CN116106579A - MEMS inertial sensor, detection method and electronic equipment - Google Patents

MEMS inertial sensor, detection method and electronic equipment Download PDF

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Publication number
CN116106579A
CN116106579A CN202310028372.4A CN202310028372A CN116106579A CN 116106579 A CN116106579 A CN 116106579A CN 202310028372 A CN202310028372 A CN 202310028372A CN 116106579 A CN116106579 A CN 116106579A
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China
Prior art keywords
electrode
inertial sensor
mems inertial
elastic beam
capacitor
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CN202310028372.4A
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Chinese (zh)
Inventor
周志健
高阳
邓仕阳
陈磊
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Goertek Microelectronics Inc
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Goertek Microelectronics Inc
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Priority to CN202310028372.4A priority Critical patent/CN116106579A/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B81—MICROSTRUCTURAL TECHNOLOGY
    • B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
    • B81B7/00—Microstructural systems; Auxiliary parts of microstructural devices or systems
    • B81B7/02—Microstructural systems; Auxiliary parts of microstructural devices or systems containing distinct electrical or optical devices of particular relevance for their function, e.g. microelectro-mechanical systems [MEMS]
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
    • G01C21/00—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00
    • G01C21/10—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00 by using measurements of speed or acceleration
    • G01C21/12—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00 by using measurements of speed or acceleration executed aboard the object being navigated; Dead reckoning
    • G01C21/16—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00 by using measurements of speed or acceleration executed aboard the object being navigated; Dead reckoning by integrating acceleration or speed, i.e. inertial navigation
    • G01C21/166—Mechanical, construction or arrangement details of inertial navigation systems
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
    • G01P15/00—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration
    • G01P15/02—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses
    • G01P15/08—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values
    • G01P15/125—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values by capacitive pick-up
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B81—MICROSTRUCTURAL TECHNOLOGY
    • B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
    • B81B2201/00—Specific applications of microelectromechanical systems
    • B81B2201/02—Sensors
    • B81B2201/0221—Variable capacitors
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
    • G01P15/00—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration
    • G01P15/02—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses
    • G01P15/08—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values
    • G01P2015/0862—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values being provided with particular means being integrated into a MEMS accelerometer structure for providing particular additional functionalities to those of a spring mass system

Abstract

The embodiment of the application provides an MEMS inertial sensor, a detection method and electronic equipment; the MEMS inertial sensor comprises a substrate, a first electrode, a second electrode, a mass block and an elastic beam; an insulating layer is arranged on one side of the substrate; the first electrode and the second electrode are arranged on the insulating layer at intervals; the mass block is suspended above the substrate and comprises a first part, a second part and a third part; the elastic beam is used for connecting the substrate and the mass block, the elastic beam is connected to the anchor point of the substrate, and the first part, the third part and the second part are positioned on two sides of the elastic beam; the second part and the second electrode form a first capacitor, and the third part and the first electrode form a second capacitor; the second capacitor can form a collapse working mode, the first capacitor is used for forming a detection end in the collapse working mode, and the MEMS inertial sensor can detect and sense according to the acquired capacitance variation in the collapse working mode.

Description

MEMS inertial sensor, detection method and electronic equipment
Technical Field
The application relates to the technical field of sensor detection, in particular to an MEMS inertial sensor, a detection method and electronic equipment.
Background
At present, a capacitive voice acceleration sensor for voice call noise reduction has the problem of low detection sensitivity, and high-definition pickup and noise reduction processing in a noisy environment, for example, cannot be realized. In order to solve the problem of low detection sensitivity, a dc bias voltage is generally applied. The higher the applied dc bias voltage, the higher the detection sensitivity obtained, but this also results in attraction between the fixed and movable electrodes, resulting in failure of the detection function.
The voice acceleration sensor can adopt a single-ended capacitance detection mode, and the traditional acceleration sensor generally adopts differential capacitance detection. From the detection mode to the performance characteristics, two acceleration sensors of different types have corresponding advantages and disadvantages, the performance advantages are difficult to complement, and the two acceleration sensors cannot be used instead of each other.
Disclosure of Invention
The purpose of the application is to provide a novel technical scheme of MEMS inertial sensor, detection method and electronic equipment, two formed capacitors are mutually matched, so that the MEMS inertial sensor can be used for motion acceleration detection, collapse working mode can be realized, voice acceleration detection can be realized, and the MEMS inertial sensor can have a double-working mode.
In a first aspect, the present application provides a MEMS inertial sensor. The MEMS inertial sensor includes:
a substrate, one side of which is provided with an insulating layer;
the first electrode and the second electrode are arranged on the insulating layer at intervals;
the mass block is suspended above the substrate and comprises a first part, a second part and a third part;
the elastic beam is used for connecting the substrate and the mass block, the elastic beam is connected to an anchor point of the substrate, and the first part, the third part and the second part are positioned on two sides of the elastic beam;
the second portion forms a first capacitor with the second electrode, and the third portion forms a second capacitor with the first electrode; the second capacitor can form a collapse working mode, the first capacitor is used for forming a detection end in the collapse working mode, and the MEMS inertial sensor can detect and sense according to the acquired capacitance variation in the collapse working mode.
Optionally, the third portion is connected between the first portion and the second portion, and the third portion is located on the same side of the elastic beam as the first portion;
in the Z-axis direction, the height of the third part is larger than that of the first part, so that the third part and the first part form a step structure on one side of the elastic beam.
Optionally, the first capacitor and the second capacitor can also be used to form a differential capacitance detector; the first electrode and the second electrode are detection electrodes and are used as differential capacitance detection output signal ports.
Optionally, when the first capacitor and the second capacitor form a differential capacitance detector, and an acceleration change in the Z-axis direction is obtained, the elastic beam generates torsional deformation and forms a rotating shaft, and the mass block can rotate around the formed rotating shaft.
Optionally, in the collapse working mode, the MEMS inertial sensor applies a first direct current voltage to the first electrode, an electrostatic force is formed between the first electrode and the mass block, the first electrode forms a pull-in electrode, and the mass block serves as a single-ended capacitance output signal port.
Optionally, when the first direct current voltage is greater than the pull-in voltage U pull-in When the first part and the insulating layer form a contact state, and the mass block and the first electrode, the second electrode and the substrate form an electric insulating state.
Alternatively, when a second direct current voltage is applied to the first electrode and the second direct current voltage is greater than the first direct current voltage, the elastic beam is bent and deformed, and the distance between the second portion and the first electrode and the second electrode is reduced.
Alternatively, when an acceleration change in the Z-axis direction is obtained, the mass moves up and down around a contact point where the first portion contacts the insulating layer under the support of the elastic beam.
Optionally, the MEMS inertial sensor can be used for voice detection of a voice acceleration sensor in the collapse mode of operation.
Optionally, the substrate is made of monocrystalline silicon or polycrystalline silicon.
In a second aspect, an embodiment of the present application provides a detection method of a MEMS inertial sensor, applying the MEMS inertial sensor according to the first aspect, where the detection method includes:
applying a first direct current voltage to the first electrode, wherein the first part is in contact with the insulating layer and forms a contact point, the second capacitor formed by the third part and the first electrode enters a collapse working mode, and the elastic beam is bent and deformed;
the mass block moves up and down along the Z-axis direction around the contact point under the support of the elastic beam, and the first capacitor formed by the second part and the second electrode is used as a detection end for acquiring capacitance variation.
Optionally, the detection method of the MEMS inertial sensor further includes:
the first capacitor and the second capacitor form a differential capacitance detector, wherein the first electrode and the second electrode are used as differential capacitance output ports;
the elastic beam generates torsional deformation, and the mass block rotates around a rotating shaft formed by the torsion of the elastic beam under the support of the elastic beam.
In a third aspect, an embodiment of the present application provides an electronic device. The electronic device includes:
the MEMS inertial sensor of the first aspect.
The beneficial effects of this application are:
the MEMS inertial sensor provided by the embodiment of the application adopts a new structural design, one capacitor can be used as a detection end in two formed capacitors, and the other capacitor can form collapse, so that a new working mode, namely a collapse working mode, of the MEMS inertial sensor is provided, and the formed MEMS inertial sensor can have more working modes by adopting the design.
Other features of the present specification and its advantages will become apparent from the following detailed description of exemplary embodiments thereof, which proceeds with reference to the accompanying drawings.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the specification and together with the description, serve to explain the principles of the specification.
FIG. 1 is a schematic diagram of a MEMS inertial sensor according to an embodiment of the present disclosure;
FIG. 2 is a second schematic diagram of a MEMS inertial sensor according to an embodiment of the present disclosure;
FIG. 3 is a third schematic diagram of a MEMS inertial sensor according to an embodiment of the present disclosure;
FIG. 4 is a schematic diagram of a MEMS inertial sensor according to an embodiment of the present disclosure;
FIG. 5 is a schematic diagram of a MEMS inertial sensor according to an embodiment of the present disclosure;
fig. 6 is a schematic view of section A-A of fig. 5.
Reference numerals illustrate:
1. a MEMS inertial sensor; 2. a mass block; 2a, a first part; 2b, a second part; 2c, a third part; 3. a rotating shaft; 4. an insulating layer; 5. a substrate; 6. a first electrode; 7. a second electrode; 8. an elastic beam; 8a, a first section; 8b, a second section; 9. an anchor point; 10. contact points.
Detailed Description
Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that: the relative arrangement of the components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present application unless it is specifically stated otherwise.
The following description of at least one exemplary embodiment is merely exemplary in nature and is in no way intended to limit the application, its application, or uses.
Techniques and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but should be considered part of the specification where appropriate.
In all examples shown and discussed herein, any specific values should be construed as merely illustrative, and not a limitation. Thus, other examples of exemplary embodiments may have different values.
It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further discussion thereof is necessary in subsequent figures.
The MEMS inertial sensor and the electronic device provided in the embodiments of the present application are described in detail below with reference to the accompanying drawings.
According to an aspect of the embodiments of the present application, there is provided a MEMS inertial sensor, as shown in fig. 1 to 6, which can be used as a voice acceleration sensor for voice noise reduction, or as an acceleration sensor for motion detection, and has a dual-working mode.
Referring to fig. 1 to 6, the MEMS inertial sensor provided in the embodiment of the present application includes: a substrate 5, a first electrode 6 and a second electrode 7, a mass 2 and a spring beam 8; an insulating layer 4 is arranged on one side of the substrate 5; the first electrode 6 and the second electrode 7 are arranged on the insulating layer 4 at intervals; the mass block 2 is suspended above the substrate 5, and the mass block 2 comprises a first part 2a, a second part 2b and a third part 2c; the elastic beam 8 is used for connecting the substrate 5 and the mass block 2, the elastic beam 8 is connected to an anchor point 9 of the substrate 5, and the first part 2a, the third part 2c and the second part 2b are positioned on two sides of the elastic beam 8; the second portion 2b forms a first capacitor with the second electrode 7, and the third portion 2c forms a second capacitor with the first electrode 6; the second capacitor can form a collapse working mode, the first capacitor is used for forming a detection end in the collapse working mode, and the MEMS inertial sensor can detect and sense according to the acquired capacitance variation in the collapse working mode.
The capacitive sensor is a conversion device that converts a physical quantity or a mechanical quantity to be measured into a capacitance variation quantity by using various types of capacitors as sensing elements, and is actually a capacitor with variable parameters.
According to the structural design of the MEMS inertial sensor provided by the above embodiment of the present application, in the two capacitors, namely the first capacitor and the second capacitor, the first capacitor may be used as a detection end, and the second capacitor may form a collapse, which gives the MEMS inertial sensor a new operation mode, namely a collapse operation mode, so that the formed MEMS inertial sensor may have more operation modes.
Referring to fig. 4 and 5, the MEMS inertial sensor may have a large detection bandwidth in the collapse working mode, and may not need to consider the actuation voltage in the detection process, and may be used as a voice acceleration sensor for voice noise reduction in the collapse working mode.
In addition, the MEMS inertial sensor can also realize the traditional working state such as detecting acceleration change based on the design of two capacitors, has high sensitivity and signal-to-noise ratio, and can be used as an acceleration sensor for detecting motion, and is shown in fig. 3. Therefore, the MEMS inertial sensor provided by the embodiment of the application has double working modes, so that the MEMS inertial sensor is flexible and convenient to use.
The MEMS inertial sensor provided by the embodiment of the application adopts the same MEMS sensor structure, but can select different working modes. For example, the detection of a capacitive acceleration sensor can be realized, and the collapse working mode can be used for voice acceleration detection, so that the application of voice call noise reduction and the like can be realized. Different resonant frequencies or bandwidths can be selected and switched according to different application scenes, the use is flexible, the respective relevant performance is not sacrificed, and therefore the design and processing manufacturing cost can be reduced.
The elastic beam 8 has a certain elasticity, and can deform in different forms according to different working states. Referring to fig. 2, the elastic beam 8 includes a first section 8a and a second section 8b. For example, the spring beam 8 itself may be subjected to bending deformation when the MEMS inertial sensor is in the collapse operation mode in the above-described embodiment. The elastic beam 8 may then be torsionally deformed when the MEMS inertial sensor is in a conventional acceleration detection mode.
The insulating layer 4 covers the surface of the substrate 5, and the first electrode 6 and the second electrode 7 are fixed electrodes, which are arranged on the insulating layer 4 at intervals. The insulating layer 4 may be used to electrically isolate the first electrode 6, the second electrode 7 and the substrate 5. And, the first electrode 6 and the second electrode 7 have different functions in different working modes, so that the formed MEMS inertial sensor has different working modes.
Specifically, in the embodiment of the present application, by disposing the insulating layer 4 with a set thickness between the substrate 5 and the two fixed electrodes, the two fixed electrodes are not in direct contact with the substrate 5, but there is a certain distance, that is, the thickness (the dimension in the Z-axis direction) of the insulating layer 4. The insulating layer 4 is arranged such that the distance between the substrate 5 and the first electrode 6 and the second electrode 7 is from none to none. The working principle of the capacitor is as follows: when the distance between the first electrode 6 and the second electrode 7 and the substrate 5 is from scratch, the capacitance between the first electrode 6 and the second electrode 7 and the substrate 5 is reduced, so that the coupling capacitance value between the first electrode 6 and the second electrode 7 and the substrate 5 can be reduced, the output of the effective capacitance of the MEMS inertial sensor is ensured, and the detection precision of the MEMS inertial sensor is improved.
In some examples of the present application, referring to fig. 1, the mass 2 includes three parts, namely, a first part 2a, a second part 2b, and a third part 2c, which are disposed side by side in the above embodiment; wherein the third portion 2c is designed to be located between the first portion 2a and the third portion 2 c.
Alternatively, referring to fig. 1, the third portion 2c is connected between the first portion 2a and the second portion 2b, and the third portion 2c is located on the same side of the elastic beam 8 as the first portion 2 a; in the Z-axis direction, the height of the third portion 2c is greater than the height of the first portion 2a, so that the third portion 2c and the first portion 2a form a stepped structure on one side of the elastic beam 8.
Referring to the up-down, left-right direction shown in fig. 1, on the right side of the elastic beam 8, the third portion 2c on the mass 2 is integrally connected with the first portion 2a and forms a stepped structure. This structural design in this application for under acceleration detection mode of operation, can increase the mass 2 around the moment of inertia that deflects of pivot 3 (elastic beam 8 twists reverse formation pivot 3), see fig. 3, can reduce resonant frequency, increase detection sensitivity. At the same time, the moment of inertia about the contact point 10 shown in fig. 4 can be increased also in the collapse operation mode, so as to achieve the purpose of improving the detection sensitivity.
The third portion 2c and the first portion 2a on the mass block 2 form a step structure, and in the collapse working mode, the attraction area between the mass block 2 and the insulating layer 4 can be reduced. For example, only the first portion 2a is attracted to the insulating layer 4, which also facilitates desorption.
In some examples of the present application, referring to fig. 1-3, the first capacitor, the second capacitor can also be used to make up a differential capacitance detector; the first electrode 6 and the second electrode 7 are detection electrodes, and are used as differential capacitance detection output signal ports.
Specifically, referring to fig. 3, when the first capacitor and the second capacitor form a differential capacitance detector and an acceleration change in the Z-axis direction is obtained, the elastic beam 8 is torsionally deformed and forms a rotation axis 3, and the mass 2 can rotate around the formed rotation axis 3.
Referring to fig. 3, the MEMS inertial sensor according to the embodiment of the present application may also be used as a capacitive acceleration sensor, where the first capacitor and the second capacitor form a differential capacitance detector.
When the first capacitor and the second capacitor form a differential capacitance detector, if an acceleration input in the Z-axis direction is detected, the mass 2 rotates around the formed rotating shaft 3, wherein the elastic beam 8 is torsionally deformed to form a virtual rotating shaft 3. On this basis, the first electrode 6, the second electrode 7 and the mass 2 constitute a differential capacitance for detecting such movements. Under the motion form, the resonance frequency is smaller, the detection sensitivity is higher when the detection is carried out, and the method is suitable for the motion detection of the acceleration sensor.
In some examples of the present application, in the collapse operation mode, the MEMS inertial sensor may form an electrostatic force between the first electrode 6 and the mass 2 by applying a first dc voltage to the first electrode 6, where the first electrode 6 forms an actuation electrode and the mass 2 acts as a single-ended capacitive output signal port.
When the MEMS inertial sensor is in the collapse mode, as shown in fig. 4 to 6, the first electrode 6 may be used as a pull-in electrode, and by applying a high dc voltage (i.e., the first dc voltage described above), a large electrostatic force can be generated between the first electrode 6 and the mass 2. The electrostatic force can cause the mass 2 to move up and down around the rotation axis 3.
When in the collapsed mode of operation, both the first electrode 6 and the second electrode 7 are located between the mass 2 and the substrate 5 in the Z-axis direction. For example, the first electrode 6 is loaded with a dc bias voltage, and at this time, the mass block 2 may be used as an output signal port, so that the parasitic capacitance is small in this way, on one hand, the sensitivity of single-ended capacitance detection may be improved, and on the other hand, the processing difficulty is not increased for reducing the parasitic capacitance.
In the above example, when the first direct voltage is greater than the pull-in voltage U pull-in When the first portion 2a is in contact with the insulating layer 4, the mass 2 is in an electrically insulating state with the first electrode 6, the second electrode 7 and the substrate 5.
When in the collapse mode of operation, see fig. 4-6, the first electrode 6 acts as an actuation electrode, and a large electrostatic force is generated between the first electrode 6 and the mass 2 by loading a high dc voltage. The electrostatic force can cause the mass 2 to move up and down (deflect) about the axis of rotation 3. When the applied dc voltage is greater than the pull-in voltage, the first portion 2a of the mass 2 will be in contact with the insulating layer 4, but the other two portions of the mass 2 will not be in contact with the first electrode 6. The mass 2 is electrically insulated from the first electrode 6, the second electrode 7 and the substrate 5.
In the above example, when the second direct current voltage is applied to the first electrode 6 and the second direct current voltage is larger than the first direct current voltage, the elastic beam 8 is bent and deformed, and the distance between the second portion 2b and the first electrode 6 and the second electrode 7 is reduced.
Specifically, when an acceleration change in the Z-axis direction is obtained, the mass 2 moves up and down around the contact point 10 where the first portion 2a contacts the insulating layer 4, supported by the elastic beam 8.
For example, the elastic beam 8 is bent (not twisted) by increasing the DC voltage applied to the first electrode 6 (e.g., applying a second DC voltage), and the second mass 2 is deformed
The portion 2b will decrease in distance from the first electrode 6 and the second electrode 7 and the resulting capacity of the electric 5 will increase. At this time, when an external acceleration is input in the Z-axis direction, the mass 2 moves up and down around the contact point 10 under the support of the elastic beam 8, see fig. 4 and 5.
Wherein the elastic beam 8 is bent and deformed, and the mass block 2 moves up and down along the Z-axis direction on the rotating shaft 3, see fig. 6. The first electrode 6, the second electrode 7 and the second portion 2b of the mass 2 form a single-ended detection capacitance for detecting movement of the mass 2.
0 in the collapsed mode of operation, the contact point 10 may correspond to a fixed constraint, the spring beam 8
Bending deformation occurs instead of torsional deformation, and under this condition the resonant frequency of the structure increases and the detection bandwidth increases. Meanwhile, as can be seen from the above, the detection capacitance is properly increased, so that not only can the sensitivity reduction caused by the increase of the resonant frequency be compensated, but also the output sensitivity can be increased, and the working mode is very suitable for the voice detection of the voice acceleration sensor.
5 in addition, when the collapse operation mode is switched to the acceleration detection operation mode, only the direct current voltage loaded on the first electrode 6 needs to be reduced, so that the mass block 2 and the insulating layer 4 are separated from suction.
The MEMS inertial sensor provided in the embodiment of the present application may have two working states, which are a first state and a second state respectively; wherein the first state is configured for speech acceleration
Detecting the voice of the sensor; the second state is configured for motion detection of the acceleration sensor. 0 in particular, the MEMS inertial sensor can be used for voice detection of a voice acceleration sensor in the collapse mode of operation.
That is, the same MEMS inertial sensor structure may select different modes of operation: the acceleration detection working mode can be used for detecting motion acceleration; collapse mode of operation, which can be used as speech plus
And detecting the speed, so as to realize the application of voice call noise reduction and the like. Different application scenes can select to switch different resonant frequencies or bandwidths of 5, the use is flexible, the related performance is not sacrificed, and the design and processing cost can be reduced.
Optionally, the substrate 5 is made of monocrystalline silicon or polycrystalline silicon.
Optionally, the MEMS inertial sensor further comprises a controller. The controller is used for controlling the MEMS inertial sensor to freely switch between the collapse working mode and the acceleration detection working mode. The controller may be, for example, an ASIC chip or a control system, for switching the dual operating states of the MEMS inertial sensor.
Specifically, the MEMS inertial sensor provided in the embodiments of the present application may select any one of the following operation modes by using an ASIC chip or a control system in combination: and selecting an acceleration detection working mode and a collapse working mode.
According to another aspect of the embodiments of the present application, there is provided a detection method of a MEMS inertial sensor, the detection method including:
step 101, applying a first direct voltage to the first electrode 6, wherein the first portion 2a is in contact with the insulating layer 4 and forms a contact point 10; the second capacitor formed by the third part 2c and the first electrode 6 enters a collapse working mode, and the elastic beam 8 is bent and deformed;
step 102, the mass block 2 moves up and down along the Z-axis direction around the contact point 10 under the support of the elastic beam 8, and the first capacitor formed by the second portion 2b and the second electrode 7 is used as a detection end to obtain the capacitance variation.
The above-described steps 101 and 102 illustrate the collapse mode of operation.
And in the collapse working mode, outputting a large bandwidth acceleration detection signal.
According to the steps 101 and 102, the resonance frequency in the motion mode is increased, the detection bandwidth is increased, and meanwhile, the detection capacitance is appropriately increased according to the above knowledge, so that not only can the sensitivity reduction caused by the increase of the resonance frequency be compensated, but also the output sensitivity is increased, and the working mode is suitable for the voice detection of the voice acceleration sensor.
Optionally, the detection method shown in the foregoing embodiment further includes the following steps 201 to 202:
step 201, the first capacitor and the second capacitor form a differential capacitance detector, wherein the first electrode 6 and the second electrode 7 are both used as differential capacitance output ports;
step 202, the elastic beam 8 generates torsional deformation, and the mass block 2 rotates around the rotating shaft 3 formed by twisting the elastic beam 8 under the support of the elastic beam 8.
The above steps 201 and 202 show the working process of the MEMS inertial sensor in the acceleration detection working mode, in which the small bandwidth acceleration detection signal is output.
According to the steps 201 and 202, the resonance frequency in the motion mode is smaller, the detection sensitivity is higher, and the method is suitable for motion detection of a traditional acceleration sensor.
According to yet another aspect of the embodiments of the present application, an electronic device is also provided. The electronic device may comprise a MEMS inertial sensor 1 as described above.
The electronic device provided in the embodiment of the application includes, but is not limited to, being applied to a smart phone, and also being applicable to other forms of electronic devices, such as a tablet computer, a notebook computer, etc., and the specific type of the electronic device is not limited in the embodiment of the application.
The specific implementation manner of the electronic device in the embodiment of the present application may refer to each embodiment of the MEMS inertial sensor, so at least the technical solution of the foregoing embodiment has all the beneficial effects, which are not described in detail herein.
The foregoing embodiments mainly describe differences between the embodiments, and as long as there is no contradiction between different optimization features of the embodiments, the embodiments may be combined to form a better embodiment, and in consideration of brevity of line text, no further description is given here.
Although some specific embodiments of the present application have been described in detail by way of example, it should be understood by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present application. It will be appreciated by those skilled in the art that modifications may be made to the above embodiments without departing from the scope and spirit of the present application. The scope of the application is defined by the appended claims.

Claims (13)

1. A MEMS inertial sensor, comprising:
a substrate (5), wherein an insulating layer (4) is arranged on one side of the substrate (5);
a first electrode (6) and a second electrode (7), wherein the first electrode (6) and the second electrode (7) are arranged on the insulating layer (4) at intervals;
the mass block (2) is suspended above the substrate (5), and the mass block (2) comprises a first part (2 a), a second part (2 b) and a third part (2 c);
an elastic beam (8), wherein the elastic beam (8) is used for connecting the substrate (5) and the mass block (2), the elastic beam (8) is connected to an anchor point (9) of the substrate (5), and the first part (2 a), the third part (2 c) and the second part (2 b) are positioned on two sides of the elastic beam (8);
-said second portion (2 b) forms a first capacitor with said second electrode (7), and-said third portion (2 c) forms a second capacitor with said first electrode (6);
the second capacitor can form a collapse working mode, the first capacitor is used for forming a detection end in the collapse working mode, and the MEMS inertial sensor can detect and sense according to the acquired capacitance variation in the collapse working mode.
2. MEMS inertial sensor according to claim 1, characterized in that the third portion (2 c) is connected between the first portion (2 a) and the second portion (2 b), and the third portion (2 c) is located on the same side of the elastic beam (8) as the first portion (2 a);
in the Z-axis direction, the height of the third portion (2 c) is greater than the height of the first portion (2 a), so that the third portion (2 c) and the first portion (2 a) form a stepped structure on one side of the elastic beam (8).
3. The MEMS inertial sensor of claim 1, wherein the first capacitor, the second capacitor are further operable to form a differential capacitance detector; the first electrode (6) and the second electrode (7) are detection electrodes, and are used as differential capacitance detection output signal ports.
4. A MEMS inertial sensor according to claim 3, characterized in that the elastic beams (8) are torsionally deformed and form a rotation axis (3) when the first and second capacitors constitute a differential capacitance detector and an acceleration change in the Z-axis direction is obtained, the mass (2) being rotatable about the rotation axis (3) formed.
5. MEMS inertial sensor according to claim 1, characterized in that in the collapsed operation mode, the MEMS inertial sensor is operated by applying a first dc voltage to the first electrode (6), an electrostatic force being formed between the first electrode (6) and the mass (2), the first electrode (6) forming an actuation electrode, the mass (2) acting as a single ended capacitive output signal port.
6. The MEMS inertial sensor of claim 5, wherein when the first dc voltage is greater than pull-in voltage U pull-in When the first part (2 a) and the insulating layer (4) form a contact state, the mass (2) and the first electrode (6), the second electrode (7) and the substrate (5) form an electric insulation state.
7. MEMS inertial sensor according to claim 5, characterized in that the elastic beam (8) is subjected to bending deformation when a second direct voltage is applied to the first electrode (6) and is greater than the first direct voltage, the distance between the second portion (2 b) and the first electrode (6) and the second electrode (7) being reduced.
8. MEMS inertial sensor according to claim 7, characterized in that the mass (2) moves up and down around the contact point (10) of the first part (2 a) with the insulating layer (4) supported by the elastic beam (8) when an acceleration change in the Z-axis direction is obtained.
9. The MEMS inertial sensor of claim 1, wherein the MEMS inertial sensor is operable for voice detection of a voice acceleration sensor in the collapsed mode of operation.
10. MEMS inertial sensor according to claim 1, characterized in that the substrate (5) is made of monocrystalline or polycrystalline silicon.
11. A method of detecting a MEMS inertial sensor according to any one of claims 1 to 10, comprising:
-applying a first direct voltage to said first electrode (6), said first portion (2 a) being in contact with said insulating layer (4) and forming a contact point (10); the second capacitor formed by the third part (2 c) and the first electrode (6) enters a collapse working mode, and the elastic beam (8) is bent and deformed;
the mass block (2) moves up and down along the Z-axis direction around the contact point (10) under the support of the elastic beam (8), and the first capacitor formed by the second part (2 b) and the second electrode (7) is used as a detection end to acquire the capacitance variation.
12. The method of MEMS inertial sensor detection of claim 11, further comprising:
the first capacitor and the second capacitor form a differential capacitance detector, wherein the first electrode (6) and the second electrode (7) are used as differential capacitance output ports;
the elastic beam (8) generates torsional deformation, and the mass block (2) rotates around a rotating shaft (3) formed by twisting the elastic beam (8) under the support of the elastic beam (8).
13. An electronic device, comprising:
MEMS inertial sensor (1) according to any one of claims 1-12.
CN202310028372.4A 2023-01-09 2023-01-09 MEMS inertial sensor, detection method and electronic equipment Pending CN116106579A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116577525A (en) * 2023-07-14 2023-08-11 苏州敏芯微电子技术股份有限公司 Inertial sensor

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116577525A (en) * 2023-07-14 2023-08-11 苏州敏芯微电子技术股份有限公司 Inertial sensor
CN116577525B (en) * 2023-07-14 2023-09-12 苏州敏芯微电子技术股份有限公司 Inertial sensor

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