WO2022248057A1 - Temperature stable acceleration sensor based on 2d materials and its use - Google Patents

Temperature stable acceleration sensor based on 2d materials and its use Download PDF

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Publication number
WO2022248057A1
WO2022248057A1 PCT/EP2021/064303 EP2021064303W WO2022248057A1 WO 2022248057 A1 WO2022248057 A1 WO 2022248057A1 EP 2021064303 W EP2021064303 W EP 2021064303W WO 2022248057 A1 WO2022248057 A1 WO 2022248057A1
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Prior art keywords
materials
acceleration
acceleration sensor
sensors
sensing
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PCT/EP2021/064303
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French (fr)
Inventor
Borna RADATOVIC
Valentino JADRISKO
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Nanoing J.D.O.O.
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Priority to PCT/EP2021/064303 priority Critical patent/WO2022248057A1/en
Publication of WO2022248057A1 publication Critical patent/WO2022248057A1/en

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    • 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
    • G01P15/12—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 alteration of electrical resistance
    • 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
    • G01P15/09—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 piezoelectric pick-up
    • 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

Definitions

  • the present invention discloses an acceleration sensor based on two- dimensional (2D) materials and its use. From the nature of invention, the said invention belongs to the technical field of acceleration measurement where solid seismic mass is used. The distortion of 2D materials used for sensing acceleration significantly change their electric resistance. Said strain gauge factor of the used 2D material is well known in the related art. Secondly by performing capacitance measurements simultaneously improves calculations of an acceleration to which system of sensors is exposed. In addition to improved sensing, the invention enables application of accelerometers that operate in high range of temperatures.
  • the main technical problem solved by the present invention is improvement of operability of nanometre sized accelerometers on large range of temperatures.
  • the disclosed acceleration sensor is based on 2D materials with high strain gauge factors which results in significant change in resistivity and capacitance induced by change of acceleration.
  • Each sensing material is connected to heat conductive layer which ensures temperature equilibrium, and which act as common proof mass, i.e. seismic mass, which ensures adequate strain transfer throughout said materials.
  • this configuration enables improved precision and reliability in detecting acceleration due to simultaneous measurements of resistance and capacitance on all sensing materials.
  • the disclosed acceleration sensor is designed to be used on commercial Silicon wafers, on top of which sensors are fabricated in array, equidistantly separated and perpendicular or parallel respective to each other.
  • Such setup enables combination of accelerometers into a NEMS (nanoelectromechanical system) of sensors for highly precise determination of acceleration vector in arbitrary directions.
  • NEMS nanoelectromechanical system
  • Reference 1 discloses only general principles used in the field without disclosing specific sensors architectures.
  • Reference 2 teaches about the system of resonators formed as the U- shaped structure made of carbon film, i.e., highly oriented pyrolytic graphite, graphene or carbon nanotubes; with the proof mass attached on one end and packed in the form of a cube.
  • the described system of resonators is capable to determine acceleration vector.
  • Reference 3 teaches about flexible MoS 2 FETs.
  • Atomically thin molybdenum disulfide is found to be a promising two-dimensional semiconductor for high-performance flexible electronics, sensors, transducers, and for the energy conversion systems.
  • a piezoresistive strain sensing with flexible MoS 2 FETs made from highly uniform large- area films is demonstrated in the reference 8).
  • the said reference discloses the way said FETs are made on flexible substrate.
  • Reference 4 teaches about MoS 2 based acceleration sensors specifically designed in the form of the Wheatstone bridge that allows four MOS 2 resistors to be measured with only 4 contacts, said resistors are distributed evenly over the central proof mass.
  • Reference 5 discloses a standard NEMS construction of the pressure sensor, strain gauge, acceleration sensor or an angular velocity sensor. It uses a strain resistance film formed on a rigid surface of the SiCU substrate, wherein the strain resistance film is formed as a film of graphene or a transition metal dichalcogenide having a single atom layer thickness or a multi-atom layer thickness.
  • the used NEMS geometry is rather generic.
  • the suspended two-dimensional material is selected from the following group: graphene (graphene), hexagonal boron nitride (hBN), molybdenum disulfide (M0S2), tungsten diselenide (WSe2), molybdenum diselenide (MoSe2), tungsten disulfide (WS2), platinum diselenide (PtSe2), molybdenum diselenide (MoTe2), tungsten diselenide (WTe2), vanadium diselenide (VSe2), chromium disulfide (CrS2), chromium diselenide (CrSe2), other transition metal dichalcogenides (TMDC), and black phosphorus (P).
  • a typical acceleration sensor usually includes a suspended mass structure, which is displaced with the applied acceleration and which causes
  • an accelerometer comprises a substrate; a membrane suspended over an opening in the substrate to form a suspended membrane, wherein the membrane is composed of a two-dimensional material; a mass structure coupled to the suspended membrane; wherein the mass structure distorts the suspended membrane about a first axis in response to an applied acceleration providing a first and instantaneous change in a conductance of the suspended membrane, so that the applied acceleration along the first axis can be detected.
  • Paragraph [0024] of reference 8) quotes that used two-dimensional materials may comprise a single atomic layer to several atomic layers, and in addition to graphene, materials such as molybdenum disulfide (M0S2), tungsten diselenide (WSe2) can be used.
  • M0S2 molybdenum disulfide
  • WSe2 tungsten diselenide
  • the present invention discloses an acceleration sensor based on two dimensional materials with significant strain gauge factor. It comprises at least three sensing layers which share a common proof mass in a form of a heat conductive layer which ensures temperature equilibrium of complete configuration. Each sensing layer is suspended over pairs of electrodes and connected with heat dissipation rods. Three- and two-dimensional acceleration detection is implemented combining uniaxial acceleration sensors described below.
  • 2D materials that are used as sensing layer can be from a single material or combination of them in a form of heterostructure. Number of layers span from monolayer to plurality of atomic layers in a Z direction which results that a height of accelerometer is in a range of nanometers. 2D materials are shaped as an arbitrary polygon that spans over the corresponding pairs of electrodes in the X-Y plane. In lateral X-Y plane, dimensions of sensing layers can vary from nanometres to centimetres.
  • Sensing layers are suspended over pairs of electrodes which are separated from few nanometres up to dozens of micrometres. Each electrode is shaped as an elongated parallelepiped that extends in the Y direction, where said electrodes are spaced one from another, over the X direction. Such setup allows 2 or 4 contact resistivity measurements of said sensing layers. At least two sensing layers are separated in Z direction with common proof mass, which enables measurement of capacitance between pairs of electrodes of displaced sensing layers. Sensing layers share common proof mass in a form of a heat conductive layer which ensures that each sensing materials is in temperature equilibrium.
  • Geometrically heat conductive layer is arbitrary shaped with lateral dimensions in a range as a chosen dimensions of sensing layers but large enough to cover all sensing layers.
  • Said heat conductive layer which has a geometry larger than areas of the used 2D materials, is disposed above first two 2D materials and where third 2D material is placed on top of the heat conductive layer, covering larger part of the said heat conductive layer, where third 2D material in combination with any of first 2D material forms capacitor.
  • Each sensing layer is protruded and connected with heat dissipation rod which joins sensing layer with heat conductive layer. Lower pair of rods connects heat conductive layer and rigid substrate which carries all elements.
  • Each electrode has one or more heat dissipation rods, geometrical shaped to fit within, and to protrude out of the corresponding electrode in Z direction towards a heat conductive layer.
  • the strain gauge of the said unit sensor is determined by simultaneously measuring resistance between the pairs of electrodes of each sensing layer and capacitance between pairs of electrodes of vertically displaced sensing layers.
  • the acceleration sensor for sensing acceleration dominantly in Z direction is formed in a way that heat conductive layer acts as a sensor's common proof mass and which is bounded to all sensing 2D materials which are suspended over the corresponding pairs of electrodes where all heat dissipation rods protrude through corresponding 2D materials and thermally connect the heat conductive layer with the electrodes.
  • the uniaxial acceleration data are calculated from the set of resistivity and/or capacitance data measured from all sensing layers according to the calibration model.
  • each uniaxial acceleration sensor (100) comprises of at least three sensing layers each composed of monolayer of the same 2D material.
  • all three sensing layers are detecting acceleration in the same Z direction. Two of them are on same position while third is displaced in Z direction. Third sensing layer is equidistantly separated from first two sensing layers.
  • acceleration sensors are also disclosed.
  • all elements of individual acceleration sensors are place on rigid substrate and detect uniaxial acceleration.
  • array of individual uniaxial sensors are spread across the substrate, in configuration in which they are all perpendicular or parallel in correspondence to each other.
  • arrays of uniaxial acceleration sensors are formed.
  • X-Y-Z sensors three or more modified sensors are connected into cubic shape or any other polyhedron shape with well-defined angles.
  • Figure 1 shows configuration of an acceleration sensor in the side view.
  • Figure 2 represents top view of acceleration sensor depicted on Figure 1.
  • Figures 3A - 3B shows top view and back view of modified acceleration sensor constructed from array of accelerometers depicted on Figure 1 and Figure 2.
  • Figure 4 shows X-Y-Z acceleration sensor constructed from modified acceleration sensors connected into cube or any other polyhedron.
  • FIG. 5 depicts flowchart with the steps A-G of acceleration sensor formation.
  • acceleration sensors based on solid seismic mass or proof mass are well known in the art, see the references l)-8) cited before.
  • Novel materials such as 2D materials, help to make acceleration sensors very small and to be packed as NEMS (nanoelectromechanical system). Therefore, the inner geometry plays the important role in forming the reliable acceleration sensor. With adequate placement and connection of each element of accelerometer temperature equilibrium is ensured, which is important for use of accelerometers in environment that has large range of temperatures.
  • Figure 1 illustrate, so-called, uniaxial acceleration sensor (100) which is formed on rigid substrate (60).
  • This substrate can be commercially used Silicon wafers or any rigid substrate with adequate heat conductivity.
  • the rigid substrate (60) is significantly longer and wider than the uniaxial acceleration sensor (100), as obvious from Figures 1, 2, 3A-3B and should be capable to carry plurality of uniaxial acceleration sensors (100).
  • Pairs of electrodes (20, 21) are formed from conductive materials, such as gold or platinum, by direct write lithography or e-beam and stencil lithography in combination with thermal evaporation and sputtering in order to produce thin metal film.
  • conductive materials such as gold or platinum
  • 2D material is used for forming the said electrode (40) instead of metal
  • a stamping transfer is employed and 2D material with high conductivity is used for the mentioned purpose, i.e., graphene.
  • Thermal evaporation, sputtering and stamping transfer are well known techniques in the field.
  • pairs of electrodes (20, 21) On top of pairs of electrodes (20, 21) corresponding heat dissipation rods (30, 31) are fabricated out of heat conductive material such as gold or thermally conductive plastic TCP, via methods as previously described for fabrication of pairs of electrodes (20, 21). Over the pairs of electrodes (20, 21) and corresponding heat dissipation rods (30, 31) 2D materials which are used as a sensing layers (10, 11) are transferred. Each sensing layer is suspended over the pair of electrodes while rods protrude through 2D materials, which ensures stabile edges of sensing layers. 2D materials can have arbitrary shape. In preferred configuration they are used in the form of elongated rectangle, as depicted in Figure 1 and 2.
  • the nano- and micro- scale 2D materials usually grow in triangular or hexagonal form.
  • the consequence of that fact is that rectangles are formed only on rather bigger lateral scales.
  • the heat conductive layer (40) is formed over the said sensing layers (10, 11) as depicted on Figure 1. This layer ensures that whole system has adequate heat transfer which ensures temperature equilibrium. Said layer act as a proof mass which ensures adequate strain transfer into the sensing layers due to acceleration system is exposed. There are various possibilities in formation of the said layer depending of the type of materials used. If the heat layer (40) is made out of thermally conductive plastic TCP, it can be formed by placing thin film of TCP on top of pairs of electrodes or by dripping polymer film which is spin coated and dried while rods protrude part of heat layer.
  • the heat layer (40) is made out of thin oxide-layer, e.g., AI2O3, then the Atomic Layer Deposition (ALD) or the sputtering method can be used.
  • ALD Atomic Layer Deposition
  • non-conductive 2D material i.e., hexagonal boron nitride (hBN) or calcium fluoride (CaF2)
  • hBN hexagonal boron nitride
  • CaF2 calcium fluoride
  • a stamping transfer can be employed equally well.
  • small layer of polymer can be placed between two sensing layers and afterwards when heat conductive layer is placed, that polymer can be washed away leaving heat layer on designated place.
  • the thickness of the heat layer should be chosen depending on dimension of sensing layers and it should be enough to ensure operability and sensibility of acceleration sensor (100).
  • third sensing layer (12) Over the heat conductive layer (40) third sensing layer (12), with corresponding pair of electrodes (22) and heat dissipation rods (32), is formed in a way as described for first two sensing layers.
  • Third sensing layer (12) has same orientation as firs two sensing layers (10, 11), and it is placed equidistantly from them, in the middle but with vertical displacement in a form of head conductive layer (40) which separates first two sensing layers from third.
  • Third sensing layer is placed on top of heat conductive layer, which covers first two sensing layers, and gap between them, what results in that that third layer can be also considered suspended.
  • Said 2D materials used for sensing layers (10, 11, 12) should be chosen to have a significant strain gauge factor.
  • Suitable 2D materials are selected from the group of metal dichalcogenides, with the thickness ranging from monolayer to a plurality of atomic layers, preferably formed from molybdenum disulphide (M0S2) or platinum diselenide (PtSe2).
  • M0S2 molybdenum disulphide
  • PtSe2 platinum diselenide
  • Said 2D materials are placed on dedicated position by stamping transfer in a way that all heat dissipation rods (30, 30'; 31, 31'; 32, 32'), protrude through corresponding 2D materials (10, 11, 12) and thermally connect the heat conductive layer (40) with the electrodes (20, 20'; 21, 21'; 22, 22').
  • Stamping transfer can be the PDMS Stamp Assisted Mechanical Exfoliation or, sensing layers can be formed on another substrate by any other convenient technique known in the related art and subsequently transferred to the position).
  • Molybdenum disulphide (M0S2) or platinum diselenide (PtSe2) is found to be an excellent choice having in mind comparably high resistivity that has some advantages in resistivity measuring by two contacts only vs. highly conductive 2D materials, e.g. graphene resistivity measurements with four contacts.
  • the sensor (100) encapsulation is performed by dripping the encapsulating polymer (50) over the top of the unit acceleration sensor (100).
  • the whole preparation process is summarised on Figure 5, via steps A.-G.
  • the whole unit acceleration sensor can be formed to have thickness less than 100 pm, over the rigid substrate, which is thickest part of the device, rendering such sensor applicable everywhere.
  • the construction of the mentioned unit acceleration sensor is very similar to those described in the reference 8) TWO-DIMENSIONAL MATERIAL-BASED ACCELEROMETER.
  • the novel part of the said invention is the fact that an improved acceleration sensor (100) is based on 2D material and common proof mass in the form of a heat conductive layer (40), where it connects at least two sensing layers (10, 11) from their top side and at last one sensing layer (12) from its bottom side as depicted in Figure 1.
  • Important improvement of acceleration sensor (100) in comparison with previous accelerometers based on 2D materials is adequate heat management throughout system, which ensure temperature stability and equilibrium of all elements. This configuration enables simultaneous determination of acceleration from all sensing layers which enables differential measurements for elimination of thermal noise and other spurious signals such as parasitic mechanical vibrations.
  • Acceleration sensor (100) can be used for highly precise accelerometer which operates on large range of temperatures with reliability and durability. As previously mentioned, sensors use three sensing layers which are all connected to common proof mass on which they are suspended. Heat conductive layer (40) acts as a proof mass. Any change in acceleration in lateral direction, i.e., direction parallel with the rigid substrate (60) will certainly displace heat layer (40) over the rigid substrate (60) in the same direction resulting with no detected acceleration.
  • the selected 2D materials used for sensing layers (10, 11, 12), as depicted in Figure 1 will record almost no change in resistivity ( Rio , Rii , R 12 ) and modest changes in capacitances ( Cion , C1012) due to the slight change of geometrical factors that forms parallel plate capacitors between heat conductive layer and sensing layers sandwiched between pairs of electrodes (22, 20; 22, 21).
  • the resistivities are measured via pairs of electrodes (20. 20'; 21, 21'; 22, 22') respectively, or in the case where high conductivity 2D materials are used, such as graphene, with 4 contact technique where auxiliary surface electrodes (20'', 20'" , 21" ; 21'" , 22" , 22'” ) are used as voltage electrodes and the first side electrodes (20, 20'; 21, 21'; 22, 22') as current contacts.
  • Capacitance ( Cion , C1012) is measured between pairs of electrodes (22, 20; 22, 21) that sandwich heat conductive layer (40) and sensing layers (12, 10; 12, 11). This configuration is equivalent as parallel plate capacitors with dielectric inserted between the plates.
  • the electrodes (22, 20; 22, 21) forms the contacts for measuring the said capacitances having in mind that the corresponding 2D materials (10, 11, 12) are semiconductive or conductive and capable to redistribute the electrical charge over their surfaces. Capacitance can be measured by various techniques, with astonishing precision, see reference 9) below:
  • the selected 2D materials will record a significant change in their resistivities ( Rio , Rn , R 12 ) and again modest changes in capacitances ( Cion , C 1012 ) due to the slight change of geometrical factors that forms capacitors due to the displacement of the heat layer (40).
  • the advantage of the disclosed design is that the differential measurement of ( Rio , Rn , R 12 ; Cion , C 1012 ) is possible, which offers a better insight regarding the whole sensor (100) status and better noise cancelation / suppression.
  • the offset values can be previously recorded or balanced in a way that ( Rio - Rn ) is set to 0 in case of no acceleration, and where any acceleration will gain the value of the said difference.
  • Improved acceleration sensor (100) uses the same layer for proof mass as a heat conductive layer (40) which ensures that whole system has adequate thermal management. All sensing layer (10, 11, 12) are connected with heat layer (40) with dissipation rods (30, 31, 32) which ensure heat transfer from sensing layers towards heat conductive layer (40).
  • Heat conductive layer (40) is anchored with heat dissipation rods (30, 31, 32) which protrude through sensing layers (10, 11, 12). This ensures that heat conductive layer (40) has significant thermal contact with all other elements of acceleration sensor (100). Heat conductive layer (40) has to have insulating interfaces with sensing layers (10, 11, 12), their corresponding electrodes (20, 21, 22) and heat dissipation rods (30, 31, 32) to ensure stabile dielectric environment in the key elements of acceleration sensor (100). Meaning that natural choice of material for heat conductive layer (40) are standard polymers used for electronics. Choice of material used for heat conductive layer (40) results from consideration of Wiedemann- Franz law.
  • heat conductive layer (40) Electrically insulating materials are usually also thermally insulating but in this configuration enhancement in the view of heat dissipation rods (30, 31, 32) ensures that large enough area is in contact with heat conductive layer (40) where charge can redistribute to establish thermal equilibrium. What results that the choice of heat conductive layer (40) can be expanded on standard polymer insulators and similar materials even though they are not highly thermally conductive in principle.
  • Figures 3A-3B and 4 depicts further possibilities of the acceleration sensor (100) formation where more individual uniaxial acceleration sensors (100) are used.
  • Figure 3A shows embodiment of modified acceleration sensor (200) which is constructed by joining two or more uniaxial acceleration sensors (100) in an array of them where each is perpendicular or parallel in respect to each other, so one can easily eliminate any lateral contribution of acceleration vector.
  • Figure 4 shows embodiment of X-Y-Z acceleration sensor (300) which is constructed by joining three or more modified acceleration sensors (200) into a cube or any polyhedron shape with well-defined angles.
  • Modified acceleration sensor (200) contains at least two acceleration sensors (100, 100') disposed perpendicularly one to another in the same X-Y plane, in a way that their corresponding X axes are perpendicular one to another.
  • Modified acceleration sensors (200) are used for forming an X-Y or X-Y-Z acceleration sensor (300) where, said X-Y-Z acceleration sensor (300) contains at least three modified acceleration sensors (200, 200', 200”) disposed perpendicularly one to another, in a way that their corresponding X-Y planes are perpendicular one to another.
  • Rigid substrate (60) can be formed to be tick from dozens of micrometres to several centimetres. Depending on the number of rigid substrate (60) used for connecting multiaxial systems, a system may achieve desired accuracy within the theoretical limits imposed by the used 2D materials within the acceleration sensors (100).
  • the present invention discloses a novel acceleration sensor based on two-dimensional (2D) materials, more particularly materials that are selected from the group of metal dichalcogenides, molybdenum disulphide (M0S2) or platinum diselenide (PtSe2) ⁇ Said materials are suspended with common proof mass that act as a heat conductive layer which ensures temperature equilibrium of system.
  • the said acceleration sensors are formed in array on commercial Silicon wafer substrates which ensures improved accuracy.
  • the industrial applicability of the mentioned sensors is primarily for circuits and devices that require accelerometers that can operate reliably in large range of temperatures. Reference numbers
  • heat dissipation rod for material 12 40 heat conductive layer 50 encapsulation 60 substrate 100 acceleration sensor 200 modified acceleration sensors 300 X-Y-Z acceleration sensors

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Abstract

The present invention discloses an improved acceleration sensor based on 2D materials with heat dissipation elements (30, 31, 32) which are connected to heat conductive layer (40) that serve as common proof mass. It contains at least three sensing layers of 2D materials (10, 11, 12) suspended over pairs of electrodes (20, 20'; 21, 21'; 22, 22') with corresponding heat dissipation elements (30, 30'; 31, 31'; 32, 32'). Rigid substrate (60) carries all sensor's elements, which are encapsulated with the layer (50). The strain gauge of the 2D materials is measured via change in resistivity (R10, R11, R12) between pairs of electrodes (20, 20'; 21, 21'; 22, 22') and change in capacitance (C1012, C1112) between 2D materials. All elements are linked to heat conductive layer (40) which ensures temperature stability while performing measurements of resistivity and capacitance. In multi axial measurements at least three sensors are used.

Description

TEMPERATURE STABLE ACCELERATION SENSOR BASED ON 2D MATERIALS AND ITS
USE
DESCRIPTION
Technical Field
The present invention discloses an acceleration sensor based on two- dimensional (2D) materials and its use. From the nature of invention, the said invention belongs to the technical field of acceleration measurement where solid seismic mass is used. The distortion of 2D materials used for sensing acceleration significantly change their electric resistance. Said strain gauge factor of the used 2D material is well known in the related art. Secondly by performing capacitance measurements simultaneously improves calculations of an acceleration to which system of sensors is exposed. In addition to improved sensing, the invention enables application of accelerometers that operate in high range of temperatures.
Technical Problem
The main technical problem solved by the present invention is improvement of operability of nanometre sized accelerometers on large range of temperatures. The disclosed acceleration sensor is based on 2D materials with high strain gauge factors which results in significant change in resistivity and capacitance induced by change of acceleration. Each sensing material is connected to heat conductive layer which ensures temperature equilibrium, and which act as common proof mass, i.e. seismic mass, which ensures adequate strain transfer throughout said materials. In addition, this configuration enables improved precision and reliability in detecting acceleration due to simultaneous measurements of resistance and capacitance on all sensing materials.
Furthermore, the disclosed acceleration sensor is designed to be used on commercial Silicon wafers, on top of which sensors are fabricated in array, equidistantly separated and perpendicular or parallel respective to each other. Such setup enables combination of accelerometers into a NEMS (nanoelectromechanical system) of sensors for highly precise determination of acceleration vector in arbitrary directions.
State of the Art
The development of novel two dimensional materials with significant strain gauge factors propelled the field of NEMS accelerometers based on 2D materials. In the reference 1) it is quoted that layered two- dimensional (2D) materials possess outstanding electronic, optical, chemical, and mechanical properties for a wide range of potential future nanoelectronics devices. Besides the carbon-based graphene, many other 2D materials are being investigated, like phosphorene, hexagonal boron nitride and transition metal dichalcogenides (TMDs), where later are used in the present invention. The large-area growth of these materials is now possible and their transfer to arbitrary substrates enable future volume production for commercial wafer-based applications. Furthermore, other techniques which differ from wafer- based applications are also disclosed.
1) Stefan Wagner, 2D MATERIALS FOR PIEZORESISTIVE STRAIN GAUGES AND MEMBRANE BASED NANOELECTROMECHANICAL SYSTEMS, dissertation; Faculty of Electrical Engineering and Information Technology of the Rheinisch-Westfalische Technische Hochschule Aachen; DE, on July 16, 2018. Source: https://d-nb.info/1181193214/34
The above cited reference is an excellent review of the current know how in the field of used 2D materials with the present invention. Reference 1) discloses only general principles used in the field without disclosing specific sensors architectures.
2) CN patent application published as CN109470886 for the invention
MULTI-AXIS PAPER-BASED ACCELERATION SENSOR AND PREPARATION METHOD THEREOF, filed in the name of Jiangsu Jicui Micro Nano Automation System and Equipment Tech Research Institute Co Ltd.
Reference 2) teaches about the system of resonators formed as the U- shaped structure made of carbon film, i.e., highly oriented pyrolytic graphite, graphene or carbon nanotubes; with the proof mass attached on one end and packed in the form of a cube. The described system of resonators is capable to determine acceleration vector.
3) Tsai, M.-Y., Tarasov, A., Hesabi, Z. R., Taghinejad, H., Campbell, P. M., Joiner, C. A., ...Vogel, E. M. (2015). FLEXIBLE MoS2 FIELD- EFFECT TRANSISTORS FOR GATE-TUNABLE PIEZORESISTIVE STRAIN SENSORS. ACS Applied Materials & Interfaces, 7(23), 12850-12855. doi:10.1021/acsami.5b02336.
Reference 3) teaches about flexible MoS2 FETs. Atomically thin molybdenum disulfide is found to be a promising two-dimensional semiconductor for high-performance flexible electronics, sensors, transducers, and for the energy conversion systems. A piezoresistive strain sensing with flexible MoS2 FETs made from highly uniform large- area films is demonstrated in the reference 8). In addition, the said reference discloses the way said FETs are made on flexible substrate.
4) CN patent application published as CN109507451 for the invention MOLYBDENUM DISULFIDE FILM BASED ACCELERATION SENSOR CHIP AND PROCESSING METHOD THEREOF, filed in the name of UNIV XI AN JIAOTONG.
Reference 4) teaches about MoS2 based acceleration sensors specifically designed in the form of the Wheatstone bridge that allows four MOS2 resistors to be measured with only 4 contacts, said resistors are distributed evenly over the central proof mass.
5) International PCT patent application published as WO2017022577A1, for the invention STRAIN RESISTANCE ELEMENT, PRESSURE SENSOR, STRAIN GAUGE, ACCELERATION SENSOR, AND ANGULAR VELOCITY SENSOR, filed in the name of Murata Manufacturing Co.
Reference 5) discloses a standard NEMS construction of the pressure sensor, strain gauge, acceleration sensor or an angular velocity sensor. It uses a strain resistance film formed on a rigid surface of the SiCU substrate, wherein the strain resistance film is formed as a film of graphene or a transition metal dichalcogenide having a single atom layer thickness or a multi-atom layer thickness. The used NEMS geometry is rather generic.
6) CN patent application published as CN110531113 for the invention A PLANAR DIFFERENTIAL ACCELEROMETER DEVICE BASED ON GRAPHENE RESONATORS AND A PROCESSING METHOD THEREOF, filed in the name of Southeast University.
The technical problem solved in reference 6) is ability to overcome the problems and deficiencies in the prior art with the setup having two counterphase formed graphene resonators.
7) CN patent application published as CN111983257 for the invention AN ACCELERATION SENSOR BASED ON SUSPENDED TWO-DIMENSIONAL MATERIAL AND HETEROGENEOUS LAYER SUSPENDED MASS, filed in the name of jSIflSI.
The above cited reference teaches about an accelerometer with a proof mass attached to the suspended 2D material. In reference 7) the suspended two-dimensional material is selected from the following group: graphene (graphene), hexagonal boron nitride (hBN), molybdenum disulfide (M0S2), tungsten diselenide (WSe2), molybdenum diselenide (MoSe2), tungsten disulfide (WS2), platinum diselenide (PtSe2), molybdenum diselenide (MoTe2), tungsten diselenide (WTe2), vanadium diselenide (VSe2), chromium disulfide (CrS2), chromium diselenide (CrSe2), other transition metal dichalcogenides (TMDC), and black phosphorus (P). Furthermore, see paragraph [0034], reference 2 quotes that a typical acceleration sensor usually includes a suspended mass structure, which is displaced with the applied acceleration and which causes the resistance or capacitance of the sensing structure of the said acceleration sensor to change.
8) US patent US 10,228,387 for the invention TWO-DIMENSIONAL MATERIAL-BASED ACCELEROMETER, filed in the name of Kulite Semiconductor Products Inc.
Reference 8) discloses system and method for a two-dimensional material-based accelerometer. In one embodiment, an accelerometer comprises a substrate; a membrane suspended over an opening in the substrate to form a suspended membrane, wherein the membrane is composed of a two-dimensional material; a mass structure coupled to the suspended membrane; wherein the mass structure distorts the suspended membrane about a first axis in response to an applied acceleration providing a first and instantaneous change in a conductance of the suspended membrane, so that the applied acceleration along the first axis can be detected. Paragraph [0024] of reference 8) quotes that used two-dimensional materials may comprise a single atomic layer to several atomic layers, and in addition to graphene, materials such as molybdenum disulfide (M0S2), tungsten diselenide (WSe2) can be used.
Reference 8) is possibly the closest prior art document having in mind that the disclosed unit acceleration sensor, based on 2D material, operates on similar principle but with different configuration and with no adequate heat management.All prior art documents cited hereby are just the documents defining general state, e.g., use of metal dichalcogenides for accelerometers and without particular relevance for the claimed subject matter.
Summary of the Invention
The present invention discloses an acceleration sensor based on two dimensional materials with significant strain gauge factor. It comprises at least three sensing layers which share a common proof mass in a form of a heat conductive layer which ensures temperature equilibrium of complete configuration. Each sensing layer is suspended over pairs of electrodes and connected with heat dissipation rods. Three- and two-dimensional acceleration detection is implemented combining uniaxial acceleration sensors described below.
• 2D materials that are used as sensing layer can be from a single material or combination of them in a form of heterostructure. Number of layers span from monolayer to plurality of atomic layers in a Z direction which results that a height of accelerometer is in a range of nanometers. 2D materials are shaped as an arbitrary polygon that spans over the corresponding pairs of electrodes in the X-Y plane. In lateral X-Y plane, dimensions of sensing layers can vary from nanometres to centimetres.
• Sensing layers are suspended over pairs of electrodes which are separated from few nanometres up to dozens of micrometres. Each electrode is shaped as an elongated parallelepiped that extends in the Y direction, where said electrodes are spaced one from another, over the X direction. Such setup allows 2 or 4 contact resistivity measurements of said sensing layers. At least two sensing layers are separated in Z direction with common proof mass, which enables measurement of capacitance between pairs of electrodes of displaced sensing layers. Sensing layers share common proof mass in a form of a heat conductive layer which ensures that each sensing materials is in temperature equilibrium. Geometrically heat conductive layer is arbitrary shaped with lateral dimensions in a range as a chosen dimensions of sensing layers but large enough to cover all sensing layers. Said heat conductive layer, which has a geometry larger than areas of the used 2D materials, is disposed above first two 2D materials and where third 2D material is placed on top of the heat conductive layer, covering larger part of the said heat conductive layer, where third 2D material in combination with any of first 2D material forms capacitor. • Each sensing layer is protruded and connected with heat dissipation rod which joins sensing layer with heat conductive layer. Lower pair of rods connects heat conductive layer and rigid substrate which carries all elements. Number of individual rods that protrude each sensing layer can span from one to few hundreds, depending on lateral dimension of the used sensing layers. Each electrode has one or more heat dissipation rods, geometrical shaped to fit within, and to protrude out of the corresponding electrode in Z direction towards a heat conductive layer.
• All components are deposited on an insulating rigid substrate and encapsulated with encapsulation material (50) that encloses all acceleration sensor components, where said sensor has the prominent Z direction.
• The strain gauge of the said unit sensor is determined by simultaneously measuring resistance between the pairs of electrodes of each sensing layer and capacitance between pairs of electrodes of vertically displaced sensing layers.
The acceleration sensor for sensing acceleration dominantly in Z direction is formed in a way that heat conductive layer acts as a sensor's common proof mass and which is bounded to all sensing 2D materials which are suspended over the corresponding pairs of electrodes where all heat dissipation rods protrude through corresponding 2D materials and thermally connect the heat conductive layer with the electrodes. The uniaxial acceleration data are calculated from the set of resistivity and/or capacitance data measured from all sensing layers according to the calibration model.
The suitable 2D materials for the sensing layers are selected from the group of metal dichalcogenides, with the thickness ranging from monolayer to a plurality of atomic layers. The most suitable metal dichalcogenides are molybdenum disulphide (M0S2) or platinum diselenide (PtSe2)· In the preferred embodiment, each uniaxial acceleration sensor (100) comprises of at least three sensing layers each composed of monolayer of the same 2D material.
In preferred embodiment all three sensing layers are detecting acceleration in the same Z direction. Two of them are on same position while third is displaced in Z direction. Third sensing layer is equidistantly separated from first two sensing layers.
Use of the acceleration sensors are also disclosed. In one variant all elements of individual acceleration sensors are place on rigid substrate and detect uniaxial acceleration. For modified sensors (200) array of individual uniaxial sensors are spread across the substrate, in configuration in which they are all perpendicular or parallel in correspondence to each other. In multiaxial representations arrays of uniaxial acceleration sensors are formed. For X-Y-Z sensors (300) three or more modified sensors are connected into cubic shape or any other polyhedron shape with well-defined angles.
Description of Figures
Figure 1 shows configuration of an acceleration sensor in the side view. Figure 2 represents top view of acceleration sensor depicted on Figure 1.
Figures 3A - 3B shows top view and back view of modified acceleration sensor constructed from array of accelerometers depicted on Figure 1 and Figure 2.
Figure 4 shows X-Y-Z acceleration sensor constructed from modified acceleration sensors connected into cube or any other polyhedron.
Figure 5 depicts flowchart with the steps A-G of acceleration sensor formation. Detailed Description of the Invention
The acceleration sensors based on solid seismic mass or proof mass are well known in the art, see the references l)-8) cited before. Novel materials, such as 2D materials, help to make acceleration sensors very small and to be packed as NEMS (nanoelectromechanical system). Therefore, the inner geometry plays the important role in forming the reliable acceleration sensor. With adequate placement and connection of each element of accelerometer temperature equilibrium is ensured, which is important for use of accelerometers in environment that has large range of temperatures.
Figure 1 illustrate, so-called, uniaxial acceleration sensor (100) which is formed on rigid substrate (60). This substrate can be commercially used Silicon wafers or any rigid substrate with adequate heat conductivity. The rigid substrate (60) is significantly longer and wider than the uniaxial acceleration sensor (100), as obvious from Figures 1, 2, 3A-3B and should be capable to carry plurality of uniaxial acceleration sensors (100).
Pairs of electrodes (20, 21) are formed from conductive materials, such as gold or platinum, by direct write lithography or e-beam and stencil lithography in combination with thermal evaporation and sputtering in order to produce thin metal film. In case that some 2D material is used for forming the said electrode (40) instead of metal, a stamping transfer is employed and 2D material with high conductivity is used for the mentioned purpose, i.e., graphene. Thermal evaporation, sputtering and stamping transfer are well known techniques in the field.
On top of pairs of electrodes (20, 21) corresponding heat dissipation rods (30, 31) are fabricated out of heat conductive material such as gold or thermally conductive plastic TCP, via methods as previously described for fabrication of pairs of electrodes (20, 21). Over the pairs of electrodes (20, 21) and corresponding heat dissipation rods (30, 31) 2D materials which are used as a sensing layers (10, 11) are transferred. Each sensing layer is suspended over the pair of electrodes while rods protrude through 2D materials, which ensures stabile edges of sensing layers. 2D materials can have arbitrary shape. In preferred configuration they are used in the form of elongated rectangle, as depicted in Figure 1 and 2. In practice, the nano- and micro- scale 2D materials usually grow in triangular or hexagonal form. The consequence of that fact is that rectangles are formed only on rather bigger lateral scales. For smaller dimensions, it is necessary to use an etching process, a plasma cleaner, or a focused ion beam technique to shape the 2D material (10, 11) according to the needs, i.e., to produce elongated-like rectangles, or other suitable geometries.
The heat conductive layer (40) is formed over the said sensing layers (10, 11) as depicted on Figure 1. This layer ensures that whole system has adequate heat transfer which ensures temperature equilibrium. Said layer act as a proof mass which ensures adequate strain transfer into the sensing layers due to acceleration system is exposed. There are various possibilities in formation of the said layer depending of the type of materials used. If the heat layer (40) is made out of thermally conductive plastic TCP, it can be formed by placing thin film of TCP on top of pairs of electrodes or by dripping polymer film which is spin coated and dried while rods protrude part of heat layer. If the heat layer (40) is made out of thin oxide-layer, e.g., AI2O3, then the Atomic Layer Deposition (ALD) or the sputtering method can be used. Finally, if non-conductive 2D material is used for the layer (50), i.e., hexagonal boron nitride (hBN) or calcium fluoride (CaF2), a stamping transfer can be employed equally well. To ensure that heat conductive layer will be suspended between firs two sensing layers, small layer of polymer can be placed between two sensing layers and afterwards when heat conductive layer is placed, that polymer can be washed away leaving heat layer on designated place. The thickness of the heat layer should be chosen depending on dimension of sensing layers and it should be enough to ensure operability and sensibility of acceleration sensor (100).
Over the heat conductive layer (40) third sensing layer (12), with corresponding pair of electrodes (22) and heat dissipation rods (32), is formed in a way as described for first two sensing layers. Third sensing layer (12) has same orientation as firs two sensing layers (10, 11), and it is placed equidistantly from them, in the middle but with vertical displacement in a form of head conductive layer (40) which separates first two sensing layers from third. Third sensing layer is placed on top of heat conductive layer, which covers first two sensing layers, and gap between them, what results in that that third layer can be also considered suspended.
Said 2D materials used for sensing layers (10, 11, 12) should be chosen to have a significant strain gauge factor. Suitable 2D materials are selected from the group of metal dichalcogenides, with the thickness ranging from monolayer to a plurality of atomic layers, preferably formed from molybdenum disulphide (M0S2) or platinum diselenide (PtSe2). Said 2D materials are placed on dedicated position by stamping transfer in a way that all heat dissipation rods (30, 30'; 31, 31'; 32, 32'), protrude through corresponding 2D materials (10, 11, 12) and thermally connect the heat conductive layer (40) with the electrodes (20, 20'; 21, 21'; 22, 22'). Stamping transfer can be the PDMS Stamp Assisted Mechanical Exfoliation or, sensing layers can be formed on another substrate by any other convenient technique known in the related art and subsequently transferred to the position).. Molybdenum disulphide (M0S2) or platinum diselenide (PtSe2) is found to be an excellent choice having in mind comparably high resistivity that has some advantages in resistivity measuring by two contacts only vs. highly conductive 2D materials, e.g. graphene resistivity measurements with four contacts.
Once all elements are formed on top of rigid substrate, the sensor (100) encapsulation is performed by dripping the encapsulating polymer (50) over the top of the unit acceleration sensor (100). The whole preparation process is summarised on Figure 5, via steps A.-G.
The person skilled in the art will immediately recognise that the whole unit acceleration sensor can be formed to have thickness less than 100 pm, over the rigid substrate, which is thickest part of the device, rendering such sensor applicable everywhere.
The construction of the mentioned unit acceleration sensor is very similar to those described in the reference 8) TWO-DIMENSIONAL MATERIAL-BASED ACCELEROMETER. However, the said invention goes broader that the mentioned teaching. The novel part of the said invention is the fact that an improved acceleration sensor (100) is based on 2D material and common proof mass in the form of a heat conductive layer (40), where it connects at least two sensing layers (10, 11) from their top side and at last one sensing layer (12) from its bottom side as depicted in Figure 1. Important improvement of acceleration sensor (100) in comparison with previous accelerometers based on 2D materials is adequate heat management throughout system, which ensure temperature stability and equilibrium of all elements. This configuration enables simultaneous determination of acceleration from all sensing layers which enables differential measurements for elimination of thermal noise and other spurious signals such as parasitic mechanical vibrations.
Acceleration sensor (100) can be used for highly precise accelerometer which operates on large range of temperatures with reliability and durability. As previously mentioned, sensors use three sensing layers which are all connected to common proof mass on which they are suspended. Heat conductive layer (40) acts as a proof mass. Any change in acceleration in lateral direction, i.e., direction parallel with the rigid substrate (60) will certainly displace heat layer (40) over the rigid substrate (60) in the same direction resulting with no detected acceleration. While any change in acceleration in transversal direction, i.e., direction perpendicular to the rigid substrate (60) will displace heat layer (40) far of the rigid substrate (60), or closer to the rigid substrate (60), depending on the acceleration direction and proof mass inertia, i.e., heat conductive layer (40) inertia.
For the lateral movement of the heat conductive layer (40), the selected 2D materials used for sensing layers (10, 11, 12), as depicted in Figure 1, will record almost no change in resistivity ( Rio , Rii , R12 ) and modest changes in capacitances ( Cion , C1012) due to the slight change of geometrical factors that forms parallel plate capacitors between heat conductive layer and sensing layers sandwiched between pairs of electrodes (22, 20; 22, 21).
The resistivities are measured via pairs of electrodes (20. 20'; 21, 21'; 22, 22') respectively, or in the case where high conductivity 2D materials are used, such as graphene, with 4 contact technique where auxiliary surface electrodes (20'', 20'" , 21" ; 21'" , 22" , 22'" ) are used as voltage electrodes and the first side electrodes (20, 20'; 21, 21'; 22, 22') as current contacts.
Capacitance ( Cion , C1012) is measured between pairs of electrodes (22, 20; 22, 21) that sandwich heat conductive layer (40) and sensing layers (12, 10; 12, 11). This configuration is equivalent as parallel plate capacitors with dielectric inserted between the plates. The electrodes (22, 20; 22, 21) forms the contacts for measuring the said capacitances having in mind that the corresponding 2D materials (10, 11, 12) are semiconductive or conductive and capable to redistribute the electrical charge over their surfaces. Capacitance can be measured by various techniques, with astonishing precision, see reference 9) below:
9) Rui Yang, Tupta, M. A., Marcoux, C., Andreucci, P., Duraffourg, L., & Feng, P. X.-L. (2015). Capacitance-voltage (C-V) characterization in very thin suspended silicon nanowires for NEMS-CMOS integration in 160nm Silicon-on-Insulator (SOI). 2015 IEEE 15th International Conference on Nanotechnology (IEEE-NANO). doi:10.1109/nano.2015.7388835 or via standard change in resonant frequencies of some driven oscillators where ( Cion , C1012) determines capacitance in the RC constant of some oscillatory circuits.
For the transversal movement of the heat layer (40), the selected 2D materials will record a significant change in their resistivities ( Rio , Rn , R12 ) and again modest changes in capacitances ( Cion , C1012 ) due to the slight change of geometrical factors that forms capacitors due to the displacement of the heat layer (40). The advantage of the disclosed design is that the differential measurement of ( Rio , Rn , R12 ; Cion , C1012 ) is possible, which offers a better insight regarding the whole sensor (100) status and better noise cancelation / suppression. Certainly, the offset values can be previously recorded or balanced in a way that ( Rio - Rn ) is set to 0 in case of no acceleration, and where any acceleration will gain the value of the said difference.
All the mentioned measurements are temperature dependant meaning that any temperature variation can result in errors in determination of acceleration. Improved acceleration sensor (100) uses the same layer for proof mass as a heat conductive layer (40) which ensures that whole system has adequate thermal management. All sensing layer (10, 11, 12) are connected with heat layer (40) with dissipation rods (30, 31, 32) which ensure heat transfer from sensing layers towards heat conductive layer (40).
Heat conductive layer (40) is anchored with heat dissipation rods (30, 31, 32) which protrude through sensing layers (10, 11, 12). This ensures that heat conductive layer (40) has significant thermal contact with all other elements of acceleration sensor (100). Heat conductive layer (40) has to have insulating interfaces with sensing layers (10, 11, 12), their corresponding electrodes (20, 21, 22) and heat dissipation rods (30, 31, 32) to ensure stabile dielectric environment in the key elements of acceleration sensor (100). Meaning that natural choice of material for heat conductive layer (40) are standard polymers used for electronics. Choice of material used for heat conductive layer (40) results from consideration of Wiedemann- Franz law. Electrically insulating materials are usually also thermally insulating but in this configuration enhancement in the view of heat dissipation rods (30, 31, 32) ensures that large enough area is in contact with heat conductive layer (40) where charge can redistribute to establish thermal equilibrium. What results that the choice of heat conductive layer (40) can be expanded on standard polymer insulators and similar materials even though they are not highly thermally conductive in principle.
Figures 3A-3B and 4 depicts further possibilities of the acceleration sensor (100) formation where more individual uniaxial acceleration sensors (100) are used. Figure 3A shows embodiment of modified acceleration sensor (200) which is constructed by joining two or more uniaxial acceleration sensors (100) in an array of them where each is perpendicular or parallel in respect to each other, so one can easily eliminate any lateral contribution of acceleration vector. Figure 4 shows embodiment of X-Y-Z acceleration sensor (300) which is constructed by joining three or more modified acceleration sensors (200) into a cube or any polyhedron shape with well-defined angles.
However, the setups depicted on Figure 3A and 4 are different. It is obvious that these setups enable all the features previous explained for uniaxial sensors, plus additional sensing of the acceleration vector which is not perpendicular to the rigid substrate (60). If one imagines the acceleration vector that is laying in arbitrary direction, combining multiple modified acceleration sensors (200, 200', 200''...) in three directions will result in precise determination of acceleration. Each sensor will show various readings that will be recorded, and which are projections of acceleration vector on Z direction of each acceleration sensor. From there comes the possibility to have various alignments which opens the whole new perspective for measuring the acceleration vector via moving the heat layer (40) acting as the common proof mass / solid mass. The person skilled in the art will immediately recognize that various alignments of the unit sensors (100, 100', ...) helps to measure projection of the actual acceleration vector out of the plane of the heat layer (40) proof mass. It is known in the art that practical use of the acceleration sensor (100) composed form multiple sensing layers (10, 11, 12), requires calibration process before any use. The calibration process can be manual or machine supported and completely automatized.
The way the number of electrode contacts can be minimised is disclosed in reference 4) where four contacts are used to monitor four 2D unit sensor mounted on the same proof mass forming an acceleration sensor. Such wiring in the form of Wheatstone bridge is commonly used for minimising number of measuring contacts. The person skilled in the art will certainly employ one or more similar solutions for analysing the grid of 2D resistors in order to accurately read all the 2D sensors used.
It is obvious from the Figure 1 that any bending of the heat conductive layer (40) will affect each sensing layer (10, 11, 12) of acceleration sensor (100. Once the acceleration is applied to the rigid substrate (60) heat conductive layer will be slightly deformed out of original position, inducing strain into sensing layers (10, 11, 12) which will record different values then in stationary condition when no acceleration is applied. For the cube depicted in Figure 4 it is essential to check the data of acceleration sensors (100) positioned on the opposite side of the said cube to establish the difference. Knowing the exact positions of all sensors (100) and measured data, it is very simple to establish the 3D acceleration vector applied to the body, especially if the pre-calibrated modified sensors (200) are used. If the sensors (100) are not pre-calibrated, then the calibration of all sensors (200), fixed to the cubic body, can be performed subsequently in accordance with the acceleration measurement.
With connecting all sensors (100) to modified acceleration sensors (200) any lateral movement, to detecting Z direction of sensors (200), can be easily eliminated. Modified acceleration sensor (200) contains at least two acceleration sensors (100, 100') disposed perpendicularly one to another in the same X-Y plane, in a way that their corresponding X axes are perpendicular one to another. Modified acceleration sensors (200) are used for forming an X-Y or X-Y-Z acceleration sensor (300) where, said X-Y-Z acceleration sensor (300) contains at least three modified acceleration sensors (200, 200', 200") disposed perpendicularly one to another, in a way that their corresponding X-Y planes are perpendicular one to another. Connecting modified sensors (200) into cubic or other polyhedron shape with well-known geometry to form X-Y- Z acceleration sensor (300) and by applying machine learning optimizations it is possible to increase accuracy to an even greater extent. Rigid substrate (60) can be formed to be tick from dozens of micrometres to several centimetres. Depending on the number of rigid substrate (60) used for connecting multiaxial systems, a system may achieve desired accuracy within the theoretical limits imposed by the used 2D materials within the acceleration sensors (100).
Industrial Applicability
The present invention discloses a novel acceleration sensor based on two-dimensional (2D) materials, more particularly materials that are selected from the group of metal dichalcogenides, molybdenum disulphide (M0S2) or platinum diselenide (PtSe2)· Said materials are suspended with common proof mass that act as a heat conductive layer which ensures temperature equilibrium of system. The said acceleration sensors are formed in array on commercial Silicon wafer substrates which ensures improved accuracy. The industrial applicability of the mentioned sensors is primarily for circuits and devices that require accelerometers that can operate reliably in large range of temperatures. Reference numbers
10, 11, 12 2D material used for sensing 20 electrodes for material 10 21 electrodes for material 11 22 electrodes for material 12
30 heat dissipation rod for material 10
31 heat dissipation rod for material 11
32 heat dissipation rod for material 12 40 heat conductive layer 50 encapsulation 60 substrate 100 acceleration sensor 200 modified acceleration sensors 300 X-Y-Z acceleration sensors

Claims

1. An acceleration sensor (100), based on two dimensional (2D) materials with high strain gauge factor and high lateral thermal conductivity through its 2D plane that defines X-Y plane of the sensor (100), which is constructed in a way that:
2D materials (10, 11, 12) are shaped as an arbitrary polygon that spans over the corresponding pairs of electrodes (20, 20'; 21, 21'; 22, 22') in the X-Y plane; where each electrode (20, 20'; 21, 21'; 22, 22') is shaped as an elongated parallelepiped that extends in the Y direction, where said electrodes are spaced one from another, over the X direction; where each electrode (20, 20'; 21, 21'; 22, 22') has one or more heat dissipation rods (30, 30'; 31, 31'; 32, 32'), geometrical shaped to fit within, and to protrude out of the corresponding electrode in Z direction towards a heat conductive layer (40); where said heat conductive layer (40), which has a geometry larger than areas of the used 2D materials (10, 11, 12), is disposed above 2D materials (10, 11) and where 2D material
(12) is placed on top of the layer (40), covering larger part of the said heat conductive layer (40), where the said 2D material (12) in combination with any 2D material (10, 11) forms capacitor; where all components are deposited on an insulating rigid substrate (60) and encapsulated with encapsulation material (50) that encloses all acceleration sensor (100) components, where said sensor (100) has the prominent Z direction; where the strain gauge of the said 2D materials (10, 11, 12) is measured by measuring resistivity Rio, Rn, R12 between the pair of electrodes (20, 20'; 21, 21'; 22, 22') and, optionally, using the capacitance measurements C1012 and Cm2 between the pairs of oppositely disposed 2D materials (10, 12; 11, 12) using the electrodes (20, 20'; 21, 21'; 22, 22'); characterised in that, the acceleration sensor (100) for sensing acceleration dominantly in Z direction is formed in a way that heat conductive layer (40) acts as a sensor's (100) common proof mass, bounded to all sensing 2D materials (10, 11, 12) suspended over the corresponding pairs of electrodes (20, 20'; 21, 21'; 22, 22'), where all heat dissipation rods (30, 30'; 31, 31'; 32, 32'), protrude through corresponding 2D materials (10, 11, 12) and thermally connect the heat conductive layer (40) with the electrodes (20, 20'; 21, 21'; 22, 22'); and where the acceleration data are calculated from the set of data {(Rio, Rii, R12) and (C1012, Cm2), measured from all sensing 2D materials (10, 11, 12), according to the calibration model.
2. The acceleration sensor (100) according to claim 1, where the suitable sensing 2D materials (10, 11, 12) are semiconductors selected from the group of metal dichalcogenides and insulators such as hBN, with the thickness ranging from monolayer to a plurality of atomic layers.
3. The acceleration sensor (100) according to the claim 2, where the most suitable metal dichalcogenides are molybdenum disulphide (M0S2) or platinum diselenide (PtSe2) sandwiched between hBN or CaF2.
4. The acceleration sensor (100) according to any of the preceding claims, where each sensing material (10, 11, 12) is made out of single type of material or of a combination of them formed into heterostructure.
5. The acceleration sensor (100) according to any of the preceding claims, where all centres of mass of the sensing materials (10, 11, 12) are laying on the same X direction, and where the said centres of mass are equidistantly spaced one from another.
6. Use of acceleration sensors (100) according to any of claims 1-5 for forming an modified acceleration sensor (200) where, said modified acceleration sensor (200) contains at least two acceleration sensors (100, 100') disposed perpendicularly one to another in the same X-Y plane, in a way that their corresponding X axes are perpendicular one to another.
7. Use of the acceleration sensors (100) according to claim 6, where all sensors (100) centre of masses are equidistantly placed in one plane that defines modified acceleration sensor (200).
8. Use of modified acceleration sensors (200) according to claims 6 or 7 for forming an X-Y or X-Y-Z acceleration sensor (300) where, said X-Y-Z acceleration sensor (300) contains at least three modified acceleration sensors (200, 200', 200") disposed perpendicularly one to another, in a way that their corresponding X-Y planes are perpendicular one to another.
9. Use of the acceleration sensors (100) according to any of the preceding claims, where all sensors (100) share a common rigid substrate (60).
10. Use of the Z direction acceleration sensors (100) or modified acceleration sensors (200) according to any of previous claims, where at least three equal modified acceleration sensors (200) are connected into a cubic or other polyhedron shape with well- known geometry to form X-Y-Z acceleration sensor (300).
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Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20130205899A1 (en) * 2012-02-14 2013-08-15 Asia Pacific Microsystems, Inc. Combo Transducer and Combo Transducer Package
US20150362521A1 (en) * 2014-06-16 2015-12-17 Kulite Semiconductor Products, Inc. Two-dimensional material-based accelerometer
US20160209441A1 (en) * 2011-10-28 2016-07-21 President And Fellows Of Harvard College Capacitive, paper-based accelerometers and touch sensors
WO2017022577A1 (en) 2015-08-06 2017-02-09 株式会社村田製作所 Strain resistance element, pressure sensor, strain gauge, acceleration sensor, and angular velocity sensor
CN109470886A (en) 2018-12-27 2019-03-15 江苏集萃微纳自动化系统与装备技术研究所有限公司 Multiaxis paper base acceleration transducer and preparation method thereof
CN109507451A (en) 2018-10-24 2019-03-22 西安交通大学 A kind of acceleration sensor chip and its processing method based on molybdenum disulfide film
CN110531113A (en) 2019-09-17 2019-12-03 东南大学 Plane differential type accelerometer device and its processing method based on graphene resonator
CN111983257A (en) 2020-08-22 2020-11-24 范绪阁 Acceleration sensor based on suspension two-dimensional material and heterogeneous layer suspension mass block

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20160209441A1 (en) * 2011-10-28 2016-07-21 President And Fellows Of Harvard College Capacitive, paper-based accelerometers and touch sensors
US20130205899A1 (en) * 2012-02-14 2013-08-15 Asia Pacific Microsystems, Inc. Combo Transducer and Combo Transducer Package
US20150362521A1 (en) * 2014-06-16 2015-12-17 Kulite Semiconductor Products, Inc. Two-dimensional material-based accelerometer
US10228387B2 (en) 2014-06-16 2019-03-12 Kulite Semiconductor Products, Inc. Two-dimensional material-based accelerometer
WO2017022577A1 (en) 2015-08-06 2017-02-09 株式会社村田製作所 Strain resistance element, pressure sensor, strain gauge, acceleration sensor, and angular velocity sensor
CN109507451A (en) 2018-10-24 2019-03-22 西安交通大学 A kind of acceleration sensor chip and its processing method based on molybdenum disulfide film
CN109470886A (en) 2018-12-27 2019-03-15 江苏集萃微纳自动化系统与装备技术研究所有限公司 Multiaxis paper base acceleration transducer and preparation method thereof
CN110531113A (en) 2019-09-17 2019-12-03 东南大学 Plane differential type accelerometer device and its processing method based on graphene resonator
CN111983257A (en) 2020-08-22 2020-11-24 范绪阁 Acceleration sensor based on suspension two-dimensional material and heterogeneous layer suspension mass block

Non-Patent Citations (4)

* Cited by examiner, † Cited by third party
Title
LE MINH-QUY: "Cohesive energy in graphene/MoS2heterostructures", MECCANICA, KLUWER ACADEMIC PUBLISHERS, DORDRECHT, NL, vol. 52, no. 1, 29 February 2016 (2016-02-29), pages 307 - 315, XP036109851, ISSN: 0025-6455, [retrieved on 20160229], DOI: 10.1007/S11012-016-0402-6 *
RUI YANGTUPTA, M. A.MARCOUX, C.ANDREUCCI, P.DURAFFOURG, L.FENG, P. X.-L.: "Capacitance-voltage (C-V) characterization in very thin suspended silicon nanowires for NEMS-CMOS integration in 160nm Silicon-on-Insulator (SOI", 2015 IEEE 15TH INTERNATIONAL CONFERENCE ON NANOTECHNOLOGY (IEEE-NANO, 2015
STEFAN WAGNER: "dissertation", 16 July 2018, FACULTY OF ELECTRICAL ENGINEERING AND INFORMATION TECHNOLOGY OF THE RHEINISCH-WESTFALISCHE TECHNISCHE HOCHSCHULE AACHEN, article "2D MATERIALS FOR PIEZORESISTIVE STRAIN GAUGES AND MEMBRANE BASED NANOELECTROMECHANICAL SYSTEMS"
TSAI, M.-Y.TARASOV, A.HESABI, Z. R.TAGHINEJAD, H.CAMPBELL, P. M.JOINER, C. A.VOGEL, E. M.: "FLEXIBLE MoS FIELD-EFFECT TRANSISTORS FOR GATE-TUNABLE PIEZORESISTIVE STRAIN SENSORS", ACS APPLIED MATERIALS & INTERFACES, vol. 7, no. 23, 2015, pages 12850 - 12855

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