阅读说明：本技术 谐振式电场传感器及其制备方法 (Resonant electric field sensor and preparation method thereof ) 是由 彭春荣 李嘉晨 毋正伟 郑凤杰 任仁 吕曜 于 2021-09-10 设计创作，主要内容包括：本公开提供了一种谐振式电场传感器及其制备方法。该电场传感器包括：衬底；支撑梁,设置在所述衬底上；振动单元,通过所述支撑梁悬空形成于所述衬底上；驱动单元,形成于所述衬底上的所述振动单元的外围,用于驱动所述振动单元产生谐振式振动；检测单元,设置在所述衬底上；所述检测单元用于检测所述振动单元在外界电场作用下的谐振频率的变化。本公开的电场传感器在不同外界电场作用下谐振频率发生变化,通过谐振频率来表征外界电场的场强,抗干扰能力强,灵敏度高,可用于交直流电场测量或非接触式电压测量。(The disclosure provides a resonant electric field sensor and a preparation method thereof. The electric field sensor includes: a substrate; a support beam disposed on the substrate; the vibration unit is formed on the substrate in a suspended mode through the supporting beam; the driving unit is formed at the periphery of the vibration unit on the substrate and used for driving the vibration unit to generate resonant vibration; a detection unit disposed on the substrate; the detection unit is used for detecting the change of the resonant frequency of the vibration unit under the action of an external electric field. The electric field sensor disclosed by the invention has the advantages that the resonance frequency changes under the action of different external electric fields, the field intensity of the external electric fields is represented through the resonance frequency, the anti-interference capability is strong, the sensitivity is high, and the electric field sensor can be used for measuring alternating current and direct current electric fields or non-contact voltage.)

1. A resonant electric field sensor, comprising:

a substrate;

a support beam disposed on the substrate;

the vibration unit is formed on the substrate in a suspended mode through the supporting beam;

the driving unit is formed at the periphery of the vibration unit on the substrate and used for driving the vibration unit to generate resonant vibration; and

a detection unit disposed on the substrate; the detection unit is used for detecting the change of the resonant frequency of the vibration unit under the action of an external electric field.

2. The electric field sensor according to claim 1, wherein the substrate comprises:

the middle part of the supporting layer forms a recess or a window; and

and the fixing layer is formed on the supporting layer, and at least one part of the driving unit and at least one part of the detection unit are connected to the fixing layer, so that the vibration unit, the supporting beam and the detection unit are suspended relative to the supporting layer and the fixing layer.

3. The electric field sensor according to claim 2, wherein the detection unit comprises one of a piezoresistive detection unit, a capacitive detection unit, or an optical detection unit;

preferably, the piezoresistive detection unit comprises a piezoresistive beam-type detection unit or a piezoresistive detection unit;

preferably, the piezoresistive beam type sensing unit includes:

a detection unit anchoring portion formed on the fixed layer; and

and the piezoresistive beam is fixed and suspended through the anchoring part of the detection unit, and the supporting beam is connected between the piezoresistive beam and the vibration unit.

4. The electric field sensor according to claim 3, wherein the structure of the piezoresistive beam-like detection unit comprises: one of a straight beam structure, a folded beam structure, or a tuning fork beam structure.

5. The electric field sensor according to claim 2, wherein the driving unit comprises one of an electrostatic driving unit, an electromagnetic driving unit, a piezoelectric driving unit, and a thermal excitation driving unit.

6. The electric field sensor according to claim 5, wherein the electrostatic driving unit includes:

the fixed electrode is fixed and suspended through the anchoring part of the driving unit and comprises a plurality of fixed comb tooth parts connected with the anchoring part of the driving unit; and

the vibrating electrode comprises a plurality of vibrating comb tooth parts connected to the vibrating unit, and the plurality of vibrating comb tooth parts and the plurality of fixed comb tooth parts extend towards each other and are respectively and alternately arranged;

the electrostatic driving unit comprises a parallel plate type driving unit, a comb type driving unit, an array type driving unit and a push-pull type driving unit.

7. The electric field sensor according to claim 1, further comprising a tuning unit for adjusting a resonance frequency of the vibrating unit or introducing the measured quantity as a disturbing electrode;

preferably, the tuning unit includes:

a tuning electrode disposed at one side of the detection unit; and

one end of the connecting beam is connected with the tuning electrode, and the other end of the connecting beam is connected with a tuning unit anchoring part formed on the fixed layer;

wherein, the tuning electrode comprises a flat plate type tuning electrode or a comb-tooth type tuning electrode.

8. The electric field sensor according to any of claims 1-4, wherein the shape of the vibrating unit comprises a circle or a polygon;

wherein, the vibration unit is also provided with a through hole;

wherein the shape of the through hole comprises at least one of a star shape, a fan shape, a rectangular shape, a square shape, a circular shape or a triangular shape.

9. A method for manufacturing an electric field sensor according to any one of claims 1 to 8, comprising:

patterning a device layer on the fixed layer, spin-coating a photoresist layer on the patterned device layer, then exposing, developing, etching the device layer to form a vibration unit, a support beam, a driving unit, a detection unit, an anchoring part and a tuning unit, and removing the photoresist layer;

wherein the anchoring part comprises a detection unit anchoring part, a driving unit anchoring part and a tuning unit anchoring part;

etching a window on the supporting layer; and

and etching the fixed layer through the window, releasing the device layer, and finishing the preparation of the electric field sensor.

10. A spatial electric field sensor, comprising:

a plurality of electric field sensors according to any one of claims 1 to 9 in different planes for two-dimensional or three-dimensional electric field measurements.

Technical Field

The invention relates to the field of sensors and Micro Electro Mechanical systems (MEMS for short), in particular to a resonant electric field sensor.

Background

An electric field sensor based on MEMS is a device for measuring the electric field intensity, and is widely applied to various fields of climate weather, power grids, petrochemical industry, aerospace and the like. When the electric field sensors form a wireless sensing network and are used for monitoring a power grid, the energy consumption, the volume, the anti-interference performance and the sensitivity of the sensing nodes are the problems which need to be considered.

With the development of MEMS technology, the MEMS technology-based electric field sensor is reduced in size, easier to manufacture and integrate, relative to existing electric field sensors. Most of the MEMS electric field sensors with excellent performance utilize an external driving voltage to drive a driving structure to displace, and then realize the measurement of an electric field to be measured based on a charge induction principle. However, the MEMS electric field sensor is limited by its working principle, and also has disadvantages of high power consumption, low sensitivity, and poor interference rejection.

Disclosure of Invention

In view of the above, the present disclosure provides a resonant micro electric field sensor, which is intended to at least partially solve one of the above-mentioned technical problems.

An aspect provided by the present disclosure provides a resonant electric field sensor, including:

a substrate;

a support beam disposed on the substrate;

a vibration unit formed on the substrate in a suspended manner by the support beam;

a driving unit formed on the periphery of the vibrating unit on the substrate, for driving the vibrating unit to generate resonant vibration; and

a detection unit provided on the substrate; the detection unit is used for detecting the change of the resonant frequency of the vibration unit under the action of an external electric field.

According to an embodiment of the present disclosure, the substrate includes:

the middle part of the supporting layer forms a recess or a window; and

and a fixing layer formed on the support layer, wherein at least a portion of the driving unit and at least a portion of the detecting unit are connected to the fixing layer, so that the vibrating unit, the support beam, and the detecting unit are suspended from the support layer and the fixing layer.

According to an embodiment of the present disclosure, the detection unit includes one of a piezoresistive detection unit, a capacitive detection unit, or an optical detection unit;

preferably, the piezoresistive detection unit includes a piezoresistive beam-type detection unit or a piezoresistive detection unit;

preferably, the piezoresistive beam type detecting unit includes:

a detection unit anchoring portion formed on the fixed layer; and

and a piezoresistive beam fixed to the detection unit anchoring portion and suspended therefrom, wherein the support beam is connected between the piezoresistive beam and the vibration unit.

According to an embodiment of the present disclosure, the structure of the piezoresistive beam type detection unit includes: one of a straight beam structure, a folded beam structure, or a tuning fork beam structure.

According to an embodiment of the present disclosure, the driving unit includes one of an electrostatic driving unit, an electromagnetic driving unit, a piezoelectric driving unit, and a thermal excitation driving unit.

According to an embodiment of the present disclosure, the electrostatic driving unit includes:

a fixed electrode fixed and suspended by the drive unit anchoring part and including a plurality of fixed comb teeth parts connected with the drive unit anchoring part; and

a vibration electrode including a plurality of vibration comb portions connected to the vibration unit, the plurality of vibration comb portions and the plurality of fixed comb portions extending in opposite directions and alternately arranged, respectively;

the electrostatic driving unit comprises a parallel plate type driving unit, a comb type driving unit, an array type driving unit and a push-pull type driving unit.

According to an embodiment of the present disclosure, the electric field sensor further includes a tuning unit for adjusting a resonance frequency of the vibration unit or introducing the measured quantity as a disturbing electrode;

preferably, the tuning unit includes:

a tuning electrode disposed on one side of the detection unit; and

a connection beam having one end connected to the tuning electrode and the other end connected to a tuning-unit anchoring portion formed on the fixed layer;

the tuning electrode comprises a flat plate type tuning electrode or a comb-tooth type tuning electrode.

According to an embodiment of the present disclosure, the shape of the vibration unit includes a circle or a polygon;

wherein, the vibration unit is also provided with a through hole;

wherein, the shape of the through hole comprises at least one of a star shape, a fan shape, a rectangle shape, a square shape, a circle shape or a triangle shape.

Another aspect of the present disclosure provides a method for manufacturing a resonant electric field sensor, including:

patterning a device layer on a fixed layer, spin-coating a photoresist layer on the patterned device layer, exposing, developing, etching the device layer to form a vibration unit, a support beam, a driving unit, a detection unit, an anchoring part and a tuning unit, and removing the photoresist layer;

wherein the anchoring part comprises a detection unit anchoring part, a driving unit anchoring part and a tuning unit anchoring part;

etching a window on the supporting layer; and

and etching the fixing layer through the window, releasing the device layer and finishing the preparation of the electric field sensor.

Yet another aspect of the present disclosure also provides a spatial resonance type electric field sensor, including:

a plurality of the above-described electric field sensors, in different planes, are used for two-dimensional or three-dimensional electric field measurements.

According to the embodiment of the disclosure, the vibration unit in the electric field sensor is excited by the driving unit to generate resonance, the resonance frequency of the vibration unit is changed under the action of the electric field to be measured, the field intensity of the external electric field is represented by the resonance frequency, the anti-interference capability is strong, the sensitivity is high, and the vibration unit can be used for alternating current/direct current electric field measurement or non-contact voltage measurement.

Drawings

The above and other objects, features and advantages of the present disclosure will become more apparent from the following description of embodiments of the present disclosure with reference to the accompanying drawings, in which:

fig. 1 schematically illustrates a structural schematic diagram of a resonant electric field sensor according to an embodiment of the present disclosure;

fig. 2 schematically shows a structural schematic of a resonant electric field sensor according to another embodiment of the present disclosure;

fig. 3 schematically shows a structural schematic of a resonant electric field sensor according to a further embodiment of the present disclosure;

4A-4D schematically illustrate four mating configurations of a drive unit and a vibratory unit according to embodiments of the present disclosure;

FIG. 5 schematically illustrates five implementations of a support beam according to an embodiment of the present disclosure;

FIG. 6 schematically illustrates four embodiments of piezoresistive beams of a piezoresistive beam type sensing unit, according to an embodiment of the present disclosure;

fig. 7 schematically illustrates a flow diagram of a method of fabricating a resonant electric field sensor according to an embodiment of the present disclosure; and

fig. 8A-8D schematically illustrate a process for manufacturing a resonant electric field sensor according to an embodiment of the present disclosure.

In the above figures, the reference numerals have the following meanings:

1. a vibration unit; 2. a support beam; 21. a straight beam; 22. a serpentine beam; 23. an L-shaped beam; 24. a U-shaped beam; 25. an irregular beam; 3. a drive unit; 31. a vibrating electrode; 311. vibrating the comb teeth part; 312. a second base; 32. a fixed electrode; 321. fixing the comb teeth part; 322. a first base; 4. a detection unit; 51. a tuning unit anchoring section; 52. a drive unit anchoring section; 53. a detection unit anchoring section; 54. a piezoresistive beam; 541. a straight beam structure; 542. a folded beam structure; 543. a tuning fork beam structure; 544. an irregular beam structure; 6. a connecting beam; 7. a tuning electrode; 8. a device layer; 9. a fixed layer; 10. and (4) a support layer.

Detailed Description

The present disclosure is described in further detail below with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the disclosure and not restrictive thereof, and that various features described in the embodiments may be combined to form multiple alternatives. It should be further noted that, for the convenience of description, only some of the structures relevant to the present disclosure are shown in the drawings, not all of them.

According to the present general inventive concept, there is provided a resonant type electric field sensor, including: a substrate. And a support beam disposed on the substrate. And the vibration unit is formed on the substrate in a suspended mode through the supporting beam. And the driving unit is formed at the periphery of the vibration unit on the substrate and is used for driving the vibration unit to generate resonant vibration. A detection unit disposed on the substrate; the detection unit is used for detecting the change of the resonant frequency of the vibration unit under the action of an external electric field.

According to another general inventive concept of the present disclosure, there is provided a method of manufacturing a resonant electric field sensor, including: patterning the device layer on the fixed layer, spin-coating a photoresist layer on the patterned device layer, exposing, developing, etching the device layer to form a vibration unit, a support beam, a driving unit, a detection unit, an anchoring part and a tuning unit, and removing the photoresist layer. The anchoring portion includes a detection unit anchoring portion, a driving unit anchoring portion, and a tuning unit anchoring portion. And etching a window on the support layer. And etching the fixed layer through the window, releasing the device layer, and finishing the preparation of the resonant electric field sensor.

According to still another aspect of the present general inventive concept, there is provided a spatial resonance type electric field sensor including: a plurality of the above-described electric field sensors, in different planes, are used for two-dimensional or three-dimensional electric field measurements.

Fig. 1 schematically illustrates a structural schematic diagram of a resonant electric field sensor according to an embodiment of the present disclosure;

referring to fig. 1, according to an embodiment of an aspect of the present disclosure, there is provided a resonant electric field sensor, which may include a substrate, a vibration unit 1, a support beam 2, a driving unit 3, and a detection unit 4.

A substrate.

And a support beam 2 disposed on the substrate.

The vibration unit 1 is formed on the substrate in a suspended manner by a support beam 2.

And the driving unit 3 is formed at the periphery of the vibration unit 1 on the substrate and is used for driving the vibration unit 1 to generate resonant vibration.

And a detection unit 4 disposed on the substrate. The detection unit 4 is used for detecting the change of the resonant frequency of the vibration unit 1 under the action of an external electric field.

According to the embodiment of the disclosure, the vibration unit 1 in the resonant electric field sensor is excited by the driving unit 3 to resonate, and under the action of an electric field to be detected, the resonance frequency of the vibration unit 1 is changed, and the detection unit is used for detecting the change of the resonance frequency of the vibration unit under the action of an external electric field. The electric field sensor disclosed by the invention represents the field intensity of an external electric field through the resonant frequency, and has strong anti-interference capability and high sensitivity.

According to the embodiment of the disclosure, the electric field sensor is small in size and simple in structure, is beneficial to realizing batch manufacturing and system integration, reduces manufacturing cost, can be used for alternating current-direct current electric field measurement or non-contact voltage measurement, and is beneficial to wide application of the electric field sensor in the fields of power internet of things and smart grid measurement.

Referring to fig. 1, according to an embodiment of the present disclosure, a substrate may include a support layer 10 and a fixing layer 9.

A support layer 10 in which a recess or window is formed.

And a fixing layer 9 formed on the supporting layer 10, and at least a portion of the driving unit 3 and at least a portion of the sensing unit 4 are connected to the fixing layer 9 such that the vibration unit 1, the support beam 2, and the driving unit 3 are suspended with respect to the supporting layer 10 and the fixing layer 9.

According to an embodiment of the present disclosure, referring to fig. 1, the resonant electric field sensor may further include a device layer 8.

The vibration unit 1, the driving unit 3, the support beam 2, and the detection unit 4 are formed by performing a patterning process once on the device layer 8 formed on the fixed layer 9. In this way, the vibration unit 1, the driving unit 3, the supporting beam 2 and the detecting unit 4 are all formed by the device layer 8, are located at the same height, and only one patterning process is performed, so that the manufacturing cost can be reduced.

According to an embodiment of the present disclosure, the detection unit 4 may include one of a piezoresistive detection unit 4, a capacitive detection unit 4, or an optical detection unit 4.

Preferably, the piezoresistive detection unit 4 may include a piezoresistive beam-type detection unit or a piezoresistive detection unit 4.

Preferably, the piezoresistive beam type sensing unit 4 may include:

the detection unit anchor 53 is formed on the fixed layer 9.

The piezoresistive beam 54 is fixed to the detection unit anchor 53 and suspended, and the support beam 2 is connected between the piezoresistive beam 54 and the vibration unit 1.

According to the embodiment of the present disclosure, the number of the sensing units 4 is at least one, and is disposed at least one side of the vibration unit 1.

In some embodiments, the piezoresistive detection unit 4 measures the measured electric field or voltage by measuring the resonant frequency from the resistance change. The capacitive detection unit 4 measures the measured electric field or voltage by measuring the resonance frequency from the capacitance change. The optical detection unit 4 detects the displacement or deflection angle of the vibration unit 1 by an optical method, so as to measure the electric field or voltage to be measured.

In some embodiments, the piezoresistive detection device 4 may be a piezoresistive beam-type detection unit 4 or a piezoresistive detection unit 4. The piezoresistive beam 54 of the piezoresistive beam type detecting unit 4 is connected to the vibration unit 1 via the support beam 2, and both ends of the piezoresistive beam 54 are fixed by the detecting unit anchoring portion 51 on the fixing layer 9 to suspend the piezoresistive beam 54.

FIG. 6 schematically illustrates four embodiments of piezoresistive beams in a piezoresistive beam type sensing unit, according to an embodiment of the present disclosure.

According to an embodiment of the present disclosure, referring to fig. 1 and 6, the structure of the piezoresistive beam 54 may include one of a straight beam structure 541, a folded beam structure 542, a tuning fork beam structure 543, and an irregular beam structure 544.

According to the embodiment of the present disclosure, the piezoresistive beam type sensing unit 4 may be disposed in a direction parallel to the vibration direction of the vibration unit 1, and may also be disposed in a direction perpendicular to the vibration direction of the vibration unit 1. At least one piezoresistive beam-type detecting unit 4 is provided. In an exemplary embodiment, the two piezoresistive beam type detecting units 4 of the straight beam structure 541 are respectively disposed on two opposite sides of the vibration unit 1, and the disposed direction is parallel to the vibration direction of the vibration unit 1.

According to an embodiment of the present disclosure, the material from which the piezoresistive beams are fabricated includes at least one of metal, silicon, doped silicon.

According to the embodiment of the disclosure, the piezoresistor can be prepared by forming doped silicon through ion implantation and diffusion, and can also be prepared through thin film deposition and sputtering processes.

According to an embodiment of the present disclosure, the capacitive detection device 4 may be an interdigital capacitive structure or a plate capacitive structure.

According to the electric field sensor disclosed by the embodiment of the disclosure, the resonance frequency is detected by using modes such as piezoresistance, capacitance, optics and the like, and the electric field or voltage to be detected is measured by measuring the resonance frequency of the vibration unit 1.

According to the embodiment of the present disclosure, the driving unit 3 may include one of an electrostatic driving unit 3, an electromagnetic driving unit 3, a piezoelectric driving unit 3, and a thermal excitation driving unit 3. In an embodiment, the driving unit 3 may be an electrostatic driving unit 3.

According to an embodiment of the present disclosure, referring to fig. 1, the electrostatic driving unit 3 may include a fixed electrode 32 and a vibration electrode 31.

The fixed electrode 32 is fixed and suspended by the driving unit anchoring portion 52, and may further include a plurality of fixed comb-teeth portions 321 connected to the driving unit anchoring portion 32.

The vibration electrode 31 may include a plurality of vibration comb portions 311 connected to the vibration unit 1, and the plurality of vibration comb portions 311 and the plurality of fixed comb portions 321 extend toward each other and are alternately disposed, respectively.

Fig. 4A-4D schematically show four types of matching configurations of the driving unit and the vibration unit according to the embodiment of the present disclosure.

According to an embodiment of the present disclosure, the electrostatic driving unit 3, referring to fig. 4, may include a parallel plate type driving unit 3, a comb type driving unit 3, an array type driving unit 3, and a push-pull type driving unit.

According to an embodiment of the present disclosure, referring to fig. 4B-4D, the fixed electrode 32 may further include a first base 322 extending from the driving unit anchoring portion 52, and the plurality of fixed comb-tooth portions 321 extend from the first base 322 perpendicularly to an extending direction of the first base 322. The vibrating portion 31 may further include a second base 312 extending from the vibrating unit 1, and the plurality of vibrating comb-teeth portions 311 extend from the second base 312 perpendicularly to the extending direction of the second base 312.

According to an embodiment of the present disclosure, referring to fig. 4A, the driving unit 3 may be a parallel plate type structure and may include a vibration electrode 31 and a fixed electrode 32.

The vibration electrode 31 may include a plurality of vibration comb parts 311 connected to the vibration unit 1.

The fixed electrode 32 may include a driving unit anchoring portion 52 formed on the fixed layer 9, and a plurality of fixed comb-tooth portions 321 connected to the driving unit anchoring portion 52, and extend opposite to the plurality of vibration comb-tooth portions 311, and are alternately disposed, respectively.

According to an embodiment of the present disclosure, referring to fig. 4B, the driving unit 3 may be a comb-tooth structure including a vibrating electrode 31 and a fixed electrode 32.

The vibration electrode 31 may include two second bases 312 extending from the vibration unit 1, and a plurality of vibration comb portions 311 oppositely extending from the two second bases 312 perpendicular to an extending direction of the second bases 312.

The fixed electrode 32 may include a first base 322 extending from the driving unit anchoring portion 52, and the first base 322 is disposed between the two second bases 312, and a plurality of fixed comb portions 321 extend from the first base 322 perpendicular to an extending direction of the first base 322.

According to an embodiment of the present disclosure, referring to fig. 4C, the driving unit 3 may be an array structure including a vibration electrode 31 and a fixed electrode 32.

The vibration electrode may include two second bases 312 extending from the vibration unit 1, and the plurality of vibration comb portions 311 oppositely extend from the two second bases 312 perpendicular to the extending direction of the second bases 312.

The fixed electrode may include two first base portions 322 extending from the driving unit anchoring portion 52, a plurality of fixed comb-tooth portions 321 extending from the first base portions 322 perpendicularly to an extending direction of the first base portions 322, and the fixed comb-tooth portions 321 on each of the first base portions 322 and the vibration comb-tooth portions 311 on the second base portion 312 extend toward each other and are alternately disposed, respectively.

The array-type driving units 3 arranged on the two opposite sides of the vibration unit 1 are arranged in the same manner, and the voltages applied to the two array-type driving units 3 are reverse voltages.

According to an embodiment of the present disclosure, referring to fig. 4D, the driving unit 3 may be a push-pull structure, and may include a movable portion 31 and a stationary portion 32.

The push-pull type driving unit 3 has a structure in which the driving units 3 disposed on opposite sides of the vibration unit 1 are oppositely disposed compared to the array type driving unit 3.

According to the embodiment of the present disclosure, the driving units 3 are at least one group, each group containing two driving units 3; wherein the drive unit 3 should be arranged at least on one side of the periphery of the vibration unit 1. In an exemplary embodiment, the driving unit 3 is disposed at the other corresponding two sides of the vibration unit 1 without the detection unit, and two vibration units 3 are disposed at each side for causing the vibration unit 1 to generate resonant vibration.

According to an embodiment of the present disclosure, the shape of the vibration unit 1 may be a circle or a polygon. The vibration unit 1 may be further provided with a through hole. The shape of the through-hole may include at least one of a star shape, a fan shape, a rectangular shape, a square shape, a circular shape, or a triangular shape.

According to the embodiment of the disclosure, the through holes are formed in the vibration unit 1, so that the mass of the vibration unit can be reduced, the process release is facilitated, and the damage of the vibration unit caused by the overlarge surface pressure bearing of the vibration unit 1 when each component of the etched electric field sensor is released is prevented, and the yield of the electric field sensor is further reduced.

According to an embodiment of the present disclosure, referring to fig. 1, the vibration unit 1 has a substantially rectangular surface, and two sets of driving units 3 are respectively disposed outside two opposite first sides of the vibration unit 1. A set of detection units 4 is disposed outside two opposite second sides of the vibration unit 1, respectively. The support beam 2 may be connected to both the side edges of the vibration unit 1 and the top corners of the vibration unit 1, for example, the support beam 2 is connected to the middle of the side edges of the vibration unit 1.

FIG. 5 schematically shows five implementation schemes of the support beam according to the embodiment of the disclosure.

According to an embodiment of the present disclosure, referring to fig. 1 and 5, the support beam 2 may be one of a straight beam 21, a serpentine beam 22, an L-shaped beam 23, a U-shaped beam 24, and an irregular beam 25. In one embodiment, the support beam 2 is a straight beam 21.

According to an embodiment of the present disclosure, referring to fig. 1, the electric field sensor may further include a tuning unit for adjusting a resonance frequency of the vibration unit 1 or introducing the measured quantity as a disturbing electrode.

Preferably, the tuning unit may include a connection beam 6, a tuning electrode 7, and a tuning unit anchoring portion 51.

And a tuning electrode 7 provided on one side of the detection unit 4.

The connection beam 6 has one end connected to the tuning electrode 7 and the other end connected to a tuning-element anchoring portion 51 formed on the fixed layer 9.

The tuning electrode 7 may comprise a plate-type tuning electrode 7 or a comb-shaped tuning electrode 7.

In one embodiment, the tuning unit includes: a tuning electrode 7 provided on one side of the detection device 4; and a connection beam 6, one end of the connection beam 6 being connected to the tuning electrode 7, and the other end thereof being connected to a third anchor portion 51 formed on the fixed layer 9.

According to an embodiment of the present disclosure, the tuning electrode 7 comprises a planar tuning electrode 7 or a comb-like tuning electrode 7. The tuning unit is arranged on at least one side of the detection unit 4 by capacitive coupling. In one embodiment, the tuning electrode 7 is a flat plate structure and is disposed on a side of the detection unit 4 away from the vibration unit 1.

According to the embodiment of the disclosure, in the actual working process of the resonant electric field sensor, the preset resonant frequency may not be reached due to the influence of the process or the working environment thereof, and the tuning unit is arranged on at least one side of the detection device, so that the resonant electric field sensor can reach the preset resonant frequency through the tuning effect of the tuning unit when the resonant electric field sensor does not reach the preset resonant frequency, thereby improving the measurement accuracy of the resonant electric field sensor. The tuning unit can also be introduced as a perturbation electrode for measurement, which is used to widen the parameter measurement range of the resonant electric field sensor.

According to embodiments of the present disclosure, the electric field sensor of the present disclosure may also be used to measure a two-dimensional electric field or a three-dimensional electric field.

Fig. 2 schematically shows a structural schematic diagram of a resonant electric field sensor according to another embodiment of the present disclosure.

Fig. 3 schematically shows a structural schematic diagram of a resonant electric field sensor according to yet another embodiment of the present disclosure.

According to an embodiment of the present disclosure, referring to fig. 1 and 2, the resonant electric field sensor in fig. 2 is a modified embodiment based on the resonant electric field sensor shown in fig. 1.

The difference is that the resonant electric field sensor in fig. 2 is not provided with a tuning unit, the piezoresistive beam type detecting unit 4 and the electrostatic driving unit 3 are both arranged outside two opposite sides of the vibrating unit 1, and the support beam 2 is arranged between the two sets of electrostatic driving units 3; the piezoresistive beam 54 in the piezoresistive beam type detection unit 4 is a tuning fork beam structure 543.

Referring to fig. 1 and 3, the electric field sensor of fig. 3 is another modified embodiment based on the electric field sensor shown in fig. 1.

The difference is that a set of electrostatic driving units 3 is respectively arranged outside two opposite first sides of the vibration unit 1 of the electric field sensor in fig. 3; a pair of piezoresistive beam type detecting units 4 and two sets of electrostatic driving units 3 are respectively disposed outside two opposite second sides of the vibration unit 1, the support beam 2 is disposed between the two sets of driving units 3, and the piezoresistive beams 54 in the piezoresistive beam type detecting units 4 are tuning fork beam structures 543.

Fig. 7 schematically illustrates a flow chart of a method of manufacturing a resonant electric field sensor according to another embodiment of the present disclosure; fig. 8A-8D schematically illustrate a process for fabricating a resonant electric field sensor according to an embodiment of the present disclosure.

Referring to fig. 1, 7 and 8, an embodiment of the present disclosure provides a method for manufacturing an electric field sensor, including step S701, step S702, and step S703.

Pads (not shown) are fabricated by sputtering metal onto the device layer 801 of the SOI wafer.

In step S701, the device layer 8 on the fixed layer 9 is patterned, a photoresist layer is spin-coated on the patterned device layer 8, and then the device layer 8 is exposed, developed, etched, formed with a vibration unit, a support beam, a driving unit, a detection unit, an anchor portion, and a tuning unit, and removed.

The anchoring portion may include a detection unit anchoring portion, a driving unit anchoring portion, and a tuning unit anchoring portion.

In accordance with an embodiment of the present disclosure, referring to fig. 8, a wafer having a support layer 10, a fixed layer 9, and a device layer 8 is prepared before patterning the device layer 8. In one embodiment, the wafer with the support layer 10, the fixed layer 9, and the device layer 8 is an SOI wafer, as shown in fig. 8A.

Patterning the device layer 8 of the SOI wafer, spin-coating a photoresist layer, exposing, developing, and etching the device layer 8 on the SOI wafer to form the vibration unit 1, the support beam 2, the driving unit 3, the detecting unit 4, the anchor portion, and the tuning unit, and removing the photoresist layer to form the structure shown in fig. 8B.

In step S702, a window is etched in the support layer 10.

According to the embodiment of the present disclosure, a window region is formed by an etching process in a region of the support layer 10 corresponding to the vibration unit 1, the driving unit 3, the support beam 2, and the detection unit 4, resulting in a structure as shown in fig. 8C.

In step S703, the fixing layer 9 is etched through the window, and the device layer 8 is released, thereby completing the fabrication of the electric field sensor.

According to the embodiment of the present disclosure, the fixed layer 9 is etched in the window region to release the suspended portions of the vibration unit 1, the support beam 2, the driving unit 3, the detecting unit 4, and the tuning unit obtained by etching the device layer 8, resulting in the structure shown in fig. 8D.

According to the embodiment of the disclosure, the method for preparing the electric field sensor is beneficial to realizing batch manufacturing and system integration and reducing manufacturing cost. The electric field sensor is beneficial to wide application in the field of measurement of the power internet of things and the smart grid.

The above description is only exemplary of the present disclosure and should not be taken as limiting the disclosure, as any modification, equivalent replacement, or improvement made within the spirit and principle of the present disclosure should be included in the scope of protection of the present disclosure.