JP2001043518A - Thin film magnetic head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase current density by forming a lower gap layer and / or an upper gap layer with an insulating film having AlN, forming an amorphous intercrystalline phase between a crystalline phase and an amorphous phase, and controlling a peak intensity ratio (002)face/(220)face in the X-ray diffraction to a specified range. SOLUTION: A lower gap layer 2 and an upper gap layer 6 are formed with insulating films such as AlN excellent in thermal conductivity and heat generated from a magneto-resistive element layer 16 is released through the lower gap layer 2 and the upper gap layer 6 to a lower shield layer 1 and an upper shield layer 7. If the lower and upper gap layers 2 and 6 are made of AlN, the (002) face or (220) face of a crystalline phase is preferably oriented in a direction perpendicular to the film surface or further the peak intensity ratio (002) face/(220) face in the X-ray diffraction is preferably more than 0 and 3.5 or less, or more than 9.7 for further enhancing thermal conductivity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin-film magnetic head mounted on, for example, a hard disk drive and the like, and more particularly to a thin-film magnetic head by improving the material and structure of a gap layer formed above and below a magnetoresistive element layer. The present invention relates to a thin-film magnetic head having improved thermal conductivity of a gap layer.

[0002]

2. Description of the Related Art FIG. 16 is an enlarged sectional view showing a conventional thin film magnetic head viewed from a side facing a recording medium.

This thin film magnetic head is a read head utilizing the magnetoresistance effect, and is provided, for example, on a trailing side end surface of a slider constituting a floating head. Note that a so-called inductive head for writing may be stacked on the thin-film magnetic head (read head) shown in FIG.

[0004] Reference numeral 1 shown in FIG.
-A lower shield layer formed of an Fe-based alloy (Permalloy) or the like. On the lower shield layer 1, Al
A lower gap layer 20 made of a nonmagnetic material such as ₂ O ₃ (alumina) is formed, and a magnetoresistive element layer 16 is further formed thereon.

An AMR (amisotropic magnet) using an element exhibiting a magnetoresistance effect is formed in the magnetoresistance effect element layer 16.
or giant magnetoresistive (GMR) element using an element exhibiting a giant magnetoresistive effect.
It is preferable to use an MR element. There are several types of structures that produce the giant magnetoresistance effect. Among them, a structure called a spin-valve thin-film element has a relatively simple structure and changes its resistance with a weak magnetic field.

The spin-valve thin film element has the simplest structure and is composed of four layers, a free magnetic layer (Ni-Fe alloy), a non-magnetic conductive layer (Cu), and a fixed magnetic layer (Ni-Fe).
Alloy) and an antiferromagnetic layer (such as an Fe-Mn alloy).

As shown in FIG. 16, a hard bias layer 4 is formed as a vertical bias layer on both sides of the magnetoresistive element layer 16, and Cu (copper), W ( The electrode layer 5 of a non-magnetic conductive material having a small electric resistance such as tungsten is formed. In addition,
When the magnetoresistive element layer 16 is formed of the above-described spin-valve thin-film element, when a detection current (sense current) is applied to the electrode layer 5, the detection current becomes fixed magnetic property of the spin-valve thin-film element. Layer, the non-magnetic conductive layer, and the free magnetic layer.

Then, as shown in FIG. 16, an upper gap layer 21 made of a non-magnetic material such as alumina is formed on the electrode layer 5.
An upper shield layer 7 of sendust, permalloy, or the like is formed on the upper surface.

[0009]

By the way, in order to further improve the reproduction sensitivity of the magnetoresistive element layer 16 with the increase in recording density, it is necessary to increase the current density from the electrode layer 5. When the current density is increased, the amount of heat generated from the magnetoresistive element layer 16 increases, and as a result, there is a problem that the element temperature of the magnetoresistive element layer 16 increases.

This is because the gap layers 20 and 21 formed above and below the magnetoresistive element layer 16 are formed of an insulating film having a low thermal conductivity such as Al ₂ O ₃ .

When the temperature of the element portion of the magnetoresistive element layer 16 rises, for example, when the magnetoresistive element layer 16 is formed of a spin-valve thin film element, Ni constituting the fixed magnetic layer and the free magnetic layer is formed. -N in Fe-based alloys
i and Cu constituting the nonmagnetic conductive layer cause diffusion,
There was a problem that the multilayer structure collapsed. When the multilayer structure collapses, the resistance change rate of the spin-valve thin film element decreases,
Reproduction sensitivity is reduced. Further, not only in the spin-valve thin film element, but also in a thin film magnetic head utilizing the AMR effect, an increase in the temperature of the element causes electromigration, thereby reducing the reliability of the element and the life of the element.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and improves the material or structure of a gap layer formed above and below a magnetoresistive element layer to increase the thermal conductivity of the gap layer. By doing so, the heat generated in the element portion can be released to the upper and lower shield layers, so that the current density can be increased, and the reproduction sensitivity of the magnetoresistive element layer can be improved. It is an object to provide a thin film magnetic head.

[0013]

The present invention provides a magnetoresistive element layer formed on a lower shield layer via a lower gap layer, an electrode layer for applying a detection current to the magnetoresistive element layer, In a thin-film magnetic head comprising an upper shield layer formed on the electrode layer via an upper gap layer, at least one of the lower gap layer and the upper gap layer is formed of an insulating film containing AlN. The structure has a crystalline phase and an amorphous grain boundary phase formed between the crystalline phases.
2) The peak intensity ratio of the plane / (220) plane is larger than 0 and not more than 3.5, or not less than 9.7.

The above-described insulating film having AlN has a higher thermal conductivity than the thermal conductivity of Al ₂ O ₃ or the like conventionally used as a gap layer.

Further, in the present invention, (00)
2) The peak intensity ratio of the plane / (220) plane is larger than 0 and equal to or smaller than 3.5, or equal to or larger than 9.7.

This numerical range is calculated from an experimental result described later. First, when forming an AlN film, N ₂
The AlN film was formed by changing the flow ratio, and the relationship between the N ₂ flow ratio and the peak intensity ratio of the (002) plane / (220) plane at this time is shown in FIG.

Next, FIG. 14 shows the relationship between the sense current and the rate of temperature rise of the element portion at each peak intensity ratio, and the obtained curve of each peak intensity ratio is taken as a quadratic function (Y = aX ² + b). The a value on each curved surface was examined.

The relationship between the peak intensity ratio and the a-value is graphed (FIG. 15), and the range of the peak intensity ratio where the a-value is 1.0 or less is obtained from this graph, and the result is as described above. Numeric range.

Since the value a of Al ₂ O ₃ conventionally used as a gap layer is larger than 2.0, the value of a
Setting the value to 1.0 or less means that the temperature rise rate of the element portion can be reduced as compared with the case of using Al ₂ O ₃ .

As described above, (002) plane / (220) plane
By setting the peak intensity ratio of the surface to be greater than 0 and not more than 3.5 or not less than 9.7, the Al
It is possible to improve the thermal conductivity as compared with the case where ₂ O ₃ is used, and to suppress a rise in the temperature of the element portion.

In the present invention, (0)
The peak intensity ratio of the (02) plane / (220) plane may be larger than 0 and smaller than 1.0.

The present invention also provides a magneto-resistance effect element layer formed on a lower shield layer via a lower gap layer,
An electrode layer for applying a detection current to the magnetoresistive element layer,
In a thin-film magnetic head comprising an upper shield layer formed on the electrode layer via an upper gap layer, at least one of the lower gap layer and the upper gap layer is formed of an insulating film containing AlN. The structure has a crystalline phase and an amorphous grain boundary phase formed between the crystalline phases, and the (002) plane of the crystalline phase is oriented in a direction perpendicular to the film surface. It is characterized by the following.

In this invention, unlike the above invention, only the (002) plane of the crystalline phase is oriented in a direction perpendicular to the film surface. This can also improve the thermal conductivity of the gap layer.

The present invention also provides a magnetoresistive element layer formed on a lower shield layer via a lower gap layer,
An electrode layer for applying a detection current to the magnetoresistive element layer,
In a thin-film magnetic head comprising an upper shield layer formed on the electrode layer via an upper gap layer, at least one of the lower gap layer and the upper gap layer is formed of an insulating film containing AlN. It has a crystalline phase and an amorphous grain boundary phase formed between the crystalline phases, and the (220) plane of the crystalline phase is oriented in a direction perpendicular to the film surface. It is characterized by the following.

According to the present invention, only the (220) plane is oriented in a direction perpendicular to the film surface, and the thermal conductivity of the gap layer can be improved also by this.

Next, in the present invention, it is preferable that columnar crystals exist in the crystalline phase from the lower surface of the film toward the upper surface of the film. The presence of columnar crystals in the crystalline phase makes it easier for heat to be transmitted in the direction perpendicular to the film surface, increasing heat dissipation,
It is possible to appropriately suppress a rise in the temperature of the element portion.

In the present invention, the grain boundary phase is B,
It is preferable that the amorphous phase contains one or more light elements of C, O, and Si.

Furthermore, in the present invention, it is preferable that a protective layer made of an insulating material is formed on the insulating film.

In particular, when the insulating film is formed of AlN, the protective layer is provided to further improve the corrosion resistance of AlN to an alkaline aqueous solution and to flatten the surface of the gap layer formed of AlN. Can be

The protective layer is made of Al ₂ O ₃ , SiO ₂ ,
It is preferable to be formed of one or a mixture of two or more of Ta ₂ O ₅ and SiC.

In the present invention, the lower layer of the insulating film includes:
It is preferable that a base adhesion layer made of an insulating material and having an amorphous phase be formed.

The underlayer adhesion layer is made of Al ₂ O ₃ , Si,
It is preferable to be formed of one or a mixture of two or more of SiO ₂ , SiN, and SiC.

Further, it is preferable that the underlayer adhesion layer is formed at a thickness of 100 Å or less.

The reason why the undercoating adhesive layer is provided as a lower layer of the insulating film is that, particularly when the insulating film is formed of AlN, DLC, or the like, the insulating film has very poor adhesion to the undercoating layer. This is because there was a problem that the insulating film was easily peeled off due to a large stress.

For this reason, when the insulating film is formed of AlN or DLC, an underlying adhesion layer of Al ₂ O ₃ or the like having good adhesion and small film stress is formed in advance as an underlying layer of the insulating film. It is preferable that the peeling of the insulating film can be reduced.

In this case, however, it is necessary to form the undercoating layer as thin as possible, specifically, at 100 angstrom or less, and to make the film structure of the undercoating layer an amorphous phase.

If the underlying adhesion layer is a crystalline phase, the difference between the lattice constant of the crystalline phase in the underlying adhesion layer and the lattice constant of the crystalline phase in the insulating film is as follows.
This is because the film stress of the insulating film is increased, and the insulating film is easily peeled.

As described above, in the present invention, by improving the material and structure of the gap layer, it is possible to improve the thermal conductivity of the gap layer while maintaining the insulating properties of the gap layer.

Therefore, even if the current density is increased with the increase in the recording density, the heat generated from the magnetoresistive element layer is transmitted to the shield layer via the gap layer having excellent thermal conductivity.
It is possible to suppress an increase in the temperature of the element portion of the magnetoresistive element layer, thereby improving the reproduction sensitivity of the magnetoresistive element layer.

[0040]

FIG. 1 is an enlarged sectional view showing a thin-film magnetic head according to a first embodiment of the present invention from the side facing a recording medium, FIG. 2 is a plan view of FIG. 1, and FIG. 3 shown in 2
It is sectional drawing of the -3 line.

The thin-film magnetic head shown in FIGS. 1 to 3 is formed on the trailing side end surface of a slider constituting a flying head, and is constituted only by a read head. However, in the present invention, a so-called MR / inductive composite thin film magnetic head may be used in which a writing inductive head including a core and a coil is stacked on the read head.

The read head detects a leakage magnetic field from a recording medium such as a hard disk by utilizing a magnetoresistance effect and reads a recording signal.

The lowermost layer shown in FIGS. 1 and 3 is made of Sendust or a Ni—Fe alloy (Permalloy).
A lower gap layer 2 is provided on the lower shield layer 1.

On the lower gap layer 2, a magnetoresistive element layer 16 is formed. The magnetoresistive element layer 16 is made of, for example, an SAL layer made of a soft magnetic material (a Co—Zr—Mo alloy or a Ni—Fe—Nb alloy);
An AMR element formed of a three-layer structure of a SHUNT layer (for example, Ta (tantalum)) made of a nonmagnetic material and an MR layer (Ni-Fe alloy) having a magnetoresistance effect, and an antiferromagnetic layer (for example, Pt-Mn) Alloy), fixed magnetic layer (for example, Ni-
Fe-based alloy, Co, Co-Fe-based alloy, Co-Ni-based alloy, Ni-Fe-Co-based alloy), non-magnetic conductive layer (C
u), and a free magnetic layer (for example, a Ni—Fe alloy,
Co, Co-Fe alloy, Co-Ni alloy, Ni-F
and a spin-valve thin film element (one kind of GMR element) formed with a four-layer structure of an e-Co alloy).

On both sides of the magnetoresistive element layer 16,
The hard bias layer 4 and the electrode layer 5 are formed. For example, when the magnetoresistive element layer 16 is formed of the above-described spin-valve thin film element, a bias magnetic field from the hard bias layer 4 is applied to a free magnetic layer, and a detection current ( Sense current) is given to the fixed magnetic layer, the nonmagnetic conductive layer, and the free magnetic layer.

The hard bias layer 4 is made of, for example, C
o-Pt (cobalt-platinum) alloy or Co-Cr-Pt
(Cobalt-chromium-platinum) alloy or the like. The electrode layer 5 is formed of Cr (chromium), Ta (tantalum), Cu (copper), or the like.

On the electrode layer 5, an upper gap layer 6
The upper shield layer 7 made of a magnetic material such as permalloy is formed on the upper gap layer 6. The upper shield layer 7 has a shape as shown in FIG. 2 when viewed from above.

As shown in FIGS. 2 and 3, a main electrode layer 8 is formed on the upper gap layer 6 at a position facing the electrode layer 5.

As shown in FIG. 3, the upper gap layer 6 where the electrode layer 5 and the main electrode layer 8 face each other has the electrode layer 5
A connection portion 9 made of Cu (copper), Cr (chromium), or the like is formed similarly to the main electrode layer 8, and the connection portion 9 electrically connects the electrode layer 5 and the main electrode layer 8. It has become.

In the present invention, at least one of the lower gap layer 2 and the upper gap layer 6 (hereinafter referred to as gap layers 2 and 6) is made of AlN, SiC, DLC (diamond-like carbon), BN, MgO, SiAlON. ,
AlON, Si ₃ N ₄ , SiCO, SiN, SiON, S
It is formed of an insulating film made of one or more of iCON.

Each of these insulating films is made of Al ₂ O ₃ or S
It has a higher thermal conductivity than iO ₂ . For this reason,
In the present invention, the thermal conductivity of the gap layers 2 and 6 can be improved by forming the gap layers 2 and 6 from the above-described insulating films. Table 1 below shows, for reference, the thermal conductivity in the bulk material of the main insulating material.

[0052]

[Table 1]

As shown in Table 1, A used in the present invention
The thermal conductivity of an insulating material such as 1N or SiC shows a higher value than the thermal conductivity of Al ₂ O ₃ or SiO ₂ conventionally used as a gap layer.

Table 1 shows that the thermal conductivity of C (Diamond) is 660 (W / mK). It can be seen that this value is much higher than the thermal conductivity of other insulating materials.

In the present invention, DLC (diamond-like carbon) in which a crystalline phase and an amorphous phase are mixed can be used as the gap layers 2 and 6, and this DLC contains an amorphous phase. Therefore, the thermal conductivity of the DLC is C
It is presumed that the thermal conductivity is lower than that of (Diamond). However, it is possible to increase the thermal conductivity of the DLC by increasing the proportion of the crystalline phase in the DLC.

As described above, since the thermal conductivity of each insulating material shown in Table 1 is a value of a bulk material, the thermal conductivity of each insulating material when the insulating material is formed by a sputtering method or the like. It is assumed that the rate shows a slightly different value as compared with the thermal conductivity shown in Table 1.

Incidentally, in the present invention, the gap layers 2 and
In order to further improve the thermal conductivity of the insulating film such as AlN used as 6, the volume ratio of the crystalline phase in the insulating film may be increased. More preferably, the entire film structure of the insulating film is a crystalline phase.

In the present invention, the insulating film such as AlN
When nonmagnetic metal particles having higher thermal conductivity than the insulating film are mixed, the thermal conductivity can be further improved.

The non-magnetic metal particles are made of Cu, A
It is preferable to be formed of one or more alloys of g, Au, Ti, and Cr.

As described above, Al containing nonmagnetic metal particles
If the gap layers 2 and 6 are formed of an insulating film such as N,
It is possible to further increase the thermal conductivity while maintaining the insulating properties of the gap layers 2 and 6.

However, if the average particle size of the non-magnetic metal particles is very large and the volume ratio of the insulating film occupying the gap layers 2 and 6 is extremely reduced, the insulating properties of the gap layers 2 and 6 are reduced. Adjacent non-magnetic metal particles may overlap to be in a conductive state, and the insulating properties of the gap layers 2 and 6 may be completely lost.

Therefore, in the present invention, it is preferable that the average particle size of the nonmagnetic metal particles is not so large, specifically, it is several nm or less.

In order to mix non-magnetic metal particles in the insulating film, simultaneous formation of an insulating material and a non-magnetic metal by sputtering or the like may be performed.

As described above, in the present invention, the lower gap layer 2 and the upper gap layer 6 (or one of them)
Is formed of an insulating film having excellent thermal conductivity, such as AlN or SiC, so that heat generated from the magnetoresistive element layer 16 can be efficiently transmitted through the gap layers 2 and 6 to the shield layer 1. , 7.

In the present invention, the thermal conductivity of the gap layers 2 and 6 is further improved by increasing the proportion of the crystalline phase in the insulating film or by mixing non-magnetic metal particles in the insulating film. It is possible.

In the present invention, among the above-mentioned insulating films, it is particularly preferable to use AlN as the gap layers 2 and 6.

This is because AlN has good crystallinity and high thermal conductivity as shown in Table 1.

In particular, in order to improve the thermal conductivity of the insulating film formed of AlN, for example, the (002)
Preferably, the plane is oriented in a direction perpendicular to the film surface, or the (220) plane of the crystalline phase is oriented in a direction perpendicular to the film surface.

Alternatively, the (002) plane by X-ray diffraction /
It is preferable that the peak intensity ratio of the (220) plane is larger than 0 and not more than 3.5, or not less than 9.7.

Experiments have shown that when the peak intensity ratio of the (002) plane / (220) plane is between 3.5 and 9.7, the thermal conductivity decreases and the element temperature rise rate increases. Was. (See FIG. 15: the explanation of the graph will be described later.) That is, when the gap layers 2 and 6 are formed of AlN, the (002) plane of the crystalline phase is oriented in a direction perpendicular to the film plane, or The (220) plane is oriented in a direction perpendicular to the film plane, or further (002) by X-ray diffraction.
2. The peak intensity ratio of plane / (220) plane is greater than 0;
It is preferable to be 5 or less or 9.7 or more from the viewpoint that the thermal conductivity can be further improved.

By the way, as described above, AlN has good crystallinity and high thermal conductivity.
Although it is one of the most preferable insulating materials as the insulating film used as 6, it has the property of being easily soluble in an alkaline aqueous solution.

Since the aqueous alkaline solution is used as a developing solution at the time of resist patterning, the gap layers 2 and 6 need to have a property of being hardly soluble in the aqueous alkaline solution.

[0073]

[Table 2]

Table 2 shows the etching rates of the respective insulating materials with respect to the aqueous alkali solution.

As can be seen from this table, Al ₂ O ₃ and SiO ₂ conventionally used as the gap layers 2 and 6 are used.
_It can be seen that the etching rate of AlN is much higher than that of insulating materials such as ₂ .

FIG. 7 shows a high resolution TEM (Transmission) of the AlN film when the AlN film is formed on the substrate.
FIG. 8 is a schematic diagram showing a part of the high-resolution TEM image photograph shown in FIG.

The high-resolution TEM images shown in FIGS. 7 and 8 have a crystalline phase at the portion indicated by No. 1, which indicates that the crystalline phase is a columnar crystal.

As can be seen from FIG. 7, the crystalline phase is very large in one lump, and is formed as columnar crystals from the substrate to the film surface.

One of the reasons that the thermal conductivity of the AlN film is high is as follows.
The crystalline phase is a columnar crystal as shown in FIG.

Further, between each of the crystalline phases is a crystal grain boundary phase formed in an amorphous state. As described above, since the crystalline phase is a columnar crystal, it is considered that the crystal grain boundary phase formed between the crystalline phases is formed from the film surface to the substrate (the lower surface of the film).

An alkaline aqueous solution is used to remove AlN from the crystal grain boundary phase formed (exposed) on the surface of the AlN film.
It is presumed that it permeates into the film and dissolves the AlN film.

Therefore, in the present invention, a light element having higher chemical stability to an aqueous alkali solution than AlN, specifically, any one of B, C, O, and Si, or a mixture of two or more thereof Is precipitated in the crystal grain boundary phase to improve the corrosion resistance of the AlN film.

As shown in Table 2, Al ₂ O ₃ containing oxygen (O ₂ ), SiO ₂ containing silicon (Si), etc.
Since the etching rate for an alkaline aqueous solution is lower than that of 1N, it is presumed that the corrosion resistance can be improved by adding O or Si.

In order to deposit an amorphous phase containing a light element in the grain boundary phase of the AlN film, an AlN target containing a light element such as B, C, O or Si may be used for sputtering.

FIG. 9 shows that AlN containing a light element in the grain boundary phase.
A high-resolution TEM (Transmission Electron Microscopy) image of the AlN film when the film is formed on a substrate;
FIG. 10 is a schematic diagram showing a part of the high-resolution TEM image photograph shown in FIG.

Reference numerals 1 in the high-resolution TEM images shown in FIGS.
Is a crystalline phase, and reference numeral 2 is a grain boundary phase.

It can be seen that the crystalline phases shown in FIGS. 9 and 10 are columnar like the crystalline phases shown in FIGS.

In the high-resolution TEM image photograph of FIG. 9, the grain boundary phase (symbol 2) formed in a strip shape adjacent to the crystalline phase (symbol 1) is shown in white. This is because the crystal grain boundary phase contains light elements such as B and O.

On the other hand, in the high-resolution TEM image photograph of FIG. 7, the crystal grain boundary phase formed between the crystalline phases (reference numeral 1) is not clear, and the crystal grain boundary phase (reference numeral 2) shown in FIG. There is no white part as shown.

This is because the AlN film shown in FIG. 7 does not contain light elements such as B and O in its crystal grain boundary phase.

It is considered that by including a light element such as B or C in the grain boundary phase of AlN as in the present invention, the thermal conductivity in the grain boundary phase is reduced. Since the crystalline phase of the AlN film is columnar, heat can be transmitted through the crystalline phase satisfactorily. Therefore, it is considered that the presence of the grain boundary phase having a small thermal conductivity does not significantly affect the heat transfer.

Further, by precipitating an amorphous phase containing a light element such as B or C in the grain boundary phase of AlN as in the present invention, the corrosion resistance of AlN to an alkaline aqueous solution is improved, and the etching rate is reduced. Specifically, it can be reduced from 410 (angstrom / min) when no light element is contained in the grain boundary phase (see Table 2) to about 75 (angstrom / min).

FIG. 4 shows that the lower gap layer 2 has an AlN film 13.
FIG. 3 is a cross-sectional view of a thin-film magnetic head showing a preferable structure when using a magnetic head.

As shown in FIG. 4, a lower adhesion layer 12 made of an insulating material is formed on the lower shield layer 1, and an AlN film 13 is formed on the lower adhesion layer 12.

The AlN film 1 is formed directly on the lower shield layer 1.
3, the lower shield layer 1 and the AlN film 13
The reason why the underlying adhesion layer 12 is interposed between the AlN film 13 and the lower layer (the lower shield layer 1) is that the AlN film 13 has poor adhesion.
Also, because the film stress is large, peeling is likely to occur.

Therefore, in the present invention, the lower shield layer 1
First, an underlying adhesion layer 12 of an insulating material is formed, and then an AlN film 13 is formed on the underlying adhesion layer 12.

In the present invention, the base adhesion layer 12 must be in an amorphous phase. It is assumed that the underlayer adhesion layer 12
Is a crystalline phase, the film stress of the AlN film 13 is further increased due to the difference between the lattice constant of the AlN film 13 and the lattice constant of the underlying adhesion phase 12.

In the present invention, the base adhesion layer 12 is made of Al ₂ O ₃ , Si, S which is small in film stress and excellent in adhesion.
It is preferable to be formed of any one of iO ₂ , SiN, and SiC, or a mixture of two or more of them.

In the present invention, the thickness of the base adhesion layer 12 is preferably as small as possible.
Angstrom or less.

It is not preferable that the thickness of the underlying adhesion layer 12 is large. When the underlying adhesion layer 12 is formed of an insulating material having low thermal conductivity such as Al ₂ O ₃ , This is because the thermal conductivity is reduced and the film thickness is increased, so that the base adhesion layer 12 contains a crystalline phase, and the film stress of the AlN film 13 is increased as described above.

When the insulating film is formed of a DLC (diamond-like carbon) film, it is preferable to form the base adhesion layer 12 under the insulating film.

Further, as shown in FIG. 4, a protective layer 14 made of an insulating material is formed on the AlN film 13.

One of the reasons for forming the protective layer 14 is as follows.
Since the surface of the AlN film 13 is very rough, it is difficult to form the magnetoresistive element layer 16 and the like directly on the AlN film 13. The protective layer 14 is provided on the film 13.

The AlN film 13 has poor corrosion resistance to an aqueous alkali solution, and it is therefore preferable to improve the corrosion resistance by precipitating a chemically stable light element such as B or C in the grain boundary phase. As described above, in the present invention,
If an insulating material having high corrosion resistance to an alkaline aqueous solution is used as the protective layer 14, the corrosion resistance of the AlN film 13 can be further improved.

For this reason, in the present invention, the protective layer 14
Al with high corrosion resistance shown in 2 _TwoO_Three, SiO_Two, T
a_TwoO_FiveAny one of these, or a mixture of two or more
It is preferable to use

The protective layer 14 is preferably as thin as possible. In the thin-film magnetic head shown in FIG. 4, the upper gap layer 6 is formed of Al ₂ O ₃ or the like conventionally used as an insulating material.
Similarly, the upper gap layer 6 may be formed of the AlN film 13.

In this case, an underlying adhesion layer 12 made of an insulating material is formed under the AlN film 13,
It is more preferable to provide a protective layer 14 made of an insulating material on the upper side.

In the present invention, the AlN film
Nonmagnetic metal particles having higher thermal conductivity than the 1N film 13 may be mixed.

The non-magnetic metal particles are made of Cu, A
It is preferable to be formed of one or more alloys of g, Au, Ti, and Cr.

Next, in the present invention, in order to further improve the thermal conductivity of the gap layers 2 and 6, the structure of the lower gap layer 2 and / or the upper gap layer 6 (or one of them) is improved.

FIG. 5 is a partially enlarged sectional view of the lower gap layer 2 and the upper gap layer 6. As shown in the figure, the gap layers 2 and 6 have a multilayer structure in which insulating layers 10 and nonmagnetic metal layers 11 are alternately stacked.

The insulating layer 10 is made of AlN, SiC, DLC (diamond-like carbon), BN, MgO, SiAlON, AlON, Si
_{3 N 4, SiCO, SiN,} SiON, it is preferably formed by any one or insulating film of two or more SiCON.

Among them, it is particularly preferable to use AlN as the insulating film. The nonmagnetic metal layer 11 is
It is preferable to be formed of one or more alloys of Cu, Ag, Au, Ti, and Cr.

In the present invention, since the nonmagnetic metal layer 11 having a higher thermal conductivity than the insulating layer 10 is interposed between the insulating layers 10, 10, the insulating layer 10 is formed as a single layer. It is possible to further improve the thermal conductivity as compared with the case. The insulating properties of the gap layers 2 and 6 are sufficiently ensured by the insulating properties of the insulating layer 10.

As described above, the insulating layer 10
Is preferably formed of an insulating film such as AlN having excellent thermal conductivity, but other insulating films, that is,
Al ₂ O ₃ or S conventionally used as a gap layer
iO ₂ or the like may be used as the insulating layer 10. A
Although l ₂ O ₃ and SiO ₂ have low thermal conductivity, they have very high insulating properties.

However, when the insulating layer 10 is made of Al ₂ O ₃ or SiO
When the insulating layer 10 is formed of, for example, ₂ , the insulating layer 10 is preferably formed as thin as possible. Al ₂ O ₃ or Si
Since the thermal conductivity of the insulating layer 10 formed of O ₂ is low,
This is because if the insulating layer 10 is formed too thick, heat will not be transmitted through the insulating layer 10 and the element temperature of the magnetoresistive element layer 16 will increase as in the related art. It should be noted that even if the thickness of the insulating film 10 formed of Al ₂ O ₃ or SiO ₂ is small, sufficient insulation can be ensured.

Even when the insulating layer 10 is formed of the above-mentioned insulating film having excellent thermal conductivity such as AlN, the insulating film 10 can be formed as long as a sufficient insulating property can be ensured. It is preferable to form as thin as possible. By forming the insulating film 10 thin, the heat generated from the magnetoresistive element layer 16 can be more efficiently
This is because it can escape to the shield layers 1 and 7.

In the present invention, the gap layers 2 and 6 are formed as shown in FIG.
In the case of a multilayer structure shown in FIG. 1, the layer on the side facing the magnetoresistive element layer 16 needs to be formed of the insulating layer 10. That is, when the lower gap layer 2 is formed with the multilayer structure shown in FIG. 5, when the upper layer of the lower gap layer 2 is formed with the insulating layer 10 and the upper gap layer 6 is formed with the multilayer structure shown in FIG. The lower layer of the upper gap layer 6 is formed of an insulating layer 10.

This is because, if the layers of the gap layers 2 and 6 in contact with the magnetoresistive element layer 16 are formed of the nonmagnetic metal layer 11, the detection current flowing through the magnetoresistive element layer 16 decreases. This is because it also flows to the nonmagnetic metal layer 11.

When the upper gap layer 6 is formed in the multilayer structure shown in FIG. 5, the non-magnetic metal layer 11 must not be formed around the connection 9 shown in FIG.

As described above, the detection current flows from the main electrode layer 8 to the electrode layer 5 through the connection portion 9, and the nonmagnetic metal layer 11 is formed in contact with the connection portion 9. This causes the detection current to flow from the connection portion 9 to the nonmagnetic metal layer 11 as well.

FIG. 6 is a sectional view of the thin film magnetic head in the case where the lower gap layer 2 is formed in the simplest structure of the multilayer structure shown in FIG. 5, that is, in a two-layer structure.

As shown in FIG.
The lower layer facing the lower gap layer 2 is formed of an insulating layer 10, and the lower layer facing the lower shield layer 1 is formed of a nonmagnetic metal layer 11.

In the present invention, the upper gap layer 6 may be formed in a two-layer structure similarly to the lower gap layer 2, and in this case, the lower layer of the upper gap layer 6 facing the magnetoresistive element layer 16 is formed. Is the insulating layer 10 and the upper shield layer 7
Is formed of the nonmagnetic metal layer 11.

However, when the upper gap layer 6 is formed in a two-layer structure, the non-magnetic metal layer 11 must not be formed around the connection 9 shown in FIG.
This is because if the nonmagnetic metal layer 11 is formed in contact with the connection portion 9, a current also flows from the main electrode layer 8 to the nonmagnetic metal layer 11.

Although the upper gap layer 6 shown in FIG. 6 is formed as a single layer, the upper gap layer 6 may be formed from the above-mentioned insulating film such as AlN or SiC having excellent thermal conductivity. preferable.

As described above, the insulating layer 10 constituting the lower gap layer 2 is made of AlN or Si having excellent thermal conductivity.
It is preferably formed of an insulating film such as C, but may be formed of Al ₂ O ₃ or SiO ₂ having low thermal conductivity. However, in this case, it is preferable to make the thickness of the insulating layer 10 as thin as possible.

The nonmagnetic metal layer 11 is made of Cu, A
It is preferable to be formed of one or more alloys of g, Au, Ti, and Cr.

In the present invention, the lower gap layer 2 is formed with the simplest two-layer structure among the multilayer structures shown in FIG. ) And can be easily manufactured.

In addition, since the lower gap layer 2 is formed with the nonmagnetic metal layer 11 having excellent thermal conductivity, the magnetoresistive layer has a higher efficiency than the upper gap layer 6 formed of a single layer. The heat generated from the effect element layer 16 can be released to the lower shield layer 1.

As described above, in the present invention, the material and structure of at least one of the lower gap layer and the upper gap layer 6 (hereinafter, referred to as gap layers 2 and 6) are improved so that the gap layers 2 and 6 are improved. Improves thermal conductivity.

In the present invention, AlN,
SiC, DLC (diamond-like carbon), B
N, MgO, SiAlON, AlON, Si ₃ N ₄ , Si
Examples of the insulating film include one or more of CO, SiN, SiON, and SiCON. Each of these insulating films has a higher thermal conductivity than the thermal conductivity of Al ₂ O ₃ , SiO ₂ or the like conventionally used as a gap layer.

In the present invention, in order to further increase the thermal conductivity, the crystallinity of the insulating film is improved, or the insulating film is mixed with non-magnetic metal particles.

In particular, in the present invention, it is preferable to use AlN having good crystallinity and high thermal conductivity as the gap layers 2 and 6.

In this case, the crystal plane with the crystalline phase is preferentially oriented in the direction perpendicular to the film surface. For example, the (002) plane of the crystalline phase is oriented in the direction perpendicular to the film surface.
Alternatively, the (220) plane is oriented in a direction perpendicular to the film surface,
Alternatively, the (002) plane of the crystalline phase is preferentially oriented in a direction perpendicular to the film surface.
2) The peak intensity ratio of the plane / (220) plane is preferably larger than 0 and equal to or smaller than 3.5, or equal to or larger than 9.7.

With the above-described orientation, the thermal conductivity of the AlN film can be further improved.

In the present invention, a light element such as B or C is precipitated in the grain boundary phase of the AlN film to form the AN film.
It is preferable to improve the alkali resistance of the 1N film, and it is preferable to provide a protective layer formed of an insulating material having high alkali resistance on the AlN film.

It is preferable to form a base adhesion layer of an insulating material below the AlN film to prevent the AlN film from peeling off. However, the base adhesion layer must be an amorphous phase.

Next, in the present invention, the structure of the gap layers 2 and 6 conventionally formed as a single layer is changed to a multi-layer structure including an insulating layer and a non-magnetic metal layer, or a two-layer structure. The thermal conductivity of the gap layers 2 and 6 can be further increased.

The gap layers 2 and 6 whose materials or structures are improved as described above have insulating properties and high thermal conductivity. Therefore, even if the current density is increased in order to cope with a higher recording density, the heat generated from the magnetoresistive element layer 16 efficiently passes through the gap layers 2 and 6 to the shield layers 1 and 7. As a result, it is possible to suppress an increase in the element temperature of the magnetoresistive element layer 16 and to obtain good reproduction sensitivity.

[0141]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, a thin-film magnetic head in which the lower gap layer 2 and the upper gap layer 6 shown in FIG. Was formed from Al ₂ O ₃ , and the relationship between the detected current and the rate of temperature rise of the magnetoresistive element 16 in both thin film magnetic heads was examined. The result is shown in FIG. The thin-film magnetic heads of the examples and comparative examples have their element DC resistance (DC
R) have the same value.

As shown in FIG.
As in forming by ₂ O _3, be either in the case where the gap layer 2,6 are formed with AlN, the detection current is increased, but the element temperature rise rate of the magnetoresistive element layer 16 is increased, the gap It can be seen that the temperature rise rate can be suppressed more when the layers 2 and 6 are formed of AlN than when the gap layers 2 and 6 are formed of Al ₂ O ₃ .

This is because AlN has a higher thermal conductivity than Al ₂ O _3.
By forming with 1N, the heat generated from the magnetoresistive element layer 16 can be efficiently released to the shield layers 1 and 7, and an increase in the element temperature of the magnetoresistive element layer 16 can be suppressed. Becomes

Next, in the present invention, (00)
2) The orientation of the plane was examined, and the relationship between the degree of orientation of the (002) plane and the rate of temperature rise of the element was measured.

FIG. 12 is an X-ray diffraction image of an AlN film formed by using an AlN target and changing the flow rate ratio of nitrogen (N ₂ ) to 5%, 10%, and 20%.

As shown in FIG. 12, the N ₂ flow rate ratio was 5%,
In both cases of 10% and 20%, (002)
The peak of the surface is the largest.

Here, at each N ₂ flow rate ratio,
A diffraction line from the (002) plane of the X-ray diffraction image;
When the intensity ratio of the diffraction line from the surface was examined, the N ₂ flow rate ratio was 5%.
In the case of (2), the peak intensity ratio of the (002) plane / (220) plane is 7.0, and when the N ₂ flow rate ratio is 10%, the peak intensity ratio of the (002) plane / (220) plane is 10.
7. (002) face / N ₂ flow rate ratio is 20% /
The peak intensity ratio of the (220) plane was found to be 4.3.

Next, in the present invention, the N ₂ flow rate ratio is set to 5%, 10%.
% And 20% were used for the gap layers 2 and 6 shown in FIG. 1, and the temperature rise of the element portion of the magnetoresistive element layer 16 was measured.

The temperature rise of the element portion is calculated by (element temperature when sense current Is is 20 mA) / (sense current I
(the temperature of the element portion when s is 1 mA). FIG. 13 shows the experimental results. Each thin-film magnetic head is formed such that its DC resistance (DCR) has the same value in all the thin-film magnetic heads.

As shown in FIG. 13, the N ₂ flow rate ratio was 10%.
In other words, when the (002) plane / (220) plane peak intensity ratio is 10.7, the temperature rise of the element portion is the smallest,
Next, the degree of temperature rise of the element portion is reduced when the N ₂ flow rate ratio is 20%, that is, (002) plane / (220)
This is when the surface peak intensity ratio is 4.3.

The temperature rise of the element portion is largest when the N ₂ flow rate ratio is 5%, that is, the (002) plane /
This is when the (220) plane peak intensity ratio is 7.0.

It is clear from the experimental results that (0
That is, it cannot be said that the larger the peak intensity ratio of the (02) plane / (220) plane, the lower the temperature rise of the element portion can be.

As shown in FIG. 13, (002) plane / (2
20) When the plane peak intensity ratio is 7.0, the temperature rise of the element portion is such that the (002) plane / (220) plane peak intensity ratio is 4.
In the case of No. 3, the temperature rise is larger than the temperature rise of the element portion.

That is, it is considered that the peak intensity ratio of the (002) plane / (220) plane has an optimum range in which the temperature rise of the element portion can be further reduced.

FIG. 14 shows the relationship between the detected current (sense current) and the rate of temperature rise of the element portion when the (002) plane / (220) plane peak intensity ratio is 7.0, 10.0, and 4.0. FIG.

As shown in FIG. 14, when the detected current is increased, the peak intensity ratio of the (002) plane / (220) plane becomes 7.
In the case of 0, the temperature rise rate of the element portion is the largest, and the temperature rise rate of the element portion can be minimized in the (002) plane /
The (220) plane peak intensity ratio is 10.0.

Here, the curve of each peak intensity ratio shown in FIG. 14 was taken as a quadratic function (Y = aX ² + b; a and b are constants), and the a value in each curve was examined.

In the experiment, (002) plane / (220) plane
When the surface peak intensity ratio is 2.0, 3.0, 6.0, 8.0,
The relationship between the detected current at 12.0 and 13.0 and the rate of temperature rise of the element portion was also measured, and the value a at each peak intensity ratio was determined. FIG. 15 shows the experimental results.

As shown in FIG. 15, (002) plane / (2
20) The value a increases as the plane peak intensity ratio increases, and the (002) plane / (220) plane peak intensity ratio is about 7.
At 0, the a value is at a maximum. Also, (002) plane / (22
0) It can be seen that when the plane peak intensity ratio becomes about 7.0 or more, the value a decreases.

The smaller the value a, the smaller the rate of temperature rise of the element portion with respect to the detected current.
The case where the value is 1.0 or less was taken as a preferable range, and the peak intensity ratio of the (002) plane / (220) plane where the a value was 1.0 or less was determined from FIG.

As shown in FIG. 15, (002) plane / (2
20) When the plane peak intensity ratio is 3.5 or less, or 9.7 or more, the value a can be reduced to 1.0 or less, which is preferable.

As shown in FIG. 15, the (002) plane /
It is considered that the thermal conductivity of the AlN film can be improved even when the (220) plane peak intensity ratio approaches 0.

When the (002) plane / (220) plane peak intensity ratio falls below 1.0 and approaches 0, the (220) plane is preferentially oriented in a direction perpendicular to the film surface.

That is, in order to improve the thermal conductivity of the AlN film, the plane having the crystalline phase of the AlN film only needs to be preferentially oriented in a direction perpendicular to the film surface. For example, as shown in FIG. As described above, the peak intensity ratio of the (002) plane / (220) plane is larger than 0 and 3.5 or less, or 9.
It is preferably 7 or more.

Alternatively, when the peak intensity ratio of the (002) plane / (220) plane becomes 0, that is, (2) of the crystalline phase
20) that the plane is oriented in a direction perpendicular to the film surface,
Alternatively, the (002) plane of the crystalline phase is preferably oriented in a direction perpendicular to the film plane.

[0166]

According to the present invention described in detail above, the lower gap layer and / or the upper gap layer have a thermal conductivity higher than that of Al ₂ O ₃ conventionally used as a gap layer. Since it is formed of AlN, SiC, or the like having the following, heat generated from the magnetoresistive element layer can be efficiently transmitted to the shield layer.

In the present invention, the (002) plane / (22)
0) The range of the peak intensity of the plane is optimized, or (002)
By aligning the plane or the (220) plane in a direction perpendicular to the film plane, the thermal conductivity of the gap layer can be further increased.

As described above, according to the present invention, the thermal conductivity of the gap layer can be improved by improving the material of the gap layer. Efficiently generate heat from the effect element layer,
It can be transmitted to the shield layer, so that the rise in the element temperature of the magnetoresistive element layer can be suppressed, and good reproduction sensitivity can be obtained.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view of a thin-film magnetic head showing a structure according to a first embodiment of the present invention;

FIG. 2 is a plan view of FIG. 1;

FIG. 3 is a sectional view taken along line 3-3 shown in FIG. 2;

FIG. 4 is an enlarged sectional view of a thin-film magnetic head showing a structure according to a second embodiment of the present invention;

FIG. 5 is an enlarged partial sectional view of a gap layer showing a structure according to a third embodiment of the present invention;

FIG. 6 is an enlarged sectional view of a thin-film magnetic head showing a structure according to a fourth embodiment of the present invention;

FIG. 7 is a high-resolution TEM image photograph of an AlN film containing no light element,

FIG. 8 is a partial schematic view of the high-resolution TEM image photograph shown in FIG.

FIG. 9 is a high-resolution TEM image photograph of an AlN film containing a light element,

10 is a partial schematic diagram of the high-resolution TEM image photograph shown in FIG.

FIG. 11 is a graph showing the relationship between the detected current and the temperature rise rate of the magnetoresistive element when the gap layer is formed of AlN and when the gap layer is formed of Al ₂ O ₃ ;

FIG. 12 is an X-ray diffraction image of an AlN film when the N ₂ flow rate ratio is set to 5%, 10%, and 20%.

FIG. 13 is a graph showing the relationship between the N ₂ flow rate ratio during sputtering and the temperature rise of the element portion when the gap layer is formed of AlN.

FIG. 14 shows a graph of (0) of the AlN film formed as a gap layer.
The peak intensity ratio of the (02) plane / (220) plane is 4.0,
A graph showing the relationship between the detected current and the temperature rise rate of the element portion in the case of 7.0 and 10.0;

FIG. 15 shows a case where curves at respective intensity ratios shown in FIG. 14 are taken as a quadratic function (Y = aX ² + b);
A graph showing the relationship between the peak intensity ratio of the plane / (220) plane and the a value;

FIG. 16 is an enlarged sectional view of a thin-film magnetic head showing a structure of a conventional embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lower shield layer 2 Lower gap layer 4 Hard bias layer 5 Electrode layer 6 Upper gap layer 7 Upper shield layer 8 Main electrode layer 9 Connection part 10 Insulating layer 11 Nonmagnetic metal layer 12 Underlayer adhesion layer 13 AlN film 14 Protective layer 16 Magnet Resistance effect element

Claims (11)

[Claims] 1. A magnetoresistive element layer formed on a lower shield layer via a lower gap layer, an electrode layer for applying a detection current to the magnetoresistive element layer, and an upper gap formed on the electrode layer. In a thin-film magnetic head including an upper shield layer formed with a layer interposed therebetween, at least one of the lower gap layer and the upper gap layer is formed of an insulating film having AlN, and the film structure includes a crystalline phase and An amorphous grain boundary phase formed between the crystalline phases, and a peak intensity ratio of a (002) plane / (220) plane by X-ray diffraction is larger than 0 and 3.5 or less. Or 9.7 or more. 2. The (002) plane / (2) by the X-ray diffraction.
20. The thin-film magnetic head according to claim 1, wherein a peak intensity ratio of the plane is larger than 0 and smaller than 1.0. 3. A magnetoresistive element layer formed on a lower shield layer via a lower gap layer, an electrode layer for applying a detection current to the magnetoresistive element layer, and an upper gap formed on the electrode layer. In a thin-film magnetic head including an upper shield layer formed with a layer interposed therebetween, at least one of the lower gap layer and the upper gap layer is formed of an insulating film having AlN, and the film structure includes a crystalline phase and A thin-film magnetic head comprising: an amorphous crystal grain boundary phase formed between the crystalline phases; and a (002) plane of the crystalline phase is oriented in a direction perpendicular to a film surface. . 4. A magnetoresistive element layer formed on a lower shield layer via a lower gap layer, an electrode layer for applying a detection current to the magnetoresistive element layer, and an upper gap formed on the electrode layer. In a thin-film magnetic head including an upper shield layer formed with a layer interposed therebetween, at least one of the lower gap layer and the upper gap layer is formed of an insulating film having AlN, and the film structure includes a crystalline phase and A thin-film magnetic head comprising: an amorphous grain boundary phase formed between the crystalline phases; and a (220) plane of the crystalline phase is oriented in a direction perpendicular to a film surface. . 5. The thin-film magnetic head according to claim 1, wherein the crystalline phase has columnar crystals from the lower surface of the film toward the upper surface of the film. 6. The crystal grain boundary phase according to claim 1, wherein the crystal grain boundary phase is an amorphous phase containing at least one of B, C, O, and Si. Thin film magnetic head. 7. The thin-film magnetic head according to claim 1, wherein a protective layer made of an insulating material is formed on the insulating film. 8. The protective layer is made of Al ₂ O ₃ , SiO ₂ , T
a ₂ O _5, any one or claims 7 thin-film magnetic head according formed by a mixture of two or more of SiC. 9. The thin-film magnetic head according to claim 1, wherein an underlayer adhesion layer made of an insulating material and having an amorphous phase is formed under the insulating film. 10. The base adhesion layer is made of Al ₂ O ₃ , Si,
SiO _2, SiN, any one or a thin film magnetic head according to claim 9, wherein is formed of a mixture of two or more of SiC. 11. The thin-film magnetic head according to claim 9, wherein the underlayer adhesion layer is formed with a thickness of 100 Å or less.