Acceleration sensor and method for manufacturing the same

Abstract

The present application discloses an acceleration sensor and a preparation method thereof, belonging to the field of semiconductor technology. The acceleration sensor includes a substrate, four induction resistors and four mass blocks. Two input terminals are electrically connected to the four induction resistors to form an equivalent circuit. When the measured direction provides acceleration, the four induction resistors will respectively produce a change in resistance under the force of the mass blocks. The acceleration can be detected by measuring the voltage change of the two output terminals in the equivalent circuit. In the embodiment of the present application, the four induction resistors are electrically connected to form a circuit structure to calculate the acceleration, which can avoid the influence of other environmental factors on the calculation results, and is conducive to improving the accuracy of the calculation results. In addition, the four induction resistors are all high electron mobility transistors, with a large piezoresistance coefficient and high sensitivity. They have high reliability in both low and high temperature environments, thereby improving the sensitivity and reliability of the acceleration sensor.

Description

Technical Field

[0001] The present application belongs to the field of semiconductor technology, and in particular relates to an acceleration sensor and a method for preparing the same. Background Art

[0002] Traditional acceleration sensors are mostly based on the principles of piezoresistive effect, piezoelectric effect or capacitive effect, and are made of silicon materials. Boron doping is generally used as the piezoresistive material. The piezoresistive coefficient is small and the sensitivity is low. In low or high temperature environments, the temperature drift is too large and the sensor will fail.

[0003] How to improve the sensitivity of the acceleration sensor and improve the reliability of the acceleration sensor in high and low temperature environments has become a problem to be solved urgently in this field. Summary of the invention

[0004] The present application provides an acceleration sensor and a preparation method thereof, aiming to improve the sensitivity and reliability of the acceleration sensor.

[0005] In a first aspect, the present application provides an acceleration sensor, comprising a substrate, a plurality of inductive resistors and a plurality of mass blocks. The plurality of inductive resistors comprises a first inductive resistor, a second inductive resistor, a third inductive resistor and a fourth inductive resistor, and the plurality of mass blocks comprises a first mass block, a second mass block, a third mass block and a fourth mass block. The first mass block is connected to the substrate via a first inductive resistor, the second mass block is connected to the substrate via a second inductive resistor, the third mass block is connected to the substrate via a third inductive resistor, and the fourth mass block is connected to the substrate via a fourth inductive resistor.

[0006] The acceleration sensor also includes a first input terminal and a second input terminal, and a first output terminal and a second output terminal. The multiple sensing resistors are all high electron mobility transistors. The source of the first sensing resistor is electrically connected to the first input terminal, the drain of the first sensing resistor is electrically connected to the first output terminal and the source of the second sensing resistor, the drain of the second sensing resistor is electrically connected to the second input terminal and the drain of the third sensing resistor, the source of the third sensing resistor is electrically connected to the second output terminal and the drain of the fourth sensing resistor, and the source of the fourth sensing resistor is electrically connected to the first input terminal.

[0007] In some embodiments, the acceleration sensor further includes a plurality of cantilever structures, the mass block includes a first end and a second end opposite to each other along a first direction, and the first direction is parallel to the plane where the substrate is located. The first end of the first mass block is connected to the substrate through a first sensing resistor, and the first end of the first mass block is also connected to the substrate through a cantilever structure. The first end of the second mass block is connected to the substrate through a second sensing resistor, and the first end of the second mass block is also connected to the substrate through a cantilever structure. The second end of the third mass block is connected to the substrate through a third sensing resistor, and the second end of the third mass block is also connected to the substrate through a cantilever structure. The second end of the fourth mass block is connected to the substrate through a fourth sensing resistor, and the second end of the fourth mass block is also connected to the substrate through a cantilever structure. The cantilever structure includes a first side and a second side opposite to each other along a second direction, the first sensing resistor and the third sensing resistor are both located on the first side of the corresponding cantilever structure, the second sensing resistor and the fourth sensing resistor are both located on the second side of the corresponding cantilever structure, the second direction intersects with the first direction, and the second direction is parallel to the plane where the substrate is located.

[0008] In some embodiments, the acceleration sensor further includes a connecting arm, and the sensing resistor is connected to the substrate through the connecting arm.

[0009] In some embodiments, the acceleration sensor further includes a substrate, the substrate includes a first surface and a second surface opposite to each other, the base, the plurality of sensing resistors and the plurality of mass blocks are all disposed on the first surface. The substrate further includes a through cavity, and the orthographic projections of the plurality of sensing resistors on the first surface are located within the range of the orthographic projections of the cavity on the first surface.

[0010] In some embodiments, the acceleration sensor further includes a base disposed on the second surface, the base includes a third surface close to the substrate, the third surface is provided with a groove, and the orthographic projections of the plurality of sensing resistors and the plurality of mass blocks on the third surface are located within the region where the groove is located.

[0011] In some embodiments, the sensing resistor further includes a gate, and the gate is disposed between the source and the drain of the sensing resistor.

[0012] In some embodiments, the sensing resistor further includes a stacked channel layer and a barrier layer, the material of the channel layer includes at least one of gallium nitride, gallium arsenide, or indium gallium arsenide, and the material of the barrier layer includes at least one of indium gallium nitride, aluminum gallium nitride, indium phosphide, aluminum gallium arsenide, or indium aluminum arsenide.

[0013] In a second aspect, the embodiment of the present application also provides a method for preparing an acceleration sensor, the preparation method comprising forming a substrate, a plurality of inductive resistors and a plurality of mass blocks. Among them, the plurality of inductive resistors include a first inductive resistor, a second inductive resistor, a third inductive resistor and a fourth inductive resistor, the plurality of mass blocks include a first mass block, a second mass block, a third mass block and a fourth mass block, the first mass block is connected to the substrate through the first inductive resistor, the second mass block is connected to the substrate through the second inductive resistor, the third mass block is connected to the substrate through the third inductive resistor, and the fourth mass block is connected to the substrate through the fourth inductive resistor. The acceleration sensor also includes a first input terminal and a second input terminal, and a first output terminal and a second output terminal, the plurality of inductive resistors are all high electron mobility transistors, the source of the first inductive resistor is electrically connected to the first input terminal, the drain of the first inductive resistor is electrically connected to the first output terminal and the source of the second inductive resistor, the drain of the second inductive resistor is electrically connected to the second input terminal and the drain of the third inductive resistor, the source of the third inductive resistor is electrically connected to the second output terminal and the drain of the fourth inductive resistor, and the source of the fourth inductive resistor is electrically connected to the first input terminal.

[0014] In some embodiments, the preparation method of forming a substrate, a plurality of sensing resistors and a plurality of mass blocks includes the following steps S10 to S40:

[0015] Step S10: forming a channel layer on the substrate to obtain a base body.

[0016] Step S20: forming a barrier layer on a side of the channel layer away from the substrate.

[0017] Step S30: forming a source electrode and a drain electrode on a side of the barrier layer away from the substrate to obtain a plurality of inductive resistors.

[0018] Step S40: etching the channel layer and the substrate to obtain a plurality of mass blocks, wherein the substrate includes a penetrating cavity, and the orthographic projections of the plurality of inductive resistors on the substrate are located within the region where the cavity is located.

[0019] In some embodiments, the preparation method further includes the following steps S50 to S60:

[0020] Step S50: forming grooves on the surface of the substrate.

[0021] Step S60: bonding the substrate to the substrate, the substrate is located on a side of the substrate away from the channel layer, and the surface of the substrate with the groove is close to the substrate, and the positive projections of the multiple sensing resistors and the multiple mass blocks on the substrate are located within the area where the groove is located.

[0022] In the embodiment provided in the present application, the acceleration sensor includes a substrate, a plurality of inductive resistors and a plurality of mass blocks, wherein the plurality of inductive resistors include four inductive resistors, the plurality of mass blocks include four mass blocks, and the four mass blocks are respectively connected to the substrate through the four inductive resistors.

[0023] The acceleration sensor also includes a first input terminal and a second input terminal, and a first output terminal and a second output terminal. Among the four sensing resistors, the source of the first sensing resistor is electrically connected to the first input terminal, the drain of the first sensing resistor is electrically connected to the first output terminal and the source of the second sensing resistor, the drain of the second sensing resistor is electrically connected to the second input terminal and the drain of the third sensing resistor, the source of the third sensing resistor is electrically connected to the second output terminal and the drain of the fourth sensing resistor, and the source of the fourth sensing resistor is electrically connected to the first input terminal.

[0024] That is, four inductive resistors are electrically connected to form a circuit structure. When acceleration is provided in the measured direction, the four mass blocks will not move with the substrate due to inertia, so the four inductive resistors that play a connecting role will each undergo a slight deformation. After the four inductive resistors are subjected to stress due to deformation, a change in resistance will occur under the piezoresistive effect. The magnitude of the acceleration can be calculated through the differential output of the circuit, and compared with the method of measuring acceleration with a single inductive resistor, the four inductive resistors are electrically connected to form a circuit structure in the embodiment of the present application to calculate the acceleration, which can avoid the influence of other environmental factors on the calculation results, which is conducive to improving the accuracy of the calculation results.

[0025] Furthermore, the four sensing resistors are all high electron mobility transistors, which have a large piezoresistance coefficient, a high sensitivity, and high reliability in both low and high temperature environments, thereby improving the sensitivity and reliability of the acceleration sensor.

[0026] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0028] Figure 1 A top view of an acceleration sensor provided in an embodiment of the present application;

[0029] Figure 2 for Figure 1 Equivalent circuit diagram of the acceleration sensor;

[0030] Figure 3 for Figure 1 A cross-sectional view of the acceleration sensor along the section line AA';

[0031] Figure 4 A flow chart of a method for preparing an acceleration sensor provided in an embodiment of the present application;

[0032] Figure 5~Figure 14 A diagram of the steps for preparing an acceleration sensor provided in an embodiment of the present application. DETAILED DESCRIPTION

[0033] The following will be combined with the accompanying drawings to clearly and completely describe the technical solutions in some embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments provided by the present application, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present application.

[0034] Unless the context requires otherwise, throughout the specification and claims, the term "comprising" is to be construed in an open, inclusive sense, ie, meaning "including, but not limited to."

[0035] In the following, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present application, unless otherwise specified, "plurality" means two or more.

[0036] When describing some embodiments, the term "connection" and its derivative expressions may be used. The term "connection" should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For example, when describing some embodiments, the term "connection" may be used to indicate that two or more components are in direct physical or electrical contact with each other.

[0037] Additionally, the use of “based on” is meant to be open and inclusive, as a process, step, calculation, or other action “based on” one or more stated conditions or values ​​may, in practice, be based on additional conditions or values ​​beyond those stated.

[0038] It will be understood that when a layer or an element is referred to as being on another layer or substrate, it can be directly on the other layer or substrate, or intervening layers may be present between the layer or element and the other layer or substrate.

[0039] Exemplary embodiments are described herein with reference to cross-sectional views that are idealized exemplary drawings. In the drawings, the thickness of layers and the area of ​​regions are exaggerated for clarity. Therefore, variations in shape relative to the drawings due to, for example, manufacturing techniques and / or tolerances are conceivable. Therefore, the exemplary embodiments should not be interpreted as being limited to the shapes of the regions shown herein, but include deviations in shape due to, for example, manufacturing. Therefore, the regions shown in the drawings are schematic in nature, and their shapes are not intended to illustrate the actual shape of regions of the device, and are not intended to limit the scope of the exemplary embodiments.

[0040] Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

[0041] At present, traditional acceleration sensors are mostly based on the principles of piezoresistive effect, piezoelectric effect or capacitive effect, and are manufactured using silicon materials, and generally use boron doping as the piezoresistive material. Due to the physical properties of the material, traditional acceleration sensors have the problems of small piezoresistive coefficient and low sensitivity. In low or high temperature environments, the temperature drift is too large and the sensor will fail.

[0042] To solve at least one of the above problems, the present application provides an acceleration sensor, aiming to improve its sensitivity and reliability, such as Figure 1~Figure 3 As shown, Figure 1 A top view of an acceleration sensor provided in an embodiment of the present application, Figure 2 for Figure 1 Equivalent circuit diagram of the acceleration sensor. Figure 3 for Figure 1 Cross-sectional view of the acceleration sensor along section line AA'.

[0043] The acceleration sensor 10 includes a substrate 100, a plurality of sensing resistors and a plurality of mass blocks. The plurality of mass blocks include a first mass block 101, a second mass block 102, a third mass block 103 and a fourth mass block 104, and the plurality of sensing resistors include a first sensing resistor 201, a second sensing resistor 202, a third sensing resistor 203 and a fourth sensing resistor 204. The first mass block 101 is connected to the substrate 100 via the first sensing resistor 201, the second mass block 102 is connected to the substrate 100 via the second sensing resistor 202, the third mass block 103 is connected to the substrate 100 via the third sensing resistor 203, and the fourth mass block 104 is connected to the substrate 100 via the fourth sensing resistor 204.

[0044] The four sensing resistors are electrically connected to form a circuit structure, such as Figure 2As shown, the acceleration sensor 10 further includes a first input terminal Vin, a second input terminal GND, and a first output terminal Vout + and the second output terminal Vout - The source of the first sensing resistor 201 is electrically connected to the first input terminal Vin, and the drain of the first sensing resistor 201 is electrically connected to the first output terminal Vout + The source of the second sensing resistor 202 is electrically connected, the drain of the second sensing resistor 202 is electrically connected to the second input terminal GND and the drain of the third sensing resistor 203, and the source of the third sensing resistor 203 is electrically connected to the second output terminal Vout. - The first sensing terminal 204 is electrically connected to the drain of the fourth sensing resistor 204 , and the source of the fourth sensing resistor 204 is electrically connected to the first input terminal Vin.

[0045] For example, Figure 2 As shown, the resistance of the first sensing resistor 201 is R1, the resistance of the second sensing resistor 202 is R2, the resistance of the third sensing resistor 203 is R3, and the resistance of the fourth sensing resistor 204 is R4. In a uniform or stationary state, that is, when no acceleration is provided, the first output terminal Vout + and the second output terminal Vout - The potential difference is .

[0046] When an acceleration is provided along the measured direction Y, the four mass blocks will not move with the substrate 100 due to inertia, and the four sensing resistors that play a connecting role will respectively undergo slight deformations. For example, the first mass block 101 acts on the first sensing resistor 201 with a stretching force, and under the piezoresistive effect, the resistance R1 of the first sensing resistor 201 changes. The second mass block 102 acts on the second sensing resistor 202 with a squeezing force, and under the piezoresistive effect, the resistance R2 of the second sensing resistor 202 changes. Similar to the first sensing resistor 201, the third sensing resistor 203 is subjected to the stretching force of the third mass block 103, and the resistance R3 of the third sensing resistor 203 also changes. Similar to the second sensing resistor 202, the fourth sensing resistor 203 is subjected to the squeezing force of the fourth mass block 104, and the resistance R4 of the fourth sensing resistor 204 also changes.

[0047] Exemplarily, the acceleration here can be a positive number or a negative number.

[0048] When acceleration is provided, the resistance change of the first sensing resistor 201 is recorded as , the resistance change of the second sensing resistor 202 is , the resistance change of the third sensing resistor 203 is , the resistance change of the fourth sensing resistor 204 is , since the magnitude of the force exerted by the mass block on the corresponding inductive resistor is related to the magnitude of the acceleration, and the change in the resistance of the inductive resistor is related to the magnitude of the force it receives, based on this, the change in the resistance of the above four inductive resistors is related to the magnitude of the acceleration. Under this acceleration, the first output terminal Vout + and the second output terminal Vout - The potential difference is .

[0049] Based on this, by calibrating the first output terminal Vout + and the second output terminal Vout - The magnitude of acceleration can be detected by observing the change in the potential difference.

[0050] Compared with the method of measuring acceleration using a single inductive resistor, in the embodiment of the present application, four inductive resistors are electrically connected to form a Figure 2 The circuit structure shown in the figure calculates acceleration, which can avoid the influence of other environmental factors on the resistance change of the inductive resistor, and further avoid the influence of other environmental factors on the acceleration calculation result, which is beneficial to improve the accuracy of the calculation result.

[0051] Furthermore, the four sensing resistors are all high electron mobility transistors, which have a large piezoresistance coefficient and high sensitivity, and the resistance value changes significantly under the same force, so that the acceleration sensor 10 has a high sensitivity. Furthermore, the high electron mobility transistor has high reliability in both low and high temperature environments, so the reliability of the acceleration sensor 10 can be improved.

[0052] In some embodiments, Figure 1 As shown, the acceleration sensor 10 further includes a plurality of cantilever structures 11, and the mass block includes a first end and a second end opposite to each other along a first direction X, and the first direction X is parallel to the plane where the substrate 100 is located. The first end of the first mass block 101 is connected to the substrate 100 through the first sensing resistor 201, and the first end of the first mass block 101 is also connected to the substrate 100 through the cantilever structure 11.

[0053] The first end of the second mass block 102 is connected to the substrate 100 via the second sensing resistor 202 , and the first end of the second mass block 102 is also connected to the substrate 100 via the cantilever structure 11 .

[0054] The second end of the third mass 103 is connected to the substrate 100 through the third sensing resistor 203 , and the second end of the third mass 103 is also connected to the substrate 100 through the cantilever structure 11 .

[0055] The second end of the fourth mass 104 is connected to the base 100 via the fourth sensing resistor 204 , and the second end of the fourth mass 104 is also connected to the base 100 via the cantilever structure 11 .

[0056] The cantilever structure 11 includes a first side and a second side opposite to each other along a second direction Y. The first sensing resistor 201 and the third sensing resistor 203 are both located on the first side of the corresponding cantilever structure 11. The second sensing resistor 202 and the fourth sensing resistor 204 are both located on the second side of the corresponding cantilever structure 11. The second direction Y intersects the first direction X, and the second direction Y is parallel to the plane where the substrate is located.

[0057] Combination Figure 1 In the orientation shown, the above-mentioned “first end of the mass block along the first direction X” can be understood as the left end of the mass block along the first direction X, and the “second end of the mass block along the first direction X” can be understood as the right end of the mass block along the first direction X. The “first side of the cantilever structure 11 along the second direction Y” can be understood as the bottom of the cantilever structure 11 along the second direction Y, and the “first side of the cantilever structure 11 along the second direction Y” can be understood as the top of the cantilever structure 11 along the second direction Y.

[0058] The cantilever structure 11 plays a role in connecting and supporting the mass block, which helps to prevent the mass block from exerting too much force on the corresponding inductive resistor when the acceleration is too large, thereby causing damage to the inductive resistor. In addition, the surface of the cantilever structure 11 can also be designed for routing, so that the four inductive resistors are electrically connected to form a Figure 2 The equivalent circuit is shown.

[0059] Based on the above positional relationship, when an acceleration is provided along the detected direction Y, the force on the first sensing resistor 201 and the force on the third sensing resistor 203 have a certain similarity, and the force on the second sensing resistor 202 and the force on the fourth sensing resistor 204 have a certain similarity. Under the piezoresistive effect, the resistance of the sensing resistor is related to the force it receives. Therefore, the above-mentioned similar force characteristics are conducive to simplifying the equivalent circuit, thereby making the calculation of acceleration more concise and improving the accuracy of the detection result.

[0060] In some embodiments, Figure 1 As shown, the acceleration sensor 10 further includes a connecting arm 12 , and the sensing resistor is connected to the substrate 100 via the connecting arm 12 .

[0061] The connecting arm 12 can also play a connecting and supporting role, for example, Figure 1As shown, the thicker the connecting arm 12 is, the better its supporting effect is and the less likely it is to deform. Therefore, the force exerted by the mass block on the corresponding sensing resistor can cause deformation at the sensing resistor to the greatest extent and cause the resistance value of the sensing resistor to change, thereby avoiding the force from being transmitted to the substrate 100 through the connecting arm 12, which is beneficial to improving the sensitivity of the acceleration sensor 10.

[0062] In some embodiments, Figure 3 As shown, the acceleration sensor 10 further includes a substrate 21, the substrate 21 includes a first surface P1 and a second surface P2 opposite to each other, the base 100, the plurality of sensing resistors and the plurality of mass blocks are all arranged on the first surface P1. The substrate 21 further includes a through cavity K0, and the orthographic projections of the plurality of sensing resistors on the first surface P1 are located within the range of the orthographic projections of the cavity K0 on the first surface P1.

[0063] Combination Figure 1 It is not difficult to understand that the film structure of the sensing resistor along the direction Z does not include the substrate 21, and the film structure of the mass block along the direction Z includes the substrate 21. Since the larger the mass, the greater the force under the same acceleration, the substrate 21 can increase the mass of the mass block, so that the force exerted by the mass block on the sensing resistor is larger. In addition, the positive projection of the sensing resistor on the first surface P1 is located within the range of the positive projection of the cavity K0 on the first surface P1. By setting the cavity K0, the force conducted through the film layer of the substrate 21 can also be reduced, so that the force exerted by the mass block on the sensing resistor causes as much deformation of the sensing resistor as possible, thereby causing the potential difference between the two output ends of the equivalent circuit to change, which is beneficial to improving the sensitivity of the acceleration sensor 10.

[0064] In some embodiments, Figure 3 As shown, the acceleration sensor 10 also includes a base 22 arranged on the second surface P2, the base 22 includes a third surface P3 close to the substrate 21, the third surface P3 is provided with a groove T0, and the orthographic projections of the plurality of sensing resistors and the plurality of mass blocks on the third surface P3 are located within the region where the groove T0 is located.

[0065] The substrate 22 provides a flat surface for the acceleration sensor 10. The groove T0 is arranged so that the mass block and the corresponding sensing resistor are in a suspended structure, and the mass block is connected to the substrate 100 through the sensing resistor. In the case of providing acceleration, the possibility of the force on the mass block being transmitted through the substrate 22 is avoided, and the mass block and the sensing resistor interact with each other, thereby causing the sensing resistor to deform. The arrangement of the groove T0 on the substrate 22 is conducive to providing the sensitivity of the acceleration sensor 10.

[0066] In some embodiments, Figure 3 As shown, the sensing resistor further includes a gate G, which is arranged between a source S and a drain D of the sensing resistor.

[0067] In the embodiment of the present application, the four sensing resistors are all high electron mobility transistors. For example, by setting a gate G and applying a voltage equal to the transistor threshold voltage on the gate G, compensation of the sensing resistor equivalent to the high electron mobility transistor can be achieved, so that Figure 2 The equivalent circuit shown is closer to the ideal equivalent effect, and the sensitivity of the acceleration sensor 10 is further improved.

[0068] In some embodiments, Figure 3 As shown, the inductive resistor also includes a stacked channel layer 23 and a barrier layer 24, the material of the channel layer 23 includes at least one of gallium nitride, gallium arsenide or indium gallium arsenide, and the material of the barrier layer 24 includes at least one of indium gallium nitride, aluminum gallium nitride, indium phosphide, aluminum gallium arsenide or indium aluminum arsenide.

[0069] The sensing resistor formed by the above materials uses two-dimensional electron gas as conductive ions and has high reliability in both low and high temperature environments. In addition, the sensing resistor has a large piezoresistance coefficient and high sensitivity, which is beneficial to improving the reliability and sensitivity of the acceleration sensor 10.

[0070] In a second aspect, an embodiment of the present application further provides a method for preparing an acceleration sensor, the method comprising forming a substrate 100, a plurality of sensing resistors and a plurality of mass blocks. The plurality of sensing resistors comprises a first sensing resistor 201, a second sensing resistor 202, a third sensing resistor 203 and a fourth sensing resistor 204, the plurality of mass blocks comprises a first mass block 101, a second mass block 102, a third mass block 103 and a fourth mass block 104, the first mass block 101 is connected to the substrate 100 via the first sensing resistor 201, the second mass block 102 is connected to the substrate 100 via the second sensing resistor 202, the third mass block 103 is connected to the substrate 100 via the third sensing resistor 203, and the fourth mass block 104 is connected to the substrate 100 via the fourth sensing resistor 204. The acceleration sensor 10 further comprises a first input terminal Vin and a second input terminal GND, and a first output terminal Vout + and the second output terminal Vout - , the multiple sensing resistors are all high electron mobility transistors, the drain of the first sensing resistor 201 is connected to the first output terminal Vout + The source of the second sensing resistor 202 is electrically connected, the drain of the second sensing resistor 202 is electrically connected to the second input terminal GND and the drain of the third sensing resistor 203, and the source of the third sensing resistor 203 is electrically connected to the second output terminal Vout. - The first sensing terminal 204 is electrically connected to the drain of the fourth sensing resistor 204 , and the source of the fourth sensing resistor 204 is electrically connected to the first input terminal Vin.

[0071] The acceleration sensor 10 thus formed can be formed by electrically connecting four sensing resistors as follows Figure 2 The circuit structure shown in the figure calculates acceleration, which can avoid the influence of other environmental factors on the resistance change of the inductive resistor, and further avoid the influence of other environmental factors on the acceleration calculation result, which is beneficial to improve the accuracy of the calculation result.

[0072] Furthermore, the four sensing resistors are all high electron mobility transistors, which have a large piezoresistance coefficient and a high sensitivity. The resistance value changes significantly under the same force, so that the acceleration sensor 10 has a higher sensitivity. In addition, the high electron mobility transistor has a higher reliability in both low and high temperature environments, thereby improving the reliability of the acceleration sensor 10.

[0073] For example, Figure 4 As shown, Figure 4 A flow chart of a method for preparing an acceleration sensor provided in an embodiment of the present application, Figure 5~Figure 14 A diagram of the steps for preparing an acceleration sensor provided in an embodiment of the present application.

[0074] In some embodiments, the preparation method of forming the substrate 100, the plurality of sensing resistors and the plurality of mass blocks includes the following steps S10 to S40:

[0075] Step S10: Figure 5 As shown, a channel layer 23 is formed on a substrate 21 to obtain a base body 100 .

[0076] Exemplarily, the substrate 21 includes a first surface P1 and a second surface P2 opposite to each other. To avoid lattice mismatch and dislocation, a buffer layer 25 is usually disposed on the first surface P1 of the substrate 21 , and then a channel layer 23 is formed on a side of the buffer layer 25 away from the substrate 21 .

[0077] The substrate 21 is usually a silicon substrate, or may also be a sapphire substrate. The material of the channel layer 23 may be gallium nitride.

[0078] Step S20: Figure 6 As shown, a barrier layer 24 is formed on a side of the channel layer 23 away from the substrate 21 .

[0079] For example, the material of the barrier layer 24 may be aluminum gallium nitride, and the size and morphology of the barrier layer 24 may be reasonably designed according to requirements.

[0080] Step S30: Figure 7~Figure 9 As shown, a source S and a drain D are formed on a side of the barrier layer 24 away from the substrate 21 to obtain a plurality of inductive resistors.

[0081] To form better electrical contact, such as Figure 7As shown, an ohmic contact layer 26 may be formed on the barrier layer 24 first.

[0082] Afterwards, if Figure 8 As shown, a first passivation layer 27 is formed, and the first passivation layer 27 exposes a portion of the ohmic contact layer 26 .

[0083] Then, if Fig. 9 As shown, a source S and a drain D are formed. In some embodiments, a gate G is also formed.

[0084] Through reasonable routing design, the source S and drain D of multiple sensing resistors are electrically connected to form a Figure 2 The equivalent circuit is shown.

[0085] Afterwards, if Fig.10 As shown, a second passivation layer 28 is formed to insulate and protect multiple sensing resistors and wiring designs. The second passivation layer 28 forms a suitable pad opening for connecting an external power supply.

[0086] Step S40: Figure 11~Figure 12 As shown, the channel layer 23 and the substrate 21 are etched to obtain a plurality of mass blocks, the substrate 21 includes a penetrating cavity K0, and the orthographic projections of the plurality of inductive resistors on the substrate 21 are located within the region where the cavity K0 is located.

[0087] For example, Fig.11 As shown, the channel layer 23 is etched by an inductively coupled plasma etching process until the first surface P1 of the substrate 21 is exposed. Figure 1 Profiles of multiple masses and cantilever beams are shown.

[0088] like Fig.12 As shown, the substrate 21 is etched on the second surface P2 side of the substrate 21 by deep silicon etching to form a cavity K0, so that the orthographic projections of the plurality of sensing resistors on the substrate 21 are located within the region where the cavity K0 is located.

[0089] In order to form Figure 1 and Figure 3 In some embodiments, the preparation method further comprises the following steps S50 to S60:

[0090] Step S50: Fig.13 As shown, a trench T0 is formed on the surface of the substrate 22 .

[0091] Exemplarily, the size of the base 22 along direction X is the same as the size of the substrate 21 along direction X in step S10, and the size of the base 22 along direction Y is the same as the size of the substrate 21 along direction Y in step S10. That is, the orthographic projection of the base 22 can overlap with the orthographic projection of the substrate 21.

[0092] According to the orthographic projection positions of the plurality of mass blocks and the plurality of sensing resistors on the substrate 21 , the substrate 22 is etched to form a groove T0 , so that the orthographic projections of the plurality of sensing resistors and the plurality of mass blocks on the substrate 21 are finally located within the projection area of ​​the groove T0 on the substrate 22 .

[0093] Step S60: Fig.14 As shown, the base 22 can be bonded to the substrate 21 by silicon-silicon bonding. The base 22 is located on the side of the substrate 21 away from the channel layer 23, and the surface of the base 22 having the groove T0 is close to the substrate 21. The positive projections of the multiple sensing resistors and the multiple mass blocks on the base 22 are located within the region where the groove T0 is located.

[0094] The preparation method has a relatively simple preparation process. The prepared acceleration sensor 10 can make the force of the mass block cause the deformation of the sensing resistor as much as possible instead of being conducted through the substrate 21 or the base 22, thereby improving the sensitivity of the acceleration sensor 10.

[0095] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that a person skilled in the art can think of within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. An acceleration sensor, characterized in that: The acceleration sensor comprises a substrate, a plurality of inductive resistors, a plurality of cantilever structures and a plurality of mass blocks; The plurality of inductive resistors include a first inductive resistor, a second inductive resistor, a third inductive resistor and a fourth inductive resistor, and the plurality of mass blocks include a first mass block, a second mass block, a third mass block and a fourth mass block; the first mass block is connected to the substrate through the first inductive resistor, the second mass block is connected to the substrate through the second inductive resistor, the third mass block is connected to the substrate through the third inductive resistor, and the fourth mass block is connected to the substrate through the fourth inductive resistor; The acceleration sensor further includes a first input terminal and a second input terminal, and a first output terminal and a second output terminal; the plurality of sensing resistors are all high electron mobility transistors, the source of the first sensing resistor is electrically connected to the first input terminal, the drain of the first sensing resistor is electrically connected to the first output terminal and the source of the second sensing resistor, the drain of the second sensing resistor is electrically connected to the second input terminal and the drain of the third sensing resistor, the source of the third sensing resistor is electrically connected to the second output terminal and the drain of the fourth sensing resistor, and the source of the fourth sensing resistor is electrically connected to the first input terminal; The mass block comprises a first end and a second end opposite to each other along a first direction, wherein the first direction is parallel to the plane where the substrate is located; The first end of the first mass block is connected to the substrate through the first sensing resistor, and the first end of the first mass block is also connected to the substrate through the cantilever structure; the first end of the second mass block is connected to the substrate through the second sensing resistor, and the first end of the second mass block is also connected to the substrate through the cantilever structure; the second end of the third mass block is connected to the substrate through the third sensing resistor, and the second end of the third mass block is also connected to the substrate through the cantilever structure; the second end of the fourth mass block is connected to the substrate through the fourth sensing resistor, and the second end of the fourth mass block is also connected to the substrate through the cantilever structure; The cantilever structure includes a first side and a second side opposite to each other along a second direction, the first sensing resistor and the third sensing resistor are both located on the first side of the corresponding cantilever structure, and the second sensing resistor and the fourth sensing resistor are both located on the second side of the corresponding cantilever structure; the second direction intersects with the first direction, and the second direction is parallel to the plane where the substrate is located.

2. The acceleration sensor according to claim 1, characterized in that The acceleration sensor further includes a connecting arm, and the inductive resistor is connected to the substrate via the connecting arm.

3. The acceleration sensor according to claim 1, characterized in that: The acceleration sensor further comprises a substrate, the substrate comprising a first surface and a second surface opposite to each other, the base, the plurality of sensing resistors and the plurality of mass blocks are all arranged on the first surface; The substrate further includes a penetrating cavity, and orthographic projections of the plurality of sensing resistors on the first surface are located within a range of the orthographic projections of the cavity on the first surface.

4. The acceleration sensor according to claim 3, characterized in that: The acceleration sensor further includes a base disposed on the second surface, the base includes a third surface close to the substrate, and the third surface is provided with a groove; The orthographic projections of the plurality of sensing resistors and the plurality of proof masses on the third surface are located within a region where the grooves are located.

5. The acceleration sensor according to claim 1, characterized in that: The sensing resistor further includes a gate, and the gate is arranged between a source and a drain of the sensing resistor.

6. The acceleration sensor according to claim 1, characterized in that: The inductive resistor further includes a channel layer and a barrier layer which are stacked; The material of the channel layer includes at least one of gallium nitride, gallium arsenide or indium gallium arsenide, and the material of the barrier layer includes at least one of indium gallium nitride, aluminum gallium nitride, indium phosphide, aluminum gallium arsenide or indium aluminum arsenide.

7. A method for preparing an acceleration sensor, characterized in that: The preparation method includes forming a substrate, a plurality of inductive resistors, a plurality of cantilever structures and a plurality of mass blocks; The plurality of inductive resistors include a first inductive resistor, a second inductive resistor, a third inductive resistor and a fourth inductive resistor, and the plurality of mass blocks include a first mass block, a second mass block, a third mass block and a fourth mass block; the first mass block is connected to the substrate through the first inductive resistor, the second mass block is connected to the substrate through the second inductive resistor, the third mass block is connected to the substrate through the third inductive resistor, and the fourth mass block is connected to the substrate through the fourth inductive resistor; The acceleration sensor further includes a first input terminal and a second input terminal, and a first output terminal and a second output terminal; the plurality of sensing resistors are all high electron mobility transistors, the source of the first sensing resistor is electrically connected to the first input terminal, the drain of the first sensing resistor is electrically connected to the first output terminal and the source of the second sensing resistor, the drain of the second sensing resistor is electrically connected to the second input terminal and the drain of the third sensing resistor, the source of the third sensing resistor is electrically connected to the second output terminal and the drain of the fourth sensing resistor, and the source of the fourth sensing resistor is electrically connected to the first input terminal; The mass block comprises a first end and a second end opposite to each other along a first direction, wherein the first direction is parallel to the plane where the substrate is located; The first end of the first mass block is connected to the substrate through the first sensing resistor, and the first end of the first mass block is also connected to the substrate through the cantilever structure; the first end of the second mass block is connected to the substrate through the second sensing resistor, and the first end of the second mass block is also connected to the substrate through the cantilever structure; the second end of the third mass block is connected to the substrate through the third sensing resistor, and the second end of the third mass block is also connected to the substrate through the cantilever structure; the second end of the fourth mass block is connected to the substrate through the fourth sensing resistor, and the second end of the fourth mass block is also connected to the substrate through the cantilever structure; The cantilever structure includes a first side and a second side opposite to each other along a second direction, the first sensing resistor and the third sensing resistor are both located on the first side of the corresponding cantilever structure, and the second sensing resistor and the fourth sensing resistor are both located on the second side of the corresponding cantilever structure; the second direction intersects with the first direction, and the second direction is parallel to the plane where the substrate is located.

8. The preparation method according to claim 7, characterized in that: Forming the substrate, the plurality of inductive resistors and the plurality of mass blocks comprises: forming a channel layer on a substrate to obtain the base body; forming a barrier layer on a side of the channel layer away from the substrate; forming a source electrode and a drain electrode on a side of the barrier layer away from the substrate to obtain the plurality of sensing resistors; The channel layer and the substrate are etched to obtain the plurality of mass blocks; the substrate comprises a penetrating cavity, and the orthographic projections of the plurality of inductive resistors on the substrate are located within the region where the cavity is located.

9. The preparation method according to claim 8, characterized in that: The preparation method further comprises: forming grooves on a surface of a substrate; The base is bonded to the substrate, the base is located on a side of the substrate away from the channel layer, and the surface of the base having the groove is close to the substrate; the orthographic projections of the multiple sensing resistors and the multiple mass blocks on the base are located within the region where the groove is located.

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