JPH0366012A - Magneto-resistance effect type head - Google Patents

Abstract

PURPOSE:To inhibit the deterioration in the magnetic characteristic of the ferromagnetic magneto-resistance effect element (MR element) and amorphous soft magnetic substance layer in the heating stage by providing a nonmagnetic conductor layer consisting of a titanium nitride film between the MR element and amorphous soft magnetic substance layer. CONSTITUTION:The MR element 1 is laminated on the amorphous soft magnetic substance layer 5 through a nonmagnetic conductor layer 7 (titanium nitride layer) consisting of a titanium nitride film. Since the titanium nitride layer is thus used as the nonmagnetic conductor layer, the diffusion between the nonmagnetic conductor layer and MR element or between the nonmagnetic conductor layer and amorphous soft magnetic substance layer is prevented. As a result, the deterioration in the characteristic of the MR element or amorphous soft magnetic substance layer in the heating stage in the MR head fabricating process is inhibited.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a ferromagnetic magnetoresistive element (hereinafter abbreviated as MR element) that reads magnetic information written on a magnetic storage medium using the magnetoresistive effect. The present invention relates to a magnetoresistive head (hereinafter abbreviated as MR head) equipped with a magnetoresistive head (hereinafter abbreviated as MR head).

[Prior Art] As is well known, when an MR element is used as a highly efficient read-only magnetic head that exhibits linear response to magnetic information written on a magnetic storage medium, a sense current flowing through the MR element is required. A bias means must be provided for setting the angle θ (hereinafter referred to as bias angle) between I and the magnetization M of the MR element to a predetermined value (preferably 45 degrees).

Various methods have been disclosed as the above-mentioned bias means, but among these, in the MR head disclosed in Utility Model Application No. 59-048201 or Japanese Patent Application No. 62-072054@, a non-magnetic material is used on the MR element. It has been shown that a structure in which a conductor layer and an amorphous soft magnetic layer (for example, a COZrMO film) are sequentially laminated can provide a good bias angle θ and realize an MR head with excellent linear response.

That is, as shown in FIG. 4, M made of a ferromagnetic thin film is deposited on an insulating substrate (not shown) with a smooth surface made of glass, ferrite, etc. by sputtering or vapor deposition.
R element 1 (for example, film thickness 200 to 500A (7) Ni
Ti, MO,
An MR head is disclosed having a structure in which a non-magnetic conductor layer 2 made of Cr or the like is formed by a similar method, and an amorphous soft magnetic material layer 5 is further formed on the non-magnetic conductor layer 2 by a similar method. .

Here, 6 is a terminal for supplying current to the laminate of the MR element 1, the nonmagnetic conductor @2, and the amorphous soft magnetic layer 5.

In such an MR head, the sense current (2) supplied from the terminal 6 is shunted not only to the MR element 1 but also to the nonmagnetic conductor layer 2 and the amorphous soft magnetic material @5. Therefore,
In such a structure, the sense current (IV) shunted to the MR element 1 and the non-magnetic conductor layer 2 generates a magnetic field that passes within the plane of the amorphous soft magnetic layer 5 and is perpendicular to the direction of the sense current I. However, the magnetization direction of the amorphous soft magnetic layer 5 is rotated by this magnetic field. Therefore, the magnetization in the amorphous soft magnetic layer 5 generates a magnetic field around the amorphous soft magnetic layer 5 in a direction opposite to the direction of the magnetization, a part of which is applied to the MR element 1. . On the other hand, the sense current {circle around (2)} which is shunted into the amorphous soft magnetic layer 5 and the nonmagnetic conductor layer 2 generates a magnetic field in the plane of the MR element 1 in a direction perpendicular to the sense current I, and the direction of this magnetic field is as described above. This coincides with the direction of the magnetic field generated by the magnetization of the amorphous soft magnetic layer 5. That is, the magnetic field generated by the magnetization of the amorphous soft magnetic layer 5 and the magnetic field generated by the sense current I are applied to the MR element as a bias magnetic field. This bias magnetic field rotates the magnetization of the MR element 1 with respect to the sense current I, sets the bias angle θ of the MR element to a predetermined value (ideally 45 degrees), and realizes an MR head with excellent linear response. do.

[Problems to be solved by the invention] By the way, 1. In the MR head having the above-mentioned structure, that is, a structure in which the MR element 1, the nonmagnetic conductor layer 2, and the amorphous soft magnetic layer 5 are laminated, the nonmagnetic conductor layer 2 is made of a Ti film, an MO film, etc.
In the case of a film or C film, the magnetic properties of the amorphous soft magnetic layer 5 or the MR element 1 deteriorate during the heating step (300 to 350'C) during the manufacturing process, and the reproduction efficiency of the MR head decreases. There was a problem.

The heating step during the manufacturing process is performed in order to improve the magnetic properties of the amorphous soft magnetic layer 5 and to align the easy axis of magnetization of the amorphous soft magnetic layer 5 and the easy axis of magnetization of the MR element 1 in the same direction. This is a necessary step to achieve a good bias level in line with the MR head, and is an essential step in the MR head manufacturing process. Therefore, it is necessary to provide an MR head whose magnetic properties do not deteriorate due to heating.

The present invention has been made to solve the conventional problems as described above, and provides a magnetoresistive head that does not cause deterioration of the magnetic properties of the MR element 1 and the amorphous soft magnetic layer 5 during the heating process. The purpose is to provide

[Means for Solving the Problems] The present invention provides a structure in which a ferromagnetic magnetoresistive element and an amorphous soft magnetic layer are laminated with a nonmagnetic conductor layer interposed therebetween, and the nonmagnetic conductor layer is made of a titanium nitride film. This is a magnetoresistive head characterized by the following.

[Function] According to the inventor's study, the cause of the deterioration of characteristics during the heating process is the interface between the non-magnetic conductor layer 2 and the MR element 1, or the non-magnetic It was found that this is due to diffusion occurring at the interface between the conductor layer 2 and the amorphous soft magnetic layer 5. This point will be discussed in detail below.

Figure 3 shows an approximately 500A N i Fe film (
This is an example of analysis results in the depth direction by an Auger analyzer before and after heat treatment of a sample in which a T film (corresponding to MR element 1) and a T film (corresponding to nonmagnetic conductor layer 2) of approximately 30 OA were laminated in this order. Here, the heat treatment conditions are 300°C,
1 hour, and the heat treatment was performed in a vacuum (degree of vacuum: 2X
10-6 tons orr).

FIG. 3(a) shows the results of Auger analysis before heat treatment, and it can be said that the distribution of each element is clear at a depth of about 300 A, and that there is almost no diffusion in the NiFe film and the Li film. On the other hand, FIG. 3(b) shows the analysis results after heat treatment, and compared to FIG. 3(a), the distribution of each element is wider in the depth direction, especially Ti at a depth of 600A. It has spread to some extent.

In addition, a C film with a thickness of about 500A was applied on a Ti film with a thickness of about 30OA.
The same T1 was obtained after the sample in which the OZrMO film (corresponding to the amorphous soft magnetic material layer 5) was laminated was heat treated in vacuum (degree of vacuum: 2X10-6 Torr) for 300' C11 hours in the same manner as above. The spread of was observed.

As described above, according to the Auger analysis results, the heating process during the manufacturing process of the MR head causes the gap between the nonmagnetic conductor layer 2 and the MR element 1 or the nonmagnetic conductor layer 2 and the amorphous soft magnetic layer 5 to Diffusion occurs, and this is considered to have deteriorated the magnetic properties of the MR element 1 or the amorphous soft magnetic layer 5, such as saturation magnetization, anisotropic magnetic field, and rate of change in resistance.

Almost similar analysis results were obtained for samples using MO films or Cr films instead of Ti films, indicating that diffusion is the cause of characteristic deterioration when these materials are used as the nonmagnetic conductor layer 2. Conceivable.

On the other hand, Fig. 2 shows a NiFe film (approximately 50 OA) on a 3i substrate.
) and a TiN film of approximately 30OA (corresponding to MR element 1)
This is an example of an analysis result in the depth direction by an Auger analyzer after heat treatment of a sample in which layers (corresponding to the non-magnetic conductor layer 2) were laminated in this order. Here, the heat treatment conditions are 350°C
, 2 hours, and the heat treatment was performed in vacuum (degree of vacuum: 2
10-6 Torr). As is clear from Figure 2, even after heat treatment, the distribution of each element is approximately 30 mm deep.
It is clear with OA as the boundary, and the Ni Fe film and TiN film are hardly diffused. In addition, a sample in which a CoZrMo film with a film thickness of about 5 () OA was laminated on a DIN film with a film thickness of about 300 A was heated at 350° C. for 2 hours in a vacuum (vacuum degree: 2
Similar results were obtained even after heat treatment at 10-6 Torr).

In this way, by using the TiN film as the nonmagnetic conductor layer, diffusion between the nonmagnetic conductor layer and the MR element or the nonmagnetic conductor layer and the amorphous soft magnetic layer can be prevented, and as a result, the MR head Deterioration of the characteristics of the MR element or the amorphous soft magnetic layer during the heating step during the manufacturing process can be avoided.

[Example] Next, examples of the present invention will be described.

Example FIG. 1 is a block diagram of an embodiment of the present invention.

In FIG. 1, an MR element 1 is placed on a non-magnetic substrate (not shown) such as glass using a sputtering method in a gas atmosphere.
Permalloy (Ni82%-101) with a film thickness of 400A
8%, weight %) film was formed. In addition, at the time of vapor deposition, 100
A magnetic field of 0e was applied using a permanent magnet to impart uniaxial anisotropy to the permalloy film.

Next, in a mixed atmosphere of Ar gas and nitrogen gas (in terms of flow rate, Ar: 100 SCCm, N2:
A TiN film 7 having a thickness of 300 Å and serving as a non-magnetic conductive layer was formed on the permalloy film using a sputtering method (6 sccm). Note that during film formation, a bias voltage of -80 V was applied to the substrate side to remove impurities, particularly oxygen, in the TiN film, thereby reducing the specific resistance of the TiN film. The specific resistance of the TiN film formed was about 110 μΩ·cm.

Roughly speaking, the amorphous soft magnetic layer 7 is made of a CoZrMo film with a thickness of 300 A and an anisotropic magnetic field (k) of 50 e as the amorphous soft magnetic layer 5 (film composition is Co82%-Zr6%-MO).
12%, atomic %> was formed on the TiN film 7 by sputtering in a gas atmosphere.

After that, in order to impart −axis anisotropy to the amorphous soft magnetic layer 5 (CoZrMo film), the above-mentioned permalloy film, TiN
The film and the laminate of the CoZrMo film were heat-treated in vacuum at 350° C. for 2 hours while applying a magnetic field of 4800 e in the same direction as the easy axis of magnetization of the permalloy film.

Next, a photoresist pattern of a predetermined shape was formed on this laminate, and ion etching was performed in an Ar gas atmosphere to form a rectangular pattern with a length of 50jJIr1 and a width of 5iiIn. Here, the etching conditions are an acceleration voltage of 500 V and an Ar gas pressure of 0.1 mTorr.

Next, a terminal 6 for supplying the sense current ■ to the above-mentioned multilayer body
was formed using integrated thin film technology to produce an MR head. Note that the terminal 6 uses a laminated vapor deposited film of Ti and Au.
The thickness of each film was 50 A and 0.5 mm.

In the MR head according to this example having the above configuration, it was confirmed that the bias angle θ of the MR element 1 can be set to approximately 45 degrees when the sense current ■ is 5 to 15 mA, and it has good linear response and high reproduction. An efficient MR head has been realized.

In the above embodiments, only the example in which the MR element (permalloy film>, 'rrN film layer, and amorphous soft magnetic layer are laminated in this order) has been described, but the amorphous soft magnetic layer, the T
Even in the MR head in which the iN film layer and the MR element were laminated in this order, excellent linear response and high reproduction efficiency were obtained. Furthermore, the material forming the amorphous soft magnetic layer is not limited to the COZrMO film, but may include, for example, a COTaMO film, a CozrMO film, and a COZrMO film.
A Ta film or the like may be used.

Further, the method and conditions for forming the TiN film in the examples are merely examples, and other methods and conditions may be used. Of course, in this case, if the specific resistance of the TiN film is extremely high, the conductivity will be impaired and the problem of heat generation due to Joule heat will occur.
Care should be taken regarding the resistivity value of the TiN film formed. T
Regarding the specific resistance value of the iN film, MR to which the present invention is applied
Although it is difficult to make a general statement because it largely depends on the design and specifications of the head and the condition of the heat sink, it is desirable that the resistivity be 200 μΩ·cm or less.

Comparative Example An MR head was manufactured in the same manner as in the example except that 11 TiN films were used.

In this MR head, a permalloy film that becomes the MR element 1 or a COZrMO film that becomes the amorphous soft magnetic layer 2 is heated at 350°C for 2 hours to impart uniaxial anisotropy to the amorphous soft magnetic layer. Because the magnetic properties of the MR have deteriorated, even if a sense current of about 35 to 40 mA is applied, sufficient bias is not applied to the MR.
It became clear that the reproduction efficiency was about 30 to 50% lower than that of the MR head according to the present invention because no voltage was applied to the element, and it could not be put to practical use.

In addition, an MR head using a Cr film or an MO film in place of the TiN film was also fabricated, but as with the MR head described in this comparative example, a sufficient bias level could not be obtained. The reproduction efficiency was lower than that of the MR head.

[Effects of the Invention] As explained above, according to the present invention, Ti with low diffusivity
MR head!
l! It is possible to avoid characteristic deterioration of the MR element or the amorphous soft magnetic layer during the heating step during the manufacturing process, and to realize a magnetoresistive head with excellent linear response and high reproduction efficiency.

[Brief explanation of drawings]

Figure 1 is a block diagram of one embodiment of the present invention, Figure 2 is a NiFe
Figure 3 shows the concentration distribution in the depth direction by Auger analysis after heat treatment of a sample in which a film and a TiN film are laminated.
Figure 4 shows the concentration distribution in the depth direction by Auger analysis before and after heat treatment of a sample in which an e-film and a Ti film are laminated.
FIG. 3 is an explanatory diagram for explaining a head. 1...MR element 2...Nonmagnetic conductor layer 5
...Amorphous soft magnetic material layer 6...Terminal, 7...Titanium nitride layer 1st drawing...Nonaniji...Deep =+! ) Figure 2

Claims (1)

[Claims] (1) A magnetoresistive head characterized in that a ferromagnetic magnetoresistive element and an amorphous soft magnetic layer are laminated with a nonmagnetic conductor layer interposed therebetween, and the nonmagnetic conductor layer is made of a titanium nitride film. .