JP3596600B2 - Magnetic sensor and method of manufacturing the same - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
According to the present invention, a fixed magnetic layer in which the direction of magnetization is fixed to a predetermined direction, a free magnetic layer in which the direction of magnetization changes in accordance with an external magnetic field, and a pinned layer between the fixed magnetic layer and the free magnetic layer The present invention relates to a magnetic sensor using a magnetic tunnel effect element including an insulating layer and a method for manufacturing the same .
[0002]
[Prior art]
Conventionally, a magnetoresistive effect element (AMR element) using an anisotropic MR effect or a giant magnetoresistive element (GMR element) using a giant magnetoresistive effect has been widely known. On the other hand, recently, a magnetic tunnel effect element (TMR element) has been attracting attention as an element having a higher magnetoresistance ratio and a higher sensitivity than an AMR element or a GMR element, and application development of the element to a magnetic sensor has been advanced. ing.
[0003]
[Problems to be solved by the invention]
However, there is a problem that the magnetic tunnel effect element is difficult to use as a magnetic sensor because of its poor temperature characteristics. As an example, FIG. 8 shows a result of measuring a resistance value (output) of a predetermined magnetic tunnel effect element with respect to an external magnetic field when the environmental temperature is changed to 25, 90, and 150 ° C. As can be understood from FIG. 8 , even if the external magnetic field is largely different, the resistance value indicated by the element may be the same due to a change in the environmental temperature. Therefore, such an element is used as it is in the magnetic sensor. It is difficult.
[0004]
FIG. 9 shows the maximum and minimum values of the resistance value at each environmental temperature by taking the environmental temperature on the horizontal axis and the resistance value of the element on the vertical axis based on the measurement results shown in FIG. And solid lines. Generally, in order to detect whether the direction of a magnetic field is a predetermined direction or the direction opposite to the predetermined direction, it is necessary to determine whether the output of the magnetic sensor is equal to or more than a predetermined threshold. However, as understood from FIG. 9 , in this element, it is difficult to set an appropriate threshold value for performing such detection in an environmental temperature range of 25 to 150 ° C. (one point in the drawing). See dashed line).
[0013]
[Overview of the present invention]
Features of the present invention includes a fixed magnetization layer of hard magnetic magnetization direction is fixed in a predetermined orientation, and the free magnetic layer of the soft magnetic varying magnetization direction in response to an external magnetic field, the pinned magnetic layer and A magnetic tunnel effect element comprising an insulating layer sandwiched between the free magnetic layers, a magnetic tunnel effect element comprising a magnetically shielded and a non-magnetically shielded one constituting a full bridge circuit, thereby constituting a magnetic sensor. It is in.
[0014]
Specifically, features of the present invention includes a DC voltage source, the free pinned magnetic layer and the magnetization direction of the hard magnetic orientation is fixed in a predetermined orientation of magnetization of the soft magnetism changes according to an external magnetic field A magnetic tunnel effect element comprising a magnetic layer and an insulating layer sandwiched between the fixed magnetic layer and the free magnetic layer, wherein the magnetic tunnel effect element is magnetically shielded. A pair of circuit elements formed by connecting one end of the magnetic tunnel effect element and one end of the magnetic tunnel effect element which is not magnetically shielded, and the fixed magnetization of each of the magnetic unshielded magnetic tunnel effect elements of the pair of circuit elements The same pair of circuit elements are disposed so that the magnetization directions of the layers are substantially the same, and the other end of the magnetic tunnel effect element of one of the pair of circuit elements, which is not magnetically shielded. The other end of the magnetically shielded magnetic tunnel effect element is connected to a positive electrode and a negative electrode of the DC voltage source, respectively, and the non-magnetically shielded magnetic tunnel effect of the other circuit element of the pair of circuit elements is connected. The other end of the element and the other end of the magnetically shielded magnetic tunnel effect element are connected to a negative electrode and a positive electrode of the DC voltage source, respectively, and the magnetically shielded magnetic tunnel effect element of the pair of circuit elements and It is configured to output a potential difference between each connection point with a magnetic tunnel effect element that is not magnetically shielded. The “magnetic tunnel effect element” includes a “magnetic tunnel effect element group in which a plurality of magnetic tunnel effect elements in which the fixed magnetization directions of the fixed magnetization layers are substantially the same are electrically connected in series”. . This is the same for the other features of the present invention.
[0015]
According to this, as shown in FIG. 3, the output voltage of the full bridge circuit is Vout, the voltage of the DC voltage source is Vin, and the resistance of the magnetic tunnel effect element when no external magnetic field is applied to the element. The value of R0 is a sufficiently large external magnetic field, and the change in resistance when a magnetic field in the same or opposite direction to the magnetization direction of the fixed magnetization layer is applied to the magnetic tunnel effect element not magnetically shielded is -ΔRd, When ΔRu is set, the maximum value Vmax and the minimum value Vmin of the output voltage Vout are expressed by the following equations (3) and (4).
[0016]
Vmax = Vin / (1 + 2 · (R0 / ΔRu)) Equation 3
[0017]
Vmin = Vin / (1-2 · (R0 / ΔRd)) Equation 4
[0018]
According to Equations 3, 4 and the measurement of FIG. 8 , when the environmental temperature changes in the range of 25 to 150 ° C., the maximum value Vmax changes between 0.0317 Vin and 0.0239 Vin. On the other hand, the minimum value Vmin varies between -0.0339 Vin and -0.0239 Vin. That is, according to the above configuration, the difference between the maximum value Vmax and the minimum value Vmin (0.0656 Vin to 0.0478 Vin) of the output voltage Vout due to the environmental temperature of the output voltage Vout (for example, the maximum value Vmax) (0.0317Vin-0.0239Vin = 0.0078Vin, fluctuation due to the minimum temperature Vmin due to the environmental temperature = 0.0239Vin-0.0339Vin = 0.010Vin) is sufficiently small. Further, the magnetic tunnel effect element generally has a resistance change characteristic on the order as shown in FIG . Accordingly, the magnetic sensor having the above configuration has improved temperature characteristics as a result.
[0019]
FIG. 4 shows the maximum value Vmax (line A) and the minimum value Vmin (line B) of the output voltage Vout with respect to the environmental temperature when the magnetic tunnel effect element used in the measurement of FIG. 8 constitutes the full bridge circuit. FIG. As can be understood from FIG. 4, in the magnetic sensor, the maximum value Vmax and the minimum value Vmin of the output voltage Vout do not become the same value even when the environmental temperature changes. Thereby, the threshold value for detecting the change in the direction of the external magnetic field can be set over the entire environmental temperature range (see line C). That is, the full-bridge magnetic sensor can reliably detect the change in the direction of the external magnetic field even when the environmental temperature changes in a wide range.
[0020]
In the above-described magnetic sensor of the present invention, the fixed magnetic layer includes a magnetized ferromagnetic film and a ferromagnetic film whose magnetization direction is fixed in cooperation with the magnetized ferromagnetic film. May be. The fixed magnetic layer includes a ferromagnetic film made of a magnetized CoCr-based metal and a ferromagnetic film made of NiFe whose magnetization direction is fixed in cooperation with the magnetized ferromagnetic film. It can be done.
[0021]
Another feature of the present invention is that a fixed magnetic layer made of a hard magnetic layer whose magnetization direction is fixed to a predetermined direction and a soft magnetic layer made of a magnetic layer whose magnetization direction changes in accordance with an external magnetic field. A magnetic tunnel effect element comprising: a free magnetic layer; and an insulating layer sandwiched between the fixed magnetic layer and the free magnetic layer, wherein the magnetically shielded magnetic tunneling element and the non-magnetically shielded magnetic In a method of manufacturing a magnetic sensor including a tunnel effect element, a magnetic layer to be the fixed magnetic layer, a magnetic layer to be the free magnetic layer, and an insulating layer sandwiched between the two magnetic layers. Forming a plurality of laminated bodies on a single substrate, and performing magnetic shielding on the laminated body to be the magnetically shielded magnetic tunnel effect element among the plurality of laminated bodies, and Cannot be shielded by shielding By imparting degrees strong magnetic field is characterized by including a step of fixing the magnetization direction of the fixed magnetization layer by magnetizing the same laminate.
[0022]
According to this, it is possible to provide a magnetic sensor including a magnetic tunnel effect element that is not magnetically shielded and a magnetically shielded tunnel effect element.
[0023]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, each embodiment of the magnetic sensor using the magnetic tunnel effect element according to the present invention will be described from the magnetic tunnel effect element commonly used in each embodiment. Figure 5 is a schematic cross-sectional view showing a part of such a magnetic tunnel effect element, FIGS. 6 and 7 are schematic plan view of a magnetic tunnel effect element corresponding to FIG.
[0024]
This magnetic tunnel effect element has a substrate 10 made of, for example, SiO ₂ / Si, glass or quartz. On the substrate 10, a plurality of lower electrodes 11 having a rectangular planar shape are arranged in a row at predetermined intervals in a horizontal direction, and the lower electrodes 11 are made of a conductive non-magnetic metal material of Cr ( Or, it is formed to a thickness of about 10 nm by Ti). On each lower electrode 11, a ferromagnetic film 12 formed of a CoCr-based metal (for example, CoPtCr) and having a thickness of about 30 nm is formed in the same plane shape as the lower electrode 11. The ferromagnetic film 12 is magnetized in the direction of the arrow in FIG .
[0025]
On each ferromagnetic film 12, a pair of ferromagnetic films 13, 13 made of NiFe and having a thickness of about 5 nm are laminated at intervals. The ferromagnetic films 13 and 13 have a rectangular shape (for example, 20 × 12 μm) in plan view, and have their long sides opposed in parallel, and each short side corresponds to the magnetization direction of the ferromagnetic film 12. They are arranged to be the same. The ferromagnetic film 13 constitutes a fixed magnetic layer (fixed layer) which is a hard magnetic film whose magnetization direction is fixed in cooperation with the ferromagnetic film 12. As a result, it is magnetized in the short side direction as shown in FIG .
[0026]
On each ferromagnetic film 13, an insulating layer 14 having the same planar shape as the ferromagnetic film 13 is formed. Insulating layer 14 is made of Al ₂ O ₃ is an insulating material, its thickness is formed to be about 3 to 4 nm.
[0027]
On the insulating layer 14, a ferromagnetic film 15 having the same planar shape as the insulating layer 14 is formed. The ferromagnetic film 15 has a two-layer structure in which a Co film having a thickness of about 2 nm in contact with the insulating layer 14 is a lower layer, and a NiFe film having a thickness of about 60 nm in contact with the Co film is an upper layer. The ferromagnetic film 15 constitutes a free magnetic layer which is a soft magnetic magnetic film whose magnetization direction changes in accordance with the direction of an external magnetic field, and includes a fixed magnetic layer composed of the ferromagnetic films 12 and 13 and the insulating layer. 14 form a magnetic tunnel junction structure.
[0028]
On each ferromagnetic film 15, a dummy film 16 having the same planar shape as each of the ferromagnetic films 15 is formed. The dummy film 16 is made of a conductive non-magnetic metal material made of a Mo film having a thickness of about 30 nm.
[0029]
In a region covering the substrate 10, the lower electrode 11, the ferromagnetic films 12, 13, the insulating layer 14, the ferromagnetic film 15 and the dummy film 16, the plurality of lower electrodes 11 and the ferromagnetic film 12 are insulated and separated from each other. An interlayer insulating layer 17 for insulating and isolating a pair of ferromagnetic films 13, an insulating layer 14, a ferromagnetic film 15, and a dummy film 16 provided on the ferromagnetic film 12 is provided. The interlayer insulating layer 17 is made of, for example, SiO ₂ and has a thickness of about 250 nm.
[0030]
In the interlayer insulating film 17, contact holes 17a are formed on the respective dummy films 16. This contact hole 17a is buried and, for example, a 300 nm-thick Al film is formed so as to electrically connect one of the pair of dummy films 16 provided on the different lower electrode 11 and the ferromagnetic film 12 to each other. Upper electrodes 18 are formed. As described above, the lower electrode 11, the ferromagnetic film 12, and the upper electrode 18 allow the ferromagnetic films 15, 15 (dummy films 16, 16) and the ferromagnetic films 12 of the pair of magnetic tunnel junctions adjacent to each other. , 12 are alternately and sequentially electrically connected to each other, and a magnetic tunnel effect element (magnetic tunnel effect element group) in which a plurality of magnetic tunnel junction structures having the same magnetization direction in the fixed magnetization layer are connected in series. It is formed.
[0031]
FIG. 8 shows that 500 magnetic tunnel effect elements (one magnetic tunnel effect element has a set of fixed magnetic layer, insulating layer, and free magnetic layer) in a 2 × 2 mm ² region on the substrate 10 . Therefore, FIG. 5 shows four magnetic tunnel effect elements.) FIG. 5 is a diagram showing the temperature characteristics of a sample in which these elements are electrically connected in series. In this figure, lines A, B, and C show changes in the resistance value of the same sample to an external magnetic field when the environmental temperature was changed to 25, 90, and 150 ° C., respectively. As can be understood from FIG. 8, even when the external magnetic field is largely different, the resistance value indicated by the sample may be the same depending on the environmental temperature. Have difficulty.
[0032]
Next, each embodiment of the magnetic sensor with improved temperature characteristics according to the present invention will be individually described.
[0033]
(1st Embodiment)
The magnetic sensor according to the first embodiment shown in FIG. 1 has a magnetic tunnel effect element 31 formed on a substrate 30 corresponding to the substrate 10 in FIG. 5 , and a magnetic shield formed on the substrate 30. And a magnetic tunnel effect element 32. As shown in FIGS. 5 to 7 , each of the magnetic tunnel effect elements 31 and 32 is formed by connecting a plurality of (for example, 500) magnetic tunnel effect elements having the same configuration in series. The magnetization directions of the fixed magnetic layers of the plurality of magnetic tunnel effect elements constituting the magnetic tunnel effect elements 31 and 32 are all in the same direction (the direction indicated by the arrow in FIG. 1).
[0034]
In this magnetic sensor, a magnetic tunnel effect element 31 that is not magnetically shielded and a magnetic tunnel effect element 32 that is magnetically shielded are connected in series, and a DC constant voltage source 33 is connected in series with this. It is constituted by a half bridge circuit which takes out the voltage between both ends of the effect element 32 as an output voltage Vout.
[0035]
This magnetic sensor can be manufactured through the steps described below. That is, a laminate having layers corresponding to the layers 11 to 18 shown in FIG. 5 is formed on the substrate 30, and then the above half bridge circuit is formed. Thereafter, the laminated body to be the magnetic tunnel effect element 32 is covered with a soft magnetic material, and the laminated body is magnetically shielded. Lastly, the stacked body is magnetized (magnetized) by applying a strong magnetic field to the whole that cannot be shielded by the magnetic shield, whereby the magnetizations of the fixed magnetization layers of the magnetic tunnel effect elements 31 and 32 are changed. Fix the orientation of.
[0036]
In the magnetic sensor thus configured, since the magnetic tunnel effect element 32 is magnetically shielded, the resistance value of the element 32 is a constant value R0 regardless of the external magnetic field. On the other hand, when a sufficiently large external magnetic field in the same direction as the magnetization direction of the fixed magnetic layer of the magnetic tunnel effect element 31 is applied to the magnetic tunnel effect element 31, the resistance value of the element 31 becomes R0-ΔRd. When a sufficiently large external magnetic field in the opposite direction to the magnetization direction of the fixed magnetic layer of the magnetic tunnel effect element 31 is applied to the magnetic tunnel effect element 31, the resistance value of the element 31 becomes R0 + ΔRu. Therefore, assuming that the voltage of the DC voltage source 33 is Vin, the maximum value Vmax of the output voltage Vout is represented by Vmax = Vin / (2- (ΔRd / R0)) (Equation 1), and the minimum value Vmin is Vmin = Vin / (2+ (ΔRu / R0)) (Expression 2)
[0037]
Incidentally, the magnetic tunnel effect element has such a characteristic that even when the environmental temperature changes, the amount of change of ΔRd / R0 in the above equation (1) and ΔRu / R0 in the above equation (2) is small. For example, in the measurement example of FIG. 8 , ΔRd / R0 and ΔRu / R0 are about 0.065, 0.056, and 0.049, respectively, for the environmental temperatures of 25, 90, and 150 ° C., respectively. Accordingly, the maximum value Vmax of the output voltage Vout of the magnetic sensor is approximately 0.516 Vin, 0.514 Vin, and 0.513 Vin, respectively, for environmental temperatures of 25, 90, and 150 ° C. Further, the minimum value Vmin of the output voltage Vout of the magnetic sensor is approximately 0.484 Vin, 0.486 Vin, and 0.488 Vin for the environmental temperatures of 25, 90, and 150 ° C., respectively. That is, even when the environmental temperature changes, the maximum value Vmax of the output voltage Vout of the magnetic sensor is a substantially constant value of about 0.51 Vin, and the minimum value Vmin of the output voltage Vout is about 0.48 Vin. It becomes a constant value. Therefore, the magnetic sensor having the above characteristics has good temperature characteristics.
[0038]
As can be understood from FIG. 2 showing the maximum value Vmax and the minimum value Vmin of the output voltage Vout with respect to the environmental temperature of the magnetic sensor, the maximum value Vmax (line A) and the minimum value Vmin (line B) are as described above. The same value is not obtained over the entire range of the environmental temperature. As a result, the threshold for detecting a change in the direction of the external magnetic field (a value corresponding to the output voltage Vout when the external magnetic field is “0”) is set over the entire range of the environmental temperature as indicated by the line C. You can set a crossover. Therefore, the magnetic sensor can reliably detect a change in the direction of the external magnetic field even when the environmental temperature changes in a wide range.
[0039]
(Modification of First Embodiment)
In the modified example of the first embodiment, as shown by a broken line in FIG. 1, instead of setting the voltage between both ends of the magnetically shielded magnetic tunnel effect element 32 as the output voltage Vout, the voltage between both ends of the magnetic tunnel effect element 31 is changed. The output voltage is V'out, and the other parts are the same as in the first embodiment.
[0040]
In this case, the maximum value V'max and the minimum value V'min of the output voltage V'out are obtained by subtracting the minimum value Vmin of Expression 2 and the maximum value Vmax of Expression 1 from the voltage Vin of the DC constant voltage source 33, respectively. Value. Therefore, even when the output is taken out in this manner, the maximum value V'max and the minimum value V'min of the output voltage V'out are substantially constant regardless of the ambient temperature. That is, this magnetic sensor has improved temperature characteristics and can accurately detect a change in the direction of the external magnetic field.
[0041]
(2nd Embodiment)
The magnetic sensor according to the second embodiment shown in FIG. 3 includes magnetic tunnel effect elements 41 and 44 formed on a substrate 40 corresponding to the substrate 10 in FIG. Magnetic tunnel effect elements 42 and 43 provided. Each of the magnetic tunnel effect elements 41 to 44, as shown in FIGS. 5 to 7, a plurality of the same configuration (e.g., 500) are those of the magnetic tunnel effect element connected in series, the magnetic tunnel effect The magnetization directions of the fixed magnetic layers of the plurality of magnetic tunnel effect elements constituting each of the elements 41 to 44 are all fixed in the same direction (the direction indicated by the arrow in FIG. 3).
[0042]
In this magnetic sensor, one circuit element is formed by connecting one end of the magnetic tunnel effect element 41 that is not magnetically shielded and one end of the magnetic tunnel effect element 42 that is magnetically shielded. One end of the magnetic tunnel effect element 43 and one end of the magnetic tunnel effect element 44 not magnetically shielded are connected to form another circuit element. This pair of circuit elements is connected to a DC It constitutes a bridge circuit.
[0043]
That is, the other end of the magnetic tunnel effect element 41 and the other end of the magnetic tunnel effect element 42 are respectively connected to the positive electrode and the negative electrode of the DC constant voltage source 45, and the other end of the magnetic tunnel effect element 43 and the magnetic tunnel effect element 44 Are connected to the positive and negative electrodes of the DC constant voltage source 45, respectively. Also, the magnetic tunnel effect element 41 and the magnetic tunnel effect element 41 are arranged such that the fixed magnetization direction of the fixed magnetic layer of the magnetic tunnel effect element 41 and the fixed magnetization direction of the fixed magnetic layer of the magnetic tunnel effect element 44 are substantially the same. 44 are provided. Then, the potential at the connection point between the magnetic tunnel effect element 41 and the magnetic tunnel effect element 42 and the potential at the connection point between the magnetic tunnel effect element 43 and the magnetic tunnel effect element 44 are extracted, and the potential difference between these connection points is obtained. The output voltage Vout of the magnetic sensor is configured.
[0044]
In this magnetic sensor, a laminate having layers corresponding to the layers 11 to 18 shown in FIG. 5 is formed on a substrate 40, and these laminates are connected as described above to form a full bridge circuit. The laminated body to be the magnetic tunnel effect elements 42 and 43 is covered with a soft magnetic material to perform magnetic shielding, and finally, a strong magnetic field that cannot be shielded by the magnetic shielding is applied to the entire body to form the laminated body. It is manufactured by magnetizing the body, thereby fixing the magnetization direction of the fixed magnetization layers of the magnetic tunnel effect elements 41 to 44.
[0045]
In the magnetic sensor thus configured, since the magnetic tunnel effect elements 42 and 43 are magnetically shielded, the resistance value of the elements 42 and 43 is a constant value R0 regardless of the external magnetic field. On the other hand, when no external magnetic field is applied to the magnetic tunnel effect elements 41 and 44, the resistance values of the elements 41 and 44 also become R0. When a sufficiently large external magnetic field in the same or opposite direction as the magnetization of the fixed magnetic layer of these elements is applied to the magnetic tunnel effect elements 41 and 44, the resistances of the elements 41 and 44 become R0-Rd, respectively. Or R0 + Ru. At this time, the maximum value Vmax of the output voltage Vout is Vmax = Vin / (1 + 2 (R0 / ΔRu)) (Equation 3), and the minimum value Vmin is Vmin = Vin / (1-2 · (R0 / ΔRd)). ) (Expression 4)
[0046]
According to Equations 3, 4 and the measurement of FIG. 8 , when the environmental temperature changes in the range of 25 to 150 ° C., the maximum value Vmax changes between 0.0317 Vin and 0.0239 Vin. On the other hand, the minimum value Vmin varies between -0.0339 Vin and -0.0239 Vin. That is, according to the above configuration, the difference between the maximum value Vmax and the minimum value Vmin (0.0656 Vin to 0.0478 Vin) of the output voltage Vout due to the environmental temperature of the output voltage Vout (for example, the maximum value Vmax) (0.0317Vin-0.0239Vin = 0.0078Vin, fluctuation due to the minimum temperature Vmin due to the environmental temperature = 0.0239Vin-0.0339Vin = 0.010Vin) is sufficiently small. On the other hand, the difference ΔRmm (approximately 0.15 to 0.20Ω) between the maximum value Rmax and the minimum value Rmin of the resistance value of the sample used for the measurement in FIG . 13 to 0.20Ω). From the above, it is understood that the magnetic sensor according to the second embodiment has improved temperature characteristics. Further, the magnetic tunnel effect element generally has a resistance change characteristic on the order as shown in FIG . Accordingly, the magnetic sensor having the above configuration has improved temperature characteristics as a result.
[0047]
FIG. 4 shows the maximum value Vmax (line A) and the minimum value Vmin (line B) of the output voltage Vout with respect to the environmental temperature when the magnetic tunnel effect element used in the measurement of FIG. 8 constitutes the full bridge circuit. FIG. As can be understood from FIG. 4, as a result of the improvement in the temperature characteristics, the maximum value Vmax and the minimum value Vmin of the output voltage Vout do not take the same value even if the environmental temperature changes. Thereby, the threshold value for detecting the change in the direction of the external magnetic field can be set over the entire environmental temperature range (see line C). That is, the full-bridge magnetic sensor can reliably detect a change in the direction of the external magnetic field even when the environmental temperature changes over a wide range.
[0048]
As described above, according to each embodiment (and the modification) of the present invention, a magnetic sensor having improved temperature characteristics as compared with the case of detecting the resistance change of a single magnetic tunnel effect element group is provided. Provided. Further, since the maximum value Vmax and the minimum value Vmin of the output voltage Vout do not take the same value in the entire region where the environmental temperature can change, a certain threshold value for detecting the direction of the external magnetic field is set between them. Can be set. As a result, a sensor suitable for a sensor for detecting magnetic information or rotation of an object by changing an external magnetic field with a medium (magnetic medium) or a magnet rotor has been provided.
[0049]
Note that the present invention is not limited to the above embodiment, and various modifications can be adopted within the scope of the present invention. For example, in many of the above embodiments has been formed all of the magnetic tunnel effect elements on the same substrate, each magnetic tunnel effect element group formed in individual different substrates, and these were connected by wire Each bridge circuit may be configured.
[Brief description of the drawings]
FIG. 1 is a schematic plan view of a magnetic sensor according to a first embodiment of the present invention.
FIG. 2 is a diagram illustrating output voltages with respect to an external magnetic field of the magnetic sensors according to the first embodiment and the third embodiment with respect to an ambient temperature.
FIG. 3 is a schematic plan view of a magnetic sensor according to a second embodiment of the present invention.
4 is a diagram showing an output voltage of the magnetic sensor shown in FIG. 3 with respect to an external magnetic field with respect to an ambient temperature.
FIG. 5 is a schematic sectional view showing a part of a magnetic tunnel effect element used in each embodiment of the present invention.
6 is a schematic plan view of the magnetic tunnel effect element shown in FIG . 5 from which an interlayer insulating film and a substrate are omitted.
7 is a schematic plan view of a ferromagnetic film forming the fixed magnetic layer of the magnetic tunnel effect element shown in FIG.
FIG. 8 is a diagram showing a change in resistance of a certain magnetic tunnel effect element with respect to an external magnetic field for each environmental temperature;
FIG. 9 is a diagram showing changes in the maximum value and the minimum value of the resistance value of the magnetic tunnel effect element obtained with the result of FIG . 8 with respect to the environmental temperature.
[Explanation of symbols]
10, 30, 40 : substrate, 11: lower electrode, 12: ferromagnetic film, 13: ferromagnetic film, 14: insulating layer, 15: ferromagnetic film, 16: dummy film, 17: interlayer insulating film, 18 ... Upper electrode, 31, 32, 41 to 44 ... magnetic tunnel effect element, 33, 45 ... DC constant voltage source.

Claims (4)

DC voltage source, hard magnetic fixed magnetic layer whose magnetization direction is fixed to a predetermined direction, soft magnetic free magnetic layer whose magnetization direction changes according to an external magnetic field, the fixed magnetic layer, and the free magnetic layer A magnetic tunnel effect element comprising: an insulating layer sandwiched between
The magnetic tunnel effect element includes one pair of circuit elements formed by connecting one end of a magnetically shielded element and one end of the magnetic tunnel effect element that is not magnetically shielded. The same pair of circuit elements are disposed so that the magnetization directions of the fixed magnetization layers of the magnetic tunnel effect element that are not magnetically shielded are substantially the same, and the magnetism of one of the pair of circuit elements is reduced. The other end of the unshielded magnetic tunnel effect element and the other end of the magnetically shielded magnetic tunnel effect element are respectively connected to the positive electrode and the negative electrode of the DC voltage source, and the other of the pair of circuit elements is connected. The other end of the non-magnetically shielded magnetic tunnel effect element of the circuit element and the other end of the magnetically shielded magnetic tunnel effect element are respectively connected to the negative electrode and the positive electrode of the DC voltage source. And outputting a potential difference between connection points between the magnetically shielded magnetic tunnel effect element and the magnetically unshielded magnetic tunnel effect element of the pair of circuit elements. Sensors. The magnetic sensor according to claim 1,
The magnetic sensor, wherein the fixed magnetic layer includes a magnetized ferromagnetic film and a ferromagnetic film having a fixed magnetization direction in cooperation with the magnetized ferromagnetic film. The magnetic sensor according to claim 1,
The fixed magnetic layer includes a ferromagnetic film made of a magnetized CoCr-based metal and a ferromagnetic film made of NiFe whose magnetization direction is fixed in cooperation with the magnetized ferromagnetic film. Magnetic sensor. A fixed magnetic layer of hard magnetic material whose magnetization direction is fixed to a predetermined direction, a free magnetic layer of soft magnetism whose magnetization direction changes in accordance with an external magnetic field, and sandwiched between the fixed magnetic layer and the free magnetic layer. A magnetic tunnel effect element comprising a magnetic insulating layer and a magnetic tunnel effect element having a magnetically shielded magnetic tunnel effect element and a magnetic tunnel effect element not magnetically shielded.
Forming, on a single substrate, a plurality of laminates each including a magnetic layer to be the fixed magnetic layer, a magnetic layer to be the free magnetic layer, and an insulating layer interposed between the magnetic layers; When,
A magnetic shield is applied to the stacked body to be the magnetically shielded magnetic tunnel effect element of the plurality of stacked bodies, and a strong magnetic field that cannot be shielded by the same magnetic shield is applied to the entire stacked body. Fixing the magnetization direction of the fixed magnetization layer by magnetizing the body,
A method for manufacturing a magnetic sensor, comprising:

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