A surface acoustic wave gyroscope chip structure based on the graphene acousto-electric effect

Abstract

The present invention provides a surface acoustic wave gyroscope chip structure based on the graphene acousto-electric effect, which relates to the technical field of semiconductor sensor chips. It includes a piezoelectric substrate and a surface acoustic wave resonator and a surface acoustic wave detector disposed on the surface of the piezoelectric substrate. The surface acoustic wave resonator includes two oppositely disposed driving interdigital transducers, a wave energy modulation region is provided between the two driving interdigital transducers, and a first surface acoustic wave reflection grating is disposed outside each driving interdigital transducer. The surface acoustic wave resonator is used to generate a primary surface acoustic wave on the piezoelectric substrate through the driving interdigital transducers and generate a standing wave corresponding to the primary surface acoustic wave reflection grating on the first surface acoustic wave reflection grating; the surface acoustic wave detector includes two graphene piezoresistive strips symmetrically disposed on both sides of the wave energy modulation region, and a second surface acoustic wave reflection grating is disposed outside each graphene piezoresistive strip. The present invention helps to improve the sensitivity and signal-to-noise ratio of the surface acoustic wave gyroscope chip.

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 the graphene acousto-electric effect. Background Art

[0002] A surface acoustic wave gyroscope uses micro-nano processing technology to deposit metal transducers on a piezoelectric material, and measures the angular velocity by utilizing the influence of rotation on the propagation characteristics of surface acoustic waves. It can be regarded as a branch of MEMS gyroscopes. It has the following advantages: fabricated by MEMS process, small in size, low in power consumption, can be mass-produced, and low in cost; surface acoustic waves belong to mechanical waves, so it has strong anti-electromagnetic interference ability; since there is no vibration structure in MEMS vibration gyroscopes and no vacuum packaging is required, it has strong anti-shock and vibration resistance, high reliability, and good long-term stability. Therefore, it has a wide range of application prospects in the civilian field.

[0003] Chinese Patent with publication number CN115955210A discloses a periodic gradient surface acoustic wave filter and multiplexer. The periodic gradient surface acoustic wave filter includes interdigital transducers disposed on a piezoelectric substrate and reflection gratings on both sides of the interdigital transducers; the interdigital transducers are configured to have a periodic resonance structure with at least two different wavelengths; the reflection gratings are configured to be periodic grating structures matching the periodic resonance structure; the periodic grating structure and the periodic resonance structure form a resonance response to generate at least two transmission zeros. However, it is difficult to pick up the secondary surface acoustic wave signal for the above-mentioned scheme to form a resonance structure or a delay line structure, and the actually picked-up secondary surface acoustic wave signal is a very tiny 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 acousto-electric 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 acousto-electric effect. By integrating a surface acoustic wave resonator and a surface acoustic wave detector on the surface of a piezoelectric substrate, and simultaneously fabricating graphene piezoresistive strips on the piezoelectric substrate material and utilizing the acousto-electric effect of graphene to pick up the secondary surface acoustic wave, the sensitivity and signal-to-noise ratio of the surface acoustic wave gyroscope chip are improved.

[0005] The present invention provides a surface acoustic wave gyroscope chip structure based on the graphene acousto-electric effect, including a piezoelectric substrate and a surface acoustic wave resonator and a surface acoustic wave detector disposed on the surface of the piezoelectric substrate, wherein,

[0006] The surface acoustic wave resonator includes two oppositely arranged driving interdigital transducers, a wave energy modulation region is arranged between the two driving interdigital transducers, a first surface acoustic wave reflection grating is arranged outside each driving interdigital transducer, and the surface acoustic wave resonator is used to generate a primary surface acoustic wave on the piezoelectric substrate through the driving interdigital transducer 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 region, a second surface acoustic wave reflection grating is arranged outside each graphene piezoresistive strip, and the surface acoustic wave detector is used to generate an effective acoustic current at the graphene piezoresistive strip after a standing wave forms a secondary surface acoustic wave.

[0008] On the basis of the above technical solutions, 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 region is the difference between the distance of the wave crest and the wave trough of the secondary surface acoustic wave.

[0009] On the basis of the above technical solutions, preferably, the driving interdigital transducer includes a first bus bar, a second bus bar, a plurality of first finger electrodes and a plurality of second finger electrodes. The first finger electrodes and the second finger electrodes are arranged in an equidistant and staggered manner. One end of the plurality of first finger electrodes is connected to the first bus bar, and the other ends of the plurality of first finger electrodes are spaced from the second bus bar. One end of the plurality of second finger electrodes is connected to the second bus bar, and the other ends of the plurality of second finger electrodes are spaced from the first bus bar. The first finger electrodes and the second finger electrodes are both arc-shaped, and the arcs of the first finger electrodes and the second finger electrodes are the same.

[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 arc.

[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 arc-shaped and bent and have the same arc.

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

[0013] More preferably, it further includes a plurality of metal pins, and the metal pins are provided at both ends of the graphene piezoresistive strip and at one ends of the first bus bar and the second bus bar away from the wave energy modulation region.

[0014] More preferably, a metal lattice is provided in the wave energy modulation region, and the metal lattice includes multiple columns of metal dot groups, and each row of metal dot groups includes a plurality of rectangular metal dots distributed at intervals.

[0015] More preferably, any two adjacent metal dot groups are respectively arranged at the standing wave node position and the standing wave anti-node position of the wave energy modulation region, 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 the graphene acousto-electric 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 the piezoelectric substrate, the efficient excitation, propagation and detection of surface acoustic waves are realized. The symmetrically arranged driving interdigital transducer cooperates 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 fabricated on the piezoelectric substrate material, and the acousto-electric 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, 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 whole device easier to be applied in engineering.

[0019] (2) By adopting the structure of the driving interdigital transducer arranged in an arc-shaped and equally spaced staggered manner, combined with the surface acoustic wave reflection grating arranged in an arc-shaped and equally spaced manner, 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 region, the efficient modulation and detection of surface acoustic wave energy can be realized, thereby improving the detection sensitivity and signal conversion efficiency of the surface acoustic wave gyroscope chip. Description of the Drawings

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

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

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

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

[0024] Explanation of reference numerals: 1, piezoelectric substrate; 2, surface acoustic wave resonator; 21, driving 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 implementation manners

[0025] The following will combine the implementation manners of the present invention to clearly and completely describe the technical solutions in the implementation manners of the present invention. Obviously, the described implementation manners are only some implementation manners of the present invention, rather than all implementation manners. Based on the implementation manners in the present invention, all other implementation manners obtained by those of ordinary skill in the art without creative efforts belong to 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: A particle moving in a straight line in a rotating system, due to inertia, has a tendency to continue moving along 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 tendency, when observed from the perspective of the rotating system, will deviate to a certain extent. 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 considered that there is a force driving the particle's motion trajectory 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 the graphene acousto - electric effect, referring to Figure 1, the surface acoustic wave gyroscope chip structure includes a piezoelectric substrate and a surface acoustic wave resonator 2 and a surface acoustic wave detector 3 disposed on the surface of the piezoelectric substrate. Among them,

[0029] The surface acoustic wave resonator 2 includes two relatively arranged driving interdigital transducers 21. A wave energy modulation region 4 is provided between the two driving interdigital transducers 21. A first surface acoustic wave reflection grating 22 is provided outside each driving interdigital transducer 21. The surface acoustic wave resonator 2 is used to generate a primary surface acoustic wave on the piezoelectric substrate through the driving interdigital transducer 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 finger electrodes, and a plurality of second finger electrodes. The first finger electrodes and the second finger electrodes are arranged in an equidistant staggered manner. One end of the plurality of first finger electrodes is connected to the first bus bar, and the other ends of the plurality of first finger electrodes are spaced from the second bus bar. One end of the plurality of second finger electrodes is connected to the second bus bar, and the other ends of the plurality of second finger electrodes are spaced from the first bus bar. The first finger electrodes and the second finger electrodes are both arranged in an arc shape, and the arcs of the first finger electrodes and the second finger electrodes are the same. And the first surface acoustic wave reflection grating 22 includes a plurality of first reflection gratings arranged at equal intervals. The first reflection gratings are all in an arc shape and have the same arc. 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 of the wave crest and the wave trough of the secondary surface acoustic wave.

[0032] In this embodiment, by adopting the structure of the driving interdigital transducer 21 arranged in an equidistant staggered manner with an arc shape, combined with the surface acoustic wave reflection grating arranged in an arc shape at equal intervals, and selecting lithium niobate as the piezoelectric substrate material, the transducer efficiency and the utilization rate of the 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 precisely controlling the distance between it and the wave energy modulation region 4, the efficient modulation and detection of the surface acoustic wave energy can be realized, thereby improving the detection sensitivity and signal conversion efficiency of the overall device, making this structure have better performance in the application of surface acoustic wave devices.

[0033] A metal lattice 41 is provided in the wave energy modulation region 4. The metal lattice 41 includes multiple 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 arranged at the standing wave node position and the standing wave antinode position of the wave energy modulation region 4, and the standing wave node position and the standing wave antinode position are alternately distributed.

[0034] In this embodiment, by arranging a regularly arranged metal dot matrix 41 structure in the wave energy modulation region 4 and arranging adjacent metal dot groups at the standing wave node positions and standing wave anti-node positions respectively to form an alternating distribution layout, the characteristics of the standing wave nodes and anti-nodes can be fully utilized to achieve precise modulation of the surface acoustic wave energy. This structural design can not only optimize the spatial distribution of the 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] Please refer to Figure 2 , Figure 2 which is a schematic diagram of the structural layout of the metal dot matrix 41. The function of the metal dot matrix 41 is to increase the inertial mass, thereby increasing the magnitude of the Coriolis force generated due to the input measured angular velocity, increasing the amplitude of the secondary surface acoustic wave, and improving the sensitivity of the sensor. Since the Coriolis force belongs to the category of inertial forces distributed in a continuum, in order to reduce the cancellation effect of the Coriolis force in the piezoelectric substrate, metal nodes are placed at the nodes (the positions with the maximum amplitude) and anti-nodes (the positions with the maximum reverse amplitude) of the standing wave formed in the wave energy modulation region 4. The distance between the nodes is the wavelength of the primary surface acoustic wave, and the distance between the anti-nodes is also one wavelength. The metal dot matrices 41 on the positive and negative nodes are staggered. An optimized structural layout of the metal nodes of the metal dot matrix 41 is that the metal nodes on the anti-nodes are located exactly in the middle of the metal nodes on 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 region 4. A second surface acoustic wave reflection grating 32 is arranged outside 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. The second reflection gratings are all bent in an arc shape with the same curvature. And the width of the finger electrodes of the driving interdigital transducer 21 is the same as the distance between any two adjacent finger electrodes. The spacing between any two adjacent first reflection gratings, the spacing between any two adjacent second reflection gratings, and the width of the finger electrodes of the driving interdigital transducer 21 are all the same.

[0038] In this embodiment, by designing the arc-shaped interdigital transducer and reflection grating structure, the standing wave of the resonant cavity is formed, and the scattering of the primary surface acoustic wave generated by the driving interdigital transducer 21 is reduced, improving the sensor sensitivity. 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 graphene piezoresistive strip 31 for picking up the effective secondary surface acoustic wave and improving the resolution of the sensor.

[0039] Furthermore, according to the acousto-electric effect principle of graphene, when the width of the graphene piezoresistive strip 31 is 1 / 4 of the wavelength of the second acoustic surface wave and it is placed at the peak or trough position of the second acoustic surface wave, the generated effective acoustic current is the largest and the sensor sensitivity is the highest. Therefore, the structural dimensions and placement position of the graphene piezoresistive strip 31 depend on the wavelength of the second acoustic surface wave. The wavelength of the second acoustic surface wave depends on the wavelength of the first acoustic surface wave and the structural dimensions of the second acoustic surface wave reflection grating 32. When the instantaneously input angular velocity is a constant angular velocity, in order to improve the sensor sensitivity and maximize the standing wave energy formed, generally the width of the driving interdigital transducer 21 and the spacing between the fingers are made the same, and at the same time, the widths and spacings of the first acoustic surface wave reflection grating 22 and the second acoustic surface wave reflection grating 32 are the same as the width of the driving interdigital transducer 21 and the spacing between the fingers. The wavelength of the first acoustic surface wave depends on the structural dimensions of the driving interdigital transducer 21 and the first acoustic surface wave reflection grating. According to the application requirements of the sensor and considering the actual processing technology level, by means of theoretical calculation or finite element simulation, etc., the structural dimensions of the appropriate driving interdigital transducer 21 and the first acoustic surface wave reflection grating 22 are designed to meet the application requirements of the sensor and the processability of the sensor chip.

[0040] Working principle: Apply a driving alternating voltage to the driving interdigital transducer 21. Due to the periodic structure of the driving interdigital transducer 21, a periodic electric field distribution is formed on the piezoelectric substrate, thus exciting a first acoustic surface wave on the piezoelectric substrate. Under the action of the first acoustic surface wave reflection grating 22, the first acoustic surface wave forms a standing wave corresponding to the first acoustic surface wave in the acoustic wave resonator. When there is a rotational angular velocity input, due to the Coriolis effect, the mass points in the piezoelectric substrate will be subjected to a Coriolis force of -2m(ω z ×V). Under the action of the Coriolis force, a second acoustic surface wave is generated in the direction perpendicular to the direction of the mass point movement velocity and the direction of the input measured angular velocity, and the amplitude of the second acoustic surface wave is proportional to the input rotational angular velocity. Through the acousto-electric effect of the graphene piezoresistive strip 31 arranged outside the wave energy modulation region 4 (i.e., the resonator), that is, due to the periodic propagation of the acoustic surface wave, it causes periodic changes in the valence band and conductivity 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 circuit, a voltage is generated in the open circuit). The magnitude of the current generated in the graphene piezoresistive strip 31 is proportional to the amplitude of the acoustic surface wave. The acoustic current generated in the graphene piezoresistive strip 31 consists of a constant bias current generated by the scattering of the first acoustic surface wave and the acoustic current generated by the second acoustic surface wave. Among them, the acoustic current generated by the second acoustic surface wave contains information and is the effective signal.

[0041] In one example, the measurement of the magnitude of the acoustic current is achieved by selecting an appropriate detection interface circuit. The detection interface circuit can select a Wheatstone bridge, such as Figure 3As shown in the figure, the light-colored resistors in the upper left and lower right of the figure are graphene piezoresistive strips 31, and the dark-colored resistors in the lower left and upper right are fixed-value resistors externally connected to the detection interface circuit.

[0042] When there is no angular velocity input to the detection interface circuit, the graphene piezoresistive strip 31 generates a sound current I1 under the action of a first acoustic surface wave scattering. At this time, the equivalent DC resistance of the graphene piezoresistive strip 31 is R. When there is an input of the measured angular velocity, due to the Coriolis effect, a second acoustic surface wave is generated. On the graphene piezoresistive strip 31, a sound current I2 will be generated due to the second acoustic surface wave, and the current in the graphene becomes I1 + I2. At this time, the equivalent resistance of the graphene becomes R1, resulting in a change in the output voltage V0. According to the principle of the Coriolis effect, the amplitude of the second acoustic surface wave caused is proportional to the amplitude of the first acoustic surface wave and the input measured angular velocity ω z in magnitude. The amplitude of the first acoustic surface 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 first acoustic surface wave is a fixed value, and the vibration amplitude of the second acoustic surface wave is only proportional to the input measured angular velocity ω z in magnitude. Since the magnitude of the sound current I2 in the graphene piezoresistive strip 31 caused by the second acoustic surface wave is proportional to the amplitude of the second acoustic surface wave, the sound current I2 is proportional to the input measured angular velocity ω z in magnitude.

[0043] By setting an appropriate DC bias voltage V of the Wheatstone bridge through the interface circuit d and selecting a suitable fixed resistor, the sound current I1 can be made zero, which can further improve the linearity of the acoustic surface wave gyroscope. Thus, the magnitude of the sound current I2 caused by the angular velocity is manifested as a change in the equivalent resistance R1 of the graphene piezoresistive strip 31 in the Wheatstone bridge circuit. By testing the change in the output voltage V0 through the interface circuit, the magnitude of the input measured angular velocity can be determined. The detection interface circuit with a Wheatstone half-bridge structure provided above is only a scheme of a detection interface circuit. Other forms of interface circuits can also be used to measure the magnitude of the sound current generated in the graphene piezoresistive strip 31 due to the second acoustic surface wave, so as to determine the magnitude of the input measured angular velocity ω z in magnitude, which will not be listed one by one here.

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

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

[0046] Utilize the acousto-electric effect of the graphene piezoresistive strip 31, that is, due to the periodic propagation of the surface acoustic wave in the piezoelectric medium, it causes periodic changes in the valence band and conductivity in the low-dimensional semiconductor material, thereby generating a current in the graphene piezoresistive strip 31 (in the case of a closed circuit, a voltage is generated in the open circuit). The magnitude of the current generated in the graphene piezoresistive strip 31 is proportional to the amplitude of the second-order surface acoustic wave. According to the Coriolis effect, the amplitude of the second-order surface acoustic wave is proportional to the input measured angular velocity. By means of an appropriate driving and detection interface circuit, the magnitude of the acousto-current in the graphene piezoresistive strip 31 is measured, thereby obtaining 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 as arc-shaped structures, so that the energy of the first-order surface acoustic wave excited by the driving interdigital transducer 21 can be concentrated in the wave energy modulation region 4, reducing the scattering of the first-order surface acoustic wave, improving the sensitivity of the surface acoustic wave gyroscope, and reducing the acousto-current generated by the first-order surface acoustic wave in the graphene piezoresistive strip 31, thereby improving the signal-to-noise ratio of the sensor and the accuracy of the sensor.

[0047] The magnitude of the input acceleration is detected by the magnitude of the acousto-current generated by the acousto-electric effect of the graphene piezoresistive strip 31, avoiding the use of interdigital transducers to form a resonator or a delay line structure to pick up very small alternating current second-order surface acoustic wave signals and convert the second-order surface acoustic wave signals into direct current or voltage signals. For example, a DC Wheatstone bridge can be used to extract the effective second-order surface acoustic wave signals, thereby simplifying the interface circuit design and reducing the power consumption of the surface acoustic wave gyroscope chip. By optimizing the positions of the driving 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 region 4 (resonant cavity), and the outer shape structure of the graphene piezoresistive strip 31, the sensitivity of the sensor is improved to solve the problems of small sensitivity of the surface acoustic wave gyroscope, complex interface circuit, and difficulty in engineering application.

[0048] Unless otherwise defined, technical terms or scientific terms used in the present invention shall have the ordinary meanings as understood by those of ordinary skill in the art to which the present invention pertains. The "first", "second" and similar terms used in the present invention do not denote any order, quantity or importance, but are only used to distinguish different components. Similarly, words such as "a" or "an" do not denote a quantity limitation, but rather denote the existence of at least one. The terms "connected" or "coupled" and the like are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The terms "upper", "lower", "left", "right" and the like are only used to indicate relative positional relationships, and when the absolute position of the object being described changes, the relative positional relationships change accordingly.

[0049] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A surface acoustic wave gyroscope chip structure based on the graphene acousto-electric effect, characterized in that It includes a piezoelectric substrate (1), a surface acoustic wave resonator (2) and a surface acoustic wave detector (3) disposed on the surface of the piezoelectric substrate (1). Among them, the surface acoustic wave resonator (2) includes two relatively arranged driving interdigital transducers (21). A wave energy modulation region (4) is disposed between the two driving interdigital transducers (21). A first surface acoustic wave reflection grating (22) is disposed outside each driving interdigital transducer (21). The surface acoustic wave resonator (2) is used to generate a primary surface acoustic wave on the piezoelectric substrate (1) through the driving interdigital transducer (21), and generate a standing wave corresponding to the primary surface acoustic wave reflection grating on the first surface acoustic wave reflection grating (22); the driving interdigital transducer (21) includes a first bus bar, a second bus bar, a plurality of first finger electrodes and a plurality of second finger electrodes. The first finger electrodes and the second finger electrodes are arranged in an equidistant staggered manner. One end of the plurality of first finger electrodes is connected to the first bus bar, and the other ends of the plurality of first finger electrodes are spaced from the second bus bar. One end of the plurality of second finger electrodes is connected to the second bus bar, and the other ends of the plurality of second finger electrodes are spaced from the first bus bar. The first finger electrodes and the second finger electrodes are both arc-shaped, and the arcs of the first finger electrodes and the second finger electrodes are the same; the first surface acoustic wave reflection grating (22) includes a plurality of first reflection gratings arranged at equal intervals. The first reflection gratings are all arc-shaped and have the same arc; the surface acoustic wave detector (3) includes two graphene piezoresistive strips (31) symmetrically disposed on both sides of the wave energy modulation region (4). A second surface acoustic wave reflection grating (32) is disposed outside 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; a metal lattice (41) is disposed in the wave energy modulation region (4). The metal lattice (41) includes multiple 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 disposed at the standing wave node position and the standing wave anti-node position of the wave energy modulation region (4), and the standing wave node position and the standing wave anti-node position are alternately distributed.

2. The surface acoustic wave gyroscope chip structure according to claim 1, wherein 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 of the wave crest and the wave trough of the secondary surface acoustic wave.

3. The surface acoustic wave gyroscope chip structure according to claim 1, characterized in that the second surface acoustic wave reflection grating (32) includes a plurality of second reflection gratings arranged at equal intervals. The second reflection gratings are all arc-shaped and bent with the same arc; 4. The surface acoustic wave gyroscope chip structure according to claim 1, characterized in that the width of the finger electrodes of the driving interdigital transducer (21) is the same as the distance between any two adjacent finger electrodes. The spacing between any two adjacent first reflection gratings, the spacing between any two adjacent second reflection gratings, and the width of the finger electrodes of the driving interdigital transducer (21) are all the same.

5. The surface acoustic wave gyroscope chip structure according to claim 1, characterized in that, Further included are a plurality of metal pins, and the metal pins are provided at both ends of the graphene piezoresistive strip (31), and at one ends of the first bus bar and the second bus bar away from the wave energy modulation region (4).

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

Images