WO2015029514A1 - Détecteur de champ magnétique comprenant un élément à effet de magnétorésistance, et détecteur de courant - Google Patents

Détecteur de champ magnétique comprenant un élément à effet de magnétorésistance, et détecteur de courant Download PDF

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WO2015029514A1
WO2015029514A1 PCT/JP2014/063721 JP2014063721W WO2015029514A1 WO 2015029514 A1 WO2015029514 A1 WO 2015029514A1 JP 2014063721 W JP2014063721 W JP 2014063721W WO 2015029514 A1 WO2015029514 A1 WO 2015029514A1
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magnetic field
magnetoresistive effect
effect element
layer
magnetoresistive
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PCT/JP2014/063721
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English (en)
Japanese (ja)
Inventor
隆志 長永
陽亮 津嵜
泰助 古川
福本　宏
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三菱電機株式会社
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Priority to JP2015534027A priority Critical patent/JP6116694B2/ja
Publication of WO2015029514A1 publication Critical patent/WO2015029514A1/fr

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F10/00—Thin magnetic films, e.g. of one-domain structure
    • H01F10/32—Spin-exchange-coupled multilayers, e.g. nanostructured superlattices
    • H01F10/324—Exchange coupling of magnetic film pairs via a very thin non-magnetic spacer, e.g. by exchange with conduction electrons of the spacer
    • H01F10/3286—Spin-exchange coupled multilayers having at least one layer with perpendicular magnetic anisotropy
    • 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
    • G01R33/098—Magnetoresistive devices comprising tunnel junctions, e.g. tunnel magnetoresistance sensors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F10/00—Thin magnetic films, e.g. of one-domain structure
    • H01F10/32—Spin-exchange-coupled multilayers, e.g. nanostructured superlattices
    • H01F10/324—Exchange coupling of magnetic film pairs via a very thin non-magnetic spacer, e.g. by exchange with conduction electrons of the spacer
    • H01F10/3254—Exchange coupling of magnetic film pairs via a very thin non-magnetic spacer, e.g. by exchange with conduction electrons of the spacer the spacer being semiconducting or insulating, e.g. for spin tunnel junction [STJ]
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N50/00—Galvanomagnetic devices
    • H10N50/10—Magnetoresistive devices

Definitions

  • the present invention relates to a magnetoresistive effect element utilizing a tunnel magnetoresistive effect and a product to which the magnetoresistive effect element is applied, and in particular, a magnetic field detector provided with a magnetoresistive effect element having improved performance and ease of manufacture, And a current detector.
  • TMR tunneling magnetoresistance
  • the TMR element a three-layer film structure comprising a ferromagnetic layer / insulating layer / ferromagnetic layer is used as the simplest structure. Then, by injecting electrons with an external magnetic field or spin polarized, the spins of the two ferromagnetic layers are set parallel or antiparallel to each other, thereby increasing the tunnel current flowing through the insulating layer in the direction perpendicular to the film surface. The phenomenon that changes is used. By utilizing such a phenomenon, the TMR element can detect the relative magnetization direction of the two ferromagnetic layers by detecting the magnitude of the tunnel current.
  • an MgO (magnesium oxide) film is used as a tunnel insulating layer, and a Co—Fe—B (cobalt-iron-boron) alloy film is used as a ferromagnetic layer. It is known that a resistance change rate can be obtained. Furthermore, it is known that the magnetization of the Co—Fe—B film exhibits perpendicular magnetic anisotropy at the interface between the MgO film and the Co—Fe—B alloy film, and its application to memory is being promoted mainly. .
  • one ferromagnetic layer is exchange-coupled with an antiferromagnetic layer, and the magnetization of the ferromagnetic layer is fixed to be a fixed layer, and the magnetization of the other ferromagnetic layer is changed to an external magnetic field or spin.
  • a so-called spin-valve structure is used, which is a free layer that can be easily inverted by polarized electrons.
  • a TMR element having a spin valve structure can be used as a highly sensitive magnetic field detector.
  • the magnetization of the pinned layer is ideally completely fixed, so that only the magnetization of the free layer rotates according to the externally applied magnetic field. .
  • the relative angle of magnetization of the two ferromagnetic layers changes, and the element resistance changes due to the magnetoresistive effect.
  • This change in resistance value is detected as a change in voltage with a constant current flowing through the element, for example.
  • This voltage change is read as a signal that changes in accordance with the applied magnetic field.
  • a TMR element having a spin valve structure has a higher rate of resistance change than other magnetoresistive elements and a small magnetic interaction between the free layer and the pinned layer, so that highly sensitive magnetic field detection is possible.
  • the magnetization directions of the fixed layer and the free layer are determined in the absence of a magnetic field (when the external applied magnetic field is zero).
  • a configuration is known in which orthogonalization is performed in the film surface direction (see, for example, Patent Document 1).
  • the technique of Patent Document 1 detects the magnitude of a magnetic field applied in the magnetization direction of the pinned layer based on the magnetization direction of the free layer.
  • a technique for suppressing the occurrence of hysteresis in the ferromagnetic material constituting the free layer is shown.
  • the operating region is below a magnetic field that saturates in the axial direction where magnetization of the free layer is difficult, that is, a so-called anisotropic magnetic field.
  • a technique for orthogonalizing the magnetizations of the pinned layer and the free layer in the absence of a magnetic field is also disclosed.
  • a hard layer adjacent to the free layer is additionally provided.
  • a technique for providing a ferromagnetic layer is shown.
  • Patent Document 1 discloses a technique using a spin valve type GMR element in which a current flows in a direction in the film plane. Since the GMR element generally has a low resistance, in order to obtain a large output signal, it is necessary to increase a supply current amount, and there is a problem that power consumption increases accordingly. On the other hand, the TMR element can realize a high resistance and a high resistance change rate, and can realize a magnetic field detector with high output and low power consumption.
  • the magnetoresistive element having the configuration shown in Patent Document 1 is suitable for detecting a magnetic field along the magnetization direction of the pinned layer.
  • it is particularly suitable for measurement in which the magnetic field direction is fixed such as a current detector in which the positions of the wiring and the magnetoresistive effect element are fixed.
  • the prior art has the following problems.
  • the magnetic anisotropy of the free layer occurs, and there is a case where a domain wall exists in the free layer or a stable state occurs during magnetization rotation. As a result, there is a problem that hysteresis occurs.
  • the Co—Fe—B at the interface between the MgO film that is the tunnel insulating film of the TMR element and the Co—Fe—B alloy film that is the free layer is the characteristic that the magnetization of the film is oriented in the direction perpendicular to the film surface.
  • this means when this means is used, the contribution of perpendicular magnetic anisotropy at the interface changes depending on the thickness of the free layer. Therefore, there is a problem that the characteristics are sensitive to the thickness of the free layer.
  • the present invention has been made in view of the above-described problems, and includes a magnetoresistive effect element that achieves both high accuracy and high sensitivity characteristics that suppress hysteresis and realization of manufacturing process and ease of integration.
  • An object of the present invention is to obtain a magnetic field detector and a current detector.
  • a magnetic field detector including a magnetoresistive effect element includes a magnetoresistive effect element and at least two wires for detecting the resistance of the magnetoresistive effect element.
  • a magnetic field detector including a magnetoresistive effect element for detecting a magnetic field wherein the magnetoresistive effect element includes a cap layer containing an oxide containing Mg and a ferromagnetic layer mainly composed of Fe in contact with the cap layer
  • the magnetoresistive effect element includes a cap layer containing an oxide containing Mg and a ferromagnetic layer mainly composed of Fe in contact with the cap layer
  • a laminated structure including a free layer made of Mg, a tunnel insulating layer made of Mg-containing oxide, and a fixed layer made of a ferromagnetic layer magnetized in the film surface direction facing the free layer via the tunnel insulating layer
  • the free layer has a magnetization in the in-film direction and a magnetization in a direction perpendicular to the film surface, and the magnetization of the free layer
  • the current detector according to the present invention includes a magnetic field detector including the magnetoresistive effect element of the present invention, and a magnetic field measured by a magnetic field detector including the magnetoresistive effect element with respect to an object to be measured with a magnetic field. And an arithmetic unit for measuring the current flowing through the measured object from the relational expression between the distance between the magnetoresistive element and the measured object and the current flowing through the measured object.
  • hysteresis is suppressed by employing a magnetoresistive effect element including a free layer composed of a ferromagnetic layer formed so as to have a perpendicular magnetization component at the upper and lower interfaces together with an in-plane magnetization component.
  • a magnetoresistive effect element including a free layer composed of a ferromagnetic layer formed so as to have a perpendicular magnetization component at the upper and lower interfaces together with an in-plane magnetization component.
  • Embodiment 1 of this invention It is a schematic block diagram of the magnetic field detector in Embodiment 1 of this invention. It is a figure for demonstrating the magnetization direction of the magnetoresistive effect element used with the magnetic field detector in Embodiment 1 of this invention. It is the schematic which shows the cross-sectional structure along the transversal direction of the magnetoresistive effect element used with the magnetic field detector in Embodiment 1 of this invention. It is a figure for demonstrating the magnetization direction of the free layer of the magnetoresistive effect element in Embodiment 1 of this invention. It is an equivalent circuit schematic of the magnetic field detector in Embodiment 1 of this invention. It is the schematic which shows the laminated structure in the material of the magnetoresistive effect element in Embodiment 1 of this invention.
  • Embodiment 1 of this invention It is a figure for demonstrating the magnetization direction of the magnetoresistive effect element in Embodiment 1 of this invention. It is a figure which shows the laminated structure of the conventional magnetoresistive effect element. It is a figure for demonstrating the magnetization direction of the free layer of the conventional magnetoresistive effect element. It is the comparison figure which showed the thickness dependence of the free layer in the width
  • connection modification 4 of the magnetoresistive effect element in Embodiment 3 of this invention It is the schematic which shows the connection modification 5 of the magnetoresistive effect element in Embodiment 4 of this invention. It is a figure for demonstrating the shape dependence of the magnetic characteristic of the magnetoresistive effect element in Embodiment 5 of this invention. It is the schematic which shows the current detector in Embodiment 6 of this invention. It is the schematic which shows the connection of the magnetoresistive effect element of the current detector in Embodiment 6 of this invention. It is a schematic sectional drawing which shows a part of semiconductor integrated circuit which has a current detector in Embodiment 7 of this invention.
  • FIG. 1 is a schematic configuration diagram of a magnetic field detector according to Embodiment 1 of the present invention.
  • FIG. 2 is a figure for demonstrating the magnetization direction of the magnetoresistive effect element used with the magnetic field detector in Embodiment 1 of this invention.
  • FIG. 2A is a top view of the magnetoresistive effect element 1 shown in FIG. 1
  • FIGS. 2B and 2C are double arrows (b) shown in FIG. It is sectional drawing seen from the direction of (c).
  • FIG. 3 is a schematic diagram showing a cross-sectional structure along the short direction of the magnetoresistive effect element used in the magnetic field detector according to Embodiment 1 of the present invention.
  • the magnetic field detector 100 includes a magnetoresistive effect element 1 that uses the TMR effect and a direct current that supplies a constant current of a predetermined magnitude to the magnetoresistive effect element 1.
  • the power source 2 includes a voltmeter 3 that detects a voltage between the lower electrode layer 6 and the upper electrode layer 7 of the magnetoresistive effect element 1 (see FIG. 3).
  • the magnetoresistive effect element 1 has an upper electrode layer 7 connected to the DC power supply 2 and the voltmeter 3 by wiring 4, and a lower electrode layer 6 connected to the DC power supply 2 and the ground node of the voltmeter 3 by wiring 5. ing.
  • the mechanism for applying an external magnetic field see magnetic field Hex in FIG. 3 is not shown, but for example, the magnetic field Hex is applied by passing a current through the wiring. Can do.
  • the magnetic field detector 100 detects a magnetic field by causing a current to flow in the stacking direction of the ferromagnetic layer (free layer) 8, the tunnel insulating layer 9, and the pinned layer 10 as the free layer of the magnetoresistive effect element 1. It is configured.
  • the cap layer 12 is in contact with the free layer 8. Further, the free layer 8 and the ferromagnetic layer 10a are opposed to each other through the tunnel insulating layer 9, and the ferromagnetic layer 10a and the ferromagnetic layer 10b are opposed to each other through the nonmagnetic layer 10c. Further, the ferromagnetic layer 10b is in contact with the antiferromagnetic layer 10d.
  • the magnetoresistive effect element 1 has a top view as shown in FIG. 2 (a).
  • the magnetoresistive effect element 1 is formed in a substantially rectangular plane, and has a longitudinal direction and a lateral direction (a direction intersecting the longitudinal direction).
  • a magnetic field is applied in the short direction during the formation of the pinned layer 10 and during heat treatment.
  • the ferromagnetic layers 10a and 10b of the pinned layer 10 have short-side magnetizations 101a and 101b in the film surface (layer surface) when the magnetic field Hex from the outside is zero and the magnetic field Hex is zero (FIG. 3). See).
  • the magnetization directions 101a and 101b are opposite to each other (180 °). is there. This cancels each other's magnetizations, suppresses the influence on the free layer, and plays the role of stabilizing the magnetization fixation without being influenced by the external magnetic field Hex.
  • the magnetization direction 81 of the free layer (ferromagnetic layer) 8 when the magnetization direction 81 of the free layer (ferromagnetic layer) 8 is viewed on the projection surface from the upper surface of the element due to the perpendicular direction of the film surface and the influence of the demagnetizing field due to the element shape, the element 1 Is magnetized in the longitudinal direction.
  • the free layer 8 which is a ferromagnetic layer in the present invention has a component of magnetization in the vertical direction as well as magnetization in the in-plane direction of the film. That is, the magnetization direction 81 has an inclination from the film surface direction of the free layer 8 (see FIG. 2B).
  • FIG. 4 is a diagram for explaining the magnetization direction of the free layer 8 of the magnetoresistive effect element 1 according to the first embodiment of the present invention.
  • the double arrow of the magnetoresistive effect element 1 shown in FIG. It corresponds to a cross-sectional view seen from the direction (b).
  • FIG. 2 the case where the entire magnetization direction 81 is inclined has been described for the sake of simplicity.
  • FIG. 4 actually, in the free layer (ferromagnetic layer) 8.
  • the magnetization shows a local distribution and has a local magnetization gradient.
  • the magnetization component in the in-plane direction is relatively relative to the portion where the influence of the interface is small. It is getting bigger.
  • the magnetization 81 and the magnetization 101a of the free layer (ferromagnetic layer) 8 and the ferromagnetic layer 10a facing each other across the tunnel insulating layer 9 are When viewed from the projection surface from one upper surface, they are orthogonal to each other.
  • the magnetization direction 81 of the free layer (ferromagnetic layer) 8 and the magnetization direction 101a of the ferromagnetic layer 10a are orthogonal to each other means that the relative angle of the magnetization direction is shifted from 90 ° within a range of ⁇ 10 ° due to manufacturing error. Including the case.
  • the magnetization 81 of the free layer (ferromagnetic layer) indicates the direction in the absence of a magnetic field.
  • FIG. 5 is an equivalent circuit diagram of the magnetic field detector according to Embodiment 1 of the present invention.
  • the magnetoresistive effect element 1 since the resistance value of the magnetoresistive effect element 1 is changed by an external magnetic field, the magnetoresistive effect element 1 is indicated by a symbol of a variable resistance element.
  • a voltmeter 3 is connected in parallel with the magnetoresistive effect element 1, and a DC power supply 2 is connected in series with the magnetoresistive effect element 1.
  • the DC power supply 2 is connected between the ground node and the magnetoresistive effect element 1 (high potential side thereof), but the DC power supply 2 is connected between the power supply node and the ground node. Any device that is connected and supplies a constant current to the magnetoresistive element 1 may be used.
  • the magnetoresistive effect element 1 includes a lower electrode layer 6, an upper electrode layer 7, a free layer (ferromagnetic layer) 8, a tunnel insulating layer 9, The fixing layer 10 is provided.
  • a lower electrode layer 6 is formed on the substrate 11. Further, an antiferromagnetic film 10d is formed on the lower electrode layer 6, and a ferromagnetic layer 10b is formed at a position in contact with the antiferromagnetic film 10d.
  • FIG. 3 shows an example in which the magnetization 81 of the free layer (ferromagnetic layer) 8 is applied with a magnetic field in a direction along the magnetization 101 a of the ferromagnetic layer 10 a in the fixed layer 10.
  • FIG. 6 is a schematic diagram showing a laminated structure related to the material of the magnetoresistive effect element according to Embodiment 1 of the present invention.
  • the free layer (ferromagnetic layer) 8 is made of a Co—Fe—B (cobalt-iron-boron) alloy film.
  • the tunnel insulating layer 9 is an MgO film
  • the Co—Fe—B alloy film has a perpendicular magnetic anisotropy in the vicinity of the interface (negative if the anisotropy energy in the film surface is defined as positive). Show.
  • the free layer 8 is not limited to a Co—Fe—B alloy film, and may be any ferromagnetic film containing Fe (iron) as a main component. An effect can be obtained.
  • the thickness of the free layer 8 made of a Co—Fe—B alloy film is 1.1 nm.
  • the thickness of the free layer 8 is not limited to this, and can be changed according to the magnetic field response of the element. Further, the Co—Fe—B alloy film contains inevitable impurities.
  • the tunnel insulating layer 9 is made of an MgO (magnesium oxide) film. Note that the tunnel insulating layer 9 is not limited to this, as long as it contains Mg (magnesium) and oxygen, and may be MgAl 2 O 4 (spinel) or the like.
  • the thickness of the tunnel insulating (film) layer 9 made of MgO film is 1.7 nm.
  • the thickness of the tunnel insulating layer 9 is not limited to this and needs to be thicker than the cap layer 12 described later, but can be changed according to the resistance of the element and the magnetic field response. Further, the MgO film contains inevitable impurities.
  • the ferromagnetic layer 10a is made of a Co—Fe—B alloy film.
  • the ferromagnetic layer 10a is not limited to a Co—Fe—B alloy film, and includes at least one of Co (cobalt) such as Fe (iron) and Co (cobalt), Ni (nickel), and Fe (iron). Any ferromagnetic film may be used as long as it is a main component, and the same effect can be obtained even with a ferromagnetic film in which these films are laminated.
  • the thickness of the ferromagnetic layer 10a made of the Co—Fe—B alloy film is 1.5 nm.
  • the thickness of the ferromagnetic layer 10a is not limited to this, and can be changed according to the magnetic field response of the element. Further, the Co—Fe—B alloy film contains inevitable impurities.
  • the nonmagnetic layer 10c is made of a Ru (ruthenium) film.
  • the nonmagnetic layer 10c is not limited to a Ru film, and may be any nonmagnetic film of a transition metal mainly composed of a platinum group such as Rt and Rb, and the same effect can be obtained.
  • the thickness of the nonmagnetic layer 10c made of a Ru film is 0.8 nm.
  • the thickness of the nonmagnetic layer 10c is not limited to this, and can be changed according to the magnetic field response of the element.
  • the Ru film contains inevitable impurities.
  • the ferromagnetic layer 10b is made of a Co—Fe alloy film.
  • the ferromagnetic layer 10b is not limited to a Co—Fe alloy film, and the main component is at least one of Co (cobalt) such as Fe (iron) and Co (cobalt), Ni (nickel), and Fe (iron). The same effect can be obtained even with a ferromagnetic film in which these films are laminated.
  • the thickness of the ferromagnetic layer 10b made of a Co—Fe alloy film is 1.5 nm.
  • the thickness of the ferromagnetic layer 10b is not limited to this, and can be changed according to the resistance of the element and the magnetic field response.
  • the Co—Fe alloy film contains inevitable impurities.
  • the antiferromagnetic layer 10d is made of an Ir—Mn (iridium-manganese) alloy film.
  • the antiferromagnetic layer 10d is not limited to an Ir—Mn alloy film, and may be a Pt—Mn (platinum-manganese) alloy, an Fe—Mn (iron-manganese) alloy, a Ni—Mn (nickel-manganese) alloy, or the like. Any antiferromagnetic film may be used, and similar effects can be obtained.
  • the thickness of the antiferromagnetic layer 10d made of an Ir—Mn film is 20 nm.
  • the thickness of the antiferromagnetic layer 10d is not limited to this, and can be changed according to the resistance of the element and the magnetic field response.
  • the Ir—Mn alloy film contains inevitable impurities.
  • the lower electrode layer 6 and the upper electrode layer 7 are each made of a Ta (tantalum) film. Each of the lower electrode layer 6 and the upper electrode layer 7 may be another metal such as a Ru film, for example, but is not limited thereto.
  • the lower electrode layer 6 is connected to the wiring 5 shown in FIG. 1, and the upper electrode layer 7 is connected to the wiring 4 shown in FIG. Cu (copper) is used for each of the wirings 4 and 5.
  • the wirings 4 and 5 may be other metals such as Al (aluminum), for example, but are not limited thereto.
  • the cap layer 12 is disposed so as to have an interface with the free layer 8 and is made of an MgO (magnesium oxide) film. Note that the cap layer 12 is not limited to this, as long as it contains Mg (magnesium) and oxygen, and may be MgAl 2 O 4 (spinel) or the like.
  • the thickness of the cap layer 12 made of MgO film is 1.0 nm.
  • the resistance depending on the thickness of the MgO film generally changes by an order of magnitude at 0.3 nm.
  • the thickness of the cap layer 12 made of the MgO film is 0.7 nm thinner than the MgO film of the tunnel insulating layer 9, the resistance caused by the MgO film of the cap layer 12 is caused by the tunnel insulating layer 9. It is two orders of magnitude smaller than the resistance, and the influence on the detected resistance change rate is sufficiently small.
  • the MgO film is thinner than 0.8 nm, the film may be discontinuous or sufficient crystallinity may not be obtained, but the MgO film of the cap layer 12 here is thicker than this and sufficient An effect is obtained.
  • the thickness of the cap layer 12 is not limited to this, and it is necessary to be thinner than the tunnel insulating layer 9, but it can be changed according to the resistance of the element and the magnetic field response. Further, the MgO film contains inevitable impurities.
  • the magnetization 81 of the ferromagnetic layer 8 serving as the free layer also has a component in the direction perpendicular to the film surface.
  • the magnetization of the pinned layer 10 is in the in-plane direction of the film, but may include a vertical component.
  • Each metal film (see FIG. 3) constituting the magnetoresistive element 1 is formed on the substrate 11 by DC (direct current) magnetron sputtering.
  • the substrate 11 is made of Si (silicon), SiC (silicon carbide), GaN (gallium nitride), GaAs (gallium arsenide), glass, or the like.
  • the substrate 11 is not limited to this, and may be made of other materials, and an electronic circuit such as a wiring, a transistor, or a diode may be formed under the magnetoresistive effect element 1.
  • a Ta film is formed as the lower electrode layer 6 using DC magnetron sputtering. After the Ta film as the lower electrode layer 6 is formed, an Ir—Mn alloy film having a thickness of 20 nm is formed as the antiferromagnetic layer 10d in the same apparatus without being exposed to the atmosphere. Subsequently, a Co—Fe alloy film having a film thickness of 1.5 nm as the ferromagnetic layer 10b, a Ru film having a film thickness of 0.8 nm as the nonmagnetic layer 10c, and a film thickness 1 as the ferromagnetic layer 10a without being exposed to the atmosphere. A Co—Fe—B alloy film of .5 nm is sequentially formed.
  • the MgO film having a thickness of 1.7 nm is formed as the tunnel insulating layer 9 using RF (radio frequency) magnetron sputtering without being exposed to the atmosphere
  • the free layer (ferromagnetic film) 8 is formed using DC magnetron sputtering.
  • a Co—Fe—B alloy film having a thickness of 1.1 nm is formed.
  • an MgO film of the cap layer 12 having a thickness of 1.0 nm is formed, and a Ta film is formed as the upper electrode layer 7.
  • the films from the lower electrode layer 6 to the upper electrode layer 7 constituting the magnetoresistive effect element 1 are all formed in the same device.
  • the MgO film that is the tunnel insulating layer 9 and the cap layer 12 may be formed by forming an Mg (magnesium) film by DC magnetron sputtering and then exposing it to an oxidizing atmosphere containing oxygen.
  • heat treatment is performed.
  • the purpose is to promote crystallization of the MgO film and the two Co—Fe—B films sandwiching it, and to impart magnetic anisotropy to the pinned layer 10.
  • 15 kOe which is a magnetic field for saturating the magnetization of the Co—Fe—B film and the Co—Fe film of the pinned layer 10 is applied.
  • the direction in which the magnetic field is applied is the same as when the magnetoresistive effect element 1 is formed, and is the short direction of the magnetoresistive effect element 1 described later.
  • the heat treatment temperature of the magnetoresistive element 1 is such that the Co—Fe—B film can be crystallized, and exchange coupling between the Ir—Mn film and the Co—Fe film of the pinned layer is substantially eliminated. °C. This temperature was maintained for 1 hour.
  • the magnetizations of the ferromagnetic films 10a and 10b of the pinned layer 10 are respectively directed to 180 °. That is, the magnetization 101b of the Co—Fe alloy film and the magnetization 101a of the Co—Fe—B alloy film facing each other across the Ru film that is the nonmagnetic layer 10c are in opposite directions.
  • the magnetization 81 of the ferromagnetic layer (free layer) 8 includes the magnetic anisotropy in the vertical direction of the film depending on the crystal structure of the material. small.
  • a desired pattern is formed by photolithography.
  • a desired pattern is formed by a photoresist.
  • the shape of the magnetoresistive effect element 1 is obtained by electrically and magnetically separating the magnetoresistive effect element 1 by reactive ion etching using a desired pattern formed of a photoresist as a mask.
  • the magnetoresistive effect element 1 is rectangular as described above, and is formed in, for example, a rectangular shape having a short side ⁇ long side of 200 nm ⁇ 600 nm.
  • the longitudinal direction of the magnetoresistive effect element 1 is a direction orthogonal to the magnetic field application direction when forming the pinned layer 10 in the laminated film.
  • the magnetization 81 of the Co—Fe—B film which is the ferromagnetic layer 8 serving as the free layer, is affected by the demagnetizing field depending on the shape, and the magnetization 81 has a longitudinal component of the shape. It becomes. That is, the magnetization 81 of the ferromagnetic layer 8 has a vertical component of the film surface due to magnetic anisotropy depending on the crystal structure and a longitudinal component of the shape due to shape magnetic anisotropy.
  • the magnetoresistive effect element 1, the DC power source 2, and the voltmeter 3 are connected to each other by connecting the wirings 4 and 5 to the lower electrode layer 6 and the upper electrode layer 7, respectively. Connected. Although a detailed description of the connection method is omitted here, the magnetic field detector 100 using the magnetoresistive effect element 1 of the first embodiment is formed by performing such connection.
  • the magnetic field detection operation of the magnetic field detector according to the first embodiment will be described.
  • a constant current I is supplied from the DC power source 2 to the magnetoresistive effect element 1 through the wires 4 and 5.
  • the resistance value of the magnetoresistive effect element 1 changes according to the application direction of the magnetic field Hex from the outside.
  • the external magnetic field Hex is detected by detecting the resistance change of the magnetoresistive effect element 1
  • a constant voltage is applied to the magnetoresistive effect element 1 by the direct current (voltage) power source 2.
  • the current value at that time can also be detected by detecting with an ammeter.
  • the magnetic detector has a calculation unit (not shown) that converts the voltage value detected by the voltmeter 3 or the current value detected by the ammeter into a magnetic field intensity based on a preset conversion equation. It may be provided.
  • FIG. 7 is a diagram for explaining the magnetization direction of the magnetoresistive effect element according to the first embodiment of the present invention. More specifically, FIG. 7A is a top view of the magnetoresistive effect element 1 of FIG. 1, and FIGS. 7B and 7C are double arrows (b) of FIG. It is sectional drawing seen from the direction of (c).
  • the element resistance R is approximately expressed by the following equation: It is represented by (1).
  • R R0 ⁇ R / 2 ⁇ cos ( ⁇ 2 ⁇ 1) (1)
  • R0 is the center value of the element resistance
  • ⁇ R is the resistance change amount of the element.
  • the direction of magnetization of the ferromagnetic layer 8 of the free layer of the TMR element changes depending on the magnitude and direction of the external magnetic field.
  • ⁇ 1- ⁇ 2 changes depending on the external magnetic field. Therefore, the magnetic field is detected by measuring the element resistance R.
  • magnetization of ferromagnetic layer (free layer) 8 is performed by applying a magnetic field Hex from the outside in the direction of the arrow in FIG. 81 rotates in the direction of the external magnetic field Hex. That is, the magnetization 81 of the ferromagnetic layer 8 rotates in the direction of the magnetic field Hex and changes to the magnetization 82. Therefore, the relative magnetization directions of the ferromagnetic layer 8 and the ferromagnetic layer 10a change. Therefore, the tunnel probability of electrons through the tunnel insulating layer 9 shown in FIG. 3 also changes. Thereby, a change in the element resistance R depending on the external magnetic field Hex is obtained.
  • the magnetization of the free layer 8 has a perpendicular magnetic anisotropy at the interface between the free layer 8 and the tunnel insulating layer 9. As a result, it is possible to suppress the occurrence of the hysteresis described above with a single element, and high accuracy can be achieved.
  • FIG. 8 is a diagram showing a laminated structure of a conventional magnetoresistive effect element.
  • the laminated structure of the conventional magnetoresistive element shown in FIG. 8 unlike the laminated structure of the magnetoresistive element 1 of the present invention shown in FIG. 6, there is no MgO film as the cap layer 12, and the upper electrode layer 7 is It also serves as the cap layer 12.
  • FIG. 9 is a diagram for explaining the magnetization direction of the free layer 8 of the conventional magnetoresistive effect element, and shows the same cross section as FIG. 4 showing the magnetization direction in the first embodiment.
  • the interface that the free layer 8 has with the MgO film is only the interface with the tunnel insulating layer 9. For this reason, the perpendicular magnetic anisotropy at the interface of the free layer 8 is expressed only at one interface.
  • FIG. 10 is a comparison diagram showing the dependence of the hysteresis width and resistance change rate of the magnetoresistive effect element 1 according to Embodiment 1 of the present invention and the conventional magnetoresistive effect element on the thickness of the free layer. is there.
  • the hysteresis width is indicated by ⁇
  • the resistance change rate is indicated by ⁇ .
  • the width of the hysteresis depending on the thickness of the free layer 8 is approximately 0 at 1.4 nm or less in the conventional element, whereas the element of the first embodiment Then, it can be seen that it becomes almost 0 at 1.2 nm or less. Further, the resistance change rate also changes with the same tendency as the hysteresis width.
  • the width of the hysteresis increases rapidly at 1.4 nm or more. Therefore, in order to operate with the hysteresis suppressed, the free layer has a thickness of 1.4 nm or less. There is a need. However, the rate of change in resistance decreases sharply below 1.4 nm. Here, the sensitivity in magnetic field detection depends on the resistance change rate.
  • the sensitivity of the magnetic field detection greatly depends on the thickness of the free layer.
  • the rate of change in resistance when the thickness of the free layer 8 is 1.4 nm is 100%, the rate of change in resistance is reduced by 10% due to a change in thickness of 0.015 nm (1% with respect to the thickness).
  • the sensitivity of the magnetoresistive effect element greatly changes.
  • the thickness of the free layer 8 is 1.4 nm, in order to keep the variation in resistance change within 10%, the range within 1% with respect to the thickness set by the free layer 8 It is necessary to control with. This control is substantially difficult.
  • the hysteresis width is almost 0 at 1.2 nm or less, but the resistance change rate is abrupt and discontinuous even in a free layer thinner than that. There is no significant change. That is, it can be seen that the sensitivity is stable with respect to the thickness of the free layer as compared with the conventional device. In order to keep the variation of the resistance change rate within 10%, an error with respect to the thickness set by the free layer 8 is allowed up to 3%.
  • the free layer 8 of the magnetoresistive effect element 1 of the present invention has perpendicular magnetic anisotropy at the interface with the tunnel insulating layer 9 and is also perpendicular at the interface opposite to the tunnel insulating layer 9. This is because the perpendicular magnetic anisotropy component is more stable than the conventional structure shown in FIG. 8 due to the magnetic anisotropy.
  • the ferromagnetic layer serving as the free layer has a magnetization component in the vertical direction, and from the upper surface of the element due to the influence of the demagnetizing field depending on the shape of the free layer.
  • the magnet When viewed on the projection plane, the magnet is magnetized in the longitudinal direction of the element.
  • the free layer magnetized in the normal film plane, in order to relax the magnetization at the end portion in the longitudinal direction, the local magnetization is arranged in the plane of the free layer, which causes a hysteresis.
  • the free layer in the present invention is easily magnetized in the vertical direction, and the magnetization at the end in the longitudinal direction can be relaxed.
  • an external magnetic field when applied, it is possible to suppress the occurrence of hysteresis especially when the magnetization rotates in a low magnetic field. That is, it is possible to alleviate the change in characteristics depending on the thickness of the free layer at that time, and to realize a magnetic field detector capable of high accuracy and high integration without increasing the number of additional structures. it can.
  • the free layer in the present invention has a magnetization component in the vertical direction at the upper and lower interfaces as well as an in-plane magnetization component, thereby realizing a magnetic field response with high sensitivity and suppressed hysteresis.
  • the cap layer is also an MgO film, so that it is possible to suppress rapid fluctuations in characteristics depending on the thickness of the free layer. As a result, the controllability of the magnetic field responsiveness is improved, and it is possible to suppress fluctuations in characteristics due to the manufacturing process.
  • the thickness of the oxide containing Mg constituting the cap layer is thinner than the thickness of the tunnel insulating layer made of the oxide containing Mg. As a result, it is possible to suppress an increase in resistance and a decrease in the resistance change rate due to the addition of the MgO film (addition of series resistance to the element).
  • FIG. 11 to 14 are schematic views showing modified examples 1 to 4 of the laminated structure of the magnetoresistive effect element according to the second embodiment of the present invention.
  • the magnetoresistive effect element 1 of FIG. 11 corresponding to the laminated structure modification 1 is configured by a laminated structure in which the free layer 8 includes two ferromagnetic layers 8a and 8b.
  • the ferromagnetic film 8a is a Co—Fe—B alloy film
  • the ferromagnetic film 8b is an Fe—B alloy.
  • the free layer 8 is not limited to two layers, and can be a ferromagnetic film having two or more layers having different compositions.
  • the Co—Fe—B alloy applied as the free layer 8 in the structure of FIG. 6 in the first embodiment is known as a material capable of obtaining a large resistance change rate in the TMR element. From this, also in the magnetoresistive effect element of FIG. 11, the resistance change rate similar to FIG. 6 is obtained.
  • the structure shown in FIG. 11 further includes a Fe—B film on the Co—Fe—B alloy film. It is considered that the perpendicular magnetic anisotropy at the interface between the Co—Fe—B alloy film and the MgO film is obtained by the interaction of Fe (iron) and O (oxygen).
  • the Fe—B film has a higher Fe content than the Co—Fe—B alloy film, and a stronger vertical axis than the Co—Fe—B film at the interface between the Fe—B film 8 b and the MgO film 12 of the cap layer. Anisotropy is obtained.
  • the resistance change rate equivalent to the structure described in FIG. 6 and more stable perpendicular magnetic anisotropy can be obtained by the structure of FIG.
  • the Fe—B film is shown here as the ferromagnetic film 8b, the same effect can be obtained if the Fe content is larger than the Co—Fe—B alloy film of the ferromagnetic film 8a. It is not limited to the B film.
  • the free layer is composed of two or more ferromagnetic films having different compositions, and the Fe content of the ferromagnetic film in contact with the tunnel insulating layer is the same as that of the ferromagnetic film in contact with the cap layer.
  • the structure is smaller than the Fe content.
  • the magnetoresistive effect element 1 shown in FIG. 12 corresponding to the laminated structure modification 2 has a ferromagnetic film 13 made of a Co—Fe—B alloy film on the cap layer 12. Is further provided. The free layer 8 and the ferromagnetic film 13 are opposed to each other with the MgO film of the cap layer 12 interposed therebetween. In this structure, perpendicular magnetic anisotropy is also obtained at the interface between the ferromagnetic film 13 and the cap layer 12.
  • the ferromagnetic film 13 Since the ferromagnetic film 13 is magnetostatically coupled through the free layer 8 and the cap layer 12, it acts to stabilize the perpendicular magnetic anisotropy at the interface between the free layer 8 and the cap layer 12. That is, by having the ferromagnetic film 13, the perpendicular magnetic anisotropy component in the free layer 8 can be stabilized.
  • FIG. 13 corresponding to the variation 3 of the laminated structure shows the magnetoresistive effect element 1 in which the ferromagnetic film 13 shown in FIG. 12 is a Co—Pt laminated film.
  • the Co—Pt laminated film has a structure in which a Co film and a Pt film are repeatedly laminated, and exhibits perpendicular magnetic anisotropy at other than the interface with the MgO film.
  • the ferromagnetic film 13 is magnetostatically coupled via the free layer 8 and the cap layer 12 as described in FIG. As a result, it acts to stabilize the perpendicular magnetic anisotropy at the interface between the free layer 8 and the cap layer 12. That is, the perpendicular magnetic anisotropy component in the free layer 8 can also be stabilized by having the ferromagnetic film 13 of the Co—Pt laminated film.
  • the ferromagnetic layer 13 is formed of a ferromagnetic film mainly composed of at least one of a lanthanoid element such as Co (cobalt), Fe (iron), Ni (nickel), and Tb (terbium), or Pt (platinum). ) And Pd (palladium), or a ferromagnetic film having an interface therewith, and a material having magnetic anisotropy in the direction perpendicular to the film surface.
  • a lanthanoid element such as Co (cobalt), Fe (iron), Ni (nickel), and Tb (terbium), or Pt (platinum).
  • Pd palladium
  • a ferromagnetic film having an interface therewith and a material having magnetic anisotropy in the direction perpendicular to the film surface.
  • FIG. 14 corresponding to the laminated structure modification 4 is the structure shown in FIG. 13, in which a Ta film 12b is applied to the cap layer under the ferromagnetic film 13, and as a result, two cap layers 12a and 12b are formed. I have. In this way, by inserting the film 12b of another material on the MgO film 12a of the cap film, it is possible to arbitrarily select a base for growing the ferromagnetic film 13.
  • the cap layer 12 is further provided with the ferromagnetic film 13 that is in contact with the free layer 8 on the opposite side and has a component magnetized in the vertical direction.
  • the ferromagnetic film 13 is magnetostatically coupled to the cap layer 12 from the side opposite to the tunnel insulating layer 9, thereby assisting the free layer 8 to be magnetized in the vertical direction.
  • the magnetization in the vertical direction of the free layer 8 is stabilized.
  • the second embodiment by using a modified example of the laminated structure in the first embodiment, it is possible to stabilize the perpendicular magnetic anisotropy component or to provide a base for growing a ferromagnetic film.
  • the degree of freedom of selection can be expanded.
  • Embodiment 3 FIG. In the third embodiment, a specific example in which a plurality of magnetoresistance effect elements 1 are connected in series or in parallel using wirings 4 and 5 will be described.
  • 15 to 18 are schematic diagrams showing connection modification examples 1 to 4 of the magnetoresistive effect element according to the third embodiment of the present invention.
  • the operating principle is the same as described above.
  • the output signal is averaged by a plurality of elements. It is possible to average characteristic variations such as magnetic field responsiveness.
  • the number of magnetoresistive effect elements 1 to be connected can be adjusted by averaging resistance and variation. However, in the case of series connection, the voltage dependency symmetry of each element resistance, and a read current described later. In consideration of the symmetry of magnetic field generation due to, it is preferable that the number is even.
  • FIG. 15 corresponding to the connection modification example 1, the arrangement along the longitudinal direction of the magnetoresistive effect element 1 (in the direction in which the longitudinal ends of the magnetoresistive effect elements 1 adjacent to each other are adjacent to each other).
  • the plurality of magnetoresistive elements 1 are connected in series. In this case, it becomes easy to detect a local magnetic field generated along a straight line such as a current detector and wiring described later.
  • FIG. 16 corresponding to the connection modification example 2 is arranged along the short direction of the magnetoresistive effect element 1 (the end portions in the short direction of the magnetoresistive effect elements adjacent to each other by the plurality of magnetoresistive effect elements 1).
  • a plurality of magnetoresistive effect elements 1 are connected in series in such a manner that they are arranged so as to face each other.
  • a magnetic field in the longitudinal direction of the magnetoresistive effect element 1 having a direction different from that of the magnetic field to be detected is applied. As a result, it is possible to suppress detection errors caused by the read current.
  • the wiring 4 is located at the upper part of the magnetoresistive effect element 1, and the wiring 5 is located at the lower part. For this reason, the magnetic fields generated by the current at the position of the magnetoresistive effect element 1 are opposite to each other. As a result, it is possible to suppress a detection error caused by the read current.
  • connection of FIG. 17 corresponding to the connection modification 3 and the connection of FIG. 18 corresponding to the connection modification 4 are connected in parallel with each other along the longitudinal direction and the short direction of the magnetoresistive effect element 1.
  • the effect in this case is the same as the arrangement in series connection.
  • the resistance when connected in parallel, the resistance can be reduced in inverse proportion to the number of magnetoresistive effect elements 1, and the resistance can be adjusted according to the application and the peripheral circuit, such as when combined with the series connection. .
  • the third embodiment by using a configuration in which a plurality of magnetoresistive effect elements 1 are connected in series or in parallel, it is possible to average the influence of variation in characteristics between elements. In addition, the asymmetry of the element characteristics with respect to the current direction can be reduced, and the voltage applied to the element can be reduced. As a result, it is possible to suppress magnetic field detection errors by employing a plurality of magnetoresistive elements 1.
  • Embodiment 4 FIG.
  • connection modifications 1 to 4 in which a plurality of magnetoresistance effect elements 1 are connected in series or in parallel have been described.
  • a connection modification example 5 in which a bridge circuit is configured by using a plurality of magnetoresistive effect elements 1 will be described.
  • FIG. 19 is a schematic diagram showing connection modification 5 of the magnetoresistive effect element according to the fourth embodiment of the present invention, and corresponds to an equivalent circuit diagram of the magnetic field detector according to the fourth embodiment.
  • a magnetic field detector 100 in FIG. 19 includes a bridge circuit 30 to which a current from the DC power supply 2 is supplied, a differential amplifier 32 that differentially amplifies voltages at nodes N2 and N4 of the bridge circuit 30, and the differential amplifier. And a voltmeter 3 for detecting the voltage level of the 32 output signals. In the magnetic field detector 100, a signal corresponding to the detected magnetic field is output from the bridge circuit 30.
  • the bridge circuit 30 is connected between the node N1 and the node N4, the magnetoresistive effect element 1a connected between the node N1 and the node N2, the constant resistance element 31b connected between the node N2 and the ground node N3, and the node N1 and the node N4. Constant resistance element 31a, and magnetoresistive effect element 1b connected between node N4 and ground node N3.
  • the node N1 is connected to the DC power source 2.
  • Nodes N2 and N4 are connected to complementary inputs of the differential amplifier 32, respectively.
  • the ground node N3 is connected to the ground.
  • the two magnetoresistive elements 1a and 1b have the configuration shown in FIG. 3 described in the first embodiment.
  • the influence of the external magnetic field on the magnetoresistive effect elements 1a and 1b is the same as that described in the first embodiment.
  • the resistance values of the constant resistance elements 31a and 31b are the same.
  • a constant current is supplied from the DC power supply 2 to the node N1.
  • the resistance values change with substantially the same characteristics.
  • the magnitude of the current flowing through the two current paths in the bridge circuit 30, that is, the path of the nodes N1 ⁇ N2 ⁇ N3, and the current flowing through the nodes N1 ⁇ N4 ⁇ N3 are the same.
  • the voltage levels of the node N2 and the node N4 change complementarily to the resistance value changes of the magnetoresistive effect elements 1a and 1b, and the differential value is amplified by the differential amplifier 32.
  • the difference signal change amount of the node N2 and the node N4 becomes large, and the voltmeter 3 can detect the voltage change caused by the external magnetic field with high accuracy. it can.
  • the fourth embodiment by configuring a bridge circuit using a plurality of magnetoresistive elements, differential reading is possible and it is easy to secure 0 points. As a result, the magnetic field can be detected with high accuracy and the change in resistance of the magnetoresistive effect element depending on the temperature can be reduced.
  • Embodiment 5 FIG.
  • connection modifications 1 to 4 in which a plurality of magnetoresistance effect elements 1 are connected in series or in parallel have been described.
  • connection modification example 5 has been described in which a plurality of magnetoresistive effect elements 1 are used to form a bridge circuit.
  • the fifth embodiment a case will be described in which a plurality of magnetoresistive elements having different shapes are formed on the same substrate.
  • FIG. 20 is a diagram for explaining the shape dependence of the magnetic characteristics of the magnetoresistive effect element according to the fifth embodiment of the present invention. With reference to FIG. 20, the magnetic characteristics when the element shape is changed using the laminated structure of the magnetoresistive effect element 1 according to the fifth embodiment will be described.
  • FIG. 20A shows a case where the ratio of the length in the longitudinal direction to the length in the short direction (shape aspect ratio) is constant for the anisotropic magnetic field in which the magnetization of the ferromagnetic film 8 as the free layer is almost saturated.
  • the dependence on the length in the short direction is shown.
  • FIG. 20B shows the dependency of the shape aspect ratio when the length in the short direction is constant.
  • the anisotropic magnetic field is inversely proportional to the sensitivity of the magnetoresistive element 1 to the magnetic field.
  • the sensitivity of the magnetoresistive effect element 1 changes depending on these shapes.
  • connection modification examples 1 to 4 of the third embodiment can be adjusted by combining with the connection modification examples 1 to 4 of the third embodiment.
  • magnetoresistive elements whose sensitivity changes depending on the shape can be collectively formed on the same plane as the same film structure. That is, a plurality of elements having different sensitivities and operating magnetic fields can be simultaneously formed on the same plane.
  • Embodiment 6 the magnetoresistive effect element described in the first embodiment is suitable for detecting a magnetic field whose direction is determined (direction along the magnetization 101a in the ferromagnetic layer 10a of the fixed layer), It will be described in detail with reference to the drawings that it is suitable for a current detector used with its position fixed relative to the wiring.
  • FIG. 21 is a schematic diagram showing a current detector according to the sixth embodiment of the present invention.
  • the current detector 102 in FIG. 21 the magnetic field detector 100 having the laminated structure of FIG. 3 described in the first embodiment is used.
  • the current detector 102 is arranged at a certain distance from the wiring that is the device under test 40.
  • a current i to be measured flows through the wiring 40 that is the object to be measured.
  • the current detector 102 has all the configurations shown in the first embodiment.
  • the current detector 102 also includes an output signal detection circuit (not shown).
  • the magnetoresistive effect element 1 is disposed so that the direction of the external magnetic field Hex generated from the wiring through which the current i to be measured flows coincides with the detection direction.
  • k is a proportional constant
  • r is the distance from the wiring 40 to the magnetoresistive element 1. If the distance r between the magnetoresistive effect element 1 and the wiring 40 is measured, the proportionality constant k is known, so that the current i can be measured by measuring the magnetic field Hex.
  • the wiring that is the device under test 40 may be disposed on the same substrate as the current detector 102.
  • the current detector 102 measures the current i flowing through the device under test 40 by measuring the magnetic field Hex of the device under test 40 having a magnetic field with the magnetoresistive effect element 1.
  • the output signal detection circuit that is, the calculation unit, converts the current value or voltage value detected by the magnetic detector described in the first embodiment, or the magnetic field strength obtained by converting these values using a conversion formula, into a preset conversion.
  • a function of obtaining the current value i of the DUT 40 based on the equation is included.
  • the current i flowing through the device under test 40 is measured by measuring the magnetic field Hex of the device under test 40 with the magnetic field Hex by the magnetoresistive effect element 1. For this reason, in current detection, a stable output signal with few errors can be obtained, and highly accurate current detection can be performed. In addition, the current detector 102 can be easily formed.
  • FIG. 21 is a schematic diagram showing connection of magnetoresistive elements of the current detector in the sixth embodiment of the present invention. Specifically, the case where the connection modification example 1 shown in FIG. 15 in the third embodiment is used is shown.
  • the magnetic field generated by the current flowing in the wiring 40 is explained by a concentric distribution when viewed in the wiring cross-sectional direction. For this reason, a non-uniform magnetic field is applied to the magnetoresistive effect element 1 especially when the distance between the wiring 40 and the magnetoresistive effect element 1 is short. In order to suppress this, it is preferable to reduce the length occupied by the magnetoresistive effect element 1 in the wiring cross-sectional direction. For this purpose, as shown in FIG. Arrangement of connecting along is preferred.
  • the current detector 102 may include a number of magnetoresistive elements 1 other than that shown in FIG. 22, and these magnetoresistive elements 1 are, for example, the bridge circuit shown in FIG. 19 of the fourth embodiment. 30 may be formed. Further, as described in the fifth embodiment, magnetoresistive elements having different sensitivities can be simultaneously formed on the same surface. These Embodiments 3 to 5 can be combined in a timely manner.
  • a magnetic field whose direction is determined can be detected with high accuracy using the current detector of the present invention.
  • it is suitable for an application in which the position is fixed to the wiring.
  • Embodiment 7 FIG.
  • the semiconductor integrated circuit described in the seventh embodiment of the present invention has the magnetoresistive effect element in the first to fifth embodiments, and includes a current detector that operates in the same manner as in the sixth embodiment. Have.
  • the operation principle of the current detector is the same as that of the sixth embodiment.
  • FIG. 23 is a schematic cross-sectional view showing a part of a semiconductor integrated circuit having a current detector according to Embodiment 7 of the present invention.
  • the current detector 102 shown in FIG. 23 uses the magnetoresistive effect element 1 shown in FIG. 3 of the first embodiment.
  • the current detector 102 is installed immediately above the Cu wiring that is the device under test 40.
  • the wiring 40 and the magnetoresistive effect element 1 at this time are insulated by the interlayer insulating film 53, and the distance is determined by the thickness of the interlayer insulating film 53 and the lower electrode 50 disposed under the magnetoresistive effect element 1. Determined by the thickness.
  • a current i for measurement flows through the wiring that is the device under test 40.
  • the current detector 102 has all the configurations shown in the sixth embodiment.
  • the current detector 102 also includes an output signal detection circuit (not shown) and is formed in advance in the semiconductor integrated circuit.
  • a plurality of magnetoresistive effect elements 1 see FIG. 15 and the like
  • a direct current (current and voltage) power source 2 see FIG. 1 and the like
  • a voltmeter 3 see FIG. 1 and the like
  • a current Total wiring not shown
  • constant resistance elements 31a and 31b see FIG. 19 etc.
  • wiring 4 and 5 for connecting between the differential amplifier 32 see FIG. 19 etc.
  • plug 51, interlayer insulating films 52, 53 and 54, 55, 56 are shown. Since the operation method is the same as that of the sixth embodiment, description thereof is omitted here.
  • the magnetoresistive effect element 1 included in the semiconductor integrated circuit having the configuration shown in FIG. 23 measures the magnetic field Hex of the device under test 40 (the device under test generating the magnetic field Hex) having the magnetic field Hex.
  • the current i flowing through the device under test 40 is measured. Therefore, a stable output signal with few errors in current detection can be obtained, and highly accurate current detection can be performed.
  • the current detector 102 can be easily formed.
  • FIG. 24 is a schematic cross-sectional view showing a part of another semiconductor integrated circuit having a current detector according to Embodiment 7 of the present invention.
  • the magnetoresistive effect elements 1 a and 1 b are installed immediately above the wiring 40, and the magnetoresistive effect elements 1 c and 1 d instead of the constant resistance elements 31 a and 31 b are installed other than just above the wiring 40.
  • the magnetoresistive effect elements 1c and 1d may be left as the constant resistance elements 31a and 31b. Thereby, for example, the influence of the magnetic field generated by the peripheral device can be subtracted, and a magnetic shield for suppressing the influence of the magnetic field in the surrounding environment becomes unnecessary.
  • the seventh embodiment it is possible to detect the current using the wiring of the semiconductor integrated circuit using the effects described in the first to sixth embodiments.
  • the magnetic field detector and current detector of the present invention are configured as a semiconductor integrated circuit, the distance between the magnetoresistive effect element and the device under test is determined by the interlayer insulating film. For this reason, the distance between the magnetoresistive element and the object to be measured can be reduced, and as a result, highly sensitive detection is possible. Furthermore, the influence of the background magnetic field can be suppressed by using an element away from the object to be measured.
  • FIG. 25 is a schematic cross-sectional view showing a part of a semiconductor integrated circuit having a current detector according to Embodiment 8 of the present invention.
  • the current of the power supply line PL from the power supply unit PS to the memory M and the arithmetic circuit OP is always detected by the current detector 102 composed of a magnetoresistive effect element. The detected current value is fed back to the power supply control unit PSC for controlling the power supply unit PS.
  • the function of obtaining the current value of the object to be measured may be provided in the power supply control unit PSC.
  • the eighth embodiment it is possible to detect the current supplied to the memory and the arithmetic circuit with high accuracy and high sensitivity without affecting the integrated circuit. As a result, the power consumption of the integrated circuit can be reduced by performing monitoring and feedback of the operation state of the integrated circuit depending on the environment.
  • FIGS. 15 to 19 the various modifications shown in FIGS. 15 to 19 can be applied, and elements having different sensitivities described in FIG. 20 can be formed simultaneously.

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Abstract

L'invention concerne un détecteur de champ magnétique comprenant un élément à effet de magnétorésistance constitué par une structure en couche incluant une couche de capsulation avec de l'oxyde contenant du Mg, une couche libre en contact avec la couche de capsulation et faite d'une couche ferromagnétique avec du Fe comme composant principal, une couche isolante tunnel faite d'oxyde contenant du Mg, et une couche fixe opposée à la couche libre sur l'ensemble de la couche isolante tunnel et faite d'une couche ferromagnétique magnétisée dans la direction de la surface du film. L'invention concerne en outre un détecteur de courant utilisant ledit détecteur de champ magnétique. Dans un état tel qu'aucun champ magnétique n'est appliqué sur l'élément à effet de magnétorésistance depuis l'extérieur, la couche libre présente une magnétisation dans la direction en plan du film et une magnétisation perpendiculaire à la surface du film, et le composant qui est projeté sur la surface du film dans la magnétisation de la couche libre est orthogonal au dit composant dans la magnétisation de la couche fixe.
PCT/JP2014/063721 2013-08-29 2014-05-23 Détecteur de champ magnétique comprenant un élément à effet de magnétorésistance, et détecteur de courant WO2015029514A1 (fr)

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JP2016200522A (ja) * 2015-04-13 2016-12-01 三菱電機株式会社 電流検出装置およびこれを用いた磁界検出装置
JP2020038113A (ja) * 2018-09-04 2020-03-12 日置電機株式会社 電流測定装置および電流測定方法
WO2020049883A1 (fr) * 2018-09-04 2020-03-12 日置電機株式会社 Appareil de mesure de courant électrique et procédé de mesure de courant électrique

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