JP2008078379A - Manufacturing method of tunneling magnetic sensing element - Google Patents

Abstract

PROBLEM TO BE SOLVED: In particular, to a tunnel type magnetic sensing element in which an insulating barrier layer is formed of Mg-O, the soft magnetic characteristics of a free magnetic layer are improved, and the rate of change in resistance (ΔR / R) compared to the prior art Provided is a method for manufacturing a tunneling magnetic sensing element capable of increasing the resistance.
A portion laminated in order of an upper magnetic layer, an insulating barrier layer, and an enhancement layer from the bottom of a laminate T1 is Co _{40 at%} Fe _{40 at%} B _{20 at%} / Mg—O / Co _{50 at%} Fe _{50 at%} . Experiments on the annealing temperature dependence of the rate of change in resistance (ΔR / R) with respect to RA using a tunnel type magnetic sensing element revealed that the RA was lowered by setting the annealing temperature within a range of 270 ° C. to 310 ° C. A high resistance change rate (ΔR / R) is obtained in the range of ( ^{2 to 4} Ωμm ² ).
[Selection] Figure 7

Description

  The present invention relates to a tunnel-type magnetic detection element that is mounted on, for example, a hard disk device or used as an MRAM (magnetoresistance memory) or the like. In particular, when Mg—O is used as an insulating barrier layer, the free magnetic layer The present invention relates to a method of manufacturing a tunneling magnetic sensing element capable of maintaining a soft magnetic characteristic in a good state and increasing a rate of change in resistance (ΔR / R).

  The tunnel-type magnetic sensing element uses the tunnel effect to cause a resistance change. When the magnetization of the pinned magnetic layer and the magnetization of the free magnetic layer are antiparallel, the pinned magnetic layer and the free magnetic layer When the tunneling current becomes difficult to flow through the insulating barrier layer (tunnel barrier layer) provided between and the resistance value is maximized, while the magnetization of the fixed magnetic layer and the magnetization of the free magnetic layer are parallel to each other The tunnel current is most likely to flow and the resistance value is minimized.

  Utilizing this principle, the magnetization of the free magnetic layer fluctuates under the influence of an external magnetic field, whereby the changing electric resistance is regarded as a voltage change, and the leakage magnetic field from the recording medium is detected.

  By the way, if the material of the insulating barrier layer is changed, the characteristics represented by the rate of change in resistance (ΔR / R) will change. Therefore, it is necessary to conduct research for each material of the insulating barrier layer.

Important characteristics as a tunnel type magnetic sensing element are a resistance change rate (ΔR / R), RA (element resistance R × area A), soft magnetic characteristics represented by magnetostriction λ and coercive force Hc of a free magnetic layer, and the like. With the aim of optimizing these characteristics, the insulating barrier layer, the material of the fixed magnetic layer and the free magnetic layer formed above and below the insulating barrier layer, the improvement of the film structure, and the annealing performed during the manufacturing process Conditions are set.
JP-A-2005-85821 Japanese Patent Laid-Open No. 2003-158312 JP 2004-179187 A JP-A-2005-203702

  The above patent document discloses the use of magnesium oxide (Mg—O) as an insulating barrier layer (for example, the [0043] column of Patent Document 1). In the tunnel type magnetic sensing element in which an antiferromagnetic layer, a pinned magnetic layer, an insulating barrier layer, and a free magnetic layer are stacked in this order from the bottom, the insulating barrier layer is formed of Mg-O, and the pinned magnetic layer and the free magnetic layer are formed. It is known that a large rate of change in resistance (ΔR / R) can be obtained when it is formed of CoFeB, that is, when a CoFeB / Mg—O / CoFeB laminated structure is used.

  However, when CoFeB is used as the free magnetic layer, the magnetostriction λ and the coercive force Hc of the free magnetic layer become very large, which causes a problem of deterioration in the stability of reproduction characteristics.

  Further, in order to obtain a large resistance change rate (ΔR / R) in the above-described CoFeB / Mg—O / CoFeB laminated structure, it was necessary to perform an annealing treatment at a high temperature of 350 ° C. or higher. As shown in the experiment, it was found that when the free magnetic layer is made of CoFe / NiFe instead of CoFeB, the resistance change rate (ΔR / R) is lowered by annealing at 350 ° C. or higher.

  In each patent document, when Mg—O is used for the insulating barrier layer, an optimum layer structure of the free magnetic layer for obtaining a good soft magnetic property and a high resistance change rate (ΔR / R) of the free magnetic layer And the annealing temperature in the manufacturing process is not disclosed. For example, in Patent Document 1, although the layer structure and annealing conditions of “Example 1” are described in the columns [0067] to [0070], the insulating barrier layer is Al—O, and Mg—O is used. Not. Patent Document 2 also describes annealing conditions when Al—O is used as an insulating barrier layer in the [0026] column. In Patent Document 3, the [0033] column describes that annealing is performed at a high temperature of 400 ° C. or higher. Further, in Patent Document 4, for example, the annealing process is performed at 250 ° C. in the [0043] column, but the material of the insulating barrier layer is unknown.

  Thus, in each patent document, when Mg—O is used as the insulating barrier layer, the optimum layer structure and annealing conditions of the free magnetic layer are not disclosed.

  Accordingly, the present invention is directed to solving the above-described conventional problems, and particularly relates to a tunneling magnetic sensing element in which an insulating barrier layer is formed of Mg-O, in which the soft magnetic characteristics of the free magnetic layer are improved. And it aims at providing the manufacturing method of the tunnel type | mold magnetic detection element which can make resistance change rate ((DELTA) R / R) high compared with the past.

The present invention relates to a method of manufacturing a tunneling magnetic sensing element having a laminate formed by laminating a pinned magnetic layer, an insulating barrier layer, and a free magnetic layer in this order from below.
(A) forming an insulating barrier layer made of Mg—O on the pinned magnetic layer;
(B) forming an enhancement layer made of CoFe or Co constituting the free magnetic layer on the insulating barrier layer;
(C) forming a soft magnetic layer made of NiFe or Ni constituting the free magnetic layer on the enhancement layer;
(D) A step of annealing the laminated body in a temperature range of 270 ° C. to 310 ° C.,
It is characterized by having.

  In the present invention, the insulating barrier layer is formed of Mg-O in the step (a), and in steps (b) and (c), the free magnetic layer is an enhancement layer made of CoFe or Co from the bottom and a soft layer made of NiFe or Ni. It is formed with a laminated structure with a magnetic layer. The enhanced layer has a higher spin polarizability than the soft magnetic layer, while the soft magnetic layer has better soft magnetic properties than the enhanced layer. By forming the free magnetic layer with such a laminated structure, it is possible to ensure good soft magnetic characteristics and an improved resistance change rate (ΔR / R).

  In the present invention, as shown in step (d), the annealing treatment is performed within the range of 270 ° C. to 310 ° C. It has been proved by experiments described later that a high resistance change rate (ΔR / R) can be obtained in the low RA range in the laminated structure of the present invention within this temperature range.

  In the present invention, in the step (a), it is preferable to obtain a high rate of change in resistance (ΔR / R) by sputtering the insulating barrier layer using a target made of Mg—O.

In the present invention, in the step (a), at least an upper layer of the pinned magnetic layer that is in contact with the insulating barrier layer has an atomic ratio Z of 25 to 100 and a composition ratio α of 70 to 90 at% (Co ₁₀₀₋ It is formed by _{Z Fe Z) α B 100-} α is preferable for obtaining a high rate of change in resistance (ΔR / R).

Further, in the present invention, in the step (b), the enhancement layer is formed of Co _100-X Fe _X having an Fe composition ratio X of 10 at% or more and _{100 at} % or less, so that a high resistance change rate (ΔR / R ) Is preferable.

In the present invention, in the step (c), the soft magnetic layer may be formed of Ni _Y Fe _100-Y having a Ni composition ratio Y of 81.5 at% to 100 at%. It is preferable because magnetic characteristics can be obtained.

In the present invention, before the step (a),
(E) forming the pinned magnetic layer on the antiferromagnetic layer;
Including
In the annealing process of the step (d), an exchange coupling magnetic field is generated between the antiferromagnetic layer and the pinned magnetic layer, and the magnetization of the pinned magnetic layer is preferably pinned in a predetermined direction.

  According to the present invention, in a method for manufacturing a tunneling magnetic sensing element using Mg—O as an insulating barrier layer, a high resistance change rate (ΔR / R) can be obtained while maintaining the soft magnetic characteristics of the free magnetic layer satisfactorily. I can do it.

  1 to 4 are process diagrams showing a method for manufacturing a tunneling magnetic sensing element (tunneling magnetoresistive element) according to this embodiment. Each figure is a cross-sectional view of the tunnel-type magnetic sensing element in the manufacturing process cut from a direction parallel to the surface facing the recording medium.

  The tunnel-type magnetic detection element is provided at the trailing end of a floating slider provided in a hard disk device, and detects a recording magnetic field of a hard disk or the like. Alternatively, the tunnel type magnetic detection element is also used for an MRAM (magnetoresistance memory) or the like.

  In the figure, the X direction is the track width direction, the Y direction is the direction of the leakage magnetic field from the magnetic recording medium (height direction), the Z direction is the moving direction of the magnetic recording medium such as a hard disk and the tunnel type magnetic detection. The stacking direction of each layer of the element.

  In the process shown in FIG. 1, an underlayer 1, a seed layer 2, an antiferromagnetic layer 3, a lower magnetic layer 4a, a nonmagnetic intermediate layer 4b, and an upper magnetic layer 4c are continuously formed on the lower shield layer 21. . Each layer is formed by sputtering, for example.

In the present embodiment, the lower shield layer 21 is formed of, for example, a NiFe alloy.
The underlayer 1 is formed of a nonmagnetic material such as one or more elements of Ta, Hf, Nb, Zr, Ti, Mo, and W. The formation of the underlayer 1 is not essential.

  The seed layer 2 is formed of NiFeCr, for example. When the seed layer 2 is formed of NiFeCr, the seed layer 2 has a face-centered cubic structure (fcc), and an equivalent crystal plane represented as a {111} plane is preferentially oriented in a direction parallel to the film surface. It will be what.

  The antiferromagnetic layer 3 is made of an antiferromagnetic material containing element β (wherein β is one or more elements among Pt, Pd, Ir, Rh, Ru, and Os) and Mn. Form.

  Β-Mn alloys using these platinum group elements have excellent properties as antiferromagnetic materials, such as excellent corrosion resistance, high blocking temperature, and an increased exchange coupling magnetic field (Hex).

  The antiferromagnetic layer 3 is made of element β and element β ′ (where element β ′ is Ne, Ar, Kr, Xe, Be, B, C, N, Mg, Al, Si, P, Ti, V, One or two of Cr, Fe, Co, Ni, Cu, Zn, Ga, Ge, Zr, Nb, Mo, Ag, Cd, Sn, Hf, Ta, W, Re, Au, Pb, and rare earth elements These elements may be formed of an antiferromagnetic material containing Mn.

  As shown in FIG. 1, the pinned magnetic layer 4 is formed with a laminated ferrimagnetic structure in which a lower magnetic layer 4a, a nonmagnetic intermediate layer 4b, and an upper magnetic layer (upper layer) 4c are laminated in this order from the bottom. The lower magnetic layer 4a is generated by an exchange coupling magnetic field at the interface with the antiferromagnetic layer 3 and an antiferromagnetic exchange coupling magnetic field (RKKY-like interaction) through the nonmagnetic intermediate layer 4b generated by the later annealing process. And the magnetization directions of the upper magnetic layer 4c can be fixed in antiparallel to each other. This is called a so-called laminated ferrimagnetic structure. With this configuration, the magnetization of the pinned magnetic layer 4 can be stabilized, and an exchange coupling magnetic field generated at the interface between the pinned magnetic layer 4 and the antiferromagnetic layer 3 can be generated. It can be increased in appearance. The lower magnetic layer 4a and the upper magnetic layer 4c are formed with, for example, about 12 to 24 mm, and the nonmagnetic intermediate layer 4b is formed with about 8 to 10 mm.

  The lower magnetic layer 4a is formed of a ferromagnetic material such as CoFe, NiFe, CoFeNi. The nonmagnetic intermediate layer 4b is formed of a nonmagnetic conductive material such as Ru, Rh, Ir, Cr, Re, or Cu. The upper magnetic layer 4c may be formed of the same ferromagnetic material as that of the lower magnetic layer 4a, but is preferably formed of CoFeB.

In the present embodiment, the upper magnetic layer 4c, the atomic ratio Z is, 25 to 100, the composition ratio alpha is preferably formed in 70～90At% of _{(Co 100-Z Fe Z)} α B 100-α It is. The upper magnetic layer 4c is preferably formed within a thickness range of 10 to 30 mm.

  Next, an insulating barrier layer 5 made of Mg—O is formed on the upper magnetic layer 4c. In the present embodiment, there are two methods for forming the insulating barrier layer 5. That is, using a target made of Mg—O formed with a predetermined composition ratio, the insulating barrier layer 5 made of Mg—O is sputter-deposited on the upper magnetic layer 4 c, and the upper magnetic layer 4 c There is a method of forming an insulating barrier layer 5 made of Mg-O by sputtering an Mg layer and oxidizing the Mg layer.

  In the present embodiment, it is preferable to form the insulating barrier layer 5 using a target made of Mg—O.

The Mg composition ratio of Mg—O is preferably in the range of 40 to 60 at%, and most preferably Mg _{50 at%} O _{50 at%} . Moreover, in this embodiment, it is preferable to form the thickness of the insulating barrier layer 5 within a range of 7 to 20 mm.

  Next, in the step shown in FIG. 2, the free magnetic layer 6 including the enhancement layer 6 a and the soft magnetic layer 6 b and the protective layer 7 are formed on the insulating barrier layer 5. Each layer is formed by sputtering, for example.

  In the present embodiment, the enhancement layer 6a is made of CoFe or Co. The soft magnetic layer 6b is made of NiFe or Ni. By forming the enhancement layer 6a with CoFe or Co, the spin polarizability near the interface with the insulating barrier layer 5 can be improved. On the other hand, by forming the soft magnetic layer 6b with NiFe or Ni, the soft magnetic characteristics of the free magnetic layer 6 can be improved. By forming the free magnetic layer 6 in such a laminated structure, it is possible to improve good soft magnetic characteristics and resistance change rate (ΔR / R).

Specifically, the enhancement layer 6a is preferably formed of Co _100-X Fe _X having an Fe composition ratio X of 10 at% or more and _{100 at} % or less. The soft magnetic layer 6b is preferably formed of Ni _Y Fe _100-Y having a Ni composition ratio Y in the range of 81.5 at% to 100 at%.
Thus, a stacked body T1 in which the layers from the base layer 1 to the protective layer 7 are stacked is formed.

  Next, a lift-off resist layer 30 is formed on the laminate T1, and both end portions in the track width direction (X direction in the drawing) of the laminate T1 not covered with the lift-off resist layer 30 are etched. (See FIG. 3).

  Next, the lower insulating layer 22, the hard bias layer 23, and the upper insulating layer 24 are stacked in this order on the lower shield layer 21 on both sides in the track width direction (X direction in the drawing) of the stacked body T1. (See FIG. 4). Each layer is formed by sputtering, for example.

  Then, the lift-off resist layer 30 is removed, and an upper shield layer 26 is formed on the stacked body T1 and the upper insulating layer 24.

  In the above-described method for manufacturing a tunneling magnetic sensing element, annealing is included in the formation process. A typical annealing process is an annealing process for generating an exchange coupling magnetic field (Hex) between the antiferromagnetic layer 3 and the lower magnetic layer 4a.

  The annealing process for generating the exchange coupling magnetic field is performed after forming the stacked body T1 shown in FIG.

In the present embodiment, the annealing process is performed in a temperature range of 270 ° C. to 310 ° C. The annealing time is 3 to 5 hours. According to experiments described later, it is known that a high rate of change in resistance (ΔR / R) can be obtained in the range of low RA (element resistance R × element area A) by using this annealing temperature. RA is an extremely important value for optimizing high-speed data transfer and the like, and needs to be set to a low value. Specifically, RA is set within a range of ² to 4 Ωμm ² , preferably ² to 3 Ωμm ² .

  When the annealing temperature is lower than 270 ° C., the rate of change in resistance (ΔR / R) decreases because the internal structure of the upper magnetic layer 4c formed of CoFeB and the insulating barrier layer 5 formed of Mg—O is high. This is considered to be because the resistance change rate (ΔR / R) is insufficient.

  That is, in a tunneling magnetic sensor having an Mg—O insulating barrier layer 5, in order to obtain a high rate of change in resistance (ΔR / R), the insulating barrier layer 5 is placed in a direction parallel to the interface (XY plane). It is important to form a body-centered cubic structure in which equivalent crystal planes typically represented as {100} planes in a direction parallel to (1) are preferentially oriented. Here, “a crystal plane represented typically as {100} plane” refers to a crystal lattice plane expressed using a Miller index, and an equivalent crystal plane expressed as the {100} plane is: There are a (100) plane, a (-100) plane, a (010) plane, a (0-10) plane, a (001) plane, and a (00-1) plane.

  For such Mg—O crystal orientation, the internal structure of CoFeB and the interface structure of CoFeB / Mg—O formed thereunder are also important factors. Here, it is preferable that CoFeB (as.depo) has an amorphous structure because Mg—O can be appropriately formed into a face-centered cubic structure in which the {100} plane is preferentially oriented. The internal structure and interface structure of the upper magnetic layer 4c formed of CoFeB and the insulating barrier layer 5 formed of Mg—O depend on the annealing temperature, and are higher than 270 ° C. as shown in an experiment described later. Given that a high rate of change in resistance (ΔR / R) cannot be obtained at a low annealing temperature, it is presumed that the internal structure and interface structure will be insufficient.

  On the other hand, when the annealing temperature is higher than 310 ° C., the rate of change in resistance (ΔR / R) decreases. This is because the annealing temperature of the soft magnetic layer 6b formed of NiFe or Ni becomes high. Thus, it is assumed that the {111} plane is preferentially oriented in the direction parallel to the film surface, and the resistance change rate (ΔR / R) is likely to be lowered by the enhancement layer 6a being affected by this.

As described above, the enhancement layer 6a is preferably formed of Co _100-X Fe _X having an Fe composition ratio X of 10 at% or more and _{100 at} % or less. The Fe composition ratio X is preferably set to 30 at% or more and 90 at% or less, and more preferably 50 at% or more and 90 at% or less. After the annealing process at 270 ° C. to 310 ° C., the enhancement layer 6a is typically represented as a {100} plane in a direction parallel to the film surface (XY plane in the drawing) like the insulating barrier layer 5. It is preferable to have a body-centered cubic structure in which equivalent crystal planes are preferentially oriented. In particular, when the Fe composition ratio X is set to 30 at% or more, it is considered that the enhancement layer 6a is easily formed in a body-centered cubic structure. At this time, the lattice constant mismatch between the insulating barrier layer 5 and the enhancement layer 6a can be reduced, and the influence of the crystal orientation of the soft magnetic layer 6b on the enhancement layer 6a is small, resulting in a high resistance change. It is assumed that the rate (ΔR / R) will be obtained.

  Further, it is considered that the above-described annealing treatment causes mutual diffusion of constituent elements at the interface of each layer. By such interdiffusion, it is considered that a mixed region in which Mg—O and CoFeB are mixed is formed in the vicinity of the interface between the insulating barrier layer 5 and the upper magnetic layer 4c, and the insulating barrier layer It is considered that a mixed region in which Mg—O and CoFe are mixed is formed in the vicinity of the interface between 5 and the enhancement layer 6a. Such interdiffusion contributes to an increase in resistance change rate (ΔR / R) by, for example, reducing a lattice constant mismatch near the interface between the enhancement layer 6 a and the insulating barrier layer 5. It is also speculated.

In the above-described method for manufacturing a tunneling magnetic sensing element of the present embodiment, the insulating barrier layer 5 is formed of Mg—O, and the enhancement layer 6a formed thereon is further formed with an Fe composition ratio X of 10 at% or more. formed of 100 atomic% or less of _{Co 100-X} Fe X, further thereon, the soft magnetic layer 6b, Ni composition ratio is formed of a NiFe alloy in the range of 81.5at% ~100at%. Thereby, the magnetostriction λ (absolute value) of the free magnetic layer 6 can be reduced to 0 to 5 ppm, the coercive force Hc can be reduced to about 1 to 5 Oe, and the soft magnetic characteristics of the free magnetic layer 6 can be improved.

As the Fe composition ratio X of Co _100-X Fe _X constituting the enhancement layer 6a is higher, the resistance change rate (ΔR / R) tends to be improved when compared with the same RA (element resistance R × element area A). I know that. This is considered to be because the enhancement layer 6a can be appropriately formed into a body-centered cubic structure by increasing the Fe composition ratio X and the lattice constant mismatch with the insulating barrier layer 5 can be reduced.

  In the present embodiment, as described above, in the method for manufacturing a tunneling magnetic sensing element in which Mg—O is used for the insulating barrier layer 5 and the free magnetic layer 6 is made of CoFe / NiFe, the annealing temperature is 270 ° C. to 310 ° C. By setting to this range, a high resistance change rate (R / R) can be obtained. Note that the “anneal treatment” referred to in this embodiment is an annealing process other than that performed to generate an exchange coupling magnetic field between the antiferromagnetic layer 3 and the lower magnetic layer 4a of the pinned magnetic layer 4. Includes processing. That is, when annealing at 400 ° C. is performed in an annealing process other than the annealing process for generating the exchange coupling magnetic field, only a tunnel type magnetic sensing element having a low resistance change rate (R / R) can be obtained. There is no.

In particular, as shown in an experiment to be described later, when the resistance change rate (ΔR / R) was tested on samples having different Fe composition ratios X of the enhancement layer 6a formed of Co _100-X Fe _X , the Fe composition Although the resistance change rate (ΔR / R) differs depending on the ratio X, it can be seen that the dependency of the resistance change rate (ΔR / R) on RA on the annealing temperature is the same regardless of the Fe composition ratio X. ing. That is, at an annealing temperature lower than 270 ° C. and an annealing temperature higher than 310 ° C., the resistance change rate (ΔR / R) obtained in the annealing temperature range of 270 ° C. to 310 ° C. is all obtained when compared with the same RA. Only a low rate of change in resistance (ΔR / R) can be obtained.

  In the present embodiment, the insulating barrier layer 5 and the upper magnetic layer 4c are in direct contact, but for example, an Mg layer may be interposed between the insulating barrier layer 5 and the upper magnetic layer 4c.

Even when the Mg layer is inserted, the resistance is high in a low RA region ( ^{2 to 4} Ωμm ² , preferably ² to 3 Ωμm ² ) by setting the annealing temperature within the range of 270 ° C. to 310 ° C., as in the case where the Mg layer is not inserted. The rate of change (ΔR / R) can be obtained.

A tunneling magnetic sensing element having the laminate T1 was formed.
From the bottom, the laminated body T1 is formed from the underlayer 1; Ta (30) / seed layer 2; NiFeCr (50) / antiferromagnetic layer 3; IrMn (70) / pinned magnetic layer 4 [lower magnetic layer 4a; Co _{70 at %} Fe _{30 at%} (14) / nonmagnetic intermediate layer 4b; Ru (9.1) / upper magnetic layer 4c; CoFeB (18)] / insulating barrier layer 5; Mg—O / free magnetic layer 6 [enhancement layer 6a; CoFe (10) / soft magnetic layer; Ni _{86 at%} Fe _{14 at%} (40)] / protective layer 7; Ta (200) were laminated in this order. The numbers in parentheses indicate the average film thickness and the unit is Å.

  The insulation barrier layer 5 made of Mg—O was formed by sputtering using a target made of Mg—O (composition ratio: 50 at%: 50 at%). The thickness of the insulating barrier layer 5 was 9 to 11 mm in each sample.

  Further, before the insulating barrier layer 5 was formed, the surface of the upper magnetic layer 4c was subjected to plasma treatment.

First, in the experiment, the enhancement layer 6a was made Co _{90 at%} Fe _{10 at%} , and the upper magnetic layer 4c was made Co _{40 at%} Fe _{40 at%} B _{20 at%} .

  In addition, the basic film configuration was annealed. In the experiment, the annealing temperature was set to 250 ° C., 270 ° C., 290 ° C., and 310 ° C., and each annealing time was unified to 4 hours.

  In the experiment, the resistance change rate (ΔR / R) with respect to RA was determined for each annealing temperature. The experimental result is shown in FIG.

Next, with respect to the above-described experimental sample, the upper magnetic layer 4c is changed to Co _{60 at%} Fe _{20 at%} B _{20 at%} , and the others are set to the same settings, and the resistance change rate (ΔR / The magnitude of R) was determined for each annealing temperature. The experimental result is shown in FIG.

Next, with respect to the experimental sample used in FIG. 5, the enhancement layer 6a was changed to Co _{50 at%} Fe _{50 at%} , and other settings were the same (however, 350 ° C. was added to the annealing temperature condition), and the same as above. In addition, the magnitude of the resistance change rate (ΔR / R) with respect to RA was determined for each annealing temperature. The experimental result is shown in FIG.

Next, with respect to the experimental sample used in FIG. 5, the enhancement layer 6a is changed to Co _{50 at%} Fe _{50 at%} , the upper magnetic layer 4c is changed to Co _{60 at%} Fe _{20 at%} B _{20 at%} , and the other settings are the same. (However, 350 ° C. was added to the annealing temperature condition), and the resistance change rate (ΔR / R) with respect to RA was determined for each annealing temperature in the same manner as described above. The experimental result is shown in FIG.

From the experimental results of FIGS. 5 to 8, the annealing temperature was set within the range of 270 ° C. to 310 ° C. As shown in FIGS. 5 to 8, 2~4Ωμm ² the RA, preferably at the range of 2~3Ωμm ^2, when the annealing temperature to 270 ° C. to 310 ° C. the rate of change in resistance with respect to RA (ΔR / R) is It turns out that it becomes about the same high value. On the other hand, it was found that when the annealing temperature was set to 250 ° C. and 350 ° C., only a lower resistance change rate (ΔR / R) was obtained than when the annealing temperature was set to 270 ° C. to 310 ° C.

5 and FIG. 6, or FIG. 7 and FIG. 8, when the upper magnetic layer is made of Co _{40 at%} Fe _{40 at%} B _{20 at%} is higher than the case of Co _{60 at%} Fe _{20 at%} B _{20 at%.} It was found that the rate of resistance change (ΔR / R) can be obtained.

5 and FIG. 7, or FIG. 6 and FIG. 8, when the enhancement layer is formed with Co _{50 at%} Fe _{50 at%} , the resistance change rate (ΔR / R) is higher than that with Co _{90 at%} Fe _{10 at%.} ).

1 process drawing (sectional drawing which cut | disconnected the said tunnel type magnetic sensing element in a manufacturing process from the direction parallel to an opposing surface with a recording medium) which shows the manufacturing method of the tunnel type magnetic sensing element of this embodiment, FIG. 1 is a one-step diagram (a cross-sectional view of the tunneling magnetic sensing element in the manufacturing process cut from a direction parallel to the surface facing the recording medium); FIG. 2 is a one-step diagram (a cross-sectional view in which the tunneling magnetic sensing element in the manufacturing process is cut in a direction parallel to the surface facing the recording medium); FIG. 3 is a one-step diagram (a cross-sectional view of the tunneling magnetic sensing element in the manufacturing process cut from a direction parallel to the surface facing the recording medium); A tunnel-type magnetic sensing element in which a portion laminated in order of the upper magnetic layer, the insulating barrier layer, and the enhancement layer from the bottom of the laminate T1 is Co _{40 at%} Fe _{40 at%} B _{20 at%} / Mg—O / Co _{90 at%} Fe _{10 at%} A graph showing the annealing temperature dependence of the rate of change in resistance (ΔR / R) with respect to RA when using A tunnel-type magnetic sensing element in which the upper magnetic layer, the insulating barrier layer, and the enhancement layer are laminated in this order from the bottom of the laminate T1 to Co _{60 at%} Fe _{20 at%} B _{20 at%} / Mg—O / Co _{90 at%} Fe _{10 at%} A graph showing the annealing temperature dependence of the rate of change in resistance (ΔR / R) with respect to RA when using A tunnel-type magnetic sensing element in which a portion laminated in order of the upper magnetic layer, the insulating barrier layer, and the enhancement layer from the bottom of the laminate T1 is Co _{40 at%} Fe _{40 at%} B _{20 at%} / Mg—O / Co _{50 at%} Fe _{50 at%} A graph showing the annealing temperature dependence of the rate of change in resistance (ΔR / R) with respect to RA when using A tunnel-type magnetic sensing element in which the upper magnetic layer, the insulating barrier layer, and the enhancement layer are stacked in this order from the bottom of the laminate T1 to Co _{60 at%} Fe _{20 at%} B _{20 at%} / Mg—O / Co _{50 at%} Fe _{50 at%} A graph showing the annealing temperature dependence of the rate of change in resistance (ΔR / R) with respect to RA when using

Explanation of symbols

3 Antiferromagnetic layer 4, pinned magnetic layer 4a lower magnetic layer 4b nonmagnetic intermediate layer 4c upper magnetic layer 5 insulating barrier layer 6 free magnetic layer 6a enhanced layer 6b soft magnetic layer 7 protective layers 22, 24 insulating layer 23 hard bias Layer 30 Lift-off resist layer

Claims (6)

In the method of manufacturing a tunneling magnetic sensing element having a laminate formed by laminating a pinned magnetic layer, an insulating barrier layer, and a free magnetic layer in this order from the bottom,
(A) forming an insulating barrier layer made of Mg—O on the pinned magnetic layer;
(B) forming an enhancement layer made of CoFe or Co constituting the free magnetic layer on the insulating barrier layer;
(C) forming a soft magnetic layer made of NiFe or Ni constituting the free magnetic layer on the enhancement layer;
(D) A step of annealing the laminated body in a temperature range of 270 ° C. to 310 ° C.,
A method for manufacturing a tunneling magnetic sensing element, comprising:   2. The method for manufacturing a tunneling magnetic sensing element according to claim 1, wherein, in the step (a), the insulating barrier layer is formed by sputtering using a target made of Mg-O. In the step (a), the upper layer of the pinned magnetic layer in contact with at least the insulating barrier layer has an atomic ratio Z of 25 to 100 and a composition ratio α of (Co _100-Z Fe _Z ) _{α of} 70 to 90 at%. The method for manufacturing a tunneling magnetic sensing element according to claim 1, wherein the tunneling magnetic sensing element is formed of B _100-α . 4. The tunneling magnetic sensing element according to claim 1, wherein in the step (b), the enhancement layer is formed of Co _100-X Fe _X having an Fe composition ratio X of 10 at% or more and _{100 at} % or less. Manufacturing method. 5. The tunnel-type magnetic detection according to claim 1, wherein in the step (c), the soft magnetic layer is formed of Ni _Y Fe _100-Y having a Ni composition ratio Y of 81.5 at% to 100 at%. Device manufacturing method. Prior to the step (a),
(E) forming the pinned magnetic layer on the antiferromagnetic layer;
Including
The annealing process of the step (d) generates an exchange coupling magnetic field between the antiferromagnetic layer and the pinned magnetic layer, and fixes the magnetization of the pinned magnetic layer in a predetermined direction. A manufacturing method of the tunnel type magnetic sensing element according to claim 1.

Images