JPH1116127A - Thin-film magnetic head and magnetic recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable high-density recording by consisting a nonmagnetic insulating layer of a magnetic gap of >=1 selected from silicon nitride, silicon oxynitride, aluminum nitride, amorphous carbon and amorphous boron nitride. SOLUTION: The nonmagnetic insulating layer 5, 6 of a magnetic head preferably have an isolation voltage of >=1.0 v in order to prevent leak of sense current. The nonmagnetic insulating layers of >=25 nm are formed by any of the respective materials, by which the withstand voltage of >=1.0 V is assured. The lower limit of the preferable film thickness is varied in order to assure this withstand voltage. More specifically, the film thickness is preferably >=20 nm in the case of the silicon nitride, >=25 nm in the case of the silicon oxynitride, >=20 nm in the case of the aluminum nitride, >=15 nm in the case of the amorphous carbon and >=25 nm in the case of the amorphous boron nitride. As a result, these nonmagnetic insulating layers may be adequately used for the MR reproducing head of the narrow gap for high-density magnetic recording.

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 and a magnetic recording apparatus having the thin film magnetic head, and more particularly, to a magnetoresistive head suitable for high density recording (hereinafter referred to as "MR head"). ") And a magnetic recording device such as a magnetic hard disk drive (hereinafter referred to as" HDD ").

[0002]

2. Description of the Related Art An MR head is different from an electromagnetic induction type magnetic head in that it can function at a low speed without depending on a relative speed between a magnetic head and a recording medium. It is being used for HDDs and the like.

[0003] An MR head is used for the writing disk surface.
As shown in FIG. 4 which is a cross-sectional view of a reproducing element portion,
The magnetoresistive film portion 3 and the lead layer portion 4 are made of a nonmagnetic insulating layer 8,
9, and these are applied to the magnetic shield layers 1 and 2.
It has a sandwiched basic structure. Such a so-called
In a shield type MR head, the nonmagnetic insulating layer
8 and 9 flow into the magnetoresistive film portion 3 and the lead layer portion 4
A magnetic shield layer 1 having a sense current of an alloy soft magnetic film,
2, the film thickness is set so as not to leak. Conventionally,
The nonmagnetic insulating layers 8 and 9 are formed by a high frequency sputtering method.
Silicon oxide formed by (RF sputtering method)
(SiO_Two), Aluminum oxide (Al _TwoO_Three)
Made of a thin film.

[0004]

However, the gap 10 between the shields tends to be gradually narrowed due to the demand for high-density recording (single-wavelength recording) of the magnetic head. The film thickness has also become insufficient. In order to meet the demand for further narrowing the gap of the MR head, there is a problem that the sense current leaks to the upper and lower shield layers.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a magnetic head capable of preventing a leakage of a sense current even when a magnetic gap layer is narrowed for high-density recording. It is an object of the present invention to provide a magnetic recording apparatus which can achieve higher density recording by providing the magnetic recording apparatus.

[0006]

In order to achieve the above object, a magnetic head according to the present invention is characterized in that the nonmagnetic insulating layer of the magnetic gap layer is made of silicon nitride (SiN), silicon oxynitride (SiO
N), aluminum nitride (AlN), amorphous carbon (aC), and amorphous boron nitride (a-BN).

With such a configuration, even if the magnetic gap layer is narrowed, a magnetic head in which a sense current is less likely to leak than in the related art can be provided, and a magnetic head capable of high-density recording can be obtained. it can.

[0008] In the above structure, it is preferable that the nonmagnetic insulating layer has a film thickness with a withstand voltage corresponding to 1.0 V or more and 50 nm or less. Here, as the withstand voltage, a non-magnetic insulating layer is sandwiched between a pair of electrodes having a counter electrode area of 0.04 mm ² , and the voltage applied between the pair of electrodes is increased from 0 V, and a current of 100 μA flows. The value of the voltage measured at the start shall be adopted.

The minimum film thickness required to maintain the above-mentioned dielectric breakdown voltage differs depending on the material constituting the non-magnetic insulating layer. The withstand voltage is 1.0 V or more.

In the above structure, the nonmagnetic insulating layer is formed by an electron cyclotron resonance plasma enhanced chemical vapor deposition (ECR).
It is preferably formed by a plasma CVD method.

With this configuration, it is possible to provide a magnetic head that can more effectively suppress the leakage of the sense current. ECR plasma CVD
According to the method, since a film can be formed in a low-temperature process and while keeping the pressure of the atmosphere gas low, a nonmagnetic film formed by this film forming method can be formed by, for example, an RF sputtering method that has been frequently used in the past. Compared to the formed non-magnetic film, the film has excellent insulating properties.

The magnetic recording apparatus of the present invention comprises the above-mentioned thin film magnetic head as a constituent element, and is capable of achieving high-density recording by narrowing a magnetic gap of the magnetic head. is there.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The nonmagnetic insulating layers 5 and 6 constituting the magnetic head of the present invention shown in FIG. 1 are at least one selected from silicon nitride, silicon oxynitride, aluminum nitride, amorphous carbon and amorphous boron nitride. Consists of 1, 2 are magnetic shield layers, 3 is a magnetoresistive film portion,
Reference numeral 4 denotes a lead layer portion, and 7 denotes a magnetic gap layer. In order to prevent leakage of the sense current, the nonmagnetic insulating layer of the magnetic head preferably has a withstand voltage of 1.0 V or more. As described above, any of the above materials can be used to achieve
Even if the above non-magnetic insulating layer is formed, a withstand voltage of 1.0 V or more can be ensured, but a preferable lower limit of the film thickness for ensuring this withstand voltage differs depending on the material. Specifically, in the case of silicon nitride (SiN), it is preferably 20 nm or more, in the case of silicon oxynitride (SiON), it is preferably 25 nm or more, and in the case of aluminum nitride (AlN), it is 20 nm or more. It is preferable that the thickness of the amorphous carbon (C) is 15 nm or more.
In the case of N), the thickness is preferably 25 nm or more.

Next, an ECR plasma CVD apparatus which can be suitably used for forming a non-magnetic insulating layer in the present invention will be described with reference to FIG. In the apparatus shown in FIG. 2, the plasma generated in the ECR plasma chamber 12 and the reactive gas supplied from the gas cylinder 18 via the path 17 are sucked through the vacuum suction path 16 and held at a low pressure. 15 to form a film on the surface of the substrate 11.

A microwave (generally 2.45 GHz) is supplied from a microwave power supply 14 to the ECR plasma chamber 12 to cause a discharge, and a magnetic field is formed by the electromagnetic coil 13 in the axial direction of the plasma chamber. Electrons generated by the discharge are accelerated while rotating by an electric field that rotates around the axis of the line of magnetic force. If the rotation frequency and the frequency of the microwave are matched with each other based on the optimum magnetic flux density and resonated, the energy of the microwave is efficiently absorbed by the electrons, and plasma can be formed even in a high vacuum.

Specifically, ECR (Electron)
Plasma generation using cyclotron resonance can be performed even at a pressure of about 1 to 10 ⁻³ Pa, for example, when plasma is generated by bipolar discharge (usually a pressure range of about 10 ^{2 to 1} Pa). In comparison, plasma can be generated at a lower pressure. As described above, according to the ECR plasma CVD method, the insulating layer can be formed in a low atmosphere gas and at a relatively low temperature. It is suitable as a film forming method.

Next, raw materials for forming a nonmagnetic insulating layer by ECR plasma CVD will be described. Although not particularly limited, it is preferable to use a SiH ₄ and N ₂ is the case of forming a silicon nitride (SiN), the case of forming a silicon oxynitride (SiON) is SiH ₄ and N
It is preferable to use ₂ O, and aluminum nitride (Al
When N) is formed, Al (CH ₃ ) is preferably used, when amorphous carbon (C) is formed, CH ₄ is preferably used, and when amorphous boron nitride (BN) is formed, B ₂ H is used. It is preferable to use ₆ .

[0018]

EXAMPLE Using a device similar to that shown in FIG. 2, any one of silicon nitride, silicon oxynitride, aluminum nitride, amorphous carbon and amorphous boron nitride was shown in Table 1 as a nonmagnetic insulating layer. The film was formed to have a thickness. The above-mentioned gas was used as the atmosphere gas at this time, the ECR power was in the range of 50 to 500 W, and the substrate temperature was 100 to 150 ° C.

As shown in FIG. 3, each of these nonmagnetic insulating layers was sandwiched between a lower permalloy electrode layer 23 and an upper permalloy electrode 22, and the withstand voltage between the two electrodes was measured. As the withstand voltage, the voltage between the upper and lower permalloy electrode layers sandwiching the nonmagnetic insulating layer was increased from 0 V, and the voltage at which a current of 100 μA began to flow was adopted. The upper permalloy electrode 22 at this time is
The thickness of the lower permalloy electrode 23 was 200 μm × 200 μm (area: 0.04 mm ² ), and the lower permalloy electrode 23 had a thickness of 200 nm and a sufficiently larger area than the upper electrode.

Table 1 shows the obtained dielectric strength. In addition, Table 1 also shows the result of determining that the withstand voltage of 1.0 V or more is acceptable (○) and that of less than 1.0 V is unacceptable (X).

[0021]

[Table 1]

[0022]

As described above, according to the present invention,
Providing a magnetic head suitable for high-density recording by making the nonmagnetic insulating layer of the magnetic gap layer at least one selected from silicon nitride, silicon oxynitride, aluminum nitride, amorphous carbon and amorphous boron nitride can do. The present invention can be particularly suitably used for a narrow gap MR reproducing head for high density magnetic recording. Further, by using such a magnetic head, high-density recording is possible, and a highly reliable magnetic recording device can be provided.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view of a reproducing element portion facing a write disk surface of a thin film MR head according to an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of an apparatus of an ECR-plasma CVD method.

FIG. 3 is a perspective view showing a method for measuring the insulating properties of a non-magnetic insulating layer formed by ECR-plasma CVD.

FIG. 4 is an enlarged sectional view of a reproducing element portion facing a write disk surface of a conventional thin film MR head.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 2 Magnetic shield layer 3 Magnetic resistance film part 4 Lead layer part 5, 6 Nonmagnetic insulating layer 7 Magnetic gap layer 8, 9 Conventional nonmagnetic insulating layer 10 Conventional magnetic gap layer 11 Substrate 12 ECR plasma chamber 13 Electromagnetic coil 14 Microwave power supply 15 Vacuum chamber 16 Vacuum suction path 17 Reactive gas introduction path 18 Gas cylinder 21 Non-magnetic insulating layer 22 Upper permalloy alloy layer 23 Lower permalloy alloy layer 24 Voltage measurement section

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masatoshi Kitagawa 1006 Kadoma, Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (4)

[Claims] The non-magnetic insulating layer of the magnetic gap layer is made of silicon nitride (SiN), silicon oxynitride (SiON), aluminum nitride (AlN), amorphous carbon (aC).
And a thin-film magnetic head comprising at least one selected from amorphous boron nitride (a-BN). 2. The method according to claim 1, wherein the non-magnetic insulating layer has a thickness of 1.
2. The thin-film magnetic head according to claim 1, having a withstand voltage of 0 V or more and a thickness of 50 nm or less. 3. The thin-film magnetic head according to claim 1, wherein the nonmagnetic insulating layer is formed by an electron cyclotron resonance plasma chemical vapor deposition (ECR plasma CVD). 4. A magnetic recording apparatus comprising the thin-film magnetic head according to claim 1 as a component.