detector comprises two graphene piezoresistive strips which are symmetrically arranged on the two sides of the wave energy modulation area, and a second surface acoustic wave reflecting grating is arranged on the outer side of each graphene piezoresistive strip. According to the invention, the sensitivity and the signal-to-noise ratio of the surface acoustic wave gyroscope chip can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor sensor chips, and in particular to a surface acoustic wave gyroscope chip structure based on graphene acoustoelectric effect. Background Art

[0002] The surface acoustic wave gyroscope uses micro-nano processing technology to deposit metal transducers on piezoelectric materials, and uses the influence of rotation on the propagation characteristics of surface acoustic waves to measure angular velocity. It can be regarded as a branch of MEMS gyroscope. It has the following advantages: it is made by MEMS technology, small size, low power consumption, can be mass-produced, and low cost; surface acoustic waves are mechanical waves, so they have strong anti-electromagnetic interference ability; because there is no vibration structure of MEMS vibration gyroscope, vacuum packaging is not required, so it has strong impact resistance, vibration ability, high reliability, and good long-term stability. Therefore, it has broad application prospects in the civilian field.

[0003] A Chinese patent with publication number CN115955210A discloses a periodic gradient surface acoustic wave filter and a multiplexer. The periodic gradient surface acoustic wave filter includes an interdigital transducer arranged on a piezoelectric substrate and reflection gratings on both sides of the interdigital transducer; the interdigital transducer is configured as a periodic resonance structure with at least two different wavelengths; the reflection grating is configured as a periodic grating structure matching the periodic resonance structure; the periodic grating structure and the periodic resonance structure form a resonant response to generate at least two transmission zeros, but the above scheme forms a resonant structure or a delay line structure, which is difficult to pick up a secondary surface acoustic wave signal, and the secondary surface acoustic wave signal actually picked up is a very small AC signal with an extremely low signal-to-noise ratio. Therefore, it is very necessary to provide a surface acoustic wave gyroscope chip structure based on the graphene acoustoelectric effect to improve the sensitivity and signal-to-noise ratio of the surface acoustic wave gyroscope chip. Summary of the invention

[0004] In view of this, the present invention proposes a surface acoustic wave gyroscope chip structure based on the graphene acoustoelectric effect. The surface acoustic wave resonator and the surface acoustic wave detector are integrated on the surface of the piezoelectric substrate, and graphene piezoresistive strips are made on the piezoelectric substrate material and the acoustoelectric effect of graphene is used to pick up the secondary surface acoustic wave, thereby improving the sensitivity and signal-to-noise ratio of the surface acoustic wave gyroscope chip.

[0005] The present invention provides a surface acoustic wave gyroscope chip structure based on graphene acoustoelectric effect, comprising a piezoelectric substrate and a surface acoustic wave resonator and a surface acoustic wave detector arranged on the surface of the piezoelectric substrate, wherein:

[0006] The surface acoustic wave resonator comprises two oppositely arranged driven interdigital transducers, a wave energy modulation area is arranged between the two driven interdigital transducers, a first surface acoustic wave reflection grating is arranged on the outer side of each driven interdigital transducer, the surface acoustic wave resonator is used to generate a primary surface acoustic wave on the piezoelectric substrate through the driven interdigital transducers, and generate a standing wave corresponding to the primary surface acoustic wave reflection grating on the first surface acoustic wave reflection grating;

[0007] The surface acoustic wave detector includes two graphene piezoresistive strips symmetrically arranged on both sides of the wave energy modulation zone, and a second surface acoustic wave reflection grating is arranged on the outside of each graphene piezoresistive strip. The surface acoustic wave detector is used to generate an effective acoustic current at the graphene piezoresistive strip after the standing wave forms a secondary surface acoustic wave.

[0008] Based on the above technical solution, preferably, the width of the graphene piezoresistive strip is 1 / 4 of the wavelength of the secondary surface acoustic wave, and the distance between the graphene piezoresistive strip and the wave energy modulation zone is the difference between the crest and trough of the secondary surface acoustic wave.

[0009] On the basis of the above technical scheme, preferably, the driven interdigital transducer includes a first bus bar, a second bus bar, a plurality of first interdigital electrodes and a plurality of second interdigital electrodes, the first interdigital electrodes and the second interdigital electrodes are arranged at equal intervals and staggered, one end of the plurality of first interdigital electrodes is connected to the first bus bar, and the other end of the plurality of first interdigital electrodes is spaced apart from the second bus bar, one end of the plurality of second interdigital electrodes is connected to the second bus bar, and the other end of the plurality of second interdigital electrodes is spaced apart from the first bus bar, the first interdigital electrodes and the second interdigital electrodes are both arranged in an arc shape, and the first interdigital electrodes and the second interdigital electrodes have the same curvature.

[0010] More preferably, the first surface acoustic wave reflection grating includes a plurality of first reflection gratings arranged at equal intervals, and the first reflection gratings are all arc-shaped and have the same curvature.

[0011] More preferably, the second surface acoustic wave reflection grating includes a plurality of second reflection gratings arranged at equal intervals, and the second reflection gratings are all curved and have the same curvature.

[0012] More preferably, the interdigital electrode width of the driven interdigital transducer is the same as the distance between any two adjacent interdigital electrodes, the spacing between any two adjacent first reflection gratings, the spacing between any two adjacent second reflection gratings and the interdigital electrode width of the driven interdigital transducer are all the same.

[0013] More preferably, it further comprises a plurality of metal pins, and both ends of the graphene piezoresistive bar and ends of the first bus bar and the second bus bar away from the wave energy modulation area are provided with the metal pins.

[0014] More preferably, a metal dot matrix is ​​arranged in the wave energy modulation area, and the metal dot matrix includes a plurality of columns of metal dot groups, and each row of the metal dot group includes a plurality of rectangular metal dots distributed at intervals.

[0015] More preferably, any two adjacent metal point groups are respectively arranged at the standing wave node position and the standing wave anti-node position of the wave energy modulation zone, and the standing wave node position and the standing wave anti-node position are alternately distributed.

[0016] More preferably, the material of the piezoelectric substrate is lithium niobate.

[0017] The surface acoustic wave gyroscope chip structure based on graphene acoustoelectric effect provided by the present invention has the following beneficial effects compared with the prior art:

[0018] (1) By integrating a surface acoustic wave resonator and a surface acoustic wave detector on the surface of a piezoelectric substrate, efficient excitation, propagation and detection of surface acoustic waves are achieved. The symmetrically arranged driving interdigital transducers cooperate with the first surface acoustic wave reflection grating to generate a stable primary surface acoustic wave and form a standing wave. At the same time, a graphene piezoresistive strip is made on the piezoelectric substrate material and the acoustoelectric effect of graphene is used to pick up the secondary surface acoustic wave, and the secondary surface acoustic wave signal is converted into a DC voltage for processing the secondary surface acoustic wave signal, thereby avoiding the use of an interdigital transducer to form a resonator or a delay line structure to pick up a very small AC secondary surface acoustic wave signal, thereby simplifying the interface circuit design, improving the sensitivity and signal-to-noise ratio of the surface acoustic wave gyroscope chip, and making the entire device easier to apply in engineering.

[0019] (2) By adopting an arc-shaped, equidistantly arranged driving interdigital transducer structure, combined with an arc-shaped, equidistantly arranged surface acoustic wave reflection grating, the conversion efficiency and the utilization rate of acoustic wave energy can be significantly improved. At the same time, by setting the width of the graphene piezoresistive strip to 1 / 4 of the wavelength of the secondary surface acoustic wave and precisely controlling the distance between it and the wave energy modulation zone, efficient modulation and detection of the surface acoustic wave energy can be achieved, thereby improving the detection sensitivity and signal conversion efficiency of the surface acoustic wave gyroscope chip. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 A schematic structural diagram of the surface acoustic wave gyroscope chip structure provided by the present invention;

[0022] Figure 2 A schematic diagram of the structural layout of the metal lattice provided by the present invention;

[0023] Figure 3 A circuit diagram of a Wheatstone half-bridge detection interface provided by the present invention.

[0024] Explanation of the reference numerals: 1. piezoelectric substrate; 2. surface acoustic wave resonator; 21. driven interdigital transducer; 22. first surface acoustic wave reflection grating; 3. surface acoustic wave detector; 31. graphene piezoresistive strip; 32. second surface acoustic wave reflection grating; 4. wave energy modulation region; 41. metal lattice; 5. metal electrode. DETAILED DESCRIPTION

[0025] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] Before introducing the embodiments of the present invention, some terms and their abbreviations involved in the embodiments of the present invention are first defined and explained.

[0027] Coriolis force: Due to inertia, a particle that moves in a straight line in a rotating system tends to continue moving in the original direction of motion. However, since the system itself is rotating, after a period of motion, the position of the particle in the system will change, and the direction of its original motion trend will deviate to a certain extent if observed from the perspective of the rotating system. When a particle moves in a straight line relative to an inertial system, its trajectory is a curve relative to the rotating system. Based on the rotating system, it is believed that there is a force that drives the trajectory of the particle to form a curve, and this force is the Coriolis force.

[0028] The present invention discloses a surface acoustic wave gyroscope chip structure based on graphene acoustoelectric effect, referring to Figure 1The surface acoustic wave gyroscope chip structure includes a piezoelectric substrate and a surface acoustic wave resonator 2 and a surface acoustic wave detector 3 arranged on the surface of the piezoelectric substrate, wherein:

[0029] The surface acoustic wave resonator 2 includes two oppositely arranged driven interdigital transducers 21, a wave energy modulation area 4 is arranged between the two driven interdigital transducers 21, and a first surface acoustic wave reflection grating 22 is arranged on the outer side of each driven interdigital transducer 21. The surface acoustic wave resonator 2 is used to generate a primary surface acoustic wave on the piezoelectric substrate by driving the interdigital transducers 21, and generate a standing wave corresponding to the primary surface acoustic wave reflection grating on the first surface acoustic wave reflection grating 22.

[0030] The driving interdigital transducer 21 includes a first bus bar, a second bus bar, a plurality of first interdigital electrodes and a plurality of second interdigital electrodes, the first interdigital electrodes and the second interdigital electrodes are arranged in an equidistant and staggered manner, the plurality of first interdigital electrodes are connected to the first bus bar at one end, and the other end of the plurality of first interdigital electrodes is arranged at intervals with the second bus bar, the plurality of second interdigital electrodes are connected to the second bus bar at one end, and the other end of the plurality of second interdigital electrodes is arranged at intervals with the first bus bar, the first interdigital electrodes and the second interdigital electrodes are both arranged in an arc shape, and the first interdigital electrodes and the second interdigital electrodes have the same curvature. The first surface acoustic wave reflection grating 22 includes a plurality of first reflection gratings arranged in an equidistant manner, the first reflection gratings are all in an arc shape and have the same curvature, and the material of the piezoelectric substrate is lithium niobate.

[0031] Furthermore, the width of the graphene piezoresistive strip 31 is 1 / 4 of the wavelength of the secondary surface acoustic wave, and the distance between the graphene piezoresistive strip 31 and the wave energy modulation region 4 is the difference between the distance between the crest and the trough of the secondary surface acoustic wave.

[0032] In this embodiment, by adopting an arc-shaped structure of equally spaced interdigitated driving interdigital transducers 21, combined with arc-shaped equally spaced surface acoustic wave reflection gratings, and selecting lithium niobate as the piezoelectric substrate material, the conversion efficiency and the utilization rate of acoustic wave energy can be significantly improved. At the same time, by setting the width of the graphene piezoresistive strip 31 to 1 / 4 of the wavelength of the secondary surface acoustic wave and accurately controlling the distance between it and the wave energy modulation area 4, efficient modulation and detection of surface acoustic wave energy can be achieved, thereby improving the detection sensitivity and signal conversion efficiency of the overall device, so that the structure has a better performance in the application of surface acoustic wave devices.

[0033] A metal dot matrix 41 is provided in the wave energy modulation area 4. The metal dot matrix 41 includes a plurality of columns of metal dot groups. Each row of metal dot groups includes a plurality of rectangular metal dots distributed at intervals. Any two adjacent metal dot groups are respectively provided at the standing wave node position and the standing wave anti-node position of the wave energy modulation area 4, and the standing wave node position and the standing wave anti-node position are distributed alternately.

[0034] In this embodiment, by setting a regularly arranged metal dot lattice 41 structure in the wave energy modulation area 4, and arranging adjacent metal dot groups at the standing wave node position and the standing wave anti-node position, an alternating distribution layout is formed, which can make full use of the characteristics of the standing wave node and the anti-node to achieve accurate modulation of the surface acoustic wave energy. This structural design can not only optimize the spatial distribution of wave energy, but also significantly improve the energy modulation effect, thereby improving the energy utilization efficiency and working performance of the surface acoustic wave device.

[0035] See also Figure 2 , Figure 2 The schematic diagram of the structural layout of the metal lattice 41 is to increase the inertial mass, thereby increasing the magnitude of the Coriolis force generated by the input measured angular velocity, thereby increasing the amplitude of the secondary surface acoustic wave and improving the sensitivity of the sensor. Since the Coriolis force is a category of inertial force distributed in a continuum, in order to reduce the offsetting effect of the Coriolis force in the piezoelectric substrate, metal nodes are placed at the nodes (maximum amplitude position) and anti-nodes (reverse maximum amplitude position) of the standing wave formed in the wave energy modulation area 4. The distance between the nodes is the wavelength of the primary surface acoustic wave, and the distance between the anti-nodes is also a wavelength. The metal lattices 41 on the positive and negative nodes are staggered. An optimized metal node structural layout of the metal lattice 41 is that the metal node on the anti-node is located in the middle of the metal nodes on the two positive nodes.

[0036] The surface acoustic wave detector 3 includes two graphene piezoresistive strips 31 symmetrically arranged on both sides of the wave energy modulation zone 4, and a second surface acoustic wave reflection grating 32 is arranged on the outer side of each graphene piezoresistive strip 31. The surface acoustic wave detector 3 is used to generate an effective acoustic current at the graphene piezoresistive strip 31 after the standing wave forms a secondary surface acoustic wave.

[0037] The second surface acoustic wave reflection grating 32 includes a plurality of second reflection gratings arranged at equal intervals, and the second reflection gratings are all curved and have the same curvature. The width of the interdigital electrode driving the interdigital transducer 21 is the same as the distance between any two adjacent interdigital electrodes, and the spacing between any two adjacent first reflection gratings, the spacing between any two adjacent second reflection gratings, and the width of the interdigital electrode driving the interdigital transducer 21 are all the same.

[0038] In this embodiment, by designing an arc-shaped interdigital transducer and a reflective grating structure, a standing wave of the resonant cavity is formed, and the scattering of the primary surface acoustic wave generated by driving the interdigital transducer 21 is reduced, thereby improving the sensitivity of the sensor. At the same time, the acoustic current generated by the scattering of the primary surface acoustic wave on the graphene piezoresistive strip 31 is reduced, thereby improving the signal-to-noise ratio of the effective secondary surface acoustic wave picked up by the graphene piezoresistive strip 31, and improving the resolution of the sensor.

[0039] Further, according to the principle of the acoustoelectric effect of graphene, the width of the graphene piezoresistive strip 31 should be 1 / 4 of the wavelength of the secondary surface acoustic wave, and when it is placed at the peak or trough of the secondary surface acoustic wave, the effective acoustic current generated is the largest and the sensor sensitivity is the largest. Therefore, the structural dimensions and placement position of the graphene piezoresistive strip 31 depend on the wavelength of the secondary surface acoustic wave. The wavelength of the secondary surface acoustic wave depends on the wavelength of the primary surface acoustic wave and the structural dimensions of the second surface acoustic wave reflection grating 32. When the instantaneous input angular velocity is a constant angular velocity, in order to improve the sensitivity of the sensor and maximize the standing wave energy formed, the width of the driving interdigital transducer 21 is generally made consistent with the spacing between the interdigital fingers, and the width and spacing of the first surface acoustic wave reflection grating 22 and the second surface acoustic wave reflection grating 32 are the same as the width of the driving interdigital transducer 21 and the spacing between the interdigital fingers. The wavelength of the primary surface acoustic wave depends on the structural dimensions of the driving interdigital transducer 21 and the primary surface acoustic wave reflection grating. According to the application requirements of the sensor and taking into account the actual processing technology level, the structural dimensions of the driving interdigital transducer 21 and the first surface acoustic wave reflection grating 22 are designed appropriately through theoretical calculation or finite element simulation to meet the application requirements of the sensor and the machinability of the sensor chip.

[0040] Working principle: When a driving AC voltage is applied to the driving IDT 21, a periodic electric field distribution is formed on the piezoelectric substrate due to the periodic structure of the driving IDT 21, thereby exciting a primary surface acoustic wave on the piezoelectric substrate. Under the action of the first surface acoustic wave reflection grating 22, the primary surface acoustic wave forms a standing wave corresponding to the primary surface acoustic wave in the acoustic wave resonant cavity. When there is a rotational angular velocity input, due to the Coriolis effect, the particle in the piezoelectric substrate will be affected by a magnitude of -2m(ω z ×V), under the action of the Coriolis force, a secondary surface acoustic wave is generated in a direction perpendicular to the direction of the particle motion speed and the input measured angular velocity, and the amplitude of the secondary surface acoustic wave is proportional to the input rotation angular velocity. Through the acoustic-electric effect of the graphene piezoresistive strip 31 arranged outside the wave energy modulation zone 4 (i.e., the resonant cavity), that is, due to the periodic propagation of the surface acoustic wave, the valence band and conductivity are periodically changed in the low-dimensional semiconductor material, thereby causing a current to be generated in the graphene piezoresistive strip 31 (in the case of a closed loop, and a voltage is generated in the case of an open circuit). The magnitude of the current generated in the graphene piezoresistive strip 31 is proportional to the amplitude of the surface acoustic wave. The acoustic current generated in the graphene piezoresistive strip 31 is a constant bias current generated by the scattering of the primary surface acoustic wave and the acoustic current generated by the secondary surface acoustic wave, wherein the acoustic current generated by the secondary surface acoustic wave contains information and is an effective signal.

[0041] In one example, the acoustic current is measured by selecting a suitable detection interface circuit, and the detection interface circuit may be a Wheatstone bridge, such as Figure 3As shown, the light-colored resistors at the upper left and lower right of the figure are graphene piezoresistive strips 31, and the dark-colored resistors at the lower left and upper right are fixed-value resistors externally connected to the detection interface circuit.

[0042] In the detection interface circuit, when there is no angular velocity input, the graphene piezoresistive strip 31 generates an acoustic current I1 under the action of the primary surface acoustic wave scattering. At this time, the equivalent DC resistance of the graphene piezoresistive strip 31 is R. When there is an input angular velocity to be measured, a secondary surface acoustic wave is generated due to the Coriolis effect, and an acoustic current I2 is generated on the graphene piezoresistive strip 31 due to the secondary surface acoustic wave, and the current in the graphene becomes I1+I2. At this time, the equivalent resistance of the graphene becomes R1, which causes a change in the output voltage V0. According to the principle of the Coriolis effect, the amplitude of the secondary surface acoustic wave and the amplitude of the primary surface acoustic wave are the same as the input angular velocity to be measured ω z The amplitude of the primary surface acoustic wave is proportional to the amplitude of the driving voltage of the driving interdigital transducer 21. When the driving voltage of the driving interdigital transducer 21 is fixed, the amplitude of the primary surface acoustic wave is a fixed value, and the vibration amplitude of the secondary surface acoustic wave is only proportional to the input measured angular velocity ω. z Since the magnitude of the acoustic current I2 in the graphene piezoresistive strip 31 caused by the secondary surface acoustic wave is proportional to the amplitude of the secondary surface acoustic wave, the acoustic current I2 is proportional to the input angular velocity ω z Directly proportional.

[0043] The interface circuit sets the appropriate Wheatstone bridge DC bias voltage V d By selecting and matching a suitable fixed resistor, the acoustic current I1 can be made zero, which can further improve the linearity of the surface acoustic wave gyroscope, so that the size of the acoustic current I2 caused by the angular velocity is expressed as a change in the equivalent resistance R1 of the graphene piezoresistive strip 31 in the Wheatstone bridge circuit, and the change in the output voltage V0 is tested through the interface circuit to determine the size of the input measured angular velocity. The detection interface circuit of a Wheatstone half-bridge structure provided in the above content is only a solution for the detection interface circuit, and other forms of interface circuits can also be used to measure the size of the acoustic current generated by the secondary surface acoustic wave in the graphene piezoresistive strip 31, so as to determine the input measured angular velocity ω z The sizes are too numerous to list here.

[0044] The surface acoustic wave gyroscope chip structure also includes a plurality of metal pins. Both ends of the graphene piezoresistive strip 31 and the ends of the first bus bar and the second bus bar away from the wave energy modulation area 4 are provided with metal pins.

[0045] In one example, a graphene piezoresistive strip 31 is prepared on a piezoelectric substrate material, and then an arc-shaped driven interdigital transducer 21, a first surface acoustic wave arc-shaped metal reflection grating, a metal pin, a second surface acoustic wave reflection grating 32 and a metal lattice 41 are prepared in sequence. The graphene piezoresistive strip 31 can be prepared on a piezoelectric substrate such as lithium niobate by a preparation process route of chemical vapor deposition and polymer transfer. The metal lattice 41 can utilize mature semiconductor processes, such as low-temperature chemical vapor deposition, sputtering technology, etc., and then form a structure of a corresponding shape by graphical etching.

[0046] The acoustoelectric effect of the graphene piezoresistive strip 31 is utilized, that is, due to the periodic propagation of surface acoustic waves in the piezoelectric medium, the valence band and conductivity in the low-dimensional semiconductor material are periodically changed, thereby causing a current to be generated in the graphene piezoresistive strip 31 (in the case of a closed circuit, and a voltage to be generated in the case of an open circuit). The magnitude of the current generated in the graphene piezoresistive strip 31 is proportional to the amplitude of the secondary surface acoustic wave. According to the Coriolis effect, the amplitude of the secondary surface acoustic wave is proportional to the input measured angular velocity. Through appropriate driving and detection interface circuits, the magnitude of the acoustic current in the graphene piezoresistive strip 31 is tested to obtain the magnitude of the measured angular velocity. Among them, the driving interdigital transducer 21 and the first surface acoustic wave reflection grating 22 are designed to be an arc structure, so that the energy of the primary surface acoustic wave excited by the driving interdigital transducer 21 can be concentrated to the wave energy modulation area 4, reducing the scattering of the primary surface acoustic wave, improving the sensitivity of the surface acoustic wave gyroscope, and reducing the acoustic current generated by the primary surface acoustic wave in the graphene piezoresistive strip 31, thereby improving the signal-to-noise ratio of the sensor and improving the accuracy of the sensor.

[0047] The magnitude of the input acceleration is detected by using the acoustic current generated by the acoustic-electric effect of the graphene piezoresistive strip 31, avoiding the use of an interdigital transducer to form a resonator or a delay line structure to pick up a very small AC secondary surface acoustic wave signal, converting the secondary surface acoustic wave signal into a DC current or voltage signal, and using, for example, a DC Wheatstone bridge to extract the effective signal of the secondary surface acoustic wave, thereby simplifying the interface circuit design and reducing the power consumption of the surface acoustic wave gyroscope chip. By optimizing the position of the interdigital transducer 21, the first surface acoustic wave reflection grating 22, the second surface acoustic wave reflection grating 32, the metal lattice 41 and the graphene piezoresistive strip 31 outside the wave energy modulation area 4 (resonant cavity), and the external structure of the graphene piezoresistive strip 31, the sensitivity of the sensor is improved to solve the problems of low sensitivity, complex interface circuit, and difficulty in engineering application of the surface acoustic wave gyroscope.

[0048] Unless otherwise defined, the technical terms or scientific terms used in the present invention shall have the usual meanings understood by persons with ordinary skills in the field to which the present invention belongs. The words "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, words such as "one" or "one" do not indicate quantity restrictions, but indicate the existence of at least one. Words such as "connect" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship also changes accordingly.

[0049] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A surface acoustic wave gyroscope chip structure based on graphene acoustoelectric effect, characterized in that: The invention comprises a piezoelectric substrate (1) and a surface acoustic wave resonator (2) and a surface acoustic wave detector (3) arranged on the surface of the piezoelectric substrate (1), wherein: The surface acoustic wave resonator (2) comprises two driven interdigital transducers (21) arranged opposite to each other, a wave energy modulation area (4) is arranged between the two driven interdigital transducers (21), and a first surface acoustic wave reflection grating (22) is arranged on the outer side of each driven interdigital transducer (21), and the surface acoustic wave resonator (2) is used to generate a primary surface acoustic wave on the piezoelectric substrate (1) through the driven interdigital transducers (21), and to generate a standing wave corresponding to the primary surface acoustic wave reflection grating on the first surface acoustic wave reflection grating (22); The surface acoustic wave detector (3) comprises two graphene piezoresistive strips (31) symmetrically arranged on both sides of the wave energy modulation zone (4), a second surface acoustic wave reflection grating (32) is arranged on the outside of each graphene piezoresistive strip (31), and the surface acoustic wave detector (3) is used to generate an effective acoustic current at the graphene piezoresistive strip (31) after a standing wave forms a secondary surface acoustic wave.

2. The surface acoustic wave gyroscope chip structure as claimed in claim 1, characterized in that: The width of the graphene piezoresistive strip (31) is 1 / 4 of the wavelength of the secondary surface acoustic wave, and the distance between the graphene piezoresistive strip (31) and the wave energy modulation zone (4) is the difference between the distance between the crest and the trough of the secondary surface acoustic wave.

3. The surface acoustic wave gyroscope chip structure as claimed in claim 1, characterized in that: The driven interdigital transducer (21) comprises a first bus bar, a second bus bar, a plurality of first interdigital electrodes and a plurality of second interdigital electrodes, wherein the first interdigital electrodes and the second interdigital electrodes are arranged in an equidistant and staggered manner, one end of the plurality of first interdigital electrodes is connected to the first bus bar, and the other end of the plurality of first interdigital electrodes is arranged at intervals from the second bus bar, one end of the plurality of second interdigital electrodes is connected to the second bus bar, and the other end of the plurality of second interdigital electrodes is arranged at intervals from the first bus bar, the first interdigital electrodes and the second interdigital electrodes are both arranged in an arc shape, and the first interdigital electrodes and the second interdigital electrodes have the same arc.

4. The surface acoustic wave gyroscope chip structure as claimed in claim 3, characterized in that: The first surface acoustic wave reflection grating (22) comprises a plurality of first reflection gratings arranged at equal intervals, and the first reflection gratings are all arc-shaped and have the same curvature.

5. The surface acoustic wave gyroscope chip structure as claimed in claim 1, characterized in that: The second surface acoustic wave reflection grating (32) comprises a plurality of second reflection gratings arranged at equal intervals, and the second reflection gratings are all curved and have the same curvature.

6. The surface acoustic wave gyroscope chip structure as claimed in claim 1, characterized in that: The interdigital electrode width of the driven interdigital transducer (21) is the same as the distance between any two adjacent interdigital electrodes, and the spacing between any two adjacent first reflection gratings, the spacing between any two adjacent second reflection gratings and the interdigital electrode width of the driven interdigital transducer (21) are all the same.

7. The surface acoustic wave gyroscope chip structure as claimed in claim 3, characterized in that: It also comprises a plurality of metal pins, and both ends of the graphene piezoresistive strip (31) and the ends of the first bus bar and the second bus bar away from the wave energy modulation area (4) are provided with the metal pins.

8. The surface acoustic wave gyroscope chip structure as claimed in claim 1, characterized in that: A metal dot matrix (41) is arranged in the wave energy modulation area (4), and the metal dot matrix (41) comprises a plurality of columns of metal dot groups, and each row of the metal dot group comprises a plurality of rectangular metal dots distributed at intervals.

9. The surface acoustic wave gyroscope chip structure as claimed in claim 8, characterized in that: Any two adjacent metal point groups are respectively arranged at the standing wave node position and the standing wave anti-node position of the wave energy modulation area (4), and the standing wave node position and the standing wave anti-node position are alternately distributed.

10. The surface acoustic wave gyroscope chip structure according to claim 1, characterized in that: The material of the piezoelectric substrate (1) is lithium niobate.

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