JP5924694B2 - Magnetic field detection device, current detection device, semiconductor integrated circuit, and magnetic field detection method - Google Patents

Description

  The present invention relates to a magnetic field detection device, a current detection device, a semiconductor integrated circuit, and a magnetic field detection method, and more particularly to a magnetic field detection device, a current detection device, and a semiconductor integrated circuit that perform magnetic field detection by a giant magnetoresistance effect or a tunnel magnetoresistance effect. And a magnetic field detection method.

  In recent years, as a magnetoresistive effect element, a TMR element having a tunneling magnetoresistance (TMR) effect capable of obtaining a larger resistance change rate than a conventional giant magnetoresistance (GMR) effect has been developed. Applications to memory and magnetic heads are underway.

  The magnetoresistance (MR) effect is a phenomenon in which electric resistance changes by applying a magnetic field to a magnetic material, and is used in a magnetic field detection device, a magnetic head, or the like. In the GMR element, a laminated structure composed of a ferromagnetic layer / metal layer / ferromagnetic layer is used, and in the TMR element, a laminated structure composed of a ferromagnetic layer / insulating layer / ferromagnetic layer is used. In these elements, by setting the spins of the two ferromagnetic layers to be parallel (0 °) or antiparallel (180 °) to each other by an external magnetic field, in the GMR element, electrons at the ferromagnetic / metal layer interface Utilizing the fact that the resistance varies depending on the scattering probability, the TMR element utilizes the fact that the magnitude of the tunnel current flowing through the insulating layer in the direction perpendicular to the film surface varies. In the GMR element and the TMR element, it is possible to detect the relative magnetization directions of the two ferromagnetic layers by detecting a resistance change.

  In these magnetoresistive elements, one ferromagnetic layer is exchange-coupled with an antiferromagnetic layer to fix the magnetization of the ferromagnetic layer to a so-called pinned layer, and the magnetization of the other ferromagnetic layer with an external magnetic field. A so-called spin-valve type structure is known, which is a free layer that can be easily inverted.

  A magnetoresistive element having a spin valve structure can suppress a magnetic interaction between ferromagnetic layers through a metal layer or an insulating layer, and can be used as a highly sensitive magnetic field detection device. . When a magnetic field is applied to the spin valve magnetoresistive element from the outside, 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. As a result, 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 out as a signal that changes in accordance with the applied magnetic field, so that highly sensitive magnetic field detection is possible.

  Furthermore, instead of detecting a resistance change in a single magnetoresistive effect element, a Wheatstone bridge circuit is formed using four magnetoresistive effect elements, and elements whose magnetization directions of the pinned layer are reversed are combined. Thus, a technique has been proposed in which the output in the absence of a magnetic field is 0, and a high-power magnetic field detection device is formed (see, for example, Patent Document 1).

  Even in a half-bridge circuit in which two magnetoresistive elements whose magnetization directions of the pinned layer are opposite to each other are connected in series, the output signal is determined by the resistance ratio of the two magnetoresistive elements. It is possible to suppress the influence of resistance fluctuation caused by the manufacturing process.

  However, in order to realize the above-described bridge circuit technology, it is necessary to form magnetoresistive elements having different magnetization directions of the pinned layer on the same substrate. In this formation process, it is necessary to apply magnetic fields having different directions to each fixed layer during the heat treatment. More specifically, it is necessary to heat the pinned layer at a temperature higher than the blocking temperature and to apply a local magnetic field at which the exchange coupling between the antiferromagnetic layer and the ferromagnetic layer in contact therewith is not observed. In general, heat treatment in a magnetic field that applies a uniform magnetic field to the substrate is used, but in this case, formation is impossible. When the above-mentioned bridge is formed using a heat treatment in a magnetic field with a general uniform magnetic field, it is necessary to form a plurality of elements on the same substrate, then cut the substrate and place it in a direction rotated by 180 ° There is a problem in that a process for arranging the cut substrates and making electrical connections is required. In addition, there is a problem that the substrate area of the entire detection device increases.

  For example, another conventional technique described in Patent Document 2 proposes a technique that uses a plurality of magnetoresistive elements having the same magnetization direction of the pinned layer and different magnetization easy axis directions of the free layer. In this technique, a reference element having the same magnetization direction and simultaneously formed on the same substrate as the detection element is used. This indicates that the minimum resistance or maximum resistance of the magnetoresistive effect element for detecting a magnetic field is obtained as a constant resistance, and it is possible to form a Wheatstone bridge or a half bridge without complicated processes. It is. Since it is possible to form the detecting element and the reference element on the same substrate in the same process, it is possible to suppress the influence of the resistance variation caused by the manufacturing process and temperature in the magnetoresistive effect element. is there.

Japanese Patent No. 3017061 Japanese Patent No. 4513804

  As described above, for example, as described in Patent Document 1, in a bridge circuit using an element in which the magnetization direction of the pinned layer is reversed, the output signal is large, but formation on the same substrate is difficult. After forming a plurality of elements on the substrate, it is necessary to cut the substrate and install it in a direction rotated by 180 °, which requires a process for arranging the cut substrate and making electrical connection. there were. In addition, there is a problem that the substrate area of the entire detection device increases.

  Further, for example, as described in Patent Document 2, if a technique using a plurality of magnetoresistive effect elements having the same magnetization direction of the pinned layer and different easy axis directions of the free layer is used, the manufacturing process is complicated. It is possible to form the aforementioned Wheatstone bridge or half bridge on the same substrate by the same process. Thus, if the bridge circuit technique is used, it is possible to suppress the influence of the resistance fluctuation caused by the manufacturing process and temperature of the magnetoresistive effect element, and to obtain an output signal having a large resistance. However, the free layer of the magnetoresistive effect element for detecting the magnetic field is tilted due to the influence of the leakage magnetic field from the pinned layer and the magnetic coupling with the pinned layer via the tunnel insulating layer and the nonmagnetic layer. There is a problem that the resistance in a magnetic field changes. As a result, even when a magnetoresistive effect element for reference is used, there is a problem in that an offset occurs at the zero point of the magnetoresistive effect element for detecting a magnetic field, thereby generating a detection error.

  The present invention has been made to solve such a problem. The reference element used as a constant resistance is used to correct the offset of the magnetic field responsiveness of the detection element. An object of the present invention is to obtain a magnetic field detection device, a current detection device, a semiconductor integrated circuit, and a magnetic field detection method capable of easily controlling output.

The present invention is a magnetic field detection device that outputs an output signal corresponding to an external magnetic field, and includes two or more magnetoresistive effect elements for detecting a magnetic field provided on a substrate and two or more provided on the substrate. Magnetoresistive effect element for reference, and bias magnetic field applying wiring for applying a magnetic field in the direction of hard magnetization of the free layer of the magnetoresistive effect element for detecting magnetic field, and the magnetoresistive effect element for reference and the magnetic field detecting The magnetoresistive effect element is a free layer composed of an antiferromagnetic layer, a fixed layer composed of a magnetic layer whose magnetization direction is fixed by the antiferromagnetic layer, and a magnetic layer whose magnetization direction is changed by an external magnetic field. The two or more reference magnetoresistive elements have a structure in which the magnetization direction of the pinned layer and the magnetization direction of the free layer in the absence of a magnetic field are parallel to each other. Including those in the state of Cage, wherein the magnetic field detecting magnetoresistive element, the Ri and the magnetization direction of the pinned layer and the magnetization direction in the free field of the free layer Do different, the bias magnetic field applying wiring for applying a magnetic field to the detection magnetoresistive element Is a magnetic field detection device that simultaneously applies the magnetic field to the reference magnetoresistive element .

The present invention is a magnetic field detection device that outputs an output signal corresponding to an external magnetic field, and includes two or more magnetoresistive effect elements for detecting a magnetic field provided on a substrate and two or more provided on the substrate. Magnetoresistive effect element for reference, and bias magnetic field applying wiring for applying a magnetic field in the direction of hard magnetization of the free layer of the magnetoresistive effect element for detecting magnetic field, and the magnetoresistive effect element for reference and the magnetic field detecting The magnetoresistive effect element is a free layer composed of an antiferromagnetic layer, a fixed layer composed of a magnetic layer whose magnetization direction is fixed by the antiferromagnetic layer, and a magnetic layer whose magnetization direction is changed by an external magnetic field. The two or more reference magnetoresistive elements have a structure in which the magnetization direction of the pinned layer and the magnetization direction of the free layer in the absence of a magnetic field are parallel to each other. Including those in the state of Cage, wherein the magnetic field detecting magnetoresistive element, the Ri and the magnetization direction of the pinned layer and the magnetization direction in the free field of the free layer Do different, the bias magnetic field applying wiring for applying a magnetic field to the detection magnetoresistive element Is a magnetic field detector that simultaneously applies the magnetic field to the reference magnetoresistive effect element, so that the reference element used as a constant resistance is used to correct the magnetic field responsiveness offset of the detection element. Thus, it is possible to easily control the zero point output in the magnetic field detection apparatus.

It is a figure explaining the magnetization direction of the free layer and fixed layer of a magnetoresistive effect element for a detection. It is a figure explaining the external magnetic field dependence of the element resistance of the magnetoresistive effect element for a detection. It is a figure explaining the magnetization direction of the free layer and pinned layer of a magnetoresistive effect element for a reference. It is a figure explaining the external magnetic field dependence of the element resistance of the magnetoresistive effect element for a reference. It is a top view for demonstrating the structure of the magnetic field detection apparatus of Embodiment 1 of this invention. It is a schematic diagram of the cross-sectional structure of the magnetoresistive effect element of the magnetic field detection apparatus of Embodiment 1 of this invention. It is a figure explaining the offset which generate | occur | produces in the magnetic field response of the magnetoresistive effect element for a detection in Embodiment 1 of this invention. It is a flowchart which shows the magnetic field detection operation in Embodiment 1 of this invention. It is a figure explaining that the offset of the magnetic field responsiveness of the magnetoresistive effect element for a detection in Embodiment 1 of this invention was correct | amended. It is a figure explaining the output of the magnetic field detection apparatus according to the external magnetic field in Embodiment 1 of this invention. It is a flowchart which shows another magnetic field detection operation | movement in Embodiment 1 of this invention. It is a top view for demonstrating the structure of the magnetic field detection apparatus of Embodiment 2 of this invention. It is a top view for demonstrating the structure of the magnetic field detection apparatus of Embodiment 3 of this invention. It is a top view for demonstrating the structure of the modification of the magnetic field detection apparatus of Embodiment 3 of this invention. It is a top view for demonstrating the structure of the electric current detection apparatus of Embodiment 4 of this invention. It is a top view for demonstrating the structure of the semiconductor integrated circuit of Embodiment 4 of this invention. It is a top view for demonstrating the structure of the modification of the electric current detection apparatus of Embodiment 4 of this invention.

  Before describing the embodiment of the present invention, first, a specific detection operation of a magnetic field detection apparatus using a spin valve magnetoresistive effect element will be described with reference to FIG. The spin-valve magnetoresistive element 1 for detecting a magnetic field is configured by laminating a pinned layer and a free layer. Here, an ideal state is considered in which there is no interaction between the pinned layer and the free layer. . FIG. 1 is a schematic diagram showing the magnetization directions of the free layer and the pinned layer of the magnetoresistive element 1 for detecting a magnetic field. In FIG. 1, the magnetization direction 2 of the free layer of the spin-valve magnetoresistive element 1 in the absence of a magnetic field and the magnetization direction 3 of the fixed layer in the absence of a magnetic field are perpendicular to each other, and the angle formed by them is 90 °. . The magnetization direction 2 of the free layer in the absence of a magnetic field is determined by the shape of the free layer and is the longitudinal direction thereof. When a magnetic field H is applied in a direction along the magnetization direction 3 of the pinned layer of the spin valve magnetoresistive element 1, the magnetization of the free layer changes its direction by an external magnetic field and becomes the magnetization direction 2a. At this time, the resistance value of the magnetoresistive effect element 1 changes linearly according to the angle θ formed by the changed magnetization direction 2a of the free layer and the magnetization direction 3 of the pinned layer.

Specifically, when the magnetization direction 3 of the pinned layer is 0 °, and the angle formed by the magnetization direction 2a of the free layer when an external magnetic field H is applied to θ, the resistance of the magnetoresistive effect element 1 is The change is proportional to cos θ. If the free layer is a soft magnetic film having uniaxial anisotropy, and cosθ = H / H _k. That is, if a large external magnetic field H than a predetermined value H _k is applied, will magnetization direction 2a of the free layer is fixed to parallel (0 °) or antiparallel (180 °) the magnetization direction of the pinned layer, The resistance of the magnetoresistive effect element 1 does not change any more. That is, ideally, H _k is the saturation magnetic field of the free layer.

  As a result, the resistance (element resistance) R of the magnetoresistive effect element 1 is expressed by the following equation (2) when the magnetization direction 2 of the free layer and the magnetization direction 3 of the pinned layer are 90 ° in the absence of a magnetic field. 1), and changes as shown in FIG.

R = R _m + ΔR / 2 · H / H _k (where −H _k ≦ H ≦ H _k ) (1)

Here, R _m is the intermediate value between the maximum resistance value and minimum resistance values that can take the resistance R of the magnetoresistive element 1, by the resistance value of the magnetoresistive element 1 of the ideal no magnetic field in the is there. ΔR is the maximum magnetoresistance change amount of the magnetoresistive effect element 1 (that is, the difference between the maximum resistance value and the minimum resistance value). Since the resistance R of the magnetoresistive element 1 changes linearly with respect to the external magnetic field H, the magnitude of the external magnetic field H can be detected by obtaining the resistance R of the magnetoresistive element 1. The detected external magnetic field H is a directional component in the magnetization direction 3 of the pinned layer. The magnetic field region that can be detected in the magnetization direction of the pinned layer, that is, the operation region is −H _k ≦ H ≦ H _k .

Next, FIG. 3 is a schematic diagram showing the magnetization directions of the free layer and the pinned layer of the reference spin-valve magnetoresistive element 11. The reference magnetoresistive element 11 shown in FIG. 3 is arranged so that its longitudinal direction is orthogonal to the longitudinal direction of the magnetoresistive element 1 for detection shown in FIG. The magnetization direction 3 of the pinned layer in the magnetoresistive element 11 is the same as that of the magnetoresistive element 1 for detection shown in FIG. In FIG. 3, as in FIG. 1, the magnetization direction 3 of the pinned layer in the absence of a magnetic field is set to 0 °. In FIG. 3A, the magnetization direction 2 of the free layer of the magnetoresistive effect element 11 is the same as the magnetization direction 3 of the pinned layer in the absence of a magnetic field, and both are 0 °. That is, the magnetization direction of the pinned layer and the magnetization direction of the free layer in the absence of a magnetic field are in parallel. In this magnetoresistive effect element 11, when a magnetic field H is applied in the 0 ° direction, which is the same direction as the magnetization direction 3 of the pinned layer, the direction of the magnetic field coincides with the magnetization direction 3 in the absence of a magnetic field. Thus, the magnetization direction 2a of the free layer is stabilized. On the other hand, when a magnetic field is applied in the 180 ° direction, the magnetization direction is reversed to the magnetic field direction after maintaining the magnetization direction up to a certain magnetic field Hc. That is, since the magnetization direction 2a of the free layer and the magnetization direction 3 of the fixed layer under a magnetic field are stable at 0 ° and 180 °, the resistance value of the magnetoresistive element 11 has two values. This is shown in FIG. 4. Specifically, the resistance value represents R _m ± ΔR / 2. In this case, the resistance value of R _m −ΔR / 2 is stable when H ≦ + H _c , and the resistance value of R _m + ΔR / 2 is stable when H ≧ −H _c .

  On the other hand, in FIG. 3B, the magnetization direction 2 of the free layer of the spin valve magnetoresistive element 11 and the magnetization direction 3 of the pinned layer in the absence of a magnetic field are opposite, and the angle formed by them is 180 °. It is. That is, the magnetization direction of the pinned layer and the magnetization direction of the free layer in the absence of a magnetic field are antiparallel (parallel and reverse). Also in this case, the resistance value of the magnetoresistive effect element 11 basically shows the dependency shown in FIG. 4 with respect to the external magnetic field.

The resistance R of the magnetoresistive effect element 11 for reference exhibits a constant resistance up to a constant magnetic field without depending on the external magnetic field. Therefore, when the area of the magnetoresistive effect element for detection is the same, The maximum resistance or the minimum resistance of the magnetoresistive element for detection can be obtained from the value of the resistance R of the magnetoresistive element 11. In the reference element shown in FIG. 3A, the magnetizations of the pinned layer and the free layer are previously in parallel, and the resistance is R _m −ΔR / 2. On the other hand, in the reference element shown in FIG. 3B, the magnetization of the pinned layer and the free layer is antiparallel in advance, and the resistance is R _m + ΔR / 2.

  Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

Embodiment 1.
FIG. 5 is a top view showing the configuration of the magnetic field detection apparatus according to Embodiment 1 of the present invention. The magnetic field detection apparatus shown here includes four detection magnetoresistance effect elements 101a, 101b, 102a, and 102b (hereinafter referred to as detection elements) and four reference magnetoresistance effect elements 111a, 111b, and 112a. 112b (hereinafter referred to as a reference element). The detection elements 101 and 102 and the reference elements 111 and 112 all have the same area and the same shape (rounded rectangle) when viewed from above. However, the detection elements 101 and 102 and the reference elements 111 and 112 are arranged such that their longitudinal directions are different from each other by 90 °. That is, the longitudinal direction of the detection element is the vertical direction on the paper surface, and the longitudinal direction of the reference element is the horizontal direction on the paper surface.

  The detection elements 101a and 101b and 102a and 102b are connected in series by metal wirings 51 and 52, respectively. The reference elements 111a and 111b and 112a and 112b are connected in series by metal wirings 53 and 54, respectively. Further, the detection element 101 a and the reference element 111 a are connected by the metal wiring 55, the detection element 102 b and the reference element 112 b are connected by the metal wiring 56, and the detection element 102 a and the reference element 111 b are connected by the metal wiring 57. The detection element 101b and the reference element 112a are connected by a metal wiring 58. The metal wiring 55 is connected to a power source, and the metal wiring 56 is grounded. The metal wirings 57 and 58 are each connected to a signal detection circuit (not shown) installed outside.

The detection elements 101a and 102a and 101b and 102b are provided adjacent to each other. Immediately below the detection elements 101a, 101b, 102a, and 102b, a magnetic field application wiring 151 that is electrically insulated from the detection elements is provided, and the longitudinal direction of the magnetic field application wiring 151 is the detection element 101a. , 101b, 102a, 102b are arranged in a direction parallel to the longitudinal direction. When the bias current I _bias is passed, the magnetic field applying wiring 151 is simultaneously directed to the detection elements 101a, 101b, 102a, and 102b rightward on the paper surface (that is, in a direction orthogonal to the longitudinal direction of the detection element ( The magnetic field H _bias for biasing is arranged so as to be applied in the hard axis direction)).

  The detection elements 101a, 101b, 102a, and 102b and the reference elements 111a, 111b, 112a, and 112b all have the same laminated structure, and a schematic diagram of the cross-sectional structure is shown in FIG.

  In FIG. 6, an electrode layer 62 is formed on a substrate 61, and then an antiferromagnetic layer 63 is formed. Next, the antiferromagnetic layer 63 forms a ferromagnetic layer 64 whose magnetization direction is fixed. Subsequently, a nonmagnetic layer 65 and a ferromagnetic layer 66 are formed, a nonmagnetic layer 67 to be a tunnel insulating layer is formed, and a free layer 68 made of a magnetic material whose magnetization direction is changed by an external magnetic field is formed thereon. Has been. An electrode layer 69 is formed on the free layer 68. The ferromagnetic layers 64 and 66 are magnetically antiparallel coupled via the nonmagnetic layer 65. Here, a laminated structure including the antiferromagnetic layer 63, the ferromagnetic layer 64, the nonmagnetic layer 65, and the ferromagnetic layer 66 functions as the fixed layer 70. In the following description, the magnetization of the ferromagnetic layer 66 is referred to as the magnetization of the pinned layer 70 for simplicity of description.

  In this pinned layer 70, since the two ferromagnetic layers 64 and 66 are coupled in antiparallel, the apparent magnetization of the entire pinned layer 70 can be suppressed, and the magnetic force applied to the free layer 68 can be reduced. It is possible to suppress a general influence and an influence that the fixed layer 70 receives from a magnetic field.

  Here, the configuration in which the antiferromagnetic layer 63 to the free layer 68 are sequentially stacked is shown, but the configuration is not limited to this, and conversely, the free layer 68 is at the bottom and the free layer 68 is reversed. The elements can also be configured by stacking in this order.

  Since the free layers 68 of the detection elements 101a, 101b, 102a, 102b and the reference elements 111a, 111b, 112a, 112b have a rectangular shape and have a longitudinal direction, the free layer 68 has a shape magnetic anisotropy. The magnetization direction of 68 is the longitudinal direction of each of these elements. Since the magnetization direction of the pinned layer 70 is the same for the detection element and the reference element, in the four detection elements 101a, 101b, 102a, and 102b, the magnetization direction of the pinned layer 70 is free in a non-magnetic field. It is orthogonal to the magnetization direction of the layer 68 in the element plane (90 °). On the other hand, the magnetization direction of the pinned layer 70 of the four reference elements 111a, 111b, 112a, 112b is parallel (0 °) or antiparallel (180 °) to the magnetization direction of the free layer 68 in the absence of a magnetic field. It has become.

In the reference elements 111a and 112a, the magnetization of the pinned layer and the free layer is in an antiparallel state in advance, and the resistance value is R _m + ΔR / 2. In the reference elements 111b and 112b, the magnetizations of the fixed layer and the free layer are in a parallel state in advance, and the resistance value is R _m −ΔR / 2. Since the resistance value of the reference element with respect to the magnetic field has hysteresis as shown in FIG. 4, the resistance value can be maintained even after the current of the magnetic field application wiring 151 is stopped. In this state, 111a and 111b, 112a and 112b because it is connected in series, the resistance value of each of the series resistors, the 2R _m. Detection element also, 101a and 101b, and 102a and 102b are connected in series, the resistance value in a non-magnetic field becomes mutually equal resistance becomes 2R _m.

  Here, as a material constituting the ferromagnet in the free layer 68 and the pinned layer 70 of each element, the ferromagnetic layer 64 uses a Co—Fe alloy, and the ferromagnetic layer 66 uses a Co—Fe—B alloy. In the free layer 68, a Co—Fe—B alloy is used. However, the present invention is not limited to this, and any ferromagnetic film that has at least one of Co, Ni, and Fe such as Fe and Co as a main component may be used.

The nonmagnetic layer 67 that is a tunnel insulating layer is made of an MgO film. The tunnel insulating layer 67 is not limited to this, and may be Al ₂ O ₃ , HfO ₂ , Ta ₂ O ₅ , MgAl ₂ O _4, etc., which are oxide films of other metals, and is not limited to oxides. Nitride and fluoride may be used.

  The antiferromagnetic layer 63 that fixes the magnetization of the ferromagnetic film 64 in the fixed layer 70 is made of an Ir—Mn alloy film. Note that the antiferromagnetic layer 001c is not limited to the Ir—Mn alloy film, and may be any antiferromagnetic film such as a Pt—Mn alloy, an Fe—Mn alloy, or a Ni—Mn alloy, and obtains the same effect. Is possible.

  The nonmagnetic layer 65 in the pinned layer 70 is made of a Ru film. The nonmagnetic layer 65 is not limited to the Ru film, and may be any nonmagnetic film of a transition metal mainly composed of a platinum group such as Rt, Rb, and the like, and the same effect can be obtained.

  The lower electrode layer 62 and the upper electrode layer 69 are each made of a Ta (tantalum) film. Each of the lower electrode layer 62 and the upper electrode layer 69 may be another metal such as a Ru film, but is not limited thereto. Lower electrode layer 62 and upper electrode layer 69 are connected to respective metal wirings shown in FIG. Cu (copper) is used for each metal wiring. The metal wiring may be other metal such as Al (aluminum), and is not limited to this.

  Next, a method for manufacturing the magnetoresistive effect element and the magnetic field detection device according to the first embodiment will be described.

  Referring to FIG. 6, each metal film constituting the magnetoresistive effect element is formed on substrate 61 by DC (direct current) magnetron sputtering. The substrate 61 is made of Si (silicon), SiC (silicon carbide), GaN (gallium nitride), GaAs (gallium arsenide), glass, or the like. In addition, the board | substrate 61 is not limited to this, Other materials may be sufficient. Here, a substrate is used in which the magnetic field application wiring 151 is formed directly below the magnetoresistive effect element. Other wirings, electronic circuits such as transistors and diodes may be formed under the magnetoresistive element.

  First, a Ta film is formed on the substrate 61 as the lower electrode layer 62 using DC magnetron sputtering. After the Ta film as the lower electrode layer 62 is formed, an Ir—Mn alloy film is formed as the antiferromagnetic layer 63 in the same apparatus without being exposed to the atmosphere. Subsequently, a Co—Fe alloy film as the ferromagnetic layer 64 is formed without being exposed to the atmosphere. Next, a Ru film as the nonmagnetic layer 65 and a Co—Fe—B alloy film as the ferromagnetic layer 66 are formed. , Respectively. Subsequently, after the MgO film is formed as the tunnel insulating layer 67 using RF (radio frequency) magnetron sputtering without being exposed to the atmosphere, a Co—Fe—B alloy film is formed as the ferromagnetic film of the free layer 68. Thereafter, a Ta film is formed as the upper electrode layer 69 using DC magnetron sputtering.

  When these films are formed, a magnetic field of 100 Oe is applied in the film surface direction. Thereby, magnetic anisotropy is imparted to the Ir—Mn film, the Co—Fe film, and the Co—Fe—B film constituting the fixed layer 70. The films from the lower electrode layer 62 to the upper electrode layer 69 constituting the magnetoresistive effect element 1 are all formed in the same device. The MgO film that is the tunnel insulating layer 67 may be formed by exposing to an oxidizing atmosphere containing oxygen after the Mg film is formed by DC magnetron sputtering.

  The above film may be formed by, for example, molecular beam epitaxy (MBE) method, various sputtering methods, chemical vapor deposition (CVD) method, vapor deposition method, or plating.

  Thereafter, 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 film of the pinned layer 70. Here, 10 kOe, which is a magnetic field for saturating the magnetizations of the Co—Fe—B film as the ferromagnetic layer 64 of the pinned layer 70 and the Co—Fe film as the ferromagnetic layer 66, is applied. The direction of the magnetic field application is the same as that during film formation of the magnetoresistive effect element, and is the short direction of the detection elements 101 and 102 and the long direction of the reference elements 111 and 112. The heat treatment temperature is 300 ° C., in which the magnetoresistive element can crystallize the Co—Fe—B film, and the exchange coupling between the Ir—Mn film and the Co—Fe film of the pinned layer is substantially eliminated. Yes. This temperature was maintained for 1 hour.

  After the heat treatment described above, the magnetizations of the ferromagnetic films 64 and 66 of the pinned layer are oriented in directions different from each other by 180 °. That is, the magnetization of the Co—Fe alloy film and the magnetization of the Co—Fe—B alloy film facing each other across the Ru film which is the nonmagnetic layer 64 are opposite to each other.

  In this embodiment, since the magnetization directions of the pinned layers of the detection element and the reference element are the same, the applied magnetic field during the heat treatment may be the same direction, and a uniform magnetic field can be applied. .

  Thereafter, a desired pattern is formed by photolithography. After a film constituting the laminated magnetoresistive effect element is formed, a desired pattern is formed by a photoresist. Thereafter, the magnetoresistive effect element is electrically and magnetically separated by reactive ion etching using a desired pattern formed of a photoresist as a mask, thereby obtaining the shape of the magnetoresistive effect element. The magnetoresistive effect element here is a rounded rectangle as described above. At this time, the longitudinal direction of the detection elements 101 and 102 is a direction orthogonal to the magnetic field application direction at the time of forming the fixing layer 70 in the laminated film, and the longitudinal direction of the reference elements 111 and 112 is the fixing layer in the laminated film. This is the same direction as the magnetic field application direction when forming 70.

  The magnetoresistive effect element for detection and the magnetoresistive effect element for reference are preferably formed simultaneously on the same substrate in the same process, and these patterns are formed using electron beam lithography, focused ion beam, or ion milling. May be.

  With the above pattern formation, in the magnetoresistive effect element, the magnetization of the Co—Fe—B film, which is the ferromagnetic layer 68 serving as a free layer, is affected by the demagnetizing field depending on the shape and faces the longitudinal direction of the shape. Thereby, in the absence of a magnetic field, the magnetizations of the free layers of the detection element and the reference element are orthogonal. Note that the magnetization direction of the Co—Fe—B film with respect to the fixed layer of the detection element can be determined by locally applying a magnetic field. Alternatively, the setting using spin injection is possible by connecting the detection element by an element in which current flows from the fixed layer side and an element in which current flows from the free layer side.

  Thereafter, as shown in FIG. 5, the metal wirings 51 to 58 are connected to the magnetoresistive effect elements 101, 102, 111, and 112. As a result, the metal wiring 55 is connected to a power source (not shown), and the metal wiring 56 is grounded. The metal wires 57 and 58 are connected to a signal detection circuit that detects a voltage, respectively. Although a detailed description is omitted here, a magnetic field detection device using the magnetoresistive effect element of the present embodiment is thereby formed.

  Next, the detection operation of the magnetic field detection apparatus according to the present embodiment will be described with reference to FIG.

A predetermined constant detection current I _sense is supplied from the power supply via the metal wiring 55. At this time, since the metal wiring 56 is grounded, the current flows through the detection elements 101a and 101b and the reference element 112a to the reference element 112b, and the reference elements 111a and 111b and the detection element. There are two paths for the current flowing through the element 102a to the detecting element 102b. In no magnetic field, ideally, resistance in these pathways are both 4R _m, current is the route _{1/2 · I sense.} Further in this case, two detection elements and two reference elements are 4R _m, since the same resistance, the potential V2 of the potential V1 and the metal wiring 58 of the metal wire 57 becomes the same potential, The output voltage represented by the potential difference (V1−V2) is 0. That is, 0 output can be obtained without a magnetic field.

  The above is a description of the case where the magnetic field is 0, but an ideal state under a magnetic field is considered. Here, a state where no current is flowing through the magnetic field application wiring 151 will be described.

The output voltage ΔV in the bridge circuit shown in FIG. 5 is obtained by detecting V1-V2 when a constant detection current _Isense is flowed, and is expressed by the following equation (2).

ΔV = I _sense · ΔR / 2 · H / H _k (2)

That is, an output signal linear with respect to the magnetic field is obtained. By converting this output signal into a magnetic field, the magnetic field can be detected. Since H _c ≦ H _k , the above output signal is obtained in the region of | H | ≦ H _c . In the region of | H | ≧ H _c , the sum of the resistances of the two reference elements changes from 2R _m to 2 (R _m + ΔR) or 2 (R _m −ΔR), thereby providing a discontinuous output. Signal.

The above describes the case where the resistance values of two detection elements connected in series and two reference elements connected in series match each other under no magnetic field. However, as shown in FIG. 7, if the interaction of the magnetization of the free layer 68 and pinned layer 70 is present, the offset H _OS is generated in the magnetic field response of the free layer 68 of the detection element. As a result, the output voltage in the above-described non-magnetic field is not 0, and an offset is generated with respect to the output voltage represented by Expression (2).

  Next, consider a case where a current is passed through the magnetic field application wiring 151.

The magnetic field application wiring 151 can simultaneously apply a magnetic field to the detection elements 101a, 101b, 102a, and 102b in the hard axis direction of the free layer 68 (direction perpendicular to the longitudinal direction of the element). . Here, in the present embodiment, the resistance values of the two reference elements connected in series indicate the midpoint of the resistance values of the two detection elements connected in series. By using this to control the current I _bias of the magnetic field application wiring 151, it is possible to correct the offset H _OS of the detection element. An example of the operation for this is shown in the flowchart of FIG.

First, in step S1, a predetermined constant current _Ibias is supplied to the wiring 151 in the absence of a magnetic field, and the output signals V1-V2 are detected. Next, in step S2, it is determined whether V1-V2 is 0 or not. If V1-V2 is not 0, the current _Ibias is changed in step S6, and the processing in steps S1, S2, and S6 is repeated to obtain a current _{Ibias in} which V1-V2 is 0. If it is determined in step S2 that V1-V2 = 0, the process proceeds to step S3, and the current _Ibias is stored in a storage device in the magnetic field detection device or an external storage device. When the current I _{bias at} which V1−V2 = 0 is flowing, a magnetic field H _bias having a resistance value at the midpoint is applied to the detection element, in other words, the magnetic field response of the detection element. sexual offset H _OS is corrected. This is shown in FIG. Subsequently, the process proceeds to step S4, and the output signal V1-V2 is detected under the magnetic field in the state where the magnetic field H is applied while the current _Ibias obtained in the previous step S2 at which V1-V2 = 0 is passed through the wiring 151. To do. Next, in step S5, the detected output signal V1-V2 is converted into a magnetic field, and the magnetic field H is detected.

The output signal (V1-V2) obtained by the above is shown in FIG. The resistance value of the reference element by using the resistance value of the middle point of the detecting element, since it corrects the offset H _OS of the detection elements, characteristics to be exactly 0 output in no magnetic field is obtained, | H | in the region of ≧ H _c, linear output signal is obtained for the external magnetic field H.

Another operation example is shown in FIG. Here, in the operation by the magnetic balance system, illustrating a method for correcting an offset H _OS.

First, in step S1, a predetermined constant current _Ibias is supplied to the wiring 151 in the absence of a magnetic field, and the output signals V1-V2 are detected. In step S2, it is determined whether or not this value is 0. If not, in step S6, the current _Ibias is changed, the process returns to step S1 again, and the processes in steps S1, S2, and S6 are repeated, and V1- A current _{Ibias at} which V2 becomes 0 is obtained. The value of the current _Ibias thus obtained is stored in a storage device in the magnetic field detection device or an external storage device in step S3. In this state, a magnetic field H _{bias serving as} a midpoint resistance is applied to the detection element. In other words, the magnetic field responsive offset H _OS of the detection element is corrected. Up to this point, the operation is the same as that described with reference to FIG.

Thereafter, in Figure 11, followed by, in the state under a magnetic field a magnetic field is applied to H, and change the current _{I bias,} obtain current _{I bias} for the V1-V2 = 0. The current I _{bias at} which V 1 −V 2 becomes 0 under a magnetic field is a current that _neutralizes the external magnetic field and the offset of the magnetic field responsiveness of the detection element and makes the resistance of the detection element a middle point.

That is, in FIG. 11, in step S11, in the state under the magnetic field to which the magnetic field H is applied, the predetermined current I _bias is passed through the wiring 151, and the output signals V1-V2 are detected. In step S12, it is determined whether or not this value is 0. If not, in step S15, the current _Ibias is changed, the process returns to step S11 again, and the processes in steps S11, S12, and S15 are repeated, and step S13 is repeated. Thus, a current I _bias where V1−V2 becomes 0 is obtained. The current I _bias thus obtained, is compared with I _bias stored in the previous step S3, it excludes the influence of the offset of the magnetic field response of the sensing element. The external magnetic field H can be detected by converting the current value I _bias of the wiring 151 finally obtained in this way into a magnetic field.

  In the above-described magnetic balance system operation, it is only necessary to obtain a zero point with respect to the magnetic field, and the linearity of the detection element is not necessarily required. In addition, since a magnetic field that cancels the external magnetic field is applied and the element always operates in the vicinity of zero magnetic field, it can operate in a wide magnetic field range without depending on the characteristics of the element.

In the above, the detection operation using the constant current _Ibias has been described as an example, but a constant voltage may be used. In this case, the metal wiring 55 operates with a constant voltage _Vcc . The output signal ΔV in that case is expressed by the following equation (3).

_{ΔV = -V cc · ΔR / 2} · H / H k / (4R m + ΔR · H / H k) (3)

In the operation of the constant voltage V _cc described above, even when the resistance of the magnetoresistive effect element changes due to the manufacturing process and temperature, the output signal is determined by the relative relationship of resistance. Since all the magnetoresistive effect elements here are formed in the same process, the influence of the resistance variation caused by the manufacturing process and temperature is similarly received by all the elements. For this reason, it becomes possible to suppress the influence of the resistance fluctuation resulting from a manufacturing process or temperature.

Here, an example in which the magnetic field application wiring 151 is arranged immediately below the detection element is shown, but the direction parallel to the film surface direction of the free layer of the detection element and orthogonal to the longitudinal direction (hard magnetization axis) It is sufficient that a magnetic field can be applied in the direction), and it may be arranged immediately above the detection element. In this case, the direction of the magnetic field applied to the detection element is opposite to that described above, but the same effect can be obtained if a reverse current _Ibias is passed.

  According to the present embodiment, by using the detection element and the reference element having the same area and the magnetization being in the parallel state and the antiparallel state, the resistance at the midpoint of the detection element is obtained. Is possible. Even when there is an offset in the magnetic field responsiveness of the magnetic field detecting element, it is possible to correct the offset accurately by comparison with the midpoint resistance. As a result, a stable 0-point output can be obtained.

  These can be realized without complicating the manufacturing process.

As described above, according to the present embodiment, the magnetic field detection device that outputs the output signal (V1-V2) according to the external magnetic field H, and includes four magnetic field detection magnets provided on the substrate 61. A bias magnetic field I _bias is applied to the resistance effect elements 101 and 102, the four reference magnetoresistive effect elements 111 and 112 provided on the substrate 61, and the magnetic field detection magnetoresistive effect elements 101 and 102, and the magnetic field A magnetic field applying wiring 151 for correcting an offset Hos in the magnetic field responsiveness of the detecting magnetoresistive effect elements 101 and _{102. The} reference magnetoresistive effect elements 111 and 112 and the magnetic field detecting magnetoresistive effect elements 101 and 102 are The fixed layer 70 composed of the antiferromagnetic layer 63 and the ferromagnetic layers 66 and 64 which are magnetic layers whose magnetization directions are fixed by the antiferromagnetic layer, and the magnetic field by the external magnetic field H, respectively. The magnetic layer applying wiring 151 has a structure in which a free layer 68 made of a magnetic layer whose direction is changed is stacked, and the magnetic field applying wiring 151 applies a magnetic field in the hard axis direction of the free layer of the magnetoresistive effect element 101.102 for detecting a magnetic field. The four reference magnetoresistive elements 111 and 112 are applied in a state of being antiparallel to the reference elements 111b and 112b in which the magnetization direction of the pinned layer 70 and the magnetization direction of the free layer 68 in the non-magnetic field are parallel to each other. The magnetoresistive effect elements 101 and 102 for magnetic field detection have a configuration in which the magnetization direction of the pinned layer 70 and the magnetization direction of the free layer 68 in the absence of a magnetic field are different. Thereby, even when the characteristics of the detection elements 101 and 102 have an offset with respect to the magnetic field, the offset of the reference elements 111 and 112 can be corrected accurately by using the resistance of the reference elements 111 and 112. The influence of the resistance variation of the magnetoresistive effect element is suppressed, a stable zero point is obtained, a detection error can be suppressed, a manufacturing process is easy, and a magnetic field detection device showing a stable output signal is obtained. be able to.

  The reference elements 111 and 112 and the detection elements 101 and 102 have the same area, the same shape, are arranged in directions rotated by 90 °, and the number of the elements is equal to each other. Thereby, the detection elements 101 and 102 and the reference elements 111 and 112 can be formed simultaneously, and the same resistance can be obtained.

Further, in a state where the offset _Hos is corrected by flowing a current _Ibias having a current value at which the output signal (V1-V2) becomes 0 in a state of no magnetic field in which no external magnetic field is applied, to the magnetic field application wiring 151, An output signal corresponding to the external magnetic field H is generated. Thereby, the magnetic balance method can be applied, and if the zero point is obtained, the linearity of the detection elements 111 and 112 is not required. As a result, the operation can be realized in a wide magnetic field range without depending on the element characteristics.

Embodiment 2. FIG.
FIG. 12 is a top view showing the configuration of the magnetic field detection apparatus according to Embodiment 2 of the present invention. The magnetic field detection apparatus shown here has two detection elements 101a and 101b and two reference elements 111a and 111b. These elements are the same as those described in the first embodiment, and detailed description of the configuration, manufacturing method, and operation is omitted here.

The detection elements 101 a and 101 b are connected in series by a metal wiring 51. The reference elements 111 a and 111 b are connected in series by a metal wiring 53. Further, the detection element 101 b and the reference element 111 a are connected by a metal wiring 58. The detection element 101 a is connected to a power source (not shown) by a metal wiring 55, and the reference element 111 b is grounded by a metal wiring 56. The metal wiring 58 is connected to a signal detection circuit (not shown) provided outside in order to detect the potential _Vout .

As in the first embodiment, a magnetic field application wiring 151 that is electrically insulated is disposed immediately below the detection elements 101a and 101b. The magnetic field application wiring 151 is arranged in a direction along the longitudinal direction of the detection elements 101a and 101b, and when current is passed, the magnetic field application wiring 151 is directed rightward (longitudinal) with respect to the detection elements 101a and 101b. The bias magnetic field _Hbias can be applied in a direction perpendicular to the direction (direction of hard axis). The resistances of the two reference elements 111a and 111b are set to R _m + ΔR / 2 and R _m −ΔR / 2, respectively, in the same manner as in the first embodiment.

  The cross-sectional structures and manufacturing methods of the detection elements 101a and 101b and the reference elements 111a and 111b are the same as those in the first embodiment, and a description thereof is omitted.

  Next, the detection operation of the magnetic field detection apparatus according to the present embodiment will be described with reference to FIG.

The metal wiring 55 is kept at a constant voltage _Vcc . At this time, since the metal wiring 56 is grounded, the potential V _out in the metal wiring 58 is ideally expressed by the following formula (4).

_{V out = V cc · 2R m} / (4R m + ΔR · H / H k) (4)

Thereby, an output signal of V _cc / 2 is obtained in the absence of a magnetic field, and a voltage depending on the external magnetic field H is obtained when a magnetic field is applied from the outside.

However, as in the first embodiment, this characteristic cannot be obtained if there is an offset in the magnetic field response of the detection element. For this reason, it is necessary to cancel the offset. Also in the present embodiment, as in the first embodiment, a current is applied to the magnetic field application wiring 151 and a bias magnetic field H _bias is applied to the detection elements 101a and 101b. Although 8 is similar to the description in, here, instead of the current _{I bias} becomes V1-V2 = _0, using the current _{I bias} to be V out = 1 / _{2V cc.} Therefore, instead of detecting V1-V2 in steps S1 and S4 in FIG. 8, instead of detecting _Vout and determining in step S2 whether V1-V2 is 0 or not, _Vout = 1 / 2V _In step S5, _Vout is converted into a magnetic field instead of converting V1-V2 into a magnetic field. By doing so, the same effects as in the first embodiment can be obtained in the second embodiment.

Here, an example in which the magnetic field application wiring 151 is disposed immediately below the detection elements 101a and 101b is shown, but is parallel to the film surface direction of the free layer of the detection elements 101a and 101b and orthogonal to the longitudinal direction. Therefore, the magnetic field application wiring 151 may be disposed immediately above the detection elements 101a and 101b. In this case, the direction of the magnetic field applied to the detection element is opposite to that described above. To avoid this, the same effect can be obtained by _changing the direction of the current I _bias to the opposite direction. can get.

  In the configuration of the present embodiment, similarly to the first embodiment, even when the resistance of the magnetoresistive effect element changes due to the manufacturing process or temperature, or when the magnetic field responsiveness of the detection element has an offset, The influence can be suppressed.

According to the second embodiment, the detection elements 101a and 101b and the two reference elements 111ab and 111a having the same area and the same shape and the same magnetization direction in a parallel state and an antiparallel state are used. Therefore, it is possible to obtain a resistance at the midpoint of the detection elements 101a and 101b. Detection element 101a, even when the offset H _OS magnetic field response of 101b is present, by comparison with the midpoint resistance, it is possible to correct the correct offset. As a result, a stable zero-point output can be obtained as in the first embodiment.

  These can be realized without complicating the manufacturing process.

As described above, the second embodiment is a magnetic field detection device that outputs an output signal (V _out ) according to the external magnetic field H, and includes two magnetic field detection magnetoresistors provided on the substrate 61. Magnetic field detection is performed by applying a bias magnetic field I _bias to the effect elements 101a and 101b, the two magnetoresistive effect elements for reference 111a and 111b provided on the substrate 61, and the magnetoresistive effect elements for magnetic field detection 101a and 101b. Magnetic resistance applying elements 151a and 111b and magnetic field detecting magnetoresistive elements 101a and 101b are provided with a magnetic field applying wiring 151 for correcting offset _Hos in the magnetic field responsiveness of the magnetoresistive elements 101a and 101b. Each of the fixed layers 7 is composed of an antiferromagnetic layer 63 and ferromagnetic layers 66 and 64 which are magnetic layers whose magnetization directions are fixed by the antiferromagnetic layer. 0 and a free layer 68 made of a magnetic layer whose magnetization direction is changed by an external magnetic field H, and the magnetic field applying wiring 151 is a free layer of the magnetoresistive effect elements 101a and 101b for detecting magnetic fields. The reference magnetoresistive elements 111a and 111b are applied for reference in a state in which the magnetization direction of the pinned layer 70 and the magnetization direction of the free layer 68 in the absence of a magnetic field are parallel. The element 111b and the reference element 111a in the antiparallel state are included, and the magnetoresistive effect elements 101a and 101b for detecting the magnetic field have a configuration in which the magnetization direction of the fixed layer 70 and the magnetization direction of the free layer 68 in a non-magnetic field are different. It was. Thereby, even when the characteristics of the detection elements 101a and 101b have an offset with respect to the magnetic field, the offset of the reference elements 111a and 111b can be corrected accurately, and the temperature and the manufacturing process can be corrected. The influence of the resistance variation of the magnetoresistive effect element is suppressed, a stable zero point is obtained, a detection error can be suppressed, a manufacturing process is easy, and a magnetic field detection device showing a stable output signal is obtained. be able to.

  The reference elements 111a and 111b and the detection elements 101a and 101b have the same area, the same shape, are arranged in directions rotated by 90 ° from each other, and the number thereof is configured to be equal to each other. Accordingly, the detection elements 101a and 101b and the reference elements 111a and 111b can be formed at the same time, and the same resistance can be obtained.

In addition, the state in which the offset _Hos is corrected by causing the current _Ibias having a current value at which the output signal ( _Vout ) is 1/2 _Vcc to flow in the magnetic field application wiring 151 in the absence of a magnetic field with no external magnetic field applied. Thus, an output signal (V _out ) corresponding to the external magnetic field H is generated. Thereby, the magnetic balance method can be applied, and if the zero point is obtained, the linearity of the detection elements 111a and 111b is not required. As a result, the operation can be realized in a wide magnetic field range without depending on the element characteristics.

Embodiment 3 FIG.
FIG. 13 shows a top view of the magnetic field detection apparatus according to the third embodiment of the present invention. The configuration shown in FIG. 13 is the same as that of the first embodiment shown in FIG. 5 except for the magnetic field application wiring 151A. Here, as shown in FIG. 13, the magnetic field application wiring 151A extends not only to the detection elements 101a, 101b, 102a, and 102b but also directly below the reference elements 111a, 111b, 112a, and 112b, The magnetic field application wiring 151 </ b> A is arranged to face a direction orthogonal to the longitudinal direction of each reference element. As shown in FIG. 13, the magnetic field applying wiring 151A according to the third embodiment is arranged in a U-shape so as to be folded back multiple times, so that the two reference elements 111a and 112a connected in series are arranged. Is applied with a magnetic field opposite to the magnetic field applied to the other elements. In the first embodiment, the detection elements 101a and 101b and the detection elements 102a and 102b are disposed adjacent to each other. However, in the third embodiment, the detection elements 101a and 101b The detection elements 102a and 102b are spaced apart from each other with a predetermined distance. Note that the folding angle of the magnetic field application wiring 151A is 90 ° in FIG. 13, but the present invention is not limited to this, and it may be bent so as to be U-shaped. Since the magnetic field application wiring 151A is composed of one wiring bent at least once at 180 °, it is easy to control the magnetization of the free layers of the detection element and the reference element. Since other configurations are the same as those in the first embodiment, the description thereof is omitted here.

  As shown in FIG. 13, the magnetic field applying wiring 151 </ b> A according to the third embodiment is arranged in the same direction as the longitudinal direction of the elements 101 b and 101 a immediately below the detection elements 101 b and 101 a, and then has a U shape. So that it is bent 90 degrees to the right so that it is placed in the same direction as the short direction of the reference elements 111a and 112a, and then becomes a U-shape. In this way, the reference element 112b, the detection elements 102b and 102a, and the reference element 111b are arranged in such a manner that they are bent 90 degrees to the left and passed directly under these elements in this order. At this time, the magnetic field applying wiring 151A is arranged in the short direction of the reference element 112b, the long direction of the detection elements 102b and 102a, and the short direction of the reference element 111b.

According to the third embodiment, the magnetic field H _bias applied to the detection elements 101a, 101b, 102a, and 102b is simultaneously applied also in the longitudinal direction of the reference elements 111a, 112a, 111b, and 112b. At this time, the magnetic field _{H bias} due to the wiring 151A, relative to the one of the reference elements 111a and 112a to the paper leftward direction, and has a paper rightward relative to the other reference device 111b and 112b. With this magnetic field, it is possible to increase the reversal magnetic field of the detection element by a magnetic field H _{bias with} respect to H _c . That is, it is possible to correct the offset in the magnetic field responsiveness of the detection element while stabilizing the resistance of the reference element.

  In this structure, since the effect of increasing the reversal magnetic field of the reference element can be obtained, the influence of the offset of the magnetic field response in the reference element can be suppressed.

  The cross-sectional structures and manufacturing methods of the detection elements 101a and 101b and the reference elements 111a and 111b are the same as those in the first embodiment, and a description thereof is omitted. Also, the detection operation of the magnetic field detection device is the same as that in the first embodiment, and thus the description thereof is omitted.

  If the above configuration and operation are used, in addition to the effect of the operation described with reference to FIG. 8, the magnetic balance method is used. Therefore, the characteristics of the detection element need only stably indicate the zero point, and are necessarily linear. There is no need.

  According to the third embodiment, it is possible to stably obtain the zero point of the magnetic field detection device, and to suppress the influence of the resistance change of the element due to the temperature and the manufacturing process and the offset of the magnetic field responsiveness. It is possible to realize a magnetic field detection device with the above operation.

In this example, the magnetic field application wiring 151A is arranged immediately below the reference elements 111a, 111b, 112a, and 112b. However, the free layer film surfaces of the detection elements 101a, 101b, 102a, and 102b are shown. The magnetic field may be applied in a direction parallel to the direction and perpendicular to the longitudinal direction thereof, and may be arranged directly above the detection element. In this case, the direction of the magnetic field applied to the detection element is opposite to that described above, but a similar effect can be obtained by using the reverse current _Ibias .

  Since the operation here is only different in the extending direction of the magnetic field application wiring 151A, the magnetic field detection device described in the first and second embodiments can be modified. FIG. 14 shows an example in which the magnetic field detection apparatus according to the second embodiment shown in FIG. 12 is modified according to the third embodiment. That is, in FIG. 14, the magnetic field applying wiring 151A is arranged not only immediately below the detection elements 101a and 101b shown in FIG. 12, but also directly below the reference elements 111a and 111b. The magnetic field application wiring 151 </ b> A is composed of one wiring folded back at 180 °. Other configurations, operations, and the like are the same as those in the second embodiment, and thus description thereof is omitted.

As described above, the third embodiment is a magnetic field detection device that outputs an output signal (V1-V2) corresponding to the external magnetic field H, as in the first embodiment. Four magnetic field detecting magnetoresistive effect elements 101 and 102 provided, four reference magnetoresistive effect elements 111 and 112 provided on the substrate 61, and magnetic field detecting magnetoresistive effect elements 101 and 102 are provided. by applying a bias magnetic field _{I bias,} and a magnetic field application wire 151A to correct the offset _{H os} in the magnetic field response of the magnetic field detecting magnetoresistive elements 101 and 102, the reference magnetoresistive elements 111 and 112 and the magnetic field The magnetoresistive effect elements 101 and 102 for detection are composed of an antiferromagnetic layer 63 and ferromagnetic layers 66 and 64 which are magnetic layers whose magnetization directions are fixed by the antiferromagnetic layer, respectively. The adhesion layer 70 and a free layer 68 made of a magnetic layer whose magnetization direction is changed by the external magnetic field H are laminated. The magnetic field application wiring 151A is formed by the magnetoresistance effect element 101.102 for detecting the magnetic field. A magnetic field is applied in the direction of the hard axis of the free layer, and the four magnetoresistive elements 111 and 112 for reference refer to a state in which the magnetization direction of the fixed layer 70 and the magnetization direction of the free layer 68 in the absence of a magnetic field are parallel. Element 111b, 112b and reference elements 111a, 112a in an antiparallel state. Magnetic field detecting magnetoresistive elements 101, 102 are magnetized in the magnetization direction of pinned layer 70 and free layer 68 in the absence of a magnetic field. The configuration is different from the direction. Thereby, even when the characteristics of the detection elements 101 and 102 have an offset with respect to the magnetic field, the offset of the reference elements 111 and 112 can be corrected accurately by using the resistance of the reference elements 111 and 112. The influence of the resistance variation of the magnetoresistive effect element is suppressed, a stable zero point is obtained, a detection error can be suppressed, a manufacturing process is easy, and a magnetic field detection device showing a stable output signal is obtained. be able to.

  The reference elements 111 and 112 and the detection elements 101 and 102 have the same area, the same shape, are arranged in directions rotated by 90 °, and the number of the elements is equal to each other. Thereby, the detection elements 101 and 102 and the reference elements 111 and 112 can be formed simultaneously, and the same resistance can be obtained.

Further, in a state where the offset _Hos is corrected by flowing a current _Ibias having a current value at which the output signal (V1-V2) becomes 0 in a state of no magnetic field in which no external magnetic field is applied, to the magnetic field application wiring 151, An output signal corresponding to the external magnetic field H is generated. Thereby, the magnetic balance method can be applied, and if the zero point is obtained, the linearity of the detection elements 111 and 112 is not required. As a result, the operation can be realized in a wide magnetic field range without depending on the element characteristics.

Further, the detection magnetoresistive element 101a, 101b, 102a, a magnetic field application wire 151A for applying a magnetic field _{H bias} to 102b, at the same time, the reference magnetoresistive element 111a, 111b, 112a, the magnetic field _{H bias} to 112b Since the structure is applied, the magnetization of the free layer 68 of the reference elements 111a, 111b, 112a, 112b can be easily controlled.

Embodiment 4 FIG.
By using the magnetic field detection device according to the first to third embodiments of the present invention, a current detection device capable of outputting a stable zero point can be realized. FIG. 15 shows the configuration. FIG. 15 shows an example using the magnetic field detection apparatus according to the first embodiment shown in FIG. 15 differs from the configuration in FIG. 15 in that a metal wiring 152 through which a current to be measured by the current detection device flows is added to the configuration in FIG. Other configurations are the same as those in FIG.

The metal wiring 152 through which the current I _line to be measured flows is electrically insulated from the magnetoresistive effect element, and is disposed immediately below or immediately above the detection elements 101a, 101b, 102a, 102b. When the current I _line flows, an annular magnetic field H _line is generated in a direction perpendicular to the metal wiring 152 by the action of the current. The magnitude of the annular magnetic field H _line is expressed by the following equation (5).

H _line = k · I _line / r (5)

In the above formula (5), k is a proportionality constant, and r is the distance from the metal wiring 152 to the detection element 101a, 101b, 102a or 102b. If the distance r between the detection element 101a, 101b, 102a or 102b and the metal wiring 152 is measured, the proportionality constant k is known, so that the current I _line is measured by measuring the magnetic field H _line. Is possible.

  A magnetic field detector using a spin valve magnetoresistive element detects a magnetic field component along the pinned layer magnetization direction. For this reason, the magnetic field direction is always suitable for magnetic field detection in the same direction. The magnetic field generated by the current whose position and position of the metal wiring 152 are fixed is always in the same direction. For this reason, the magnetic field detection apparatus shown in the first embodiment is also suitable for current detection by detecting a magnetic field.

Further, according to the present embodiment, it is possible to detect the current I _line in the metal wiring 152 provided in the semiconductor integrated circuit or the like by using the effect described in the first embodiment. When applied to a semiconductor integrated circuit, the distance between the detection elements 101 and 102 and the wiring 152 which is the object to be measured is determined by the interlayer insulating film, and therefore the detection elements 101 and 102 and the wiring 152 which is the measurement object. Can be reduced, and as a result, a highly sensitive current can be detected.

  FIG. 16 shows an example of a semiconductor integrated circuit to which this is applied. In the semiconductor integrated circuit of FIG. 16, a memory unit 204 and an arithmetic circuit unit 205 are connected to a power supply unit 202 that supplies power by power lines 206 and 207 and power is supplied. These power supply lines 206 and 207 are provided with a current detection device 201 configured by a magnetic field detection device. The current detection device 201 constantly detects the currents of the power supply lines 206 and 207 of the memory unit 204 and the arithmetic circuit unit 205 and feeds back the detected current value to the control circuit 203.

  According to this configuration, it is possible to realize current detection with high accuracy and high sensitivity without affecting the semiconductor integrated circuit. As a result, the power consumption of the semiconductor integrated circuit can be reduced by monitoring and feedbacking the operation status of the semiconductor integrated circuit depending on the environment.

  Since the current is detected by a magnetic field in this operation, the magnetic field detection device described in Embodiments 1 to 3 can be applied. FIG. 17 shows an application example of the magnetic field detection apparatus shown in Embodiment 2 as an example.

  As described above, in the present embodiment, since the current detection device is configured using the magnetic field detection device shown in the first to third embodiments, the magnetic field detection device of the first to third embodiments described above. Is applied, the effects obtained in the first to third embodiments are obtained, and a stable current detection device can be realized.

  In the present embodiment, since the semiconductor integrated circuit includes the current detection device using the magnetic field detection device described in the first to third embodiments, the power consumption of the semiconductor integrated circuit can be reduced, and Integration of the functions of the magnetic field detection device and the current detection device can also be realized.

  In the first to fourth embodiments described above, the magnetic field detection device and the current detection device using the magnetic field detection device have been described. However, the present invention is not limited thereto, and any device can be used as long as the device under test generates a magnetic field. It can be widely applied to other similar devices.

  In addition, although it is preferable to use a tunnel magnetoresistive effect element as the magnetoresistive effect element, the present invention is not limited to this, and other magnetoresistive effect elements such as a giant magnetoresistive effect element including a ferromagnetic layer in which one magnetization direction is fixed are used. A magnetoresistive element may be used.

  1, 101, 102 Magnetoresistive effect element for detection (detection element), 2 Magnetization direction of free layer in non-magnetic field, 2a Magnetization direction of free layer when magnetic field is applied, 3 Magnetization direction of pinned layer, 11, 111, 112 Reference magnetoresistance effect element (reference element), 51, 52, 53, 54, 55, 56, 57, 58 Metal wiring, 61 Substrate, 62 Lower electrode layer, 63 Antiferromagnetic layer, 64, 66 Ferromagnetic layer, 65 Nonmagnetic layer, 67 Tunnel insulating layer, 68 Free layer, 69 Upper electrode layer, 70 Fixed layer, 151 Magnetic field application wiring (wiring), 152 Metal wiring, 201 Current detection device.

Claims (4)

A magnetic field detection device that outputs an output signal corresponding to an external magnetic field,
Two or more magnetoresistive elements for detecting a magnetic field provided on a substrate;
Two or more reference magnetoresistive elements provided on the substrate;
A bias magnetic field application wiring for applying a magnetic field in the direction of the hard axis of the free layer of the magnetoresistive effect element for magnetic field detection,
The magnetoresistive effect element for reference and the magnetoresistive effect element for magnetic field detection are each composed of an antiferromagnetic layer and a fixed layer composed of a magnetic layer whose magnetization direction is fixed by the antiferromagnetic layer, and an external magnetic field. It has a structure in which a free layer made of a magnetic layer whose magnetization direction changes is laminated,
The two or more reference magnetoresistive effect elements include ones in which the magnetization direction of the pinned layer and the magnetization direction of the free layer in a non-magnetic field are parallel and anti-parallel,
Wherein the magnetic field detecting magnetoresistive element, Ri and magnetization direction Do different under no magnetic field of the free layer and the magnetization direction of the pinned layer,
The bias magnetic field applying wiring for applying a magnetic field to the detection magnetoresistive effect element simultaneously applies the magnetic field to the reference magnetoresistive effect element . A current detection device using the magnetic field detection device according to claim 1 . A semiconductor integrated circuit comprising the current detection device according to claim 2 . A magnetic field detection method for outputting an output signal corresponding to an external magnetic field,
Two or more magnetoresistive effect elements for magnetic field detection provided on a substrate, two or more magnetoresistive effect elements for reference provided on the substrate, and a free layer of the magnetoresistive effect element for magnetic field detection Preparing a magnetic field detection device comprising a bias magnetic field application wiring for applying a magnetic field in the direction of the hard axis of magnetization;
In a state where a magnetic field is applied in the direction of the hard axis of the free layer of the magnetoresistive effect element for magnetic field detection by flowing a bias current through the bias magnetic field application wiring in a magnetic field without applying the external magnetic field, Detecting the output signal;
Determining whether the output signal is a predetermined value, and obtaining a value of the bias current at which the output signal becomes a predetermined value;
A state in which a bias magnetic field is applied to the magnetoresistive element for detecting a magnetic field by flowing the bias current at which the output signal has a predetermined value through the bias magnetic field applying wiring under a magnetic field to which the external magnetic field is applied And detecting the output signal, and
The magnetoresistive effect element for reference and the magnetoresistive effect element for magnetic field detection are each composed of an antiferromagnetic layer and a fixed layer composed of a magnetic layer whose magnetization direction is fixed by the antiferromagnetic layer, and an external magnetic field. It has a structure in which a free layer made of a magnetic layer whose magnetization direction changes is laminated,
The two or more reference magnetoresistive effect elements include ones in which the magnetization direction of the pinned layer and the magnetization direction of the free layer in a non-magnetic field are parallel and anti-parallel,
In the magnetoresistive effect element for detecting a magnetic field, the magnetization direction of the pinned layer and the magnetization direction of the free layer in the absence of a magnetic field are different.
Magnetic field detection method.

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