JP2006286669A - Method of manufacturing magnetoresistance effect element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enlarge an MR ratio and reduce the coercive force of a free layer in an MR element using a tunnel magnetoresistance effect. <P>SOLUTION: A method of manufacturing the MR element 5 includes a step of forming a magnetization fixed layer 22 on an underlying layer 21, a step of forming a tunnel barrier layer 23 on the magnetization fixed layer 22, and a step of forming the free layer 24 on the tunnel barrier layer 23. The step of forming the magnetization fixed layer 22 forms the magnetization fixed layer 22 in the state that the temperature of the substrate 1 is made into 0°C or higher. The step of forming the free layer 24 is conducted in the state that the temperature of the substrate 1 is 0°C or lower, and the substrate 1 is cooled so that it may become the temperature lower than 30°C or higher than the temperature of the substrate 1 in the step of forming the magnetization fixed layer 22. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to the manufacture of a magnetoresistive element using a tunnel magnetoresistive effect.

  In recent years, with the improvement of the surface recording density of magnetic disk devices, there has been a demand for improved performance of thin film magnetic heads. As a thin film magnetic head, a reproducing head having a magnetoresistive effect element for reading (hereinafter also referred to as MR (Magnetoresistive) element) and a recording head having an inductive electromagnetic transducer for writing are laminated on a substrate. A composite thin film magnetic head having the above structure is widely used.

  MR elements include an AMR element using an anisotropic magnetoresistive effect, a GMR element using a giant magnetoresistive effect, and a TMR element using a tunneling magnetoresistive effect. Etc.

  The characteristics of the reproducing head are required to be high sensitivity and high output. As a reproducing head that satisfies this requirement, GMR heads using spin-valve GMR elements have already been mass-produced. Recently, in order to cope with the further improvement of the surface recording density, development of a reproducing head using a TMR element has been advanced.

  In general, a TMR element includes a tunnel barrier layer having two surfaces facing each other, a free layer disposed adjacent to one surface of the tunnel barrier layer, and the other of the tunnel barrier layer. The pinned layer is disposed adjacent to the surface, and the antiferromagnetic layer is disposed adjacent to the surface of the pinned layer opposite to the tunnel barrier layer. The tunnel barrier layer is a non-magnetic insulating layer through which electrons can pass in a state where spin is preserved by the tunnel effect. The free layer is a ferromagnetic layer whose magnetization direction changes according to the signal magnetic field. The pinned layer is a ferromagnetic layer whose magnetization direction is fixed. The antiferromagnetic layer is a layer that fixes the direction of magnetization in the pinned layer by exchange coupling with the pinned layer.

  In the TMR element, the magnetization direction of the free layer changes according to the signal magnetic field from the recording medium, and thereby the relative angle between the magnetization direction of the free layer and the magnetization direction of the pinned layer changes. When this relative angle changes, the probability that electrons pass through the tunnel barrier layer while preserving spin changes, and as a result, the resistance value of the TMR element changes. The information recorded on the recording medium can be reproduced by detecting the change in the resistance value of the TMR element.

  As characteristics of the TMR element, in particular, a magnetoresistive change rate (hereinafter referred to as MR ratio) which is a ratio of magnetoresistive change to resistance is large, and a magnetic field sensitivity which is a ratio of magnetoresistive change to external magnetic field change. It must be large. In order to improve the magnetic field sensitivity, it is effective to reduce the coercivity of the free layer.

  Various techniques relating to a method of manufacturing a TMR element for improving the characteristics of the TMR element have been proposed. For example, Patent Document 1 describes a technique for cooling a substrate only in a step of forming a tunnel barrier layer among a step of forming a free layer, a step of forming a tunnel barrier layer, and a step of forming a pinned layer. Yes.

  Patent Document 2 describes a technique for forming all the layers constituting the TMR element on a substrate cooled to a temperature of 200K or lower.

  Further, in Patent Document 3, in a method for manufacturing a TMR element having a structure in which an electrode layer, a first ferromagnetic layer, a tunnel barrier layer, and a second ferromagnetic layer are sequentially stacked on a substrate, the temperature of the substrate is set to −100. A technique for forming an electrode layer while maintaining the temperature at or below ° C is described. Patent Document 3 further describes that a tunnel barrier layer may be formed while keeping the temperature of the substrate at −100 ° C. or lower. Patent Document 3 describes that all layers constituting the TMR element may be formed in a state where the temperature of the substrate is kept at −100 ° C. or lower.

JP 2001-203408 A JP 2002-151760 A JP 2003-69112 A

  Patent Documents 1 to 3 all disclose that the substrate is cooled at least in the step of forming the tunnel barrier layer. Thus, by forming the tunnel barrier layer in a state where the substrate is cooled, the smoothness of the tunnel barrier layer is improved, and thus the characteristics of the TMR element can be expected to be improved. However, from the experiments of the inventor described later, when all the layers constituting the TMR element are formed in a state where the substrate is cooled, the MR is compared with the case where the substrate is cooled only in the step of forming the tunnel barrier layer. The ratio was found to decrease. Moreover, it was found from this experiment that there is a method that can further improve the characteristics of the TMR element.

  The present invention has been made in view of such a problem, and an object of the present invention is to provide a magnetoresistive element using a tunnel magnetoresistive effect that can increase the MR ratio and reduce the coercivity of the free layer. It is providing the manufacturing method of an effect element.

  A magnetoresistive effect element manufactured by the magnetoresistive effect element manufacturing method of the present invention is disposed so as to be adjacent to one surface of the tunnel barrier layer, and a tunnel barrier layer having two surfaces facing opposite to each other, A free layer whose magnetization direction changes according to an external magnetic field, and a magnetization fixed layer which is arranged adjacent to the other surface of the tunnel barrier layer and whose magnetization direction is fixed.

  The method of manufacturing a magnetoresistive effect element of the present invention includes a step of forming a magnetization fixed layer on a substrate, a step of forming a tunnel barrier layer on the magnetization fixed layer, and a free layer on the tunnel barrier layer. Forming. The step of forming the magnetization fixed layer is to form the magnetization fixed layer in a state where the temperature of the substrate is 0 ° C. or higher, and the step of forming the free layer is to have the temperature of the substrate of 0 ° C. or lower and the magnetization fixed layer The free layer is formed in a state where the substrate is cooled so that the temperature is lower by 30 ° C. or more than the temperature of the substrate in the step of forming. In the step of forming the free layer, the substrate may be in a cooled state so as to have a temperature of −73 ° C. or lower.

  In the method of manufacturing a magnetoresistive effect element according to the present invention, among the steps of forming the tunnel barrier layer, at least at the start of the step, the temperature of the substrate is 0 ° C. or less and the step of forming the magnetization fixed layer is performed. The substrate may be in a cooled state so that the temperature is 30 ° C. or more lower than the temperature. Of the steps of forming the tunnel barrier layer, at least at the start of the step, the substrate may be in a state of being cooled to a temperature of −73 ° C. or lower.

  In the method of manufacturing a magnetoresistive element of the present invention, the step of forming the tunnel barrier layer includes a step of forming a layer made of a nonmagnetic metal material on the magnetization fixed layer, and a step of forming a layer made of the nonmagnetic metal material. Including the step of oxidizing to form a tunnel barrier layer, and at least in the step of forming a layer made of a nonmagnetic metal material, the substrate may be in a cooled state. Alternatively, the step of forming the tunnel barrier layer may include a step of forming a layer made of an oxide of a nonmagnetic metal material on the magnetization fixed layer.

  In the method of manufacturing a magnetoresistive element of the present invention, the magnetization fixed layer may include an antiferromagnetic layer and a ferromagnetic layer disposed on the antiferromagnetic layer and in contact with the tunnel barrier layer. Good.

  In the method of manufacturing a magnetoresistive element according to the present invention, the step of forming the magnetization fixed layer includes the step of forming the magnetization fixed layer in a state where the temperature of the substrate is 0 ° C. or higher, and the step of forming the free layer is the temperature of the substrate. The free layer is formed in a state in which the substrate is cooled so that the temperature is 0 ° C. or lower and 30 ° C. or lower than the substrate temperature in the step of forming the magnetization fixed layer. Thus, according to the present invention, it is possible to increase the MR ratio of the magnetoresistive effect element and reduce the coercivity of the free layer in the magnetoresistive effect element.

  In the method for manufacturing a magnetoresistive element of the present invention, among the steps of forming the tunnel barrier layer, at least at the start of the step, the substrate temperature is 0 ° C. or lower and the magnetization fixed layer is formed. In the case where the substrate is cooled to a temperature lower by 30 ° C. or more than the temperature of the substrate, there is an effect that the smoothness of the tunnel barrier layer can be improved.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. First, with reference to FIGS. 2 and 3, an example of a configuration and a manufacturing method of a thin film magnetic head to which a manufacturing method of a magnetoresistive effect element according to an embodiment of the present invention is applied will be described. 2 is a cross-sectional view showing a cross section perpendicular to the air bearing surface and the substrate of the thin film magnetic head, and FIG. 3 is a cross sectional view showing a cross section parallel to the air bearing surface of the magnetic pole portion of the thin film magnetic head.

In the method of manufacturing the thin film magnetic head of this example, first, insulation such as alumina (Al ₂ O ₃ ) is formed on the substrate 1 made of a ceramic material such as Altic (Al ₂ O ₃ · TiC) by sputtering or the like. The insulating layer 2 made of a material is formed to a thickness of, for example, 0.1 to 5 μm. Next, the first shield layer 3 for a reproducing head made of a magnetic material such as NiFe or FeAlSi is formed in a predetermined pattern on the insulating layer 2 by plating or the like. Next, although not shown, an insulating layer made of alumina, for example, is formed on the entire surface. Next, the insulating layer is polished by chemical mechanical polishing (hereinafter referred to as CMP) until the first shield layer 3 is exposed, and the upper surfaces of the first shield layer 3 and the insulating layer are planarized.

  Next, on the first shield layer 3, the reproducing MR element 5, two bias magnetic field application layers 6 disposed adjacent to two sides of the MR element 5, and the MR element 5 And an insulating layer 7 disposed around the bias magnetic field applying layer 6. The insulating layer 7 is formed of an insulating material such as alumina.

  Next, a second shield layer 8 for a reproducing head made of a magnetic material is formed on the MR element 5, the bias magnetic field applying layer 6 and the insulating layer 7. The second shield layer 8 is formed by, for example, a plating method or a sputtering method. Next, a separation layer 18 made of a nonmagnetic material such as alumina is formed on the second shield layer 8 by sputtering or the like. Next, a lower magnetic pole layer 19 for a recording head made of a magnetic material is formed on the separation layer 18 by, for example, plating or sputtering. The magnetic material used for the second shield layer 8 and the bottom pole layer 19 is a soft magnetic material such as NiFe, CoFe, CoFeNi, FeN or the like. Instead of the second shield layer 8, the separation layer 18, and the lower magnetic pole layer 19, a second shield layer that also serves as the lower magnetic pole layer may be provided.

  Next, the recording gap layer 9 made of a nonmagnetic material such as alumina is formed on the lower magnetic pole layer 19 to a thickness of, for example, 50 to 300 nm by sputtering or the like. Next, in order to form a magnetic path, the recording gap layer 9 is partially etched at the center portion of a thin film coil to be described later to form a contact hole 9a.

  Next, a first layer portion 10 of a thin film coil made of, for example, copper (Cu) is formed on the recording gap layer 9 to a thickness of, for example, 2 to 3 μm. In FIG. 2, reference numeral 10 a represents a connection portion of the first layer portion 10 that is connected to a second layer portion 15 of a thin film coil to be described later. The first layer portion 10 is wound around the contact hole 9a.

  Next, an insulating layer 11 made of an organic insulating material having fluidity when heated, such as a photoresist, is formed in a predetermined pattern so as to cover the first layer portion 10 of the thin film coil and the recording gap layer 9 around the first layer portion 10. . Next, heat treatment is performed at a predetermined temperature in order to flatten the surface of the insulating layer 11. By this heat treatment, the edge portions of the outer periphery and inner periphery of the insulating layer 11 become rounded slope shapes.

  Next, in a region from the slope portion on the air bearing surface 20 side, which will be described later, of the insulating layer 11 to the air bearing surface 20 side, on the recording gap layer 9 and the insulating layer 11, a magnetic material for a recording head is used. The track width defining layer 12a of the upper magnetic pole layer 12 is formed. The top pole layer 12 is composed of the track width defining layer 12a, and a coupling portion layer 12b and a yoke portion layer 12c described later.

  The track width defining layer 12a is formed on the recording gap layer 9 and is formed on the tip portion which becomes the magnetic pole portion of the upper magnetic pole layer 12 and the slope portion on the air bearing surface 20 side of the insulating layer 11, and the yoke portion. And a connection portion connected to the layer 12c. The width of the tip is equal to the recording track width. The width of the connection part is larger than the width of the tip part.

  When the track width defining layer 12a is formed, at the same time, the connection portion layer 12b made of a magnetic material is formed on the contact hole 9a, and the connection layer 13 made of a magnetic material is formed on the connection portion 10a. The coupling portion layer 12 b constitutes a portion of the upper magnetic pole layer 12 that is magnetically coupled to the lower magnetic pole layer 19.

  Next, magnetic pole trimming is performed. In other words, in the peripheral region of the track width defining layer 12a, at least a part of the magnetic gap portions of the recording gap layer 9 and the lower magnetic pole layer 19 on the recording gap layer 9 side is etched using the track width defining layer 12a as a mask. As a result, as shown in FIG. 3, a trim structure is formed in which the widths of at least a part of the magnetic pole portions of the upper magnetic pole layer 12, the magnetic gap portions of the recording gap layer 9 and the lower magnetic pole layer 19 are aligned. The According to this trim structure, an increase in effective track width due to the spread of magnetic flux in the vicinity of the recording gap layer 9 can be prevented.

  Next, an insulating layer 14 made of an inorganic insulating material such as alumina is formed to a thickness of 3 to 4 μm, for example. Next, the insulating layer 14 is polished and planarized by CMP, for example, to reach the surfaces of the track width defining layer 12a, the coupling portion layer 12b, and the connection layer 13.

  Next, a second layer portion 15 of a thin film coil made of, for example, copper (Cu) is formed on the planarized insulating layer 14 to a thickness of, for example, 2 to 3 μm. In FIG. 2, reference numeral 15 a represents a connection portion of the second layer portion 15 that is connected to the connection portion 10 a of the first layer portion 10 of the thin film coil via the connection layer 13. The second layer portion 15 is wound around the connection portion layer 12b.

  Next, an insulating layer 16 made of an organic insulating material having fluidity when heated, such as a photoresist, is formed in a predetermined pattern so as to cover the second layer portion 15 of the thin film coil and the insulating layer 14 therearound. Next, heat treatment is performed at a predetermined temperature in order to flatten the surface of the insulating layer 16. By this heat treatment, the edge portions of the outer periphery and the inner periphery of the insulating layer 16 have a rounded slope shape.

  Next, a yoke portion layer 12c constituting the yoke portion of the top pole layer 12 is formed on the track width defining layer 12a, the insulating layers 14 and 16 and the coupling portion layer 12b with a magnetic material for a recording head such as permalloy. To do. The end of the yoke portion layer 12 c on the air bearing surface 20 side is disposed at a position away from the air bearing surface 20. The yoke portion layer 12c is connected to the lower magnetic pole layer 19 through the coupling portion layer 12b.

  Next, an overcoat layer 17 made of alumina, for example, is formed so as to cover the entire surface. Finally, the slider including the above layers is machined to form the air bearing surface 20 of the thin film magnetic head including the recording head and the reproducing head, thereby completing the thin film magnetic head.

  The thin film magnetic head manufactured in this way includes an air bearing surface 20 as a medium facing surface facing the recording medium, a reproducing head, and a recording head. The configuration of the reproducing head will be described in detail later.

  The recording head includes magnetic pole portions facing each other on the air bearing surface 20 side, and the lower magnetic pole layer 19 and the upper magnetic pole layer 12 that are magnetically coupled to each other, and the magnetic pole portion of the lower magnetic pole layer 19 and the upper magnetic pole layer 12. A recording gap layer 9 provided between the magnetic pole portion and the thin film coil 10 disposed at least partially between the lower magnetic pole layer 19 and the upper magnetic pole layer 12 in an insulated state. 15. In this thin film magnetic head, as shown in FIG. 2, the length from the air bearing surface 20 to the end of the insulating layer 11 on the air bearing surface 20 side is the throat height TH. The throat height refers to the length (height) from the air bearing surface 20 to a position where the distance between the two magnetic pole layers starts to increase.

  The slider, head gimbal assembly, head arm assembly, and magnetic disk apparatus including the thin film magnetic head shown in FIGS. 2 and 3 will be described below. First, the slider 210 will be described with reference to FIG. In the magnetic disk device, the slider 210 is disposed so as to face a magnetic disk that is a disk-shaped recording medium that is rotationally driven. The slider 210 includes a substrate 211 mainly composed of the substrate 1 and the overcoat layer 17 in FIG. The base body 211 has a substantially hexahedral shape. One of the six surfaces of the substrate 211 faces the magnetic disk. An air bearing surface 20 is formed on this one surface. When the magnetic disk rotates in the z direction in FIG. 4, an air flow passing between the magnetic disk and the slider 210 causes a lift in the slider 210 in the lower direction in the y direction in FIG. 4. The slider 210 floats from the surface of the magnetic disk by this lifting force. The x direction in FIG. 4 is the track crossing direction of the magnetic disk. Near the end of the slider 210 on the air outflow side (lower left end in FIG. 4), the thin film magnetic head 100 having the configuration shown in FIGS. 2 and 3 is formed.

  Next, the head gimbal assembly 220 will be described with reference to FIG. The head gimbal assembly 220 includes a slider 210 and a suspension 221 that elastically supports the slider 210. The suspension 221 is, for example, a leaf spring-shaped load beam 222 formed of stainless steel, a flexure 223 that is provided at one end of the load beam 222 and is joined to the slider 210 to give the slider 210 an appropriate degree of freedom. And a base plate 224 provided at the other end of the beam 222. The base plate 224 is attached to an arm 230 of an actuator for moving the slider 210 in the track crossing direction x of the magnetic disk 262. The actuator has an arm 230 and a voice coil motor that drives the arm 230. In the flexure 223, a part to which the slider 210 is attached is provided with a gimbal part for keeping the posture of the slider 210 constant.

  The head gimbal assembly 220 is attached to the arm 230 of the actuator. A structure in which the head gimbal assembly 220 is attached to one arm 230 is called a head arm assembly. Further, a head gimbal assembly 220 attached to each arm of a carriage having a plurality of arms is called a head stack assembly.

  FIG. 5 shows the head arm assembly. In this head arm assembly, a head gimbal assembly 220 is attached to one end of the arm 230. A coil 231 that is a part of the voice coil motor is attached to the other end of the arm 230. A bearing portion 233 attached to a shaft 234 for rotatably supporting the arm 230 is provided at an intermediate portion of the arm 230.

  Next, an example of a head stack assembly and a magnetic disk device will be described with reference to FIGS. FIG. 6 is an explanatory view showing a main part of the magnetic disk device, and FIG. 7 is a plan view of the magnetic disk device. The head stack assembly 250 has a carriage 251 having a plurality of arms 252. A plurality of head gimbal assemblies 220 are attached to the plurality of arms 252 so as to be arranged in the vertical direction at intervals. A coil 253 that is a part of the voice coil motor is attached to the carriage 251 on the side opposite to the arm 252. The head stack assembly 250 is incorporated in a magnetic disk device. The magnetic disk device has a plurality of magnetic disks 262 attached to a spindle motor 261. For each magnetic disk 262, two sliders 210 are arranged so as to face each other with the magnetic disk 262 interposed therebetween. Further, the voice coil motor has permanent magnets 263 arranged at positions facing each other with the coil 253 of the head stack assembly 250 interposed therebetween. The head stack assembly 250 and the actuator excluding the slider 210 support the slider 210 and position it relative to the magnetic disk 262.

  In this magnetic disk apparatus, the slider 210 is moved with respect to the magnetic disk 262 by the actuator so that the slider 210 is positioned with respect to the magnetic disk 262. The thin film magnetic head 100 included in the slider 210 records information on the magnetic disk 262 by a recording head, and reproduces information recorded on the magnetic disk 262 by a reproducing head.

  Next, the configuration of the reproducing head in the present embodiment will be described in detail with reference to FIG. FIG. 1 is a cross-sectional view showing a cross section parallel to the air bearing surface of the read head. As shown in FIG. 1, the reproducing head includes a first shield layer 3 and a second shield layer 8 arranged at a predetermined interval, a first shield layer 3 and a second shield layer 8. MR element 5 disposed between the two. The MR element 5 and the second shield layer 8 are stacked on the first shield layer 3.

  The reproducing head is further disposed adjacent to two sides of the MR element 5, two bias magnetic field application layers 6 for applying a bias magnetic field to the MR element 5, and the MR element 5 and the bias magnetic field application layer. 6 and an insulating layer 7 disposed around 6. The bias magnetic field application layer 6 is configured using a hard magnetic layer (hard magnet), a laminated body of a ferromagnetic layer and an antiferromagnetic layer, or the like. The insulating layer 7 has insulating films 7a and 7b. The insulating film 7a is interposed between the first shield layer 3 and the MR element 5 and the bias magnetic field applying layer 6 and insulates them. The insulating film 7b is interposed between the bias magnetic field applying layer 6 and the second shield layer 8 to insulate them.

  The MR element 5 is a TMR element using a tunnel magnetoresistance effect. The resistance value of the MR element 5 changes according to an external magnetic field, that is, a signal magnetic field from a recording medium. The first and second shield layers 3 and 8 are used to flow a sense current, which is a magnetic signal detection current, to the MR element 5. The sense current flows in a direction perpendicular to the surface of each film constituting the MR element 5. The resistance value of the MR element 5 can be obtained from the sense current. In this way, the information recorded on the recording medium can be reproduced by the reproducing head.

  The MR element 5 includes a tunnel barrier layer 23 having two surfaces facing opposite to each other, and a free layer that is disposed adjacent to one surface of the tunnel barrier layer 23 and whose magnetization direction changes according to an external magnetic field. 24, and a magnetization fixed layer 22 which is disposed adjacent to the other surface of the tunnel barrier layer 23 and whose magnetization direction is fixed. In the present embodiment, of the magnetization fixed layer 22 and the free layer 24, the magnetization fixed layer 22 is disposed at a position closer to the first shield layer 3. The magnetization fixed layer 22 includes an antiferromagnetic layer 31 and a ferromagnetic layer 32 disposed on the antiferromagnetic layer 31 and in contact with the tunnel barrier layer 23. The MR element 5 further includes an underlayer 21 disposed between the first shield layer 3 and the antiferromagnetic layer 31, and a protective layer disposed between the free layer 24 and the second shield layer 8. 25. In the MR element 5, an underlayer 21, an antiferromagnetic layer 31, a ferromagnetic layer 32, a tunnel barrier layer 23, a free layer 24, and a protective layer 25 are sequentially stacked on the first shield layer 3.

  The antiferromagnetic layer 31 is a layer that fixes the magnetization direction in the ferromagnetic layer 32 by exchange coupling with the ferromagnetic layer 32. The underlayer 21 is provided in order to improve the crystallinity and orientation of each layer formed thereon, and in particular to improve exchange coupling between the antiferromagnetic layer 31 and the ferromagnetic layer 32. The protective layer 25 is a layer for protecting each layer below it.

  The thickness of the foundation layer 21 is 2 to 6 nm, for example. As the underlayer 21, for example, a stacked body of a Ta layer and a NiCr layer, a NiFe layer, or a NiFeCr layer is used.

The thickness of the antiferromagnetic layer 31 is, for example, 5 to 30 nm. The antiferromagnetic layer 31 is, for example, Pt, consists Ru, Rh, Pd, Ni, Cu, Ir, and at least one M _II selected from the group consisting of Cr and Fe, the antiferromagnetic material containing Mn ing. Among these, the content of Mn is preferably 35 atomic% or more and 95 atomic% or less, and the content of the other element M _II is preferably 5 atomic% or more and 65 atomic% or less. This antiferromagnetic material exhibits antiferromagnetism without heat treatment, and exhibits non-heat treatment antiferromagnetic material that induces an exchange coupling magnetic field with the ferromagnetic material, and exhibits antiferromagnetism by heat treatment. There is a heat treatment type antiferromagnetic material. The antiferromagnetic layer 31 may be composed of either of them.

  The non-heat-treatment type antiferromagnetic material includes a Mn alloy having a γ phase, and specifically, RuRhMn, FeMn, IrMn, and the like. The heat-treated antiferromagnetic material includes a Mn alloy having a regular crystal structure, and specifically includes PtMn, NiMn, PtRhMn, and the like.

  In the ferromagnetic layer 32, the magnetization direction is fixed by exchange coupling at the interface with the antiferromagnetic layer 31. The ferromagnetic layer 32 has a structure in which, for example, a first ferromagnetic layer, a coupling layer, and a second ferromagnetic layer are stacked in this order from the antiferromagnetic layer 31 side. The first ferromagnetic layer and the second ferromagnetic layer are made of, for example, a ferromagnetic material containing at least Co in the group consisting of Co and Fe. In particular, the (111) plane of this ferromagnetic material is preferably oriented in the stacking direction. The total thickness of the first and second ferromagnetic layers is, for example, 1.5 to 5 nm. The first and second ferromagnetic layers are antiferromagnetically coupled and the magnetization directions are fixed in opposite directions.

  The thickness of the coupling layer in the ferromagnetic layer 32 is, for example, 0.2 to 1.2 nm. The coupling layer is made of, for example, a nonmagnetic material including at least one selected from the group consisting of Ru, Rh, Ir, Re, Cr, Zr, and Cu. The coupling layer generates antiferromagnetic exchange coupling between the first and second ferromagnetic layers, and fixes the magnetization of the first ferromagnetic layer and the magnetization of the second ferromagnetic layer in opposite directions. Is to do. The magnetization of the first ferromagnetic layer and the magnetization of the second ferromagnetic layer are opposite to each other, not only when the directions of these two magnetizations differ from each other by 180 °, but also when the directions of the two magnetizations are 180. Including the case where the angle differs ± 20 °.

  The tunnel barrier layer 23 is a nonmagnetic insulating layer through which electrons can pass in a state where spin is preserved by the tunnel effect. The thickness of the tunnel barrier layer 23 is, for example, 0.5 to 2 nm. As a material of the tunnel barrier layer 23, for example, an oxide or nitride of Al, Gd, Mg, Ta, Mo, Ti, W, Hf, or Zr is used.

  The thickness of the free layer 24 is, for example, 1.0 to 8.0 nm. The free layer 24 may be composed of a single layer or may be composed of two or more layers. Here, an example in which the free layer 24 is composed of two soft magnetic layers will be described. Of the two soft magnetic layers, the layer on the tunnel barrier layer 23 side is called a first soft magnetic layer, and the layer on the protective layer 25 side is called a second soft magnetic layer.

  The thickness of the first soft magnetic layer is, for example, 0.5 to 3 nm. The first soft magnetic layer is made of, for example, a magnetic material including at least one of the group consisting of Ni, Co, and Fe.

  The thickness of the second soft magnetic layer is, for example, 0.5 to 8 nm. The second soft magnetic layer is made of, for example, a magnetic material containing at least Ni from the group consisting of Ni, Co, Fe, Ta, Cr, Rh, Mo, and Nb.

  The thickness of the protective layer 25 is, for example, 0.5 to 10 nm. As a material of the protective layer 25, for example, Ta is used. Further, the protective layer 25 may have a two-layer structure of a combination of Ta layer, Ru layer, etc., a three-layer structure of a combination of Ta layer, Ru layer, Ta layer, a combination of Ru layer, Ta layer, Ru layer, etc. Good.

  Next, a method for manufacturing the reproducing head shown in FIG. 1 will be described. In this reproducing head manufacturing method, first, the first shield layer 3 having a predetermined pattern is formed on the insulating layer 2 by plating or the like. Next, a film to be a layer constituting the MR element 5 is sequentially formed on the first shield layer 3 by, eg, sputtering. Next, these films are patterned by etching to form the MR element 5. Next, the insulating film 7a, the bias magnetic field applying layer 6, and the insulating film 7b are sequentially formed by, for example, sputtering. Next, the second shield layer 8 is formed on the MR element 5 and the insulating film 7b by, for example, plating or sputtering.

  Next, operations of the MR element 5 and the thin film magnetic head according to the present embodiment will be described. The thin film magnetic head records information on a recording medium with a recording head, and reproduces information recorded on the recording medium with a reproducing head.

  In the reproducing head, the direction of the bias magnetic field by the bias magnetic field application layer 6 is orthogonal to the direction perpendicular to the air bearing surface 20. In the MR element 5, when there is no signal magnetic field, the magnetization direction of the free layer 24 is aligned with the direction of the bias magnetic field. On the other hand, the magnetization direction of the ferromagnetic layer 32 is fixed in a direction perpendicular to the air bearing surface 20.

  In the MR element 5, the magnetization direction of the free layer 24 changes in accordance with the signal magnetic field from the recording medium, whereby the relative angle between the magnetization direction of the free layer 24 and the magnetization direction of the ferromagnetic layer 32. As a result, the resistance value of the MR element 5 changes. The resistance value of the MR element 5 can be obtained from the potential difference between the shield layers 3 and 8 when a sense current is passed through the MR element 5 by the first and second shield layers 3 and 8. In this way, the information recorded on the recording medium can be reproduced by the reproducing head.

  Next, a method for manufacturing the MR element 5 according to the present embodiment will be described. The manufacturing method of the MR element 5 includes a step of forming a magnetization fixed layer 22 on the substrate 1 formed up to the base layer 21, a step of forming a tunnel barrier layer 23 on the magnetization fixed layer 22, and a tunnel A step of forming a free layer 24 on the barrier layer 23 and a step of forming a protective layer 25 on the free layer 24 are provided. The step of forming the magnetization fixed layer 22 includes a step of forming the antiferromagnetic layer 31 on the underlayer 21 and a step of forming the ferromagnetic layer 32 on the antiferromagnetic layer 31. The step of forming the tunnel barrier layer 23 includes a step of forming a layer made of a nonmagnetic metal material on the fixed magnetization layer 22, and a step of oxidizing the layer made of the nonmagnetic metal material to form the tunnel barrier layer 23. May be included. Alternatively, in the step of forming the tunnel barrier layer 23, a layer made of an oxide of a nonmagnetic metal material may be formed as the tunnel barrier layer 23 by a sputtering method or the like.

  In the present embodiment, the step of forming the magnetization fixed layer 22 forms the magnetization fixed layer 22 in a state where the temperature of the substrate 1 is set to 0 ° C. or higher, and the step of forming the free layer 24 involves the temperature of the substrate 1 being The free layer 24 is formed in a state in which the substrate 1 is cooled to be 0 ° C. or lower and 30 ° C. or lower than the temperature of the substrate 1 in the step of forming the magnetization fixed layer 22. In the following description, “the state where the temperature of the substrate 1 is 0 ° C. or higher” is referred to as “the state where the substrate 1 is not cooled”, and “the temperature of the substrate 1 is 0 ° C. or lower and the magnetization fixed layer is “The state in which the substrate 1 is cooled so as to be 30 ° C. or lower than the temperature of the substrate 1 in the step of forming the substrate 22” is referred to as “the state in which the substrate 1 is cooled”. In the step of forming the free layer 24, the substrate is cooled to a temperature of −73 ° C. or lower, for example.

  In the present embodiment, at least at the start of the step of forming the tunnel barrier layer 23, the substrate 1 is in a cooled state (the temperature of the substrate 1 is 0 ° C. or lower, and the magnetization fixed layer 22). The substrate 1 may be cooled so that the temperature is 30 ° C. or more lower than the temperature of the substrate 1 in the step of forming the substrate. In this case, at least at the start of the step of forming the tunnel barrier layer 23, the substrate 1 is cooled to a temperature of −73 ° C. or lower, for example. Further, the step of forming the tunnel barrier layer 23 includes the step of forming a layer made of a nonmagnetic metal material on the magnetization fixed layer 22, and the layer made of the nonmagnetic metal material is oxidized to form the tunnel barrier layer 23. In the case of including the process, at least in the process of forming the layer made of the nonmagnetic metal material, the substrate 1 may be in a cooled state.

  The above-mentioned regulations of “0 ° C.” and “temperature lower by 30 ° C.” have the following meanings. Some thin film forming apparatuses such as a sputtering apparatus are provided with a water cooling mechanism in order to avoid a temperature rise of the substrate. In the step of forming the magnetization fixed layer 22, when the substrate 1 is cooled by a water cooling mechanism, the temperature of the substrate 1 becomes 0 ° C. or higher. Therefore, in the step of forming the magnetization fixed layer 22, the state in which the substrate 1 is cooled by the water cooling mechanism is “a state where the temperature of the substrate 1 is 0 ° C. or higher”, that is, “a state where the substrate 1 is not cooled”. It corresponds to.

  Even when the substrate 1 is cooled to near 0 ° C. by the water cooling mechanism in the step of forming the magnetization fixed layer 22, the “state in which the substrate 1 is cooled” is the temperature of the substrate 1 in the step of forming the magnetization fixed layer 22. Since the substrate 1 is in a cooled state so that the temperature is lower by 30 ° C. or more than that, the state of the substrate in the step of forming the magnetization fixed layer 22 is clearly distinguished.

  Next, let us consider a case where, in the step of forming the magnetization fixed layer 22, the magnetization fixed layer 22 is formed at a room temperature in the vicinity of 25 ° C. of the substrate 1. In this case, in the step of forming the free layer 24 and the step of forming the tunnel barrier layer 23, the substrate 1 is set to a temperature that is 30 ° C. lower than the temperature of the substrate 1 in the step of forming the magnetization fixed layer 22. If it is in a cooled state, the temperature of the substrate 1 is 0 ° C. or lower, and it is surely “the substrate 1 is cooled”.

  Next, let us consider a case where, in the step of forming the magnetization fixed layer 22, the magnetization fixed layer 22 is formed in a state where the temperature of the substrate 1 is 30 ° C. or higher. In this case, if the temperature of the substrate 1 is 0 ° C. or lower in the step of forming the free layer 24 and the step of forming the tunnel barrier layer 23, the “substrate 1 is cooled” is surely obtained. Therefore, in this case, “the state where the substrate 1 is cooled” includes the case where the temperature of the substrate 1 is 0 ° C.

  Note that there is a temperature difference of 30 ° C. or more between “the state where the substrate 1 is not cooled” and “the state where the substrate 1 is cooled”. It cannot be at 0 ° C.

  As described above, in the present embodiment, the magnetization fixed layer 22 is formed in a state where the substrate 1 is not cooled, and the free layer 24 is formed in a state where the substrate 1 is cooled. This makes it possible to increase the MR ratio of the MR element 5 and reduce the coercivity of the free layer 24, as can be seen from the experimental results shown later. Therefore, according to the present embodiment, it is possible to realize the MR element 5 that has a large MR ratio and a large magnetic field sensitivity and that can obtain a stable output signal.

  In the present embodiment, the smoothness of the tunnel barrier layer 23 is improved by causing the substrate 1 to be in a cooled state at least at the start of the step of forming the tunnel barrier layer 23. be able to. Thereby, a thin and homogeneous tunnel barrier layer 23 can be formed. As a method for improving the smoothness of the tunnel barrier layer 23, methods other than the method for forming the tunnel barrier layer 23 at least at the start of the step other than the method for bringing the substrate 1 into a cooled state may be used. is there. For example, it is also possible to improve the smoothness of the tunnel barrier layer 23 by performing plasma treatment on the surface of the ferromagnetic layer 32 that is the base of the tunnel barrier layer 23 before forming the tunnel barrier layer 23.

  Hereinafter, the results of the first to third experiments performed to confirm the effect of the method for manufacturing the MR element 5 according to the present embodiment will be described. First, in the first experiment, samples 1 to 4 of the MR element 5 shown below were manufactured and their MR ratios were obtained. Samples 1 to 4 have the same configuration of each layer constituting the MR element 5, but differ in which of the steps of forming each layer constituting the MR element 5 is the substrate 1 being cooled. It is what.

  The configuration of each layer in Samples 1 to 4 is as follows. The underlayer 21 is a laminate of a Ta layer having a thickness of 5 nm and a NiFe layer having a thickness of 2 nm. The antiferromagnetic layer 31 is a 15 nm thick PtMn layer made of PtMn (Pt: 50 atomic%, Mn: 50 atomic%). The ferromagnetic layer 32 is a laminate of a CoFe layer having a thickness of 2 nm, a Ru layer having a thickness of 0.8 nm, and a CoFe layer having a thickness of 3 nm. The CoFe layer in the ferromagnetic layer 32 is made of CoFe (Co: 70 atomic%, Fe: 30 atomic%). The tunnel barrier layer 23 is an Al oxide layer having a thickness of about 1 nm formed by oxidizing an Al layer. The free layer 24 is a laminate of a CoFe layer having a thickness of 2 nm and a NiFe layer having a thickness of 3 nm. The CoFe layer in the free layer 24 is made of CoFe (Co: 30 atomic%, Fe: 70 atomic%). The protective layer 25 is a Ta layer having a thickness of 10 nm. Each layer was formed by sputtering.

  FIG. 8 is an explanatory diagram showing in which of the steps of forming each layer constituting the MR element 5 when the samples 1 to 4 are manufactured, the substrate 1 is in a cooled state. In FIG. 8, the filled bar indicates a period during which the substrate 1 is in a cooled state. As shown in FIG. 8, when the sample 1 is manufactured, the substrate 1 is not cooled in the formation process of the magnetization fixed layer 22 including the antiferromagnetic layer 31 and the ferromagnetic layer 32 and the formation process of the free layer 24. Thus, the substrate 1 is in a cooled state at least at the start of the tunnel barrier layer 23 formation process. When the sample 2 is manufactured, the substrate 1 is not cooled in the formation process of the free layer 24, and at least at the start of the formation process of the magnetization fixed layer 22 and the formation process of the tunnel barrier layer 23. The substrate 1 is in a cooled state. When the sample 3 is manufactured, the substrate 1 is in a cooled state at least at the start of the magnetization fixed layer 22 formation process, the tunnel barrier layer 23 formation process, and the free layer 24 formation process. When the sample 4 is manufactured, the substrate 1 is not cooled in the formation process of the magnetization fixed layer 22, and at least the start time of the formation process of the tunnel barrier layer 23 and the formation process of the free layer 24. The substrate 1 is in a cooled state.

  The substrate 1 was cooled by the following method. First, the laminated body which consists of the board | substrate 1 and the several layer formed on it is conveyed to the vacuum chamber for cooling, and on the cooling trap cooled so that it might become the temperature of -223 degreeC in this vacuum chamber for cooling In addition, the substrate 1 was fixed via a sheet for improving the adhesion between the substrate 1 and the cooling trap. And this state was hold | maintained until the temperature of the board | substrate 1 became -73 degreeC or less.

  The MR ratio of samples 1 to 4 is shown in the following table. Note that the resistance values of the samples 1 to 4 are substantially equal.

  As can be seen by comparing the MR ratios of Sample 1 and Sample 2, when the substrate 1 is cooled in the formation process of the magnetization fixed layer 22, the substrate 1 is cooled in the formation process of the magnetization fixed layer 22. The MR ratio is reduced as compared with the case where there is no state. This is because when the substrate 1 is cooled in the step of forming the magnetization fixed layer 22, the crystal grain size in the magnetization fixed layer 22 becomes small, and the exchange coupling between the antiferromagnetic layer 31 and the ferromagnetic layer 32 occurs. This is considered to be because the effect of fixing the direction of magnetization is reduced. In the sample 3 produced by cooling the substrate 1 in both the formation process of the magnetization fixed layer 22 and the formation process of the free layer 24, the MR ratio is larger than that of the sample 2, but the sample 1 The MR ratio is smaller than that in FIG. On the other hand, in the sample 4 manufactured in a state in which the substrate 1 is not cooled in the formation process of the magnetization fixed layer 22 and the substrate 1 is cooled in the formation process of the free layer 24, other samples MR ratio is larger than any one of 1-3. Therefore, the MR ratio of the MR element 5 can be increased by forming the magnetization fixed layer 22 in a state where the substrate 1 is not cooled and forming the free layer 24 in a state where the substrate 1 is cooled. I understand.

  Further, by forming the free layer 24 in a state where the substrate 1 is cooled, the coercive force of the free layer 24 can be reduced. This will be described in detail with reference to the results of the second experiment and the third experiment.

  In the second experiment, Samples 5 to 7 shown below were produced. The configuration of the sample 5 is similar to the configuration of the MR element 5, but differs from the configuration of the MR element 5 in that an Al layer is provided instead of the tunnel barrier layer 23. The configurations of the samples 6 and 7 are the configurations of the MR element 5. The configuration of each layer in Samples 5 to 7 is as follows. The underlayer 21 is a laminate of a Ta layer having a thickness of 5 nm and a NiFe layer having a thickness of 2 nm. The antiferromagnetic layer 31 is a 15 nm thick PtMn layer made of PtMn (Pt: 50 atomic%, Mn: 50 atomic%). The ferromagnetic layer 32 is a laminate of a CoFe layer having a thickness of 2 nm, a Ru layer having a thickness of 0.8 nm, and a CoFe layer having a thickness of 3 nm. The CoFe layer in the ferromagnetic layer 32 is made of CoFe (Co: 90 atomic%, Fe: 10 atomic%). The thickness of the Al layer in sample 5 is 1 nm. The tunnel barrier layer 23 in the samples 6 and 7 is an Al oxide layer formed by oxidizing a 1 nm thick Al layer. Note that the oxidation treatment of the Al layer was performed in an oxygen atmosphere for 5 minutes. The free layer 24 in the samples 5 to 7 is a CoFe layer having a thickness of 1 nm made of CoFe (Co: 90 atomic%, Fe: 10 atomic%). Samples 5 to 7 include an Al layer having a thickness of 1 nm formed on the free layer 24. In Samples 5 and 6, the substrate 1 is not cooled in the formation process of the free layer 24. In the sample 7, the substrate 1 is cooled in the formation process of the free layer 24. Each layer was formed by sputtering.

  The following table shows the presence or absence of the oxidation treatment of the Al layer in Samples 5 to 7 and the state of the substrate 1 when the free layer 24 is formed. In the table below, “cooled” represents a cooled state, and “uncooled” represents an uncooled state.

  In the second experiment, the state of the free layer 24 in the samples 5 to 7 was analyzed as follows. First, with respect to Samples 5 to 7, spectra in a binding energy range of 770 eV to 800 eV were observed by X-ray photoelectron spectroscopy. In the Co spectrum obtained by X-ray photoelectron spectroscopy, an intensity peak appears in the vicinity of 780 eV. When Co is oxidized, the intensity at the energy corresponding to the Co oxide increases in the spectrum. Note that the energy corresponding to the Co oxide is higher than 780 eV. Therefore, the degree of oxidation of the free layer 24 in the samples 5 to 7 can be known by comparing the intensity at the energy corresponding to the Co oxide. In the second experiment, the intensity at the energy corresponding to the Co oxide was obtained from the spelling of the samples 6 and 7 with the spectrum of the sample 5 as a reference.

  FIG. 9 shows the intensity at the energy corresponding to the Co oxide thus obtained. Here, since the spectrum of the sample 5 is used as a reference, the intensity in the sample 5 is zero. In sample 6, the intensity at the energy corresponding to the Co oxide is large. In the sample 7, compared with the sample 6, the intensity at the energy corresponding to the Co oxide is greatly reduced. In Sample 6, the Al layer was oxidized to form the tunnel barrier layer 23, and the free layer 24 was formed on the tunnel barrier layer 23 in a state where the substrate 1 was not cooled. Sample 7 is obtained by oxidizing the Al layer to form the tunnel barrier layer 23, and forming the free layer 24 on the tunnel barrier layer 23 while the substrate 1 is cooled.

  From the result of the second experiment, the following can be understood. When the tunnel barrier layer 23 is formed by oxidizing the Al layer and the free layer 24 is formed on the tunnel barrier layer 23, the free layer 24 is oxidized. This is considered to be because oxygen diffuses from the tunnel barrier layer 23 to the free layer 24. When the free layer 24 is formed in a state where the substrate 1 is not cooled, the free layer 24 is significantly oxidized. On the other hand, if the free layer 24 is formed while the substrate 1 is cooled, oxidation of the free layer 24 is significantly suppressed. It is considered that the degree of oxidation of the free layer 24 affects the coercive force of the free layer 24.

  In the third experiment, it was confirmed that the coercive force of the free layer 24 can be reduced by forming the free layer 24 in a state where the substrate 1 is cooled. In the third experiment, Samples 11 to 16 and Samples 21 to 26 were produced as follows. In any sample, a Ta layer having a thickness of 5 nm is formed on a silicon substrate with a thermal oxide film, a Cu layer having a thickness of 2.5 nm is formed on the Ta layer, and a thickness is formed on the Cu layer. A 1 nm thick Al layer was formed. The presence or absence of the oxidation treatment of the Al layer and the oxidation treatment time vary depending on the sample. In Samples 11, 14, 21, and 24, the Al layer was not oxidized. In Samples 12, 15, 22, and 25, the Al layer was oxidized in an oxygen atmosphere for 5 minutes. In samples 13, 16, 23, and 26, the Al layer was oxidized in an oxygen atmosphere for 10 minutes. Next, in each sample, a magnetic layer having a thickness of 3 nm was formed on the Al layer (including those subjected to oxidation treatment), and a Ta layer having a thickness of 5 nm was formed on the magnetic layer. The composition of the magnetic layer and the state of the substrate when the magnetic layer is formed differ depending on the sample. The magnetic layers in the samples 11 to 16 are made of CoFe (Co: 90 atomic%, Fe: 10 atomic%). The magnetic layers in the samples 21 to 26 are made of CoFe (Co: 30 atomic%, Fe: 70 atomic%). In Samples 11-13 and 21-23, the substrate is not cooled when the magnetic layer is formed. In Samples 14-16 and 24-26, the substrate is in a cooled state when the magnetic layer is formed. The oxidized Al layer corresponds to the tunnel barrier layer 23, and the magnetic layer corresponds to the free layer 24. In the table below, “cooled” represents a cooled state, and “uncooled” represents an uncooled state.

  The conditions that differ for each sample are shown in the following table. An oxidation time of the Al layer of 0 indicates that no oxidation treatment is performed.

  The coercivity of Samples 11-16 is shown in FIG. 10, and the coercivity of Samples 21-26 is shown in FIG. 10 and 11, the horizontal axis represents the oxidation time of the Al layer, and the vertical axis represents the coercivity of the magnetic layer. The numbers written in the vicinity of the points represent the sample numbers.

  10 and 11 show the following. First, when the oxidation treatment of the Al layer is not performed, there is almost no difference in the coercive force of the magnetic layer due to the difference in the state of the substrate when the magnetic layer is formed. When the Al layer is oxidized, if the substrate is not cooled when the magnetic layer is formed, the coercive force of the magnetic layer increases significantly, but the substrate is cooled when the magnetic layer is formed. When in the state, an increase in the coercive force of the magnetic layer is suppressed.

  From the second experiment and the third experiment, it is possible to suppress the oxidation of the free layer 24 and reduce the coercive force of the free layer 24 by forming the free layer 24 with the substrate 1 cooled. I understand.

  In addition, this invention is not limited to the said embodiment, A various change is possible. For example, in the embodiment, a thin film magnetic head having a structure in which a reproducing head is formed on the substrate side and a recording head is stacked thereon has been described. However, the stacking order may be reversed.

  When used as a read-only device, the thin film magnetic head may be configured to include only the reproducing head.

  Further, the magnetoresistive effect element manufactured by the manufacturing method of the present invention is not limited to the reproducing head in the thin film magnetic head but can be used for other uses such as a magnetic sensor.

It is sectional drawing which shows a cross section parallel to the air bearing surface of the reproducing head in one embodiment of this invention. 1 is a cross-sectional view showing a cross section perpendicular to an air bearing surface and a substrate of a thin film magnetic head in an embodiment of the invention. It is sectional drawing which shows the cross section parallel to the air bearing surface of the magnetic pole part of the thin film magnetic head in one embodiment of this invention. It is a perspective view which shows the slider in one embodiment of this invention. It is a perspective view which shows the head arm assembly in one embodiment of this invention. It is explanatory drawing for demonstrating the principal part of the magnetic disc apparatus in one embodiment of this invention. 1 is a plan view of a magnetic disk device according to an embodiment of the present invention. It is explanatory drawing for demonstrating the 1st experiment performed in order to confirm the effect of the manufacturing method of MR element which concerns on one embodiment of this invention. It is a characteristic view which shows the result of the 2nd experiment performed in order to confirm the effect of the manufacturing method of MR element which concerns on one embodiment of this invention. It is a characteristic view which shows the result of the 3rd experiment performed in order to confirm the effect of the manufacturing method of MR element which concerns on one embodiment of this invention. It is a characteristic view which shows the result of the 3rd experiment performed in order to confirm the effect of the manufacturing method of MR element which concerns on one embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Board | substrate, 2 ... Insulating layer, 3 ... 1st shield layer, 5 ... MR element, 6 ... Bias magnetic field application layer, 7 ... Insulating layer, 8 ... 2nd shield layer, 22 ... Magnetization fixed layer, 23 ... Tunnel barrier layer, 24 ... free layer, 31 ... antiferromagnetic layer, 32 ... ferromagnetic layer.

Claims (7)

A tunnel barrier layer having two surfaces facing away from each other;
A free layer disposed adjacent to one surface of the tunnel barrier layer, the direction of magnetization changing according to an external magnetic field;
A magnetoresistive effect element including a magnetization fixed layer disposed adjacent to the other surface of the tunnel barrier layer and having a magnetization direction fixed;
Forming the magnetization fixed layer on the substrate;
Forming the tunnel barrier layer on the magnetization fixed layer;
Forming the free layer on the tunnel barrier layer,
The step of forming the magnetization fixed layer includes forming the magnetization fixed layer in a state where the temperature of the substrate is set to 0 ° C. or more, and the step of forming the free layer includes a temperature of the substrate of 0 ° C. or less. And the free layer is formed in a state where the substrate is cooled so that the temperature is 30 ° C. or more lower than the temperature of the substrate in the step of forming the magnetization fixed layer. .   2. The method of manufacturing a magnetoresistive element according to claim 1, wherein, in the step of forming the free layer, the substrate is cooled to a temperature of -73 [deg.] C. or less.   Among the steps of forming the tunnel barrier layer, at least at the start time thereof, the temperature of the substrate is 0 ° C. or lower, and a temperature lower by 30 ° C. or more than the temperature of the substrate in the step of forming the magnetization fixed layer; 3. The method of manufacturing a magnetoresistive effect element according to claim 1, wherein the substrate is in a cooled state.   The magnetic material according to claim 3, wherein the substrate is cooled to a temperature of −73 ° C. or lower at least at the start of the step of forming the tunnel barrier layer. A method of manufacturing a resistance effect element.   The step of forming the tunnel barrier layer includes a step of forming a layer made of a nonmagnetic metal material on the magnetization fixed layer, and a step of oxidizing the layer made of the nonmagnetic metal material to form the tunnel barrier layer. 5. The method of manufacturing a magnetoresistive effect element according to claim 3, wherein the substrate is in a cooled state in at least the step of forming the layer made of the nonmagnetic metal material.   5. The magnetic field according to claim 1, wherein the step of forming the tunnel barrier layer includes a step of forming a layer made of an oxide of a nonmagnetic metal material on the magnetization fixed layer. A method of manufacturing a resistance effect element. 7. The magnetization fixed layer includes an antiferromagnetic layer and a ferromagnetic layer disposed on the antiferromagnetic layer and in contact with the tunnel barrier layer. Manufacturing method of the magnetoresistive effect element.

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