JP2008293581A - Magnetism detecting element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetism detecting element suited to a high recording density especially by improving a substrate configuration between an insulating layer and a hard bias layer to stabilize playback characteristics. <P>SOLUTION: The magnetism detecting element is provided with an element part T1 for exhibiting magneto-resistance effect, and both side parts 22 positioned in both sides of the element part T1 in a track width direction, and including an insulating layer 23, a Ta substrate layer 24, an alignment control layer 26, a hard bias layer 27, and a protective layer 28 stacked in this order from the bottom. The alignment control layer 26 is formed at Cr<SB>100-X</SB>Ti<SB>X</SB>(Ti composition ratio X is 0 to 13 at% ). Thus, a pop cone noise generation rate is reduced compared with conventional one to stabilize playback characteristics, and the magnetism detecting element for increasing an SN ratio and achieving a high recording density is obtained. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention particularly relates to an optimum base configuration between a hard bias layer and an insulating layer in a TMR element or a CPP-GMR element.

  For example, Patent Document 1 below discloses a film configuration in which an insulating layer and a hard bias layer are stacked on both sides in the track width direction of an element portion in a CPP-GMR element.

In the CPP-GMR element, current is applied in a direction perpendicular to the film surface of each layer constituting the element part, and Al is provided on both sides of the element part in order to prevent the current from being diverted to both sides of the element part. _An insulating layer made of ₂ O ₃ or the like is provided.

The hard bias layer provided on the insulating layer is for supplying a bias magnetic field to the free magnetic layer provided in the element portion.
JP 2006-323900 A JP 2002-25019 A JP 2006-310264 A

  Under the hard bias layer, a base layer for adjusting the crystal orientation of the hard bias layer and improving the coercive force Hc and the squareness ratio S of the hard bias layer, for example, is provided. Conventionally, for example, Cr—Ti is used for the underlayer.

However, according to the experiment described later, in the configuration in which the insulating layer: Al ₂ O ₃ / Cr—Ti / hard bias layer is stacked in this order from the bottom, the popcorn noise generation rate is high, the reproduction characteristics become unstable, and the SN The ratio also decreased, and it was difficult to increase the recording density.

  Therefore, the present invention is for solving the above-described conventional problems, and in particular, by improving the base configuration between the insulating layer and the hard bias layer, it is possible to stabilize the reproduction characteristics and is suitable for increasing the recording density. An object of the present invention is to provide a magnetic detection element.

The present invention provides a magnetoresistive effect by laminating a pinned magnetic layer, a free magnetic layer, and a nonmagnetic material layer positioned between the pinned magnetic layer and the free magnetic layer at least in the film thickness direction, A hard bias layer for supplying a bias magnetic field to the free magnetic layer located on both sides of the element portion in the track width direction, and a current is perpendicular to the film surface of each layer constituting the element portion. In the magnetic detection element to be flown,
An insulating layer made of Al ₂ O ₃ is formed from the side end surface in the track width direction of the element portion to a flat surface extending on both sides of the side end surface, and a Ta underlayer, Cr is formed on the insulating layer from below. An orientation control layer formed of _100-X Ti _X (Ti composition ratio X is 0 at% or more and 13 at% or less), the hard bias layer, and the protective layer are sequentially laminated. .

  In the present invention, a Ta underlayer is interposed between the insulating layer and the orientation control layer, and the Ti composition ratio X of Cr—Ti constituting the orientation control layer is optimized. As a result, as shown in an experiment to be described later, the incidence of popcorn noise can be reduced and the reproduction characteristics can be stabilized as compared with the prior art, and the SN ratio can be improved and the magnetic detection suitable for higher recording density can be achieved. An element structure can be adopted.

  In the present invention, it is preferable that the Ti composition ratio X is 5 at% or more and 12 at% or less because the popcorn noise occurrence rate can be reduced more appropriately.

In the present invention, both end faces in the track width direction of the element portion are formed as inclined surfaces in which the width dimension in the track width direction of the element portion gradually increases from the upper surface side to the lower surface direction of the element portion,
A point where a virtual line drawn in the track width direction from the film thickness center of the free magnetic layer intersects with the inclined surface at a cut surface cut from a plane composed of a track width direction and a film thickness direction is defined as a contact point. When the tangential direction in contact with the inclined surface is A, the inclination angle θ1 formed between the tangential direction A and the lower surface of the element portion is preferably 40 ° or more and 65 ° or less.

  Thereby, it is possible to appropriately obtain the effect of inserting the Ta underlayer between the insulating layer and the orientation control layer, that is, the effect of reducing the popcorn noise occurrence rate and improving the SN ratio. In addition, the track width Tw can be reduced, and the insulation between the element portion and both sides of the element portion in the track width direction can be appropriately increased.

  In the present invention, a Ta underlayer is interposed between the insulating layer and the orientation control layer, and the Ti composition ratio X of Cr—Ti constituting the orientation control layer is optimized. As a result, the incidence of popcorn noise can be reduced and the reproduction characteristics can be stabilized as compared with the prior art, and the S / N ratio can be improved and a structure of a magnetic detecting element suitable for higher recording density can be obtained. .

  FIG. 1 is a cross-sectional view of a thin film magnetic head provided with a tunnel type magnetic sensing element (tunnel type magnetoresistive effect element) of the present embodiment, cut from a plane parallel to a surface facing a 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 based on the tunnel-type magnetoresistance effect (TMR effect). is there. 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.

  The lowermost layer in FIG. 1 is a lower shield layer 21 made of, for example, Ni—Fe. An element portion T1 is formed on the lower shield layer 21. The tunnel-type magnetic detection element includes the element portion T1 and both side portions 22 formed on both sides of the element portion T1 in the track width direction (X direction in the drawing).

  The lowest layer of the element portion T1 is a seed layer 1. The seed layer 1 is made of Ni—Fe—Cr or Cr. When the seed layer 1 is formed of Ni—Fe—Cr, the seed layer 1 has a face-centered cubic (fcc) structure, and an equivalent crystal plane represented as a {111} plane in a direction parallel to the film surface. Are preferentially oriented. In addition, when the seed layer 1 is formed of Cr, the seed layer 1 has a body-centered cubic (bcc) structure, and an equivalent crystal plane expressed as a {110} plane in a direction parallel to the film plane has priority. It will be oriented. Note that an underlayer formed of a nonmagnetic material such as one or more elements of Ta, Hf, Nb, Zr, Ti, Mo, and W may be provided under the seed layer 1. Good.

  The antiferromagnetic layer 2 formed on the seed layer 1 includes an element α (where α is one or more of Pt, Pd, Ir, Rh, Ru, and Os) and Mn. It is preferable to form with the antiferromagnetic material containing these.

  These α-Mn alloys using 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 2 includes an element α and an element α ′ (where the element α ′ 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 It may be formed of an antiferromagnetic material containing the above elements) and Mn.

  A pinned magnetic layer 3 is formed on the antiferromagnetic layer 2. The pinned magnetic layer 3 is pinned in the height direction (Y direction in the drawing) by an exchange coupling magnetic field (Hex) generated at the interface with the antiferromagnetic layer 2.

  In FIG. 1, the pinned magnetic layer 3 has a single-layer structure such as Co—Fe, but from the bottom, a first pinned magnetic layer (for example, Co—Fe), a nonmagnetic intermediate layer (for example, Ru), and a second pinned magnetic layer. A laminated ferrimagnetic structure in which (for example, Co—Fe) is laminated is preferable because the pinned magnetic layer 3 can have a large magnetization pinning force.

  An insulating barrier layer 4 is formed on the pinned magnetic layer 3. The insulating barrier layer 4 is made of, for example, titanium oxide (Ti—O) or magnesium oxide (Mg—O).

  A free magnetic layer 5 is formed on the insulating barrier layer 4. In FIG. 1, the free magnetic layer 5 has a single layer structure such as Ni—Fe, but the free magnetic layer 5 includes a soft magnetic layer made of, for example, Ni—Fe, the soft magnetic layer, and the insulating barrier layer. 4 and an enhancement layer made of, for example, Co—Fe. As a result, it is possible to improve the reproduction characteristics, such as increasing the resistance change rate (ΔR / R).

  A protective layer 6 made of a nonmagnetic metal material such as Ta is formed on the free magnetic layer 5.

  As described above, the element portion T1 that exhibits the tunnel magnetoresistive effect (TMR effect) is formed on the lower shield layer 21. Both end surfaces in the track width direction (X direction in the figure) of the element portion T1 are formed by inclined surfaces 11 and 11 so that the width dimension in the track width direction gradually increases from the upper surface side toward the lower surface direction. . The inclined surface 11 appears linearly or curvedly in the cross section shown in FIG.

As shown in FIG. 1, an insulating layer 23 is formed from the flat surface 21a corresponding to the upper surface of the lower shield layer 21 spreading on both sides of the element portion T1 to the inclined surface 11 of the element portion T1. The insulating layer 23 is made of Al ₂ O ₃ (alumina).

  As shown in FIG. 1, a Ta underlayer 24, an orientation control layer 26, a hard bias layer 27, and a protective layer 28 are sequentially stacked on the insulating layer 23 from the bottom.

The both side portions 22 have a laminated structure from the insulating layer 23 to the protective layer 28.
The orientation control layer 26 is formed of Cr _100-X Ti _X (where the Ti composition ratio X is 0 at% or more and 13 at% or less). The hard bias layer 27 is made of Co—Pt or Co—Pt—Cr. Further, the protective layer 28 is made of a non-magnetic material such as Ta.

  The orientation control layer 26 is provided to improve the crystal orientation of the hard bias layer 27. By providing the alignment control layer 26, the coercive force Hc and the squareness ratio S of the hard bias layer 27 can be increased.

  As shown in FIG. 1, the hard bias layer 27 has a tapered tip portion 27a facing the element portion T1. However, there is an appropriate gap under the Ta between the tip portion 27a and the insulating layer 23. The base layer 24 and the orientation control layer 26 are interposed.

  As shown in FIG. 1, a nonmagnetic metal layer 30 is formed from the element portion T <b> 1 to the both side portions 22, and an upper shield layer 31 is formed on the nonmagnetic metal layer 30. The nonmagnetic metal layer 30 is made of Ru, for example. The upper shield layer 31 is made of, for example, Ni—Fe.

  In the embodiment shown in FIG. 1, the lower shield layer 21 and the upper shield layer 31 function as electrode layers for the element portion T1, and are perpendicular to the film surfaces of the respective layers of the element portion T1 (parallel to the Z direction in the drawing). Direction).

  The free magnetic layer 5 receives the bias magnetic field from the hard bias layer 27 and is magnetized in a direction parallel to the track width direction (X direction in the drawing). On the other hand, the pinned magnetic layer 3 is magnetized in a direction parallel to the height direction (Y direction in the drawing). The magnetization of the fixed magnetic layer 3 is fixed (the magnetization does not fluctuate due to an external magnetic field), but the magnetization of the free magnetic layer 5 fluctuates due to an external magnetic field.

  When the magnetization of the free magnetic layer 5 is changed by an external magnetic field, the insulation provided between the fixed magnetic layer 3 and the free magnetic layer 5 when the magnetization of the fixed magnetic layer 3 and the free magnetic layer 5 is antiparallel. The tunnel current hardly flows through the barrier layer 4 and the resistance value becomes maximum. On the other hand, when the magnetizations of the fixed magnetic layer 3 and the free magnetic layer 5 are parallel, the tunnel current is most easily flowed and the resistance is increased. The value is minimized.

  Utilizing this principle, the magnetization of the free magnetic layer 5 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. .

The characteristic part of the tunnel type magnetic sensing element of this embodiment will be described. As shown in FIG. 1, the insulating layer 23 made of Al ₂ O ₃ is formed from the inclined surface 11 of the element portion T1 to the flat surface 21a of the lower shield layer 21, and on the insulating layer 23, A Ta underlayer 24, an orientation control layer 26, a hard bias layer 27, and a protective layer 28 are sequentially stacked from the bottom.

The orientation control layer 26 is formed of Cr _100-X Ti _X (where the Ti composition ratio X is 0 at% or more and 13 at% or less).

  As described above, in this embodiment, the Ta underlayer 24 is interposed between the insulating layer 23 and the orientation control layer 26, and the Ti composition ratio X of the orientation control layer 26 is optimized. As a result, the incidence of popcorn noise can be reduced and the reproduction characteristics can be stabilized, and the S / N ratio can be improved and the structure of a magnetic detecting element suitable for high recording density can be obtained. .

  The Ti composition ratio X is preferably 5 at% or more and 12 at% or less. According to an experiment described later, this can more effectively reduce the popcorn noise occurrence rate.

  Further, in the cross-sectional view shown in FIG. 1, a point where the virtual line B drawn in the track width direction from the film thickness center of the free magnetic layer 5 and the inclined surface 11 intersect is defined as a contact C. Assuming that the tangential direction in contact with the inclined surface 11 is A, the inclination angle θ1 formed by the tangential direction A and the lower surface of the element portion T1 (the lower surface of the seed layer 1 in the embodiment of FIG. 1) is 40 ° or more and 65 °. The following is preferable. The tilt angle θ1 is more preferably 53 ° or less.

  Thereby, the Ta underlayer 24 and the orientation control layer 26 are appropriately interposed between the insulating layer 23 and the tip portion 27a of the hard bias layer 27, and the magnetic characteristics of the hard bias layer of the tip portion 27a can be ensured. Effectively, the occurrence rate of popcorn noise can be reduced, and the SN ratio can be improved.

  Furthermore, by setting the inclination angle θ1 to 40 ° or more, the track width Tw of the element portion T1 can be reduced. The track width Tw is preferably about 40 to 100 nm. Further, by setting the inclination angle θ1 to 65 ° or less, more preferably 53 ° or less, the insulating layer 23 can be appropriately extended to the inclined surface 11, and the element portion T1 and the both side portions 22 can be formed. Insulating properties can be ensured, and the reproduction output can be increased.

  The average film thickness of the insulating layer 23 on the flat surface 21a is preferably in the range of 40 to 100 mm. Thereby, the insulation between the element part T1 and the side parts 22 and between the side parts 22 and the lower shield layer 21 can be kept good. Further, the distance between the free magnetic layer 5 and the hard bias layer 27 can be kept moderate.

  The average film thickness above the flat surface 21a of the Ta underlayer 24 is preferably in the range of 5 to 30 mm. The average film thickness above the flat surface 21a of the orientation control layer 26 is preferably in the range of 25 to 50 mm. Thereby, the popcorn noise occurrence rate can be reduced more effectively and the SN ratio can be improved. Furthermore, the distance between the free magnetic layer 5 and the hard bias layer 27 can be kept moderate.

  The average thickness of the hard bias layer 27 above the flat surface 21a is in the range of 100 to 300 mm.

  In the embodiment shown in FIG. 1, the tunnel type magnetic sensing element is used. However, like the tunnel type magnetic sensing element, a CPP (current perpendicular to the plane) -GMR (current flowing to the film surface) is used. The embodiment shown in FIG. 1 can also be applied to a (giant magnetoresistive effect) element. In the GMR element, the insulating barrier layer 4 shown in FIG. 1 is formed of a nonmagnetic metal material such as Cu.

  A method for manufacturing the tunneling magnetic sensing element of this embodiment will be described. 2 to 4 are partial cross-sectional views of the tunnel-type magnetic sensing element cut from the same plane as that in FIG. 1 during the manufacturing process.

  In the process shown in FIG. 2, the seed layer 1, the antiferromagnetic layer 2, the pinned magnetic layer 3, the insulating barrier layer 4, the free magnetic layer 5, and the protective layer 6 are sequentially sputtered on the lower shield layer 21 from the bottom. The film is formed by the method.

  Next, as shown in FIG. 2, a lift-off resist layer 32 is formed on the protective layer 6, and the element portion T <b> 1 from the seed layer 1 to the protective layer 6 that is not covered with the lift-off resist layer 32. Both end portions in the track width direction (X direction in the figure) are removed by etching.

  The element portion T1 is etched along the dotted line shown in FIG. Therefore, both end surfaces of the remaining element portion T1 in the track width direction (X direction in the drawing) are formed with inclined surfaces 11 in which the width dimension in the track width direction gradually decreases from the bottom to the top.

  Further, in the cross-sectional view shown in FIG. 2, a point at which the virtual line B drawn in the track width direction from the film thickness center of the free magnetic layer 5 and the inclined surface 11 intersect is defined as a contact C. Assuming that the tangential direction in contact with the inclined surface 11 is A, the inclination angle θ1 formed by the tangential direction A and the lower surface of the element portion T1 (the lower surface of the seed layer 1 in the embodiment of FIG. 1) is 40 ° or more and 65 °. The following is preferable. The tilt angle θ1 is more preferably 53 ° or less.

Next, as shown in FIG. 3, from the bottom from the flat surface 21a of the lower shield layer 21 spreading on both sides of the element portion T1 in the track width direction (X direction in the drawing) to the inclined surface 11 of the element portion T1. Then, an insulating layer 23 made of Al ₂ O ₃ (alumina) is formed by ion beam sputtering or the like. Further, a Ta underlayer 24 is formed on the insulating layer 23 by ion beam sputtering or the like.

  The film forming direction when forming the insulating layer 23 is a direction inclined by θ2 with respect to the vertical direction (Z direction in the drawing) of the flat surface 21a of the lower shield layer 21. It is preferable that the film formation angle θ2 be in the range of 30 to 50 ° because the insulating layer 23 can be appropriately formed from the inclined surface 11 of the element portion T1 to the flat surface 21a of the lower shield layer 21. is there.

  Further, the film forming direction when forming the Ta underlayer is set to a direction inclined by θ3 with respect to the vertical direction (Z direction in the drawing) of the flat surface 21a of the lower shield layer 21. Further, when the film forming angle θ3 is set in the range of 20 to 40 °, the Ta underlayer 24 is appropriately flattened from the insulating layer 23 formed on the inclined surface 11 of the element portion T1 to the lower shield layer 21. It is preferable that the film can be formed over the insulating layer 23 formed on the surface 21a.

Next, in the step shown in FIG. 4, an orientation control layer 26 made of Cr _100-X Ti _X (Ti composition ratio X is 0 at% to 13 at%) is formed on the Ta underlayer 24 by ion beam sputtering. A hard bias layer 27 made of Co—Pt or Co—Pt—Cr is formed on the orientation control layer 26 by ion beam sputtering or the like, and further, a protection made of Ta, for example, is formed on the hard bias layer 27. The layer 28 is formed by ion beam sputtering or the like.

  The film forming direction when forming the orientation control layer 26 is a direction inclined by θ4 with respect to the vertical direction (Z direction in the drawing) of the flat surface 21a of the lower shield layer 21. The film forming direction when forming the hard bias layer 27 is set to a direction inclined by θ5 with respect to the vertical direction (Z direction in the drawing) of the flat surface 21a of the lower shield layer 21. Further, the film forming direction when forming the protective layer 28 is set to a direction inclined by θ6 with respect to the vertical direction (Z direction in the drawing) of the flat surface 21a of the lower shield layer 21. By setting the film formation angles θ4, θ5, and θ6 in the range of 20 to 40 °, the orientation control layer 26, the hard bias layer 27, and the protective layer 28 can be formed to the vicinity of both sides of the element portion T1. Is preferred. Moreover, the lift-off property of the resist layer 32 can be improved by setting the film forming angles θ2 to θ6 in the steps of FIGS.

  3 and 4, the insulating layer 23 can be extended and formed on the inclined surface 11 of the element portion T1, and a Ta layer is formed between the insulating layer 23 and the leading end portion 27a of the hard bias layer 27. The underlayer 24 and the orientation control layer 26 made of Cr—Ti can be appropriately interposed.

Then, the lift-off resist layer 32 is removed, and a nonmagnetic metal layer 30 and an upper shield layer 31 are formed on the element portion T1 and the protective layer 28 in order from the bottom.
The CPP-GMR element is manufactured according to the manufacturing method shown in FIGS.

  The magnetic detection element of this embodiment can be used as an MRAM (magnetic resistance memory) or a magnetic sensor in addition to the use as a magnetic head built in a hard disk device.

[Examples 1 to 3]
An insulating layer 23 made of Al ₂ O ₃ from the bottom on both sides of the element portion T1, a Ta underlayer 24, an orientation control layer 26 made of Cr _{90 at%} Ti _{10 at %} , a hard bias layer 27 made of Co _{78 at%} Pt _{22 at%} , and The tunnel type magnetoresistive effect element shown in FIG. 1 was formed by laminating the protective layer 28 made of Ta in this order.

  The total thickness of the element portion T1 was unified to 551 mm. Further, the inclination angle θ1 shown in FIG. 1 of the element portion T1 was set within a range of 43 to 47 °. Further, the average film thickness of the insulating layer 23 on the flat surface 21a shown in FIG.

  The numerical values on the left side of each column of Table 1 below are average film thicknesses of the Ta underlayer 24, the orientation control layer 26, the hard bias layer 27, and the protective layer 28 above the flat surface 21a shown in FIG. . The numerical values on the right side of each column are the film formation angles of the respective layers (film formation angles θ3 to θ6 shown in FIGS. 3 and 4).

  As shown in Table 1, the average thickness of the hard bias layer (Co-Pt) 27 increases in the order of Example 1, Example 2, and Example 3, and Examples 1, 2, and 3 In order of 3, the average thickness of the protective layer (Ta) 28 was adjusted to be thin.

[Conventional Examples 1 to 3]
A tunnel type magnetic sensing element in which the orientation control layer 26 made of Cr _{90 at%} Ti _{10 at%} is formed directly on the insulating layer 23 without forming the Ta underlayer 24 in the film configurations of the above-described Examples 1 to 3. Formed.

  In the experiment, as shown in Table 1, the average film thickness of the hard bias layer and the protective layer of Conventional Example 1 is set to Example 1, the average film thickness of the hard bias layer and the protective layer of Conventional Example 2 is set to Example 2, and The average thicknesses of the hard bias layer and the protective layer in Example 3 were formed in accordance with Example 3.

  Further, as shown in Table 1, in Conventional Examples 1 to 3, instead of forming the Ta underlayer, the average film thickness of the orientation control layer is set to the Ta underlayer and the alignment control layer of Examples 1 to 3. And adjusted to the total thickness.

  In the experiment, many samples of Examples 1 to 3 and Conventional Examples 1 to 3 were formed, and the popcorn noise generation rate, noise, and SN ratio of each sample were measured.

  The S / N pass rate shown in Table 1 is a ratio when a sample having an SN ratio of 35 dB or more is passed. Here, the popcorn noise occurrence rate is obtained by applying the measured voltage to the output when the measurement voltage (150 mV) is passed through the MR element in order after passing through the amplifier and the band pass filter of 3 to 80 MHz in order. (Measured for 1 ms or more), count the number of times that sudden noise has occurred whose voltage exceeds the threshold of 90 μV, and divide the number by the number of test heads (60 or more) to be measured. This is the ratio of the head that generates popcorn noise. Further, in the example of Table 1, the effective value of noise detected through a low-pass filter (30 MHz or less) is divided by the inspection value with respect to the output of the QST test for the MR element incorporated in the slider. Is defined as the SN value. The conditions for these measurements are not particularly limited.

  The popcorn noise occurrence rate is summarized in the graph of FIG. As shown in FIG. 5, in each of Examples 1 to 3, the popcorn noise occurrence rate could be reduced as compared with Conventional Examples 1 to 3.

As shown in Table 1, in Examples 1 to 3, noise could be reduced as compared with Conventional Examples 1 to 3.
Furthermore, as shown in Table 1, the S / N pass rate was higher in the example than in the conventional example.

Based on the above experimental results, by inserting a Ta underlayer between the insulating layer made of Al ₂ O ₃ and the orientation control layer made of Cr—Ti, the popcorn noise generation rate and noise can be reduced and the SN ratio can be improved. I knew it was possible.

[Examples 4 to 7]
Insulating layer 23 by the _Al 2 _{O 3} from the bottom on both sides of the active element T1, Ta underlayer _{24, Cr 100-Xat% Ti} seed layer ₂₆ made of _{Xat%, Co 78at% Pt} hard bias layer 27 made of _22at%, Then, the tunnel magnetoresistive effect element shown in FIG.

  The inclination angle θ1 shown in FIG. 1 of the element portion T1 is set within the range shown in Table 2 below. Further, the average film thickness of the insulating layer 23 on the flat surface 21a shown in FIG. 1 is 80 mm, the average film thickness of the Ta underlayer 24 above the flat surface 21a shown in FIG. The average film thickness above the flat surface 21a shown in FIG. 1 is 35 mm, the average film thickness of the hard bias layer 27 above the flat surface 21a shown in FIG. The average film thickness above the surface 21a was adjusted within the range of 350 to 390 mm. The total thickness of the hard bias layer 27 and the protective layer 28 was adjusted to be 590 mm.

  In the experiment, the Ti composition ratio X of Example 4 was 0 at%, the Ti composition ratio X of Example 5 was 7 at%, the Ti composition ratio X of Example 6 was 10 at%, and the Ti composition ratio X of Example 7 was 13 at%. Set to.

[Conventional example 4]
A tunnel type magnetic sensing element in which the orientation control layer 26 made of Cr _{90 at%} Ti _{10 at%} is formed directly on the insulating layer 23 without forming the Ta underlayer 24 in the film configurations of the above Examples 4 to 7. Formed. The average film thickness of the hard bias layer 27 above the flat surface 21a shown in FIG. 1 was adjusted to 220 mm, and the average film thickness of the protective layer 28 above the flat surface 21a shown in FIG.

  In Conventional Example 4, instead of forming the Ta underlayer, the average thickness of the orientation control layer was adjusted to the total thickness of the Ta underlayer and the orientation control layer in Examples 4 to 7.

[Comparative Example 1]
Among the film configurations of Examples 4 to 7 described above, tunnel type magnetic sensing elements were formed in which the Ti composition ratio of the orientation control layer was 16 at%. The average film thickness of the hard bias layer 27 above the flat surface 21a shown in FIG. 1 was adjusted to 200 mm, and the average film thickness of the protective layer 28 above the flat surface 21a shown in FIG.

  The popcorn noise occurrence rate of each sample of Examples 4 to 7, Conventional Example 4 and Comparative Example 1 was measured. The measurement conditions at this time are the same as in Table 1. However, the measurement voltage was 170 mV.

  The popcorn noise occurrence rates shown in Table 2 are graphed in FIG. 6 with the horizontal axis representing the Ti composition ratio X.

  As shown in FIG. 6, in the example, when the Ti composition ratio X of the orientation control layer made of Cr—Ti is 10 at%, the popcorn noise occurrence rate can be minimized, and the Ti composition ratio X is smaller than 10 at%, or It was found that when the Ti composition ratio X is larger than 10 at%, the popcorn noise occurrence rate gradually increases.

  Further, as in Comparative Example 1 shown in FIG. 6, when the Ti composition ratio X is increased to 16 at%, a Ta underlayer is not inserted and the Ti composition ratio of the orientation control layer made of Cr—Ti is 10 at%. It was found that the incidence of popcorn noise was higher than 4.

Therefore, from the experimental results shown in FIG. 6, in this example in which the Ta underlayer was inserted between the insulating layer made of Al ₂ O ₃ and the orientation control layer, the orientation control layer was Cr _100-X Ti _X It was found that the popcorn noise generation rate can be effectively reduced by forming with Ti composition ratio X of 0 at% or more and 13 at% or less.

  Further, it was found that the popcorn noise generation rate can be more effectively reduced by setting the Ti composition ratio X to 5 at% or more and 12 at% or less.

[Examples 8 to 11]
Next, on the substrate of Al ₂ O ₃ , Ta underlayer: Ta (50) / orientation control layer Cr or Cr—Ti (50) / hard bias layer: Co _{78 at} % Pt _{22 at%} (200) / protection from _below Layers were stacked in the order of Ta (50). The numbers in parentheses indicate the average film thickness and the unit is Å.

In the experiment, the orientation control layer is formed of Cr _100-X Ti _X , and the Ti composition ratio X is changed to 0 at%, 7 at%, 10 at%, and 13 at%, and the coercive force Hc of the hard bias layer at this time, The squareness ratio S and Mr × t (residual magnetization Mr, film thickness t) were examined.

[Comparative Example 2]
Of the film configurations of Examples 8 to 11 described above, a laminated film in which the Ti composition ratio of the orientation control layer was 16 at% was formed, and the coercive force Hc, squareness ratio S, Mr × t (residual magnetization Mr, The film thickness t) was examined.
The experimental results are shown in Table 3 below.

  FIG. 7 shows the experimental results of the coercivity Hc of the hard bias layer with the horizontal axis representing the Ti composition ratio. FIG. 8 shows the experimental results of the squareness ratio S of the hard bias layer with the horizontal axis representing the Ti composition ratio. FIG. 9 shows the result of the Mr × t experiment of the hard bias layer with the horizontal axis representing the Ti composition ratio.

  As shown in FIG. 7, the coercive force Hc has a large dependence on the Ti composition ratio X of 0 at% to 16 at%, and the coercive force Hc is likely to vary depending on the Ti composition ratio, whereas the squareness ratio S and Mr × t are It was found that the dependence on the Ti composition ratio X of 0 at% to 16 at% is small and almost constant.

As described above, in this example in which the Ta underlayer was inserted between the insulating layer made of Al ₂ O ₃ and the orientation control layer, the orientation control layer was Cr _100-X Ti _X (however, the Ti composition ratio) It was found that when X is formed at 0 at% or more and 13 at% or less), the squareness ratio S and Mr × t can be stably set to high values, and a coercive force Hc of 1000 Oe or more can be secured. It was also found that the coercive force Hc can be increased to about 1500 Oe or more when the Ti composition ratio X is set to 5 at% or more.

  From the above, it was found that in this example, the popcorn noise occurrence rate and noise can be reduced and the SN ratio can be improved without deteriorating the characteristics of the hard bias layer.

Sectional drawing which cut | disconnected the tunnel type | mold magnetic detection element of this embodiment from the surface parallel to the opposing surface with a recording medium, 1 process drawing (sectional drawing which cut | disconnected the said tunnel type magnetic detection element in a manufacturing process from the surface parallel to a opposing surface with a recording medium) which shows the manufacturing method of the tunnel type magnetic detection element of this embodiment, FIG. 2 is a one-step diagram (a cross-sectional view of the tunneling magnetic sensing element during the manufacturing process cut from a plane parallel to the surface facing the recording medium); FIG. 3 is a one-step diagram (a cross-sectional view of the tunnel-type magnetic sensing element during the manufacturing process cut from a plane parallel to the surface facing the recording medium); Examples 1 to 3 (a configuration in which an Ta underlayer is inserted between an Al ₂ O ₃ insulating layer and an orientation control layer of Cr _{90 at%} Ti _{10 at%} ) and Conventional Examples 1 to 3 (Al ₂ O ₃ A graph showing the popcorn noise generation rate of the insulating layer and the orientation control layer of Cr _{90 at%} Ti _{10 at%} without inserting a Ta underlayer directly on the insulating layer. The graph which shows the relationship between Ti composition ratio X of the orientation control layer of _{Cr100 -Xat% TiXat%} in Examples 4-7, the prior art example 4, and the comparative example 1, and a popcorn noise generation rate, A graph showing the relationship between the Ti composition ratio X of the Cr _100-Xat% Ti _Xat% orientation control layer and the coercive force Hc of the hard bias layer in Examples 8 to 11 and Comparative Example 2. A graph showing the relationship between the Ti composition ratio X of the Cr _100-Xat% Ti _Xat% orientation control layer and the square ratio S of the hard bias layer in Examples 8 to 11 and Comparative Example 2, The graph which shows the relationship between Ti composition ratio X of the orientation control layer of _{Cr100 -Xat%} Ti _Xat% in Example 8-Example 11 and Comparative Example 2, and Mr * t of a hard bias layer,

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Seed layer 2 Antiferromagnetic layer 3 Fixed magnetic layer 4 Insulating barrier layer 5 Free magnetic layers 6 and 28 Protective layer 11 Inclined surface 21 Lower shield layer 22 Both sides 23 Insulating layer 24 Ta underlayer 26 Orientation control layer 27 Hard bias layer 30 Nonmagnetic metal layer 31 Upper shield layer 32 Lift-off resist layer

Claims (3)

An element portion that exhibits a magnetoresistive effect by laminating at least a pinned magnetic layer, a free magnetic layer, and a nonmagnetic material layer positioned between the pinned magnetic layer and the free magnetic layer in a film thickness direction, and a track of the element portion A hard bias layer for supplying a bias magnetic field to the free magnetic layer located on both sides in the width direction, and a magnetic detection in which current flows from a direction perpendicular to the film surface of each layer constituting the element unit In the element
An insulating layer made of Al ₂ O ₃ is formed from the side end surface in the track width direction of the element portion to a flat surface extending on both sides of the side end surface, and a Ta underlayer, Cr is formed on the insulating layer from below. An orientation control layer formed of _100-X Ti _X (Ti composition ratio X is 0 at% or more and 13 at% or less), the hard bias layer, and the protective layer are sequentially laminated. .   The magnetic detection element according to claim 1, wherein the Ti composition ratio X is 5 at% or more and 12 at% or less. Both end faces in the track width direction of the element portion are formed by inclined surfaces in which the width dimension in the track width direction of the element portion gradually increases from the upper surface side to the lower surface direction of the element portion,
A point where a virtual line drawn in the track width direction from the film thickness center of the free magnetic layer intersects with the inclined surface at a cut surface cut from a plane composed of a track width direction and a film thickness direction is defined as a contact point. 3. The magnetic field according to claim 1, wherein an inclination angle θ <b> 1 formed by the tangential direction A and the lower surface of the element portion is 40 ° or more and 65 ° or less, where A is a tangential direction in contact with the inclined surface. Detection element.

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