CN111141431A

CN111141431A - Graphene high-pressure sensor based on nano-pores

Info

Publication number: CN111141431A
Application number: CN202010043442.XA
Authority: CN
Inventors: 李孟委; 王俊强; 李明浩; 梁海坚
Original assignee: North University of China
Current assignee: North University of China
Priority date: 2020-01-15
Filing date: 2020-01-15
Publication date: 2020-05-12

Abstract

A nanopore based graphene high pressure sensor, the sensor comprising: the packaging structure comprises a packaging shell, a stainless steel end cover arranged at the top end of the packaging shell and a base plate arranged at the lower end in the packaging shell, wherein the stainless steel end cover is provided with a plurality of round holes, the base plate is provided with a substrate, and the center of the substrate is provided with a nano hole; a pressure detection unit disposed on the substrate; the interconnection assemblies are arranged on two sides of the pressure detection unit, one end of each interconnection assembly is connected with the pressure detection unit, and the other end of each interconnection assembly is connected with the outside. According to the invention, inert gas is filled in the nano holes, the nano films are distributed on the nano hole structure, the substrate and the base plate form an inert gas sealing cavity through metal bonding, the graphene property is utilized, the graphene can stably work in a high-pressure environment of 400MPa for a long time, the response time is less than 1 mu s, and the graphene is acid-resistant, alkali-resistant and corrosion-resistant, is suitable for various high-pressure test environments, and has very high practical value.

Description

Graphene high-pressure sensor based on nano-pores

Technical Field

The invention relates to the technical field of high-pressure testing, in particular to a graphene high-pressure sensor based on a nanopore.

Background

With the continuous development of scientific technology, the requirement for pressure measurement in many fields is increasing, and especially for pressure measurement in a long-time high-pressure severe environment, the requirement is one of the important problems facing at present. For example, in the environments of aerospace engines, in gun bores and the like, pressure sensors are required to measure pressure parameters of pressure-bearing members of the devices, so that the health condition of the pressure-bearing members is accurately evaluated, and the design of high-pressure-resistant key members is facilitated.

The graphene has excellent mechanical, electrical, thermal and chemical properties, is one of the materials with the highest known strength, has good toughness and can be bent, the theoretical Young modulus of the graphene reaches 1.0TPa, and the inherent tensile strength is 130 GPa. Meanwhile, the carrier mobility of graphene at room temperature is about 15000cm²V · s, which is more than 10 times that of silicon material, is more than twice that of indium antimonide (InSb), which is the substance with the highest carrier mobility known so far. Under certain specific conditions, such as low temperature, the carrier mobility of graphene can be even as high as 250000cm²V · s. Unlike many materials, the electron mobility of graphene is less influenced by temperature change, and the electron mobility of single-layer graphene is 15000cm at any temperature between 50 and 500K²And V · s left and right are good nano sensor materials. Its response time to pressure is extremely short.

At present, silicon piezoresistive pressure sensors are widely applied in the fields of aerospace, weaponry and the like, but the pressure measuring range is small, and the response time is long. The test requirement of the chamber pressure of 400MPa cannot be met, the precision is high and the performance is stable; but its thermal inertia is large and its response time is long. For example, in the process of launching a certain type of artillery, the pressure in a bore reaches 300-400 MPa, and the response time is less than 50 ms. Compared with the traditional silicon piezoresistive pressure sensor, the graphene high-pressure sensor based on the nano holes can be used for pressure measurement in a high-pressure severe environment.

The method is a scientific technology which needs to be solved urgently at present by using a nanopore as a sensitive structure and using a graphene material to replace a metal material and other semiconductor materials so as to develop a high-performance high-pressure sensor with quick response time and small volume.

Disclosure of Invention

In order to effectively solve the defects of the background technical problem, a graphene material is used for replacing a metal material and other semiconductor materials, and the graphene is covered on a nanopore structure, so that the nanopore-based graphene high-pressure sensor is designed. The graphene film is influenced by pressure, electrical characteristics are changed, specifically, the graphene film is deformed due to the pressure, the conductivity of the graphene is changed, and then the measurement of the pressure is realized by detecting the change of the conductivity of the graphene film through an external detection circuit.

A nanopore based graphene high pressure sensor capable of long term stable operation in a high pressure environment of 400MPa with a response time below 1 μ s, the sensor comprising:

a packaging shell, a stainless steel end cover arranged at the top end of the packaging shell and a substrate arranged at the lower end in the packaging shell, wherein the stainless steel end cover is provided with a plurality of round holes,

the substrate is arranged on the base plate, and a nanopore is arranged in the center of the substrate;

a pressure detection unit disposed on the substrate;

the interconnection assemblies are arranged on two sides of the pressure detection unit, one end of each interconnection assembly is connected with the pressure detection unit, and the other end of each interconnection assembly is connected with the outside to lead out the electrical response of the pressure detection unit.

Optionally, the pressure detection unit includes: the nano-film is arranged on the upper surface of the substrate and covers the nano-holes, the metal electrodes are respectively arranged at the corners close to the nano-film, two sides of the nano-film are respectively provided with a wiring, the metal electrodes are connected with two sides of the nano-film through the wirings at the corresponding sides, the nano-holes, the substrate and the nano-film on the substrate jointly form an inert gas sealing cavity, and inert gas is filled in the inert gas sealing cavity.

Optionally, the nano-film is composed of an upper boron nitride layer, a middle graphene layer, and a lower boron nitride layer, the upper boron nitride layer, the middle graphene layer, and the lower boron nitride layer are sequentially disposed from top to bottom, two sides of the middle graphene layer of the nano-film respectively cover the wiring of the corresponding side, and the electrical response of the middle graphene layer is led out to the metal electrode.

Optionally, the metal electrode and the bottom of the wiring are further provided with a barrier layer.

Optionally, the interconnect assembly comprises: the interconnection lead, the interconnection pad, the lead post and the external interconnection electrode are connected in sequence.

Optionally, the substrate is provided with a mounting hole for mounting the lead post, the lead post is disposed in the mounting hole, the interconnection pad is disposed on the substrate and connected to one end of the lead post, an interconnection bump is bonded to the interconnection pad, one end of the interconnection lead is connected to the interconnection bump on the interconnection pad, the other end of the interconnection lead is connected to the metal electrode, the bottom of the package housing is provided with an opening for accommodating the external interconnection electrode, the external interconnection electrode is disposed at the bottom of the substrate and connected to the other end of the lead post, and the external interconnection electrode is connected to an external detection component.

Compared with the prior art, the method has obvious advancement, the device utilizes the nano film containing the graphene to replace other metal materials or semiconductor materials, the pressure measuring interval of the pressure sensor is increased, the square-shaped nano pore structure is etched on the substrate, the pressure bearing capacity of the graphene can be improved through the nano pore structure, the upper pressure measuring limit of the pressure sensor is further increased by covering the graphene layer on the nano pore, and the device can meet the requirement of high-pressure testing. And due to the high carrier mobility of the graphene material, the response speed of the device is effectively improved. Meanwhile, the nano film is wrapped by the stainless steel end cover and the packaging shell, and the inert gas is filled in the nano hole, so that the interference factors in the surrounding environment can be effectively reduced, the stability of the device is improved, the nano film can be applied to the severe high-pressure testing environment, and the nano film is a very ideal high-pressure sensor.

Drawings

FIG. 1 is a schematic view of the external structure of the present invention;

FIG. 2 is a schematic view of the internal structure of the present invention;

FIG. 3 is a schematic diagram of the nanopore of the present invention arranged in an array;

FIG. 4 is a schematic structural diagram of a base plate, a substrate and a pressure detecting unit according to the present invention;

FIG. 5 is a schematic top view of the base plate, the substrate and the pressure detecting unit of the present invention;

FIG. 6 is a schematic bottom view of the substrate of the present invention;

FIG. 7 is a schematic structural diagram of a pressure detecting unit according to the present invention;

FIG. 8 is a schematic top view of the pressure detecting unit according to the present invention;

FIG. 9 is a schematic cross-sectional structure of a nano-film according to the present invention;

as shown in the figures, the list of reference numbers is as follows:

1. a nano-film; 2. a stainless steel end cap; 3. a circular hole; 4. a nanopore; 5. 6, 30, 31 metal electrodes; 7. 8, 26, 27 interconnect leads; 9. 10, 28, 29 interconnect bumps; 11. 12, 22, 23 interconnect pads; 13. 14, 36, 37 lead posts; 15. 16, 38, 39 external interconnection electrodes; 17. a substrate; 18. a substrate; 19. a package housing; 20. an inert gas seal chamber; 21 a pressure detection unit 21; 24. 25 wiring; 32. a barrier layer; 33. an upper boron nitride layer; 34. a middle graphene layer; 35. a lower boron nitride layer.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.

In the description of the present invention, it is to be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience in describing the present invention and simplifying the description, but do not indicate or imply that the combination or element referred to must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, are not to be construed as limiting the present invention. In addition, in the description process of the embodiment of the present invention, the positional relationships of the devices such as "upper", "lower", "front", "rear", "left", "right", and the like in all the drawings are based on fig. 1.

In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "connected" and "connected" are to be interpreted broadly, e.g., as being fixed or detachable or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

The invention is further described below with reference to the accompanying drawings:

as shown in fig. 1 to 3, which are perspective views illustrating the appearance of a first embodiment of the present invention, a nanopore-based graphene high pressure sensor is provided, which can stably operate at a high pressure of 400MPa for a long period of time and has a response time of less than 1 μ s, and the sensor includes:

the packaging shell 19 can be in the shape of a cylinder, a cube, a cuboid and the like as a whole, and is not limited in particular, in the attached drawings, only a cylinder structure is shown, and the packaging shell is used for isolating the external environment, supporting and protecting an internal structure;

stainless steel end cover 2, stainless steel end cover 2 sets up 19 tops of encapsulation shell, be provided with a plurality of round holes 3 on the stainless

steel end cover

2, 2 upper surfaces of stainless steel end cover are by a plurality of round holes 3 formation porous structure, and porous structure is favorable to pressure transmission to pressure detection unit 21 on, provides certain protection to pressure detection unit 21 simultaneously. The shape of the round hole 3 is not limited to the round shape shown in the invention, and can also be other shapes such as square and the like, and is not particularly limited;

the substrate 18 is arranged at the bottom end inside the package shell 19, the outer periphery of the substrate 18 is connected with the inner side face of the package shell 19, the substrate 17 is arranged on the substrate 18, the nano-hole 4 is arranged in the center of the substrate 17, the nano-hole 4 is not limited to one shown in the invention, and can be a plurality of array nano-holes 4, the stainless steel end cover 2, the package shell 19 and the substrate 18 jointly define a detection space, and the detection space is used for providing stable support;

a pressure detection unit 21, the pressure detection unit 21 being provided on the substrate 17;

and the interconnection assemblies are arranged on two sides of the pressure detection unit 21, one end of each interconnection assembly is connected with the pressure detection unit 21, and the other end of each interconnection assembly is connected with the outside.

In the present invention, the substrate 17 may be a cylinder, as shown in fig. 2. The nano-hole 4 can be etched on the upper layer of the substrate 17 through a wet method, preferably, the nano-hole 4 on the substrate 17 is a square hole, the square hole is easy to process, stress can be concentrated in the centers of four sides, and the nano-film 1 is caused to generate large deformation, so that a large electrical signal is output, and a better effect is achieved.

As shown in fig. 2-5, 7-9, the pressure detecting unit 21 is disposed on a side of the substrate 17 facing the inner detecting space, and the pressure detecting unit 21 includes: nanometer film 1 and

metal electrode

5, 6, 30, 31, nanometer film 1 sets up the substrate 17 upper surface and cover on the nanopore 4,

metal electrode

5, 6, 30, 31 set up respectively and are being close to the edge of nanometer film 1, nanometer film 1 both sides are provided with a

wiring

24, 25 respectively,

metal electrode

5, 6, 30, 31 through the

wiring

24, 25 of corresponding side with nanometer film 1's both sides are connected for derive nanometer film 1's electricity response, feel external pressure through nanometer film 1 and change. The nanopore 4, the substrate 18 and the nano film 1 on the substrate 17 jointly form an inert gas sealing cavity 20, and inert gas is filled in the inert gas sealing cavity 20, so that interference factors in the surrounding environment can be effectively reduced, and the stability of the device is improved. In the present invention, the area of the nano-film 1 is smaller than the upper side surface area of the substrate 17.

As shown in fig. 2-5 and 7-9, the nano-film 1 is composed of an upper layer boron nitride layer 33, a middle layer graphene layer 34, and a lower layer boron nitride layer 35, the upper layer boron nitride layer 33, the middle layer graphene layer 34, and the lower layer boron nitride layer 35 are sequentially disposed from top to bottom, two sides of the middle layer graphene layer 34 of the nano-film 1 respectively cover the

wires

24 and 25 on the corresponding sides, and the electrical response of the middle layer graphene layer 34 is led out to the

metal electrodes

5, 6, 30, and 31. The middle graphene layer 34 has a square structure, and the shape of the middle graphene layer 34 is not limited to the square structure shown in the present invention, and may also be other shapes such as a disc shape, and is not particularly limited. In other embodiments, the number of the upper boron nitride layer 33 and the lower boron nitride layer 35 is greater than or equal to 1, and the middle graphene layer 34 has a single-layer structure. The nano-film 1 can directly sense external pressure change, so that the pressure can be rapidly transmitted to the chip, and the time required by response is reduced.

As shown in fig. 2, 5 and 6, the interconnect assembly includes: the interconnection leads 7, 8, 26, 27, the

interconnection pads

11, 12, 22, 23, the lead posts 13, 14, 36, 37 and the

external interconnection electrodes

15, 16, 38, 39, and the interconnection leads 7, 8, 26, 27, the

interconnection pads

11, 12, 22, 23, the lead posts 13, 14, 36, 37 and the

external interconnection electrodes

15, 16, 38, 39 are connected in sequence. The substrate 18 is provided with mounting holes for mounting the lead posts 13, 14, 36, 37, the lead posts 13, 14, 36, 37 are arranged in the mounting holes, the

interconnection pads

11, 12, 22, 23 are arranged on the substrate 18 and connected with one ends of the lead posts 13, 14, 36, 37, interconnection bumps 9, 10, 28, 29 are bonded on the

interconnection pads

11, 12, 22, 23, one ends of the interconnection leads 7, 8, 26, 27 are connected with the interconnection bumps 9, 10, 28, 29 on the

interconnection pads

11, 12, 22, 23, the other ends of the interconnection leads 7, 8, 26, 27 are connected with the

metal electrodes

5, 6, 30, 31, the bottom of the package shell 21 is provided with openings for accommodating the

external interconnection electrodes

15, 16, 38, 39, the

external interconnection electrodes

15, 16, 38, 39 are arranged at the bottom of the substrate 18 and connected with the lead posts 13, 36, 37, 14. 36, 37, and the

external interconnection electrodes

15, 16, 38, 39 are connected to an external detection assembly for transmitting and detecting the electrical response of the graphene layer to the pressure signal, respectively, and the external detection assembly may be an assembly constituting a complete sensor structure in the prior art.

As shown in fig. 9, a barrier layer 32 is further provided on the bottom of the

metal electrodes

5, 6, 30, 31 and the

wirings

24, 25, and the barrier layer 32 is provided between the

metal electrodes

5, 6, 30, 31, the

wirings

24, 25 and the substrate 17 as a wetting layer and a protective layer to prevent mutual diffusion of metal atoms and substrate atoms of the

metal electrodes

5, 6, 30, 31 and the

wirings

24, 25.

In the invention, the substrate 17 can be selected from Si material, and the substrate 18 can be Al₂O₃The material,

metal electrodes

5, 6, 30, 31 and interconnecting

electrodes

15, 16, 38, 39 may be selected from an Au material.

In the invention, the

metal electrodes

5, 6, 30 and 31 and the

interconnection bonding pads

11, 12, 22 and 23 are connected by interconnection leads 7, 8, 26 and 27 formed by Au wire lead bonding, the substrate 17 and the substrate 18 are connected by Au-Au bonding, the packaging shell 19 is connected with the substrate 18 and is firmly welded by using laser cold welding, and the packaging shell 19 is connected with the stainless steel end cover 2 and is firmly welded by using laser cold welding.

The principle of the invention is as follows:

when an external pressure signal acts on the upper surface of the stainless steel end cover of the sensor, the pressure can be transmitted to the pressure detection unit 21 through the round hole in the middle of the stainless steel end cover, graphene covered on the nanopore structure is affected by the pressure, and the graphene force-sensitive structure deforms, so that the conductivity of the graphene is changed. The externally applied pressure value can be measured by detecting the current change in the graphene surface. Meanwhile, in the process, the contact area between the nano film and the outside is reduced by the stainless steel end cover and the packaging shell, so that the support is provided for the sensor structure, the nano film can work under a high-pressure environment, and the high-precision measurement of the pressure under the severe complex high-pressure environment is realized.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples" or the like mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents.

Claims

1. A nanopore based graphene high pressure sensor capable of long term stable operation at high pressures of 400MPa with response times below 1 μ s, the sensor comprising:

a packaging shell (19), a stainless steel end cover (2) arranged at the top end of the packaging shell (19) and a substrate (18) arranged at the lower end in the packaging shell (19), wherein a plurality of round holes (3) are arranged on the stainless steel end cover (2),

a substrate (17) is arranged on the base plate (18), and a nano hole (4) is formed in the center of the substrate (17);

a pressure detection unit (21), the pressure detection unit (21) being disposed on the substrate (17);

the interconnection components are arranged on two sides of the pressure detection unit (21), one end of each interconnection component is connected with the pressure detection unit (21), and the other end of each interconnection component is connected with the outside to lead out the electrical response of the pressure detection unit (21).

2. The nanopore based graphene high pressure sensor of claim 1, wherein the pressure detection unit (21) comprises: the nano-film structure comprises a nano-film (1) and metal electrodes (5, 6, 30 and 31), wherein the nano-film (1) is arranged on the upper surface of a substrate (17) and covers a nano-hole (4), the metal electrodes (5, 6, 30 and 31) are respectively arranged at corners close to the nano-film (1), wiring lines (24 and 25) are respectively arranged on two sides of the nano-film (1), the metal electrodes (5, 6, 30 and 31) are connected with two sides of the nano-film (1) through the wiring lines (24 and 25) on corresponding sides, the nano-hole (4) and a substrate (18) on the substrate (17) and the nano-film (1) jointly form an inert gas sealing cavity (20), and inert gas is filled in the inert gas sealing cavity (20).

3. The nanopore based graphene high-pressure sensor according to claim 2, wherein the nano-film (1) is composed of an upper boron nitride layer (33), a middle graphene layer (34) and a lower boron nitride layer (35), the upper boron nitride layer (33), the middle graphene layer (34) and the lower boron nitride layer (35) are sequentially arranged from top to bottom, two sides of the middle graphene layer (34) of the nano-film (1) respectively cover the wiring (24, 25) on the corresponding side, and the electrical response of the middle graphene layer (34) is led out to the metal electrode (5, 6, 30, 31).

4. The nanopore based graphene high pressure sensor according to claim 3, wherein the metal electrodes (5, 6, 30, 31) and the bottom of the wiring (24, 25) are further provided with a barrier layer (32).

5. The nanopore based graphene high pressure sensor of claim 3, wherein the interconnect assembly comprises: interconnection leads (7, 8, 26, 27), interconnection pads (11, 12, 22, 23), lead posts (13, 14, 36, 37) and external interconnection electrodes (15, 16, 38, 39), the interconnection leads (7, 8, 26, 27), the interconnection pads (11, 12, 22, 23), the lead posts (13, 14, 36, 37) and the external interconnection electrodes (15, 16, 38, 39) being connected in sequence.

6. The nanopore based graphene high pressure sensor according to claim 5, wherein the substrate (18) is provided with a mounting hole for mounting the lead post (13, 14, 36, 37), the lead post (13, 14, 36, 37) is disposed in the mounting hole, the interconnection pad (11, 12, 22, 23) is disposed on the substrate (18) and connected to one end of the lead post (13, 14, 36, 37), an interconnection bump (9, 10, 28, 29) is bonded to the interconnection pad (11, 12, 22, 23), one end of the interconnection lead (7, 8, 26, 27) is connected to the interconnection bump (9, 10, 28, 29) on the interconnection pad (11, 12, 22, 23), the other end of the interconnection lead (7, 8, 26, 27) is connected to the metal electrode (5, 6, 30, 31), the bottom of the packaging shell (21) is provided with an opening for accommodating the external interconnection electrode (15, 16, 38, 39), the external interconnection electrode (15, 16, 38, 39) is arranged at the bottom of the substrate (18) and is connected with the other end of the lead post (13, 14, 36, 37), and the external interconnection electrode (15, 16, 38, 39) is connected with an external detection component.