WO2020103740A1 - 一种基于磁阻元件的氢气传感器及其检测氢气的方法 - Google Patents

一种基于磁阻元件的氢气传感器及其检测氢气的方法

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WO2020103740A1
WO2020103740A1 PCT/CN2019/118051 CN2019118051W WO2020103740A1 WO 2020103740 A1 WO2020103740 A1 WO 2020103740A1 CN 2019118051 W CN2019118051 W CN 2019118051W WO 2020103740 A1 WO2020103740 A1 WO 2020103740A1
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layer
hydrogen
magnetoresistive
magnetoresistance
magnetic
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PCT/CN2019/118051
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English (en)
French (fr)
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迪克詹姆斯·G
刘宣作
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江苏多维科技有限公司
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Application filed by 江苏多维科技有限公司 filed Critical 江苏多维科技有限公司
Priority to EP19887351.5A priority Critical patent/EP3885759A4/en
Priority to US17/309,266 priority patent/US11408949B2/en
Priority to JP2021527102A priority patent/JP7134531B2/ja
Publication of WO2020103740A1 publication Critical patent/WO2020103740A1/zh

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/02—Measuring direction or magnitude of magnetic fields or magnetic flux
    • G01R33/06—Measuring direction or magnitude of magnetic fields or magnetic flux using galvano-magnetic devices
    • G01R33/09—Magnetoresistive devices
    • G01R33/091—Constructional adaptation of the sensor to specific applications
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
    • G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
    • G01N27/12—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of a solid body in dependence upon absorption of a fluid; of a solid body in dependence upon reaction with a fluid, for detecting components in the fluid
    • G01N27/125—Composition of the body, e.g. the composition of its sensitive layer
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
    • G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
    • G01N27/045—Circuits
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
    • G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
    • G01N27/12—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of a solid body in dependence upon absorption of a fluid; of a solid body in dependence upon reaction with a fluid, for detecting components in the fluid
    • G01N27/128—Microapparatus
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/0004—Gaseous mixtures, e.g. polluted air
    • G01N33/0009—General constructional details of gas analysers, e.g. portable test equipment
    • G01N33/0027—General constructional details of gas analysers, e.g. portable test equipment concerning the detector
    • G01N33/0036—General constructional details of gas analysers, e.g. portable test equipment concerning the detector specially adapted to detect a particular component
    • G01N33/005—H2
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/02—Measuring direction or magnitude of magnetic fields or magnetic flux
    • G01R33/06—Measuring direction or magnitude of magnetic fields or magnetic flux using galvano-magnetic devices
    • G01R33/09—Magnetoresistive devices
    • G01R33/093—Magnetoresistive devices using multilayer structures, e.g. giant magnetoresistance sensors
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/02—Measuring direction or magnitude of magnetic fields or magnetic flux
    • G01R33/06—Measuring direction or magnitude of magnetic fields or magnetic flux using galvano-magnetic devices
    • G01R33/09—Magnetoresistive devices
    • G01R33/096—Magnetoresistive devices anisotropic magnetoresistance sensors

Definitions

  • the invention relates to the technical field of gas sensors, in particular to a hydrogen sensor based on a magnetoresistive element and a method for detecting hydrogen.
  • Hydrogen cannot be sensed by human senses, but itself is highly flammable and explosive.
  • the flammability threshold of hydrogen in air is around 4%.
  • a reliable and highly sensitive hydrogen sensor is required.
  • the patent CN108169185A discloses an optical sensor based on surface plasmon resonance, which monitors the peak position and intensity change of the surface plasmon resonance peak of the light spectrum reflected from the surface of the metal nanorod array by a spectrometer, realizing the real-time transmission of hydrogen in the environment sense.
  • the disadvantage is that the optical measurement method is too complicated and requires a transparent test vessel.
  • the patent CN207586166U discloses a fuel cell hydrogen sensor. According to the heat generated by the exothermic chemical reaction of hydrogen and oxygen on metal platinum, the vibration frequency of the crystal substrate is affected. The difference between the frequencies before and after the reaction is used to detect The concentration of hydrogen.
  • the disadvantage is that the hydrogen concentration range that can be measured is small, only below 4%.
  • one of the most mature resistive thin-film hydrogen sensors is a palladium (Pd) / palladium alloy thin-film resistive sensor, whose principle is to use the property of metal palladium to absorb hydrogen.
  • Palladium is highly selective for the absorption of hydrogen, and this absorption is reversible. After absorption, palladium hydride will be formed.
  • the resistivity of the metal palladium changes, and the purpose of detecting the hydrogen concentration can be achieved by detecting the change in the metal palladium resistance value.
  • the main disadvantages of this type of hydrogen sensor are concentrated in: low sensitivity and long reaction time.
  • the present invention proposes a hydrogen sensor based on a magnetoresistive element and a method for detecting hydrogen.
  • the working principle is that after the Pd cover layer absorbs hydrogen, on the one hand, it changes the ferromagnetic layer adjacent to it.
  • the perpendicular magnetic anisotropy induced in the layer produces a magnetoresistance change that is positively correlated with the hydrogen concentration in the external environment; on the other hand, the hydrogen atoms dissolved and diffused into the lattice of the Pd film will cause the resistance of the Pd cover layer Change; the two effects work together to achieve high-sensitivity sensing of hydrogen concentration.
  • an embodiment of the present invention provides a hydrogen sensor based on a magnetoresistive element, including:
  • a magnetoresistive sensing unit and a magnetoresistive reference unit on the substrate the magnetoresistive sensing unit is electrically connected to form a sensing arm, the magnetoresistive reference unit is electrically connected to form a reference arm, and the sensing arm is connected to the The reference arm is electrically connected into a reference bridge structure; wherein the magnetoresistive sensing unit and the magnetoresistive reference unit are both anisotropic magnetoresistive (AnMR) units with the same magnetic multilayer film structure Or a giant magnetoresistive (GMR) unit with the same magnetic multilayer film structure; the magnetoresistive sensing unit and the magnetoresistive reference unit are respectively covered with a Pd layer, and the magnetoresistive reference The Pd layer of the unit is covered with a passivation insulating layer;
  • the magnetic multilayer film structure is made into a strip snake circuit through a semiconductor micromachining process, the parallel line segments of the strip snake circuit are along the X direction, and the corners of the strip snake circuit are along the Y direction and are adjacent A gap is formed between parallel line segments of the strip-shaped snake circuit, the long axis of the gap is along the X direction, and the short axis of the gap is along the Y direction;
  • the semiconductor micromachining process includes but is not limited to photolithography 1. Ion etching technology;
  • the Pd layer covered on the magnetoresistive sensing unit changes the magnetic anisotropy of the ferromagnetic layer in the magnetoresistive sensing unit after absorbing hydrogen; the passivation insulating layer isolates the hydrogen to avoid the magnetism of the ferromagnetic layer in the magnetoresistive reference unit Anisotropic change; detect the hydrogen concentration according to the change of the output voltage value before and after the reference bridge structure absorbs hydrogen.
  • the magnetic multilayer film structure of the AMR unit includes a seed layer and a composite intermediate layer from bottom to top; wherein, the composite intermediate layer is a [vertical magnetic anisotropic PMA (Perpendicular Magnetic Anisotropy) interface layer / ferromagnetic layer ] n , n are natural numbers.
  • PMA Perpendicular Magnetic Anisotropy
  • the magnetic multilayer film structure includes a seed layer, an antiferromagnetic layer, a PMA ferromagnetic layer, a buffer layer, and a copper (Cu) spacer layer from bottom to top , Buffer layer, ferromagnetic layer, composite intermediate layer, Pd layer; or from bottom to top: seed layer, PMA interface layer, PMA ferromagnetic layer, buffer layer, Cu spacer layer, buffer layer, ferromagnetic layer, composite intermediate Layer; wherein, the composite intermediate layer is [PMA interface layer / ferromagnetic layer] m , m is a natural number; or
  • the magnetic multilayer film structure includes a seed layer and a multi-film intermediate layer from bottom to top; wherein, the multi-film intermediate layer is [Ferromagnetic layer / Non-magnetic intermediate layer / Ferromagnetic layer] p , p is a natural number.
  • the easy axis of the ferromagnetic layer is perpendicular to the XY plane, the angle of the magnetic moment of the ferromagnetic layer deflected to the adjacent Pd layer in the XZ plane is between 10 ° and 80 °, and the ferromagnetic layer It is a magnetostrictive material, including but not limited to one of iron (Fe), cobalt (Co), nickel (Ni) single element, or cobalt iron (CoFe), nickel iron (NiFe), cobalt platinum (CoPt), One of cobalt palladium (CoPd), cobalt iron boron (CoFeB), and nickel iron cobalt (NiFeCo) alloys.
  • the block permanent magnet there is a block permanent magnet under the substrate, the block permanent magnet generates a magnetic field along the positive direction of the Z axis; or there is a thin film permanent magnet between the substrate and the reference bridge structure, The thin film permanent magnet generates a magnetic field along the positive direction of the Z axis; or there is a strip-shaped permanent magnet array above or below the strip-shaped serpentine circuit, the strip-shaped permanent magnet array includes a plurality of strip-shaped permanent magnets The strip-shaped permanent magnet is located at the gap between the parallel line segments of the strip-shaped snake circuit and generates a magnetic field along the positive direction of the Y axis.
  • the reference bridge structure includes but is not limited to a half-bridge structure, a full-bridge structure or a quasi-bridge structure.
  • the material of the substrate includes but is not limited to one of silicon (Si), silicon oxide (SiO2), and Corning glass.
  • the passivation material includes but is not limited to photoresist and aluminum oxide (Al2O3) One of silicon nitride (SiN).
  • the material of the PMA ferromagnetic layer includes but is not limited to one of cobalt and cobalt iron boron
  • the material of the buffer layer includes but is not limited to one of tantalum and ruthenium
  • the non-magnetic intermediate layer The materials include but are not limited to one of copper, ruthenium, palladium, chromium, gold, and silver.
  • An embodiment of the present invention also proposes a method for detecting hydrogen concentration using the above-mentioned hydrogen sensor based on a magnetoresistive element, which includes:
  • the hydrogen sensor is placed in a gas environment containing hydrogen, and the Pd layer covered on the magnetoresistive sensing unit absorbs hydrogen, changing the perpendicular magnetic field of the ferromagnetic layer in the magnetic multilayer film structure of the magnetoresistive sensing unit Anisotropy makes the magnetic moment of the ferromagnetic layer rotate, resulting in a change in magnetoresistance resistance that is positively related to the hydrogen concentration;
  • the change of the output voltage value of the bridge structure is obtained according to the change of the resistance value of the magnetoresistance, and the hydrogen gas concentration is detected according to the change of the output voltage value of the bridge structure.
  • the present invention has the following beneficial technical effects:
  • All bridge arms of the embodiment of the present invention have the same response to external magnetic field interference, so the present invention is immune to external magnetic field interference.
  • the present invention has good temperature compensation and high sensitivity, and has the advantages of small size, low power consumption, and wide range of detection of hydrogen concentration.
  • FIG. 1 is a schematic structural diagram of a hydrogen sensor based on a magnetoresistive element provided by an embodiment of the present invention
  • FIG. 2 (a) is a schematic structural diagram of a magnetic multilayer film of an AMR unit provided by an embodiment of the present invention
  • FIG. 2 (b) is a schematic structural diagram of a magnetic multilayer film when the GMR unit provided by the embodiment of the present invention is a GMR spin valve;
  • FIG. 2 (c) is a schematic diagram of another magnetic multilayer film structure when the GMR unit provided by the embodiment of the present invention is a GMR spin valve;
  • FIG. 3 is a schematic diagram of a magnetization direction of a ferromagnetic layer provided by an embodiment of the present invention.
  • FIG. 4 (a) is a schematic diagram of the position of the bulk permanent magnet relative to the structure of the magnetic multilayer film provided by the implementation of the present invention.
  • FIG. 4 (b) is a schematic diagram of the position of the thin film permanent magnet relative to the structure of the magnetic multilayer film provided by the embodiment of the present invention.
  • FIG. 5 is a schematic diagram of a full-bridge structure of a hydrogen sensor based on a magnetoresistive element provided by an embodiment of the present invention
  • FIG. 6 (a) is a schematic diagram of a hydrogen sensor based on a magnetoresistive element when there is no hydrogen provided by an embodiment of the present invention
  • FIG. 6 (b) is a schematic diagram of a hydrogen sensor based on a magnetoresistive element provided with hydrogen gas according to an embodiment of the present invention
  • FIG. 7 (a) is a schematic diagram of a hydrogen sensor based on a magnetoresistive element provided by an embodiment of the present invention when there is no hydrogen gas;
  • FIG. 7 (b) is a schematic diagram of a hydrogen sensor based on a magnetoresistive element provided with hydrogen gas according to an embodiment of the present invention
  • FIG. 8 (a) is a schematic diagram of a hydrogen sensor based on a magnetoresistive element provided by an embodiment of the present invention when there is no hydrogen gas;
  • FIG. 8 (b) is a schematic diagram of a hydrogen sensor based on a magnetoresistive element provided with hydrogen gas according to an embodiment of the present invention
  • FIG. 9 is a schematic diagram of the hydrogen concentration and the output voltage of the hydrogen sensor under different conditions of ⁇ max provided by this embodiment.
  • reference numerals 1-substrate, 2-magnetoresistive sensing unit, 3-magnetoresistive reference unit, 4-sensor arm, 5-reference arm, 6-bridge structure, 7-passivation insulating layer, 100-magnetic multilayer film structure, 11-seed layer, 12-PMA interface layer, 13-ferromagnetic layer, 14-Pd layer, 21-antiferromagnetic layer, 22-PMA ferromagnetic layer, 23-dispersed layer, 24 -Cu spacer layer, 25-nonmagnetic intermediate layer, 30-bulk permanent magnet, 40-thin film permanent magnet, 50-strip permanent magnet array, A-magnetic multilayer film structure.
  • FIG. 1 is a schematic structural diagram of a hydrogen sensor based on a magnetoresistive element according to an embodiment of the present invention.
  • the above hydrogen sensor based on a magnetoresistive element includes: a substrate 1 located on an X-Y plane;
  • the magnetoresistive sensing unit 2 and the magnetoresistive reference unit 3 on the substrate 1 are electrically connected to form a sensing arm 4, and the magnetoresistive reference unit 3 is electrically connected to a reference arm 5.
  • the sensing arm 4 and the reference arm 5 are electrically connected to form a reference bridge structure 6; wherein, the magnetoresistive sensing unit 2 and the magnetoresistive reference unit 3 are both AMRs having the same magnetic multilayer film structure Unit or GMR unit with the same magnetic multilayer film structure; the magnetoresistive sensing unit 2 and the magnetoresistive reference unit 3 are respectively covered with a Pd layer, and the Pd layer covering the magnetoresistive reference unit 3 is A passivation insulating layer 7 is further covered on the top.
  • the magnetic multilayer film structure is made into a strip snake circuit through a semiconductor micromachining process, the parallel line segments of the strip snake circuit are along the X direction, and the corners of the strip snake circuit are along the Y direction and are adjacent A gap is formed between parallel line segments of the strip-shaped snake circuit, the long axis of the gap is along the X direction, and the short axis of the gap is along the Y direction; the semiconductor micromachining process includes but is not limited to photolithography 1. Ion etching technology. Wherein, current flows along the serpentine circuit in the X-Y plane.
  • the Pd layer covered on the magnetoresistive sensing unit 2 absorbs hydrogen and changes the magnetic anisotropy of the ferromagnetic layer in the magnetoresistive sensing unit 2; the passivation insulating layer 7 isolates the hydrogen to avoid iron in the magnetoresistive reference unit 3 The change of the magnetic anisotropy of the magnetic layer; the hydrogen concentration is detected according to the change of the output voltage value before and after the reference bridge structure 6 absorbs hydrogen.
  • the material of the substrate 1 includes but is not limited to one of Si, SiO2, Corning glass and the like.
  • the sensor arm 4 and the reference arm 5 are connected in a full-bridge structure, the sensor arm 4 includes a first sensor arm 41 and a second sensor arm 42, and the reference arm 5 includes a first reference The arm 51 and the second reference arm 52.
  • the sensing arm 4 and the reference arm 5 are electrically connected to form a reference bridge structure 6.
  • the Pd layer of the magnetoresistive reference cell is covered with a passivation insulating layer 7; the material of the passivation insulating layer 7 includes but is not limited to one of photoresist, Al2O3, and silicon nitride SiN.
  • FIG. 2 (a) is a schematic structural diagram of a magnetic multilayer film of an AMR unit provided by an embodiment of the present invention.
  • the magnetic multilayer film structure 100 of the AMR unit includes, from bottom to top, a seed layer 11, [PMA interface layer 12 / ferromagnetic layer 13] n , and a Pd layer 14, where n belongs to Natural number.
  • FIG. 2 (b) is a schematic structural diagram of a magnetic multilayer film when the GMR unit provided by the embodiment of the present invention is a GMR spin valve.
  • the magnetic multilayer film structure 200 of the GMR spin valve from bottom to top includes: a seed layer 11, an antiferromagnetic layer 21, a PMA ferromagnetic layer 22, a buffer layer 23, and a Cu spacer layer 24 , Buffer layer 23, ferromagnetic layer 13, [PMA interface layer 12 / ferromagnetic layer 13] m , and Pd layer 14, where m is a natural number.
  • FIG. 2 (c) is a schematic structural diagram of another magnetic multilayer film when the GMR unit provided by the embodiment of the present invention is a GMR spin valve.
  • another magnetic multilayer film structure 300 of the GMR spin valve includes: a seed layer 11, a PMA interface layer 12, a PMA ferromagnetic layer 22, and a buffer layer 23 from bottom to top , Cu spacer layer 24, buffer layer 23, ferromagnetic layer 13, [PMA interface layer 12 / ferromagnetic layer 13] k, Pd layer 14, where k is a natural number.
  • FIG. 2 (d) is a schematic structural diagram of a magnetic multilayer film when the GMR unit provided by the embodiment of the present invention is a GMR multilayer film with strong interlayer antiferromagnetic coupling.
  • the magnetic multilayer thin film structure 400 when the GMR multilayer film is stacked includes from bottom to top: a seed layer 11, [Pd layer 14 / ferromagnetic layer 13 / nonmagnetic intermediate layer 25 / Ferromagnetic layer 13] p , Pd layer 14, where p belongs to a natural number.
  • the Pd layer 14 induces perpendicular magnetic anisotropy in the adjacent ferromagnetic layer 13. After the Pd layer 14 absorbs hydrogen, the perpendicular magnetic anisotropy induced in the adjacent ferromagnetic layer 13 is changed, which causes the magnetic moment of the ferromagnetic layer 13 to rotate and produce a positive correlation with the hydrogen concentration The magnetoresistance changes.
  • the material of the seed layer 11 includes but is not limited to one of tantalum Ta and tungsten W.
  • the material of the PMA interface layer 12 includes but is not limited to one of magnesium oxide MgO, palladium Pd, and platinum Pt.
  • the material of the passivation insulating layer 7 includes, but is not limited to, one of photoresist, aluminum oxide, and silicon nitride.
  • the material of the PMA ferromagnetic layer 22 includes but is not limited to one of cobalt Co and cobalt iron boron CoFeB
  • the material of the buffer layer 23 includes but not limited to one of tantalum Ta and ruthenium Ru
  • the material of the layer 25 includes, but is not limited to, one of copper Cu, ruthenium Ru, palladium Pd, chromium Cr, gold Au, silver Ag.
  • FIG. 3 is a schematic diagram of a magnetization direction of a ferromagnetic layer provided by an embodiment of the present invention.
  • the easy axis of the ferromagnetic layer 13 is perpendicular to the XY plane, and the Pd layer 14 induces perpendicular magnetic anisotropy in the ferromagnetic layer 13, so that the magnetic moment of the ferromagnetic layer 13 is in the XZ plane
  • the angle of inward deflection of the adjacent Pd layer 14 is between 10 ° and 80 °.
  • the ferromagnetic layer 13 is a magnetostrictive material, including but not limited to one of iron Fe, cobalt Co, nickel Ni single element, Or one of cobalt iron CoFe, nickel iron NiFe, cobalt platinum CoPt, cobalt palladium CoPd, cobalt iron boron CoFeB, nickel iron cobalt NiFeCo alloy.
  • a block-shaped permanent magnet is provided under the substrate 1, the block-shaped permanent magnet generates a magnetic field along the positive direction of the Z axis; or there is a thin film between the substrate 1 and the reference bridge structure 6 Permanent magnets, the thin-film permanent magnets generate a magnetic field along the positive direction of the Z axis; or there is a strip-shaped permanent magnet array above or below the strip snake circuit, the strip-shaped permanent magnet array includes a plurality of strips Permanent magnets, the elongated permanent magnets are located in the gap between the parallel line segments of the strip-shaped snake circuit, and generate a magnetic field along the positive direction of the Y-axis.
  • FIG. 4 (a) is a schematic diagram of the position of the block-shaped permanent magnets relative to the magnetic multilayer film structure provided by the implementation of the present invention. As shown in FIG. 4 (a), the bulk permanent magnet 30 is located below the substrate 1, and the bulk permanent magnet 30 generates a magnetic field along the positive direction of the Z axis. Or it may include: a thin film permanent magnet located between the substrate 1 and the magnetic multilayer thin film structure.
  • FIG. 4 (b) is a schematic diagram of the position of the thin film permanent magnet relative to the magnetic multilayer thin film structure provided by an embodiment of the present invention.
  • the thin film permanent magnet 40 is located between the substrate 1 and the magnetic multilayer thin film structure A, and the thin film permanent magnet 40 generates a magnetic field along the positive direction of the Z axis.
  • it may include: a strip-shaped permanent magnet array located in a gap formed between parallel line segments of the strip-shaped serpentine circuit, and
  • FIG. 4 (c) is a strip-shaped permanent magnet array and a strip shape provided by an embodiment of the present invention
  • the elongated permanent magnet array 50 is located in the gap formed between the parallel line segments of the ribbon-shaped serpentine circuit, the elongated permanent magnet array 50 includes a plurality of elongated permanent magnets that generate a magnetic field along the positive direction of the Y-axis.
  • the elongated permanent magnet array 50 includes a plurality of elongated permanent magnets The strip-shaped thin film permanent magnets 501, 502, ..., 50i, ..., 50M, where i is a natural number smaller than M.
  • FIG. 5 is a schematic diagram of a full-bridge structure of a hydrogen sensor based on a magnetoresistive element provided by an embodiment of the present invention.
  • the first end of the first sensor arm 41 is connected to the first end of the first reference arm 51
  • the second end of the first sensor arm 41 is connected to the first end of the second reference arm 52
  • the first The second end of the reference arm 51 is connected to the first end of the second sensor arm 42
  • the second end of the second reference arm 52 is connected to the second end of the second sensor arm 42.
  • FIG. 6 (a) is a schematic diagram of a hydrogen sensor based on a magnetoresistive element provided by an embodiment of the present invention when there is no hydrogen gas
  • FIG. 6 (b) is a schematic diagram of a hydrogen sensor provided by an embodiment of the present invention when hydrogen gas is present.
  • the magnetoresistive sensor unit 2 and the magnetoresistive reference unit 3 are AMR units having the same magnetic multilayer film structure as an example for description.
  • FIG. 7 (a) is a principle diagram of a hydrogen sensor based on a magnetoresistive element provided by an embodiment of the present invention when there is no hydrogen
  • FIG. 7 (b) is a principle of a hydrogen sensor based on a magnetoresistive element provided by an embodiment of the present invention when hydrogen is present Figure.
  • the magnetoresistive sensing unit 2 and the magnetoresistive reference unit 3 are GMR spin valves having the same magnetic multilayer film structure as an example for description.
  • FIG. 8 (a) is a schematic diagram of a hydrogen sensor based on a magnetoresistive element provided by an embodiment of the present invention when there is no hydrogen
  • FIG. 8 (b) is a principle of a hydrogen sensor based on a magnetoresistive element provided by an embodiment of the present invention when hydrogen is present Figure.
  • the magnetoresistive sensing unit 2 and the magnetoresistive reference unit 3 are GMR multilayer film stacks having the same magnetic multilayer film structure as an example for description.
  • the hydrogen sensor based on the magnetoresistive element of the present invention A brief description of how it works.
  • the resistance of the Pd layer 14 at the top of the magnetic multilayer film structure is R0, and the angle between the magnetic moment M and the current I- of the ferromagnetic layer 13 below it is ⁇ - ⁇ ,
  • the Pd layer 14 located at the top of the magnetic multilayer film structure absorbs hydrogen gas and expands, and its resistance increases to R ′ 0 .
  • FIG. 9 is a schematic diagram of the hydrogen concentration and the output voltage of the hydrogen sensor under different conditions of ⁇ max provided by this embodiment. Further, the relationship between the hydrogen concentration of ⁇ max at 50, 150, and 350 and the output voltage of the hydrogen sensor is shown in FIG. 9, as can be seen from FIG. 9, the greater the ⁇ max, the greater the detection effect of the hydrogen sensor on the hydrogen concentration. it is good.
  • the hydrogen sensor based on the magnetoresistive element includes: a substrate on the XY plane; a magnetoresistive sensing unit and a magnetoresistive reference unit on the substrate, the magnetoresistive sensing unit is electrically connected to The sensing arm and the magnetoresistive reference unit are electrically connected to form a reference arm; the sensing arm and the reference arm are electrically connected to form a reference bridge structure; the magnetoresistive sensing unit and the magnetoresistive reference unit are AMR units with the same magnetic multilayer film structure or It is a GMR spin valve or GMR multilayer film stack with the same magnetic multilayer film structure.
  • the magnetic multilayer film structure is made into a strip-shaped serpentine circuit through a semiconductor micromachining process, and a passive insulating layer is covered on the magnetoresistive reference unit.
  • the invention has good temperature compensation and high sensitivity, and has the advantages of small size, low power consumption, wide range of detection of hydrogen concentration and the like.
  • the embodiments of the present invention also provide a method for detecting the hydrogen concentration using the hydrogen sensor based on the magnetoresistive element as described above, which is characterized by including:
  • the hydrogen sensor is placed in a gas environment containing hydrogen, and the Pd layer covered on the magnetoresistive sensing unit absorbs hydrogen, changing the perpendicular magnetic field of the ferromagnetic layer in the magnetic multilayer film structure of the magnetoresistive sensing unit Anisotropy makes the magnetic moment of the ferromagnetic layer rotate, resulting in a change in magnetoresistance resistance that is positively related to the hydrogen concentration;
  • the change of the output voltage value of the bridge structure is obtained according to the change of the resistance value of the magnetoresistance, and the hydrogen gas concentration is detected according to the change of the output voltage value of the bridge structure.

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Abstract

一种基于磁阻元件的氢气传感器及其检测氢气的方法，氢气传感器包括位于X-Y平面上的衬底（1）；位于衬底上（1）的磁电阻传感单元（2）和磁电阻参考单元（3），磁电阻传感单元（2）电连接成传感臂（4），磁电阻参考单元（3）电连接成参考臂（5）；传感臂（4）与参考臂（5）电连接成参考桥式结构（6）；磁电阻传感单元（2）与磁电阻参考单元（3）是具有相同磁多层薄膜结构的AMR单元或是具有相同磁多层薄膜结构的GMR自旋阀或GMR多层膜堆栈；磁电阻传感单元（2）与磁电阻参考单元（3）的上方分别覆盖Pd层，在覆盖在磁电阻参考单元（3）的Pd层的上方再覆盖一层钝化绝缘层（7）；磁多层薄膜结构通过半导体微加工工艺制成带状蛇形电路；检测氢气的方法包括：将氢气传感器置于包含有氢气的气体环境中，磁电阻传感单元（2）上覆盖的Pd层吸收氢气，改变磁电阻传感单元（2）的磁多层薄膜结构中的铁磁层（13）的垂直磁各向异性，使得铁磁层（13）的磁矩发生旋转，产生与氢气浓度正相关的磁电阻阻值的变化；根据磁电阻阻值的变化得到参考桥式结构（6）的输出电压值的变化，根据参考桥式结构（6）的输出电压值的变化检测氢气浓度。

Description

一种基于磁阻元件的氢气传感器及其检测氢气的方法 技术领域
本发明涉及气体传感器技术领域，特别涉及一种基于磁阻元件的氢气传感器及其检测氢气的方法。
背景技术
氢气作为替代化石能源的一种可再生、无有害排放的新能源，近年来在全球范围内吸引了越来越多的目光，并得到了快速发展。目前，世界主要经济体，如美国、欧盟、日本等都在不遗余力地推进氢气作为未来车辆与家用的新能源与新燃料，丰田等公司已经开始设计生产氢燃料汽车。
氢气不能被人体感官所感知，但其本身却是高度可燃和易爆的，氢气在空气中的可燃性阈值在4％左右。为了保证使用氢气作为能源的设备的安全，需要可靠的、高灵敏度的氢气传感器。
传统的氢气传感器种类繁多。如专利CN108169185A公开了一种基于表面等离子体共振的光学传感器，通过光谱仪监测从金属纳米棒阵列表面反射光光谱的表面等离子体共振峰的峰位及强度变化，实现了对环境中氢气的实时传感。其缺点在于，光学测量方法过于复杂，并且需要透明的被测器皿。又如专利CN207586166U公开了一种燃料电池化氢气传感器，根据氢气与氧气在金属铂上发生的放热化学反应所产生的热量对水晶基板振动频率产生影响，通过反应前后频率差值的大小来检测氢气的浓度。其缺点在于，所能测量的氢气浓度范围较小，只在4％以下。
现有技术中，最为成熟的一种电阻型薄膜氢气传感器是钯(Pd)/钯合金 薄膜电阻传感器，其原理是利用金属钯吸收氢气这一性质。钯对氢的吸收具有高度选择性，并且这种吸收是可逆的，吸收后将形成钯氢化物。在吸收过程中，金属钯的电阻率发生了改变，通过检测金属钯电阻值的变化即可达到探测氢气浓度的目的。这一类氢气传感器存在的主要缺点集中在：灵敏度低、反应时间长。
发明内容
为了解决上述技术中的不足，本发明提出了一种基于磁阻元件的氢气传感器及其检测氢气的方法，其工作原理在于：Pd覆盖层吸收氢气后，一方面改变其在相邻下方铁磁层中诱导出的垂直磁各向异性，产生出与外部环境中氢气浓度正相关的磁电阻变化；另一方面，溶解扩散至Pd薄膜晶格中的氢原子，会造成Pd覆盖层自身电阻的改变；两种效应共同作用，可实现对氢气浓度的高灵敏度传感。
本发明是根据以下技术方案实现的：
第一方面，本发明实施例提供了一种基于磁阻元件的氢气传感器，包括：
位于X-Y平面上的衬底；
位于衬底上的磁电阻传感单元和磁电阻参考单元，所述磁电阻传感单元电连接成传感臂，所述磁电阻参考单元电连接成参考臂，所述传感臂与所述参考臂电连接成参考桥式结构；其中，所述述磁电阻传感单元与所述磁电阻参考单元同为具有相同磁多层薄膜结构的各向异性磁阻(Anisotropy Magneto Resistance，AMR)单元或具有相同磁多层薄膜结构的巨磁阻(Giant Magneto Resistance，GMR)单元；所述磁电阻传感单元与所述磁电阻参考单元的上分 别覆盖Pd层，在覆盖在所述磁电阻参考单元的Pd层的上方再覆盖一层钝化绝缘层；
所述磁多层薄膜结构通过半导体微加工工艺制成带状蛇形电路，所述带状蛇形电路的平行线段沿X方向，所述带状蛇形电路的拐角沿Y方向，并且相邻所述带状蛇形电路的平行线段之间形成有间隙，所述间隙的长轴沿X方向，所述间隙的短轴沿Y方向；所述半导体微加工工艺包括但不限于光刻蚀技术、离子刻蚀技术；
其中，所述磁电阻传感单元上覆盖的Pd层吸收氢气后改变磁电阻传感单元中铁磁层的磁各向异性；所述钝化绝缘层隔离氢气避免磁电阻参考单元中铁磁层的磁各向异性的变化；根据参考桥式结构吸收氢气前后的输出电压值的变化检测氢气浓度。
进一步的，所述AMR单元的磁多层薄膜结构自下而上包括：种子层、复合中间层；其中，所述复合中间层为[垂直磁各向异性PMA(PerpendicularMagneticAnisotropy)界面层/铁磁层] n，n属于自然数。
进一步的，所述GMR单元为GMR自旋阀结构时，所述磁多层薄膜结构自下而上包括：种子层、反铁磁层、PMA铁磁层、缓冲层、铜(Cu)间隔层、缓冲层、铁磁层、复合中间层、Pd层；或者自下而上包括：种子层、PMA界面层、PMA铁磁层、缓冲层、Cu间隔层、缓冲层、铁磁层、复合中间层；其中，所述复合中间层为[PMA界面层/铁磁层] m，m属于自然数；或
所述GMR单元为具有层间反铁磁耦合的GMR多层膜堆栈时，所述磁多层薄膜结构自下而上包括：种子层、多膜中间层；其中，所述多膜中间层为[铁磁层/非磁性中间层/铁磁层] p，p属于自然数。
进一步的，所述铁磁层的易轴垂直于X-Y平面，所述铁磁层的磁矩在X-Z平面内向相邻Pd层偏转的角度范围在10°至80°之间，所述铁磁层为磁致伸缩材料，包括但不限于铁(Fe)、钴(Co)、镍(Ni)单元素中的一种，或者钴铁(CoFe)、镍铁(NiFe)、钴铂(CoPt)、钴钯(CoPd)、钴铁硼(CoFeB)、镍铁钴(NiFeCo)合金中的一种。
进一步的，在所述衬底下方有块状永磁体，所述块状永磁体产生沿Z轴正方向的磁场；或者在所述衬底与所述参考桥式结构之间有薄膜永磁体，所述薄膜永磁体产生沿Z轴正方向的磁场；或者在所述带状蛇形电路上方或下方有长条状永磁体阵列，所述长条状永磁体阵列包括多个长条状永磁体，所述长条状永磁体介于所述带状蛇形电路的平行线段之间的间隙处，并产生沿Y轴正方向的磁场。
进一步的，所述参考桥式结构包括但不限于为半桥结构、全桥结构或准桥结构。
进一步的，所述衬底的材料包括但不限于硅(Si)、氧化硅(SiO2)、康宁玻璃中的一种，所述钝化材料包括但不限于为光刻胶、氧化铝(Al2O3)、氮化硅(SiN)中的一种。
上述技术方案中，所述PMA铁磁层的材料包括但不限于钴、钴铁硼中的一种，所述缓冲层的材料包括但不限于钽、钌的一种，所述非磁性中间层的材料包括但不限于铜、钌、钯、铬、金、银中的一种。
本发明实施例还提出了一种利用上述基于磁阻元件的氢气传感器检测氢气浓度的方法,包括：
将氢气传感器置于包含有氢气的气体环境中，所述磁电阻传感单元上覆 盖的Pd层吸收氢气，改变所述磁电阻传感单元的磁多层薄膜结构中的铁磁层的垂直磁各向异性，使得铁磁层的磁矩发生旋转，产生与氢气浓度正相关的磁电阻阻值的变化；
根据磁电阻阻值的变化得到桥式结构的输出电压值的变化，根据桥式结构的输出电压值的变化检测氢气浓度。
与现有技术相比，本发明具有以下有益技术效果：
本发明实施例的全部桥臂对外磁场干扰的响应是相同的，因此本发明对于外磁场干扰免疫。作为桥式结构，本发明有很好的温度补偿和高灵敏度，并具有尺寸小、功耗低、探测氢气浓度范围广等优点。
附图说明
通过阅读参照以下附图对非限制性实施例所作的详细描述，本发明的其它特征、目的和优点将会变得更明显：
图1为本发明实施例提供的基于磁阻元件的氢气传感器结构示意图；
图2(a)为本发明实施例提供的AMR单元的磁多层薄膜结构示意图；
图2(b)为本发明实施例提供的GMR单元为GMR自旋阀时的磁多层薄膜结构示意图；
图2(c)为本发明实施例提供的GMR单元为GMR自旋阀时的另一种磁多层薄膜结构示意图；
图2(d)本发明实施例提供的GMR单元为具有强的层间反铁磁耦合的GMR多层膜堆栈时的磁多层薄膜结构示意图；
图3为本发明实施例提供的铁磁层的磁化方向示意图；
图4(a)为本发明实施提供的块状永磁体相对于磁多层薄膜结构的位置示意图；
图4(b)为本发明实施例提供的薄膜永磁体相对于磁多层薄膜结构的位置示意图；
图4(c)为本发明实施例提供的长条状永磁体阵列与带状蛇形电路的相互位置示意图；
图5为本发明实施例提供的基于磁阻元件的氢气传感器的全桥结构示意图；
图6(a)为本发明实施例提供的基于磁阻元件的氢气传感器没有氢气时的原理图；
图6(b)为本发明实施例提供的基于磁阻元件的氢气传感器存在氢气时的原理图；
图7(a)为本发明实施例提供的基于磁阻元件的氢气传感器没有氢气时的原理图；
图7(b)为本发明实施例提供的基于磁阻元件的氢气传感器存在氢气时的原理图；
图8(a)为本发明实施例提供的基于磁阻元件的氢气传感器没有氢气时的原理图；
图8(b)为本发明实施例提供的基于磁阻元件的氢气传感器存在氢气时的原理图；
图9为本实施例提供的△θ max不同情况下的氢气浓度与氢气传感器输出电压之间的示意图。
其中，附图标记：1-衬底，2-磁电阻传感单元,3-磁电阻参考单元，4-传感臂，5-参考臂，6-桥式结构，7-钝化绝缘层，100-磁多层薄膜结构，11-种子层，12-PMA界面层，13-铁磁层，14-Pd层，21-反铁磁层，22-PMA铁磁层,23-散布层，24-Cu间隔层，25-非磁性中间层，30-块状永磁体，40-薄膜永磁体，50-长条状永磁体阵列，A-磁多层薄膜结构。
具体实施方式
为使本发明实施例的目的、技术方案和优点更加清楚，下面将结合本发明实施例中的附图，对本发明实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例是本发明一部分实施例，而不是全部的实施例。
下面将参考附图并结合实施例，来详细说明本发明。
图1为本发明实施例提供的基于磁阻元件的氢气传感器结构示意图，如图1所示，上述基于磁阻元件的氢气传感器包括：位于X-Y平面上的衬底1；
位于衬底1上的磁电阻传感单元2和磁电阻参考单元3，所述磁电阻传感单元2电连接成传感臂4，所述磁电阻参考单元3电连接成参考臂5，所述传感臂4与所述参考臂5电连接成参考桥式结构6；其中，所述述磁电阻传感单元2与所述磁电阻参考单元3同为具有相同磁多层薄膜结构的AMR单元或具有相同磁多层薄膜结构的GMR单元；所述磁电阻传感单元2与所述磁电阻参考单元3的上分别覆盖Pd层，在覆盖在所述磁电阻参考单元3的Pd层的上方再覆盖一层钝化绝缘层7。
所述磁多层薄膜结构通过半导体微加工工艺制成带状蛇形电路，所述带状蛇形电路的平行线段沿X方向，所述带状蛇形电路的拐角沿Y方向，并且相邻所述带状蛇形电路的平行线段之间形成有间隙，所述间隙的长轴沿X方向，所述间隙的短轴沿Y方向；所述半导体微加工工艺包括但不限于光刻蚀 技术、离子刻蚀技术。其中，电流在X-Y平面内沿着所述蛇形电路流动。
其中，所述磁电阻传感单元2上覆盖的Pd层吸收氢气后改变磁电阻传感单元2中铁磁层的磁各向异性；所述钝化绝缘层7隔离氢气避免磁电阻参考单元3中铁磁层的磁各向异性的变化；根据参考桥式结构6吸收氢气前后的输出电压值的变化检测氢气浓度。
进一步的，所述衬底1的材料包括但不限于Si、SiO2、康宁玻璃等中的一种。
进一步的，如图1所述，传感臂4和参考臂5连接为全桥结构，传感臂4包括第一传感臂41和第二传感臂42，以及参考臂5包括第一参考臂51和第二参考臂52。所述传感臂4与所述参考臂5电连接成参考桥式结构6。
所述磁电阻参考单元的Pd层的上覆盖有钝化绝缘层7；所述钝化绝缘层7的材料包括但不限于光刻胶、Al2O3、氮化硅SiN中的一种。
具体的，图2(a)为本发明实施例提供的AMR单元的磁多层薄膜结构示意图。如图2(a)所示，所述AMR单元的磁多层薄膜结构100自下而上包括：种子层11、[PMA界面层12/铁磁层13] n、Pd层14，其中n属于自然数。
具体的，图2(b)为本发明实施例提供的GMR单元为GMR自旋阀时的磁多层薄膜结构示意图。如图2(b)所示，GMR自旋阀时磁多层薄膜结构200自下而上包括：种子层11、反铁磁层21、PMA铁磁层22、缓冲层23、Cu间隔层24、缓冲层23、铁磁层13、[PMA界面层12/铁磁层13] m、Pd层14，其中，m属于自然数。
具体的，图2(c)为本发明实施例提供的GMR单元为GMR自旋阀时的另一种磁多层薄膜结构示意图。如图2(c)所示，所述GMR自旋阀时的另一种磁多 层薄膜结构300自下而上包括：种子层11、PMA界面层12、PMA铁磁层22、缓冲层23、Cu间隔层24、缓冲层23、铁磁层13、[PMA界面层12/铁磁层13]k、Pd层14，其中k属于自然数。
具体的，图2(d)本发明实施例提供的GMR单元为具有强的层间反铁磁耦合的GMR多层膜堆栈时的磁多层薄膜结构示意图。如图2(d)所示，所述GMR多层膜堆栈时的磁多层薄膜结构400自下而上包括：种子层11、[Pd层14/铁磁层13/非磁性中间层25/铁磁层13] p、Pd层14，其中p属于自然数。
在本实施例中，所述Pd层14在相邻所述铁磁层13中诱导出垂直磁各向异性。所述Pd层14吸收氢气后，改变在相邻所述铁磁层13中诱导出的垂直磁各向异性，导致所述铁磁层13的磁矩发生旋转，并产生出与氢气浓度正相关的磁电阻变化。
具体地，所述种子层11的材料包括但不限于钽Ta、钨W中的一种。所述PMA界面层12的材料包括但不限于氧化镁MgO、钯Pd、铂Pt中的一种。所述钝化绝缘层7的材料包括但不限于为光刻胶、氧化铝、氮化硅中的一种。
所述PMA铁磁层22的材料包括但不限于钴Co、钴铁硼CoFeB中的一种，所述缓冲层23的材料包括但不限于钽Ta、钌Ru的一种，所述非磁性中间层25的材料包括但不限于铜Cu、钌Ru、钯Pd、铬Cr、金Au、银Ag中的一种。
进一步的，图3为本发明实施例提供的铁磁层的磁化方向示意图。如图3所示，所述铁磁层13的易轴垂直于X-Y平面，Pd层14在铁磁层13中诱导出垂直磁各向异性，使得所述铁磁层13的磁矩在X-Z平面内向相邻Pd层14偏转的角度范围在10°至80°之间，所述铁磁层13为磁致伸缩材料，包括但不限于铁Fe、钴Co、镍Ni单元素中的一种，或者钴铁CoFe、镍铁NiFe、 钴铂CoPt、钴钯CoPd、钴铁硼CoFeB、镍铁钴NiFeCo合金中的一种。
进一步的，在所述衬底1下方设置块状永磁体，所述块状永磁体产生沿Z轴正方向的磁场；或者在所述衬底1与所述参考桥式结构6之间有薄膜永磁体，所述薄膜永磁体产生沿Z轴正方向的磁场；或者在所述带状蛇形电路上方或下方有长条状永磁体阵列，所述长条状永磁体阵列包括多个长条状永磁体，所述长条状永磁体介于所述带状蛇形电路的平行线段之间的间隙处，并产生沿Y轴正方向的磁场。
在本实施例中，为了使所述铁磁层13的磁矩M在X-Z平面内的偏转角度位于在所述优选范围内，可以根据需要添加位于X-Y平面上的永磁体。本实施例提供永磁体的类型主要包括：位于所述衬底1下方的块状永磁体，图4(a)为本发明实施提供的块状永磁体相对于磁多层薄膜结构的位置示意图，如图4(a)所示，所述块状永磁体30位于所述衬底1下方，所述块状永磁体30产生沿Z轴正方向的磁场。或者可以包括：位于所述衬底1与所述磁多层薄膜结构之间的薄膜永磁体，图4(b)为本发明实施例提供的薄膜永磁体相对于磁多层薄膜结构的位置示意图；如图4(b)所示，薄膜永磁体40位于衬底1与所述磁多层薄膜结构A之间，所述薄膜永磁体40产生沿Z轴正方向的磁场。或者可以包括：位于所述带状蛇形电路的平行线段之间形成的间隙中的长条状永磁体阵列，图4(c)为本发明实施例提供的长条状永磁体阵列与带状蛇形电路的相互位置示意图，如图4(c)所示，长条状永磁体阵列50位于所述带状蛇形电路的平行线段之间形成的间隙中，所述长条状永磁体阵列50包括多个长条状永磁体，所述长条状永磁体产生沿Y轴正方向的磁场，以所述磁电阻参考单元3为例，所述长条状永磁体阵列50包括多个长条状薄膜永磁体 501、502、…、50i、…、50M，其中i为小于M的自然数。
进一步的，所述传感臂4和参考臂5可以连接成全桥、半桥或者准桥。示例性的，图5为本发明实施例提供的基于磁阻元件的氢气传感器的全桥结构示意图。如图5所示，第一传感臂41的第一端连接第一参考臂51的第一端，第一传感臂41的第二端连接第二参考臂52的第一端，第一参考臂51的第二端连接第二传感臂42的第一端，第二参考臂52的第二端连接第二传感臂42的第二端。
图6(a)为本发明实施例提供的基于磁阻元件的氢气传感器没有氢气时的原理图，图6(b)为本发明实施例提供的氢气传感器存在氢气时的原理图。需要说明的是，本实施例是以磁电阻传感单元2与磁电阻参考单元3是具有相同磁多层薄膜结构的AMR单元为例进行说明。
图7(a)为本发明实施例提供的基于磁阻元件的氢气传感器没有氢气时的原理图，图7(b)为本发明实施例提供的基于磁阻元件的氢气传感器存在氢气时的原理图。需要说明的是，本实施例是以磁电阻传感单元2与所述磁电阻参考单元3是具有相同磁多层薄膜结构的GMR自旋阀为例进行说明。
图8(a)为本发明实施例提供的基于磁阻元件的氢气传感器没有氢气时的原理图，图8(b)为本发明实施例提供的基于磁阻元件的氢气传感器存在氢气时的原理图。需要说明的是，本实施例是以磁电阻传感单元2与所述磁电阻参考单元3是具有相同磁多层薄膜结构的GMR多层膜堆栈为例进行说明。
结合图6(a)、图6(b)、图7(a)、图7(b)、图8(a)和图8(b)所示，对本发明所述基于磁阻元件的氢气传感器的工作原理做一个简要说明。当外界环境中没有氢气时，在所述磁电阻传感单元2中，位于磁多层薄膜结构最上 方的Pd层14的电阻为R0，其下方的铁磁层13的磁矩M与电流I+的夹角为θ，所述铁磁层13的各向异性磁电阻为△Rcos 2θ，则磁电阻传感单元2的总电阻RS为R S＝R 0+△Rcos 2θ。
在所述磁电阻参考单元3中，位于磁多层薄膜结构最上方的Pd层14的电阻为R0，其下方的铁磁层13的磁矩M与电流I-的夹角为π-θ，所述铁磁层13的各向异性磁电阻为△Rcos 2(π-θ)＝△Rcos 2θ，则所述磁电阻参考单元3的总电阻Rr为R r＝R 0+△Rcos 2θ。于是，电压信号输出为
Figure PCTCN2019118051-appb-000001
当环境中存在氢气时，在所述磁电阻传感单元2中，位于磁多层薄膜结构最上方的Pd层14吸收氢气后膨胀，其电阻增加为R′ 0。而同时，位于磁多层薄膜结构最上方的Pd层14在其下方的铁磁层13中诱导的垂直磁各向异性亦发生改变，使得所述铁磁层13的磁矩M在X-Z平面内旋转，旋转角度△θ与氢气的浓度正相关，则磁矩M与电流I+的夹角变为θ′＝θ-△θ，所述铁磁层13的各向异性磁电阻增加为△Rcos 2θ′，因此，所述磁电阻传感单元2的总电阻RS′为R S′＝R 0′+△Rcos 2θ′。
在所述磁电阻参考单元3中，由于钝化绝缘层7将氢气阻隔开，故所述磁电阻参考单元3的总电阻Rr保持不变，仍然为R r＝R 0+△Rcos 2θ。
于是，电压信号输出为：
Figure PCTCN2019118051-appb-000002
其中，记θ′＝θ-△θ的最大值为△θ max。△θ max依赖于磁多层薄膜结构中薄膜的材料及厚度，也受薄膜堆叠顺序的影响。为了更直观地说明本发明的磁电阻氢气传感器对外界氢气浓度的检测效果，图9为本实施例提供的△θ max不同情 况下的氢气浓度与氢气传感器输出电压之间的示意图。进一步的，△θ max在50、150和350的氢气浓度与氢气传感器输出电压之间的关系如图9所示，由图9可知，△θ max越大，氢气传感器对氢气浓度的检测效果越好。
本发明实施例提供的基于磁阻元件的氢气传感器，包括：位于X-Y平面上的衬底；位于所述衬底上的磁电阻传感单元和磁电阻参考单元，磁电阻传感单元电连接成传感臂，磁电阻参考单元电连接成参考臂；传感臂与参考臂电连接成参考桥式结构；磁电阻传感单元与磁电阻参考单元是具有相同磁多层薄膜结构的AMR单元或是具有相同磁多层薄膜结构的GMR自旋阀或GMR多层膜堆栈。磁多层薄膜结构通过半导体微加工工艺制成带状蛇形电路，磁电阻参考单元上覆盖一层钝化绝缘层。本发明有很好的温度补偿和高灵敏度，并具有尺寸小、功耗低、探测氢气浓度范围广等优点。
在上述实施例的基础上，本发明实施例还提供了一种利用如上述基于磁阻元件的氢气传感器检测氢气浓度的方法,其特征在于，包括：
将氢气传感器置于包含有氢气的气体环境中，所述磁电阻传感单元上覆盖的Pd层吸收氢气，改变所述磁电阻传感单元的磁多层薄膜结构中的铁磁层的垂直磁各向异性，使得铁磁层的磁矩发生旋转，产生与氢气浓度正相关的磁电阻阻值的变化；
根据磁电阻阻值的变化得到桥式结构的输出电压值的变化，根据桥式结构的输出电压值的变化检测氢气浓度。
以上所述仅是本发明的优选实施方式，基于本发明中的实施例，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其他实施例，都应当属于本发明保护的范围。应当指出，对于本技术领域的普通技术人员来说，在不脱离本发明原理的前提下，还可以做出若干改进和润饰，这些改进和润 饰也应视为本发明的保护范围。

Claims (9)

  1. 一种基于磁阻元件的氢气传感器，其特征在于，包括：
    位于X-Y平面上的衬底；
    位于衬底上的磁电阻传感单元和磁电阻参考单元，所述磁电阻传感单元电连接成传感臂，所述磁电阻参考单元电连接成参考臂，所述传感臂与所述参考臂电连接成参考桥式结构；其中，所述述磁电阻传感单元与所述磁电阻参考单元同为具有相同磁多层薄膜结构的AMR单元或具有相同磁多层薄膜结构的GMR单元；所述磁电阻传感单元与所述磁电阻参考单元的上分别覆盖Pd层，在覆盖在所述磁电阻参考单元的Pd层的上方再覆盖一层钝化绝缘层；
    所述磁多层薄膜结构通过半导体微加工工艺制成带状蛇形电路，所述带状蛇形电路的平行线段沿X方向，所述带状蛇形电路的拐角沿Y方向，并且相邻所述带状蛇形电路的平行线段之间形成有间隙，所述间隙的长轴沿X方向，所述间隙的短轴沿Y方向；所述半导体微加工工艺包括但不限于光刻蚀技术、离子刻蚀技术；
    其中，所述磁电阻传感单元上覆盖的Pd层吸收氢气后改变磁电阻传感单元中铁磁层的磁各向异性；所述钝化绝缘层隔离氢气避免磁电阻参考单元中铁磁层的磁各向异性的变化；根据参考桥式结构吸收氢气前后的输出电压值的变化检测氢气浓度。
  2. 根据权利要求1所述的基于磁阻元件的氢气传感器，其特征在于，所述AMR单元的磁多层薄膜结构自下而上包括：种子层、复合中间层；其中，所述复合中间层为[PMA界面层/铁磁层] n，n属于自然数。
  3. 根据权利要求1所述的基于磁阻元件的氢气传感器，其特征在于，
    所述GMR单元为GMR自旋阀结构时，所述磁多层薄膜结构自下而上包括：种子层、反铁磁层、PMA铁磁层、缓冲层、Cu间隔层、缓冲层、铁磁层、复合中间层、Pd层；或者自下而上包括：种子层、PMA界面层、PMA铁磁层、缓冲层、Cu间隔层、缓冲层、铁磁层、复合中间层；其中，所述复合中间层为[PMA界面层/铁磁层] m，m属于自然数；或
    所述GMR单元为具有层间反铁磁耦合的GMR多层膜堆栈时，所述磁多层薄膜结构自下而上包括：种子层、多膜中间层；其中，所述多膜中间层为[铁磁层/非磁性中间层/铁磁层] p，p属于自然数。
  4. 根据权利要求2或3所述的基于磁阻元件的氢气传感器，其特征在于，所述铁磁层的易轴垂直于X-Y平面，所述铁磁层的磁矩在X-Z平面内向相邻Pd层偏转的角度范围在10°至80°之间，所述铁磁层为磁致伸缩材料，包括但不限于铁、钴、镍单元素中的一种，或者钴铁、镍铁、钴铂、钴钯、钴铁硼、镍铁钴合金中的一种，所述种子层的材料包括但不限于钽、钨中的一种，所述PMA界面层的材料包括但不限于氧化镁、钯、铂中的一种。
  5. 根据权利要求1所述的基于磁阻元件的氢气传感器，其特征在于，在所述衬底下方设置块状永磁体，所述块状永磁体产生沿Z轴正方向的磁场；
    或者，在所述衬底与所述桥式结构之间有薄膜永磁体，所述薄膜永磁体产生沿Z轴正方向的磁场；
    或者，在所述带状蛇形电路上方或下方有长条状永磁体阵列，所述长条状永磁体阵列包括多个长条状永磁体，所述长条状永磁体介于所述带状蛇形电路的平行线段之间的间隙处，并产生沿Y轴正方向的磁场。
  6. 根据权利要求1所述的基于磁阻元件的氢气传感器，其特征在于，所述参考桥式结构包括半桥结构、全桥结构或准桥结构。
  7. 根据权利要求1所述的基于磁阻元件的氢气传感器，其特征在于，所述衬底的材料包括但不限于硅、氧化硅、康宁玻璃中的一种，所述钝化绝缘层的材料包括但不限于为光刻胶、氧化铝、氮化硅中的一种。
  8. 根据权利要求4所述的基于磁阻元件的氢气传感器，其特征在于，所述PMA铁磁层的材料包括但不限于钴、钴铁硼中的一种，所述缓冲层的材料包括但不限于钽、钌的一种，所述非磁性中间层的材料包括但不限于铜、钌、钯、铬、金、银中的一种。
  9. 一种利用如权利要求1至8任一项所述的基于磁阻元件的氢气传感器检测氢气浓度的方法,其特征在于，包括：
    将氢气传感器置于包含有氢气的气体环境中，所述磁电阻传感单元上覆盖的Pd层吸收氢气，改变所述磁电阻传感单元的磁多层薄膜结构中的铁磁层的垂直磁各向异性，使得铁磁层的磁矩发生旋转，产生与氢气浓度正相关的磁电阻阻值的变化；
    根据磁电阻阻值的变化得到桥式结构的输出电压值的变化，根据桥式结构的输出电压值的变化检测氢气浓度。
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CN110726763B (zh) * 2019-10-18 2021-11-16 南京大学 一种低功耗的氢气检测方法及其装置和制备方法
CN110646502A (zh) * 2019-10-30 2020-01-03 江苏多维科技有限公司 一种基于电隔离磁阻应力敏感元件的氢气传感器
CN111948342B (zh) * 2020-07-30 2021-07-20 南京力通达电气技术有限公司 一种钯合金氢气传感器

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20020017126A1 (en) * 1999-01-15 2002-02-14 Dimeo Frank Micro-machined thin film sensor arrays for the detection of H2, NH3, and sulfur containing gases, and method of making and using the same
CN102621504A (zh) * 2011-04-21 2012-08-01 江苏多维科技有限公司 单片参考全桥磁场传感器
CN103267955A (zh) * 2013-05-28 2013-08-28 江苏多维科技有限公司 单芯片桥式磁场传感器
CN104197828A (zh) * 2014-08-20 2014-12-10 江苏多维科技有限公司 一种单芯片偏轴磁电阻z-x角度传感器和测量仪
CN104900801A (zh) * 2015-04-23 2015-09-09 美新半导体（无锡）有限公司 一种反铁磁钉扎各向异性磁电阻(amr)传感器
CN108169185A (zh) 2017-12-20 2018-06-15 中国科学院微电子研究所 一种光学氢气传感器及其制备方法和应用系统
CN207586166U (zh) 2017-12-07 2018-07-06 辽宁农业职业技术学院 一种燃料电池汽车氢气检测传感器
CN109283228A (zh) * 2018-11-19 2019-01-29 江苏多维科技有限公司 一种基于磁阻元件的氢气传感器及其检测氢气的方法
CN209400462U (zh) * 2018-11-19 2019-09-17 江苏多维科技有限公司 一种基于磁阻元件的氢气传感器

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60194347A (ja) * 1984-03-15 1985-10-02 Nec Corp 水素ガスセンサ
US6265222B1 (en) * 1999-01-15 2001-07-24 Dimeo, Jr. Frank Micro-machined thin film hydrogen gas sensor, and method of making and using the same
WO2001027592A1 (en) * 1999-10-13 2001-04-19 Nve Corporation Magnetizable bead detector
US7370511B1 (en) * 2004-03-08 2008-05-13 Mst Technology Gmbh Gas sensor with attenuated drift characteristic
US7639005B2 (en) * 2007-06-15 2009-12-29 Advanced Microsensors, Inc. Giant magnetoresistive resistor and sensor apparatus and method
IN2014CN03583A (zh) * 2011-10-19 2015-09-25 Univ Minnesota
JPWO2015033464A1 (ja) * 2013-09-09 2017-03-02 株式会社日立製作所 磁気センサ素子
JP2017059591A (ja) * 2015-09-14 2017-03-23 株式会社東芝 磁気センサおよび磁気センサ装置
JP6702034B2 (ja) * 2016-07-04 2020-05-27 株式会社デンソー 磁気センサ
TWI632368B (zh) * 2017-05-12 2018-08-11 國立交通大學 氫氣感測元件

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20020017126A1 (en) * 1999-01-15 2002-02-14 Dimeo Frank Micro-machined thin film sensor arrays for the detection of H2, NH3, and sulfur containing gases, and method of making and using the same
CN102621504A (zh) * 2011-04-21 2012-08-01 江苏多维科技有限公司 单片参考全桥磁场传感器
CN103267955A (zh) * 2013-05-28 2013-08-28 江苏多维科技有限公司 单芯片桥式磁场传感器
CN104197828A (zh) * 2014-08-20 2014-12-10 江苏多维科技有限公司 一种单芯片偏轴磁电阻z-x角度传感器和测量仪
CN104900801A (zh) * 2015-04-23 2015-09-09 美新半导体（无锡）有限公司 一种反铁磁钉扎各向异性磁电阻(amr)传感器
CN207586166U (zh) 2017-12-07 2018-07-06 辽宁农业职业技术学院 一种燃料电池汽车氢气检测传感器
CN108169185A (zh) 2017-12-20 2018-06-15 中国科学院微电子研究所 一种光学氢气传感器及其制备方法和应用系统
CN109283228A (zh) * 2018-11-19 2019-01-29 江苏多维科技有限公司 一种基于磁阻元件的氢气传感器及其检测氢气的方法
CN209400462U (zh) * 2018-11-19 2019-09-17 江苏多维科技有限公司 一种基于磁阻元件的氢气传感器

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP3885759A4

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11408949B2 (en) 2018-11-19 2022-08-09 MultiDimension Technology Co., Ltd. Magnetoresistive hydrogen sensor and sensing method thereof

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