JPH06203328A - Thin-film magnetic transducer - Google Patents

Abstract

PURPOSE: To obtain a thin film magnetic head. CONSTITUTION: This thin film magnetic head contains some groups of gap layers 31-33 each made of nitrided and hydrogenated amorphous carbon. This head contains a thin film writing layer 26 and two thin film reading layers 28 (separately positioned on the MR layer sides) and each of the layers 26, 28 is made of amorphous carbon doped with <=25at.% nitrogen and 5-25at.% hydrogen. The nitrogen existing in the amorphous carbon remarkably relieves the stresses of the layers. Since the layer 26 does not peel from its adjacent layer 30 made of other material such as ferrite or an Ni-Fe material even in the case of >=2,500Å thickness, it is not necessary to interpose a middle layer between the layers 26, 30. Since the hydrogen in the layer 26 extremely increases hardness, the wear of this head is suppressed.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to thin film magnetic heads having improved wear resistance and, more particularly, to thin film magnetic heads having a nitrided and hydrogenated amorphous carbon conversion gearstock material.

[0002]

In magnetic storage systems such as video tape systems, audio tape systems, computer data tape systems, or computer floppy disk systems, information is magnetically recorded on a magnetic tape surface. It For example, in magnetic tape systems used as peripheral storage devices to computers, digital information is displayed by selectively magnetizing a continuous magnetic region along the surface of a moving magnetic tape. When information is read from the magnetic tape, the magnetic polarity is sensed and an electrical signal is output. The read / write operation is performed by a read / write head that performs conversion close to the magnetic tape surface.

When recording information on a tape, it is desirable to record information at the highest possible information density. The magnetic flux density generated from the conversion head of the write head decreases as the distance from the conversion head increases. Therefore, a contact recording operation is used which achieves the highest possible recording density while maintaining a practical signal-to-noise ratio. The tape is kept in contact with the write head as much as possible to minimize the area of the tape surface magnetized by the write head during contact recording operations. Although magnetic tapes may accidentally leave the head due to contaminants on the tape's path or tape surface aspirate (suction), magnetic tapes typically have a minimum proximity conversion distance of the writing head. (Closest possible transducing proximity). Similarly, when reading the data written to the magnetic tape, the magnetic tape is maintained within a minimum proximate conversion distance of the read head.

Recent higher performance magnetic heads include one or more inductive type thin film write transducers and one or more read magnetoresistive (hereinafter abbreviated as MR) transducers. The thin film structure of these transducers improves saturation moment characteristics and system operating efficiency. At nominal operating speeds of magnetic tape or disk, contact between the storage medium and the read / write head causes an abrasive action that wears the head surface. The thin film in the conversion gap area is particularly sensitive to such wear.
The wear of the gear area reduces the performance of the head by increasing the effective space between the gear area and the tape surface. In addition, contaminants are collected in the abraded area and short circuit the head element if it is conductive, or otherwise insulate the head element.

The pole pieces and MR element are generally made of a material with optimum magnetic performance, such as nickel-iron material. The transducing gap region is wholly filled with a magnetic insulator to reduce the write / read boundary area. To reduce wear on the surface of the head, hard ceramic materials, such as alumina, are used in the conversion head region of the magnetic head. Unfortunately, such materials do not reduce head surface wear.

[0006]

SUMMARY OF THE INVENTION In view of the above,
It is an object of the present invention to improve thin film magnetic heads.

Another object of the present invention is to minimize wear of the conversion gap area of the thin film magnetic head.

Another object of the present invention is to reduce the additional expense of minimizing wear on the conversion gap area of a thin film magnetic head and to facilitate manufacture.

[0009]

SUMMARY OF THE INVENTION The foregoing and other objects are met by a thin film magnetic head having a conversion gear element made from nitrided and hydrogenated amorphous carbon. The magnetic head of the present invention comprises a thin film write gap layer and two thin film read gap layers (MR).
2), one on each side of the layer)
Made of amorphous carbon doped with 5 atomic percent nitrogen and 5 to 25 atomic percent hydrogen. Nitrogen present in amorphous carbon significantly reduces layer stress. Even at thicknesses above 2500 Å, this layer does not delaminate from iron or other adjacent materials such as nickel-iron materials. Therefore, there is no need to provide an intervening deposited layer between the amorphous carbon and other adjacent materials. The hydrogen present in the layers electrically insulates the layers from each other and makes the layers extremely strong, thus reducing the amount of wear.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention applied to an interleaved thin film magnetic head of a magnetic tape will be described below with reference to the accompanying drawings.

The juxtaposed thin film magnetic head reads magnetic transitions from a magnetic storage medium having a plurality of parallel tracks,
Or used to write magnetic transitions in such magnetic storage media. Such magnetic heads are used in tape drive systems, such as the IBM 3490 Magnetic Tape Subsystem. The magnetic tape is moved in both directions with respect to the magnetic head in order to read or write information using several transducers in the magnetic head. A plurality of transducers are simultaneously energized to read information from, or write information to, a plurality of tracks on the tape. The side-by-side magnetic heads are particularly important because they can increase the number of tracks and yet provide a direct readback check of the information just written on the tape by providing the action of moving the tape in both directions.

Referring to FIG. 1, an embodiment of a juxtaposed thin film magnetic head for a magnetic tape of the present invention is shown. The magnetic head 10 includes a plurality of read conversion elements R and a plurality of write conversion elements W. The read and write conversion gears are arranged in a direct alternating odd / even manner. In the preferred embodiment, 36 pairs of read and write gears are provided to provide a data format of 36 tracks across the width of the magnetic tape 12, but in another embodiment, the track Any number of pairs of read and write gears can be provided to provide a data format corresponding to the number. Odd numbered track 1,
3, 5, etc. are operated during the forward movement of the magnetic tape 12, whereas even-numbered tracks 2, 4, 6, etc. are operated during the backward movement of the magnetic tape 12.

The length direction of the magnetic tape 12 is two arrows 1
It is moved both forward and backward as indicated at 4 and 16. Arrow 14 indicates forward movement and arrow 16 indicates backward movement. The magnetic tape 12 operates in a contact conversion relationship with the magnetic head 10. The magnetic head 10 comprises two modules 18 and 20 of generally the same construction. Modules 18 and 20 are applied together to form a single physical unit. In this manner, the conversion gears of one module are closely positioned with respect to the conversion gears of the other module, and the gears of the module are precisely aligned with the direction of tape travel. Each module 18
And 20 there are 18 read transducers R and 18 write transducers W. Each of the modules 18 and 20 includes a magnetic ferrite substrate 22 and a non-magnetic ceramic encapsulation block 24. Module 18 includes a gearup line 26 and module 20 includes a gearup line 26.
Includes line 28. Photolithographic masks and etching processes are used to create the structure of the transducer elements.

Referring to FIG. 2, the write conversion element of the magnetic head 10 is shown. The write transducer is sandwiched between a magnetic ferrite substrate 22 and a non-magnetic enclosing block 24. The magnetic ferrite substrate 22 is a pole piece made of, for example, magnetic nickel-zinc ferrite or magnetic manganese-zinc ferrite. Encapsulation block 24 can be manufactured from any non-magnetic ceramic that is a non-magnetic material. Several thin films are used to make the write transducer.

A very thin undercoat layer 46, about 200 to 500 angstroms thick, is made of a non-magnetic material such as alumina. Undercoat layer 46
To provide a smooth surface for the next layer and to prevent grain growth, or replicas, of the magnetic ferrite substrate 22 in the next layer in order to stop the etch stop layer (during the next process). It is deposited on the substrate 22 as an etch-stop). The first magnetic pole chip 30 is nickel-iron, nickel-
It is made from one or more soft magnetic materials such as iron-nitride, iron-nitride and the like. The first pole tip 30 is about 9000 to 1000 on the undercoat layer 46 to improve the magnetic saturation characteristics of the pole pieces of the substrate 22.
Sputtered and debossed to a thickness of 0 angstrom.

The non-magnetic write gap area 26 is approximately 7
500 to 10000 Angstroms thick,
It is made of nitrided and hydrogenated amorphous carbon as described below. The write gap region 26 includes three separate insulating gap layers 31, 32, 33 of amorphous carbon material deposited to a thickness of at least 2500 Angstroms. In the preferred embodiment, the gear layer 31 is about 2800 angstroms, the gear layer 32 is about 3200 angstroms, and the gear layer 33 is about 3300 angstroms. A second magnetic pole chip 40 of the same soft magnetic material as the material used for the first magnetic pole chip 30 is used to form the second magnetic pole chip near the bearing surface of the magnetic head to form a second magnetic pole chip 33. 35000 to 360 on
Sputtered deposited to a thickness of 00 Angstroms. An insulator 38, which is remote from the bearing surface that supports the tape, separates the second pole tip 40 from the gear layer 33. Insulator 38 is made of hardened photoresist and includes an induction coil (not shown) in the second position.
To provide electrical isolation from the pole tip 40 of the.

A support insulator 42, preferably a hardened photoresist, is also formed on the pole tip region of the second pole tip 40. Next, a leveling layer 44 of, for example, alumina or an epoxy resin material is formed on the second magnetic pole chip 40 and the insulating layer 42. The leveling layer 44 is applied for planarization. An additional layer 48 of chrome-based material is used as a mask for etching and pins into the leveling layer 44 when forming leads (not shown) at the head away from the bearing surface. Prevents holes from being etched. An enclosure 24 is applied to complete the write conversion element.

Referring to FIG. 3, the read conversion element of the magnetic head 10 is shown. The read transducer is similar to the write transducer in that the magnetic ferrite substrate 2
2 and a nonmagnetic material enclosure 24. Several thin films are used to form the read transducer. Some thin films are the same material as the write transducer,
Its thickness is the same as that used in the write transducer (hence the same reference numeral), but
It has a different function in the reading converter.
For example, using such common layers can reduce manufacturing costs. If desired, photolithography is used to mask several layers in order to make structural differences between the write conversion element and the read conversion element.

An insulating gap layer of nitrided and hydrogenated amorphous carbon material is deposited on the substrate 22. Next, for example, a nickel-iron-rhodium, tantalum and nickel-iron MR layer 35 is applied to about 750-10.
It is sputter deposited on the gap layer 31 to a thickness of 00 Angstroms. Then, the insulating gap layer 32 of the nitrided and hydrogenated amorphous carbon material is MR
Deposited on layer 35. A read transducer nickel-iron material shield layer 40 is deposited over the insulating gap layer 32. Also, the magnetic ferrite base 2
2 functions as a shield for the read transducer. The leveling layer 44, the additional layer 48 and the encapsulant 24 complete the read conversion element.

Also, in addition to the data read transducer R described above, the substrate 22 can include MR servo read transducer elements (not shown). Such elements form a continuous servo loop for maintaining the lateral position of the magnetic head 10 with respect to the magnetic tape 12 (ie, maintaining the alignment of the transducer with respect to the tracks to which the transducer is associated). Used only. Since the servo read conversion element follows a prerecorded pattern on one or more tracks of the magnetic tape 12, it therefore need not have the same operating parameter requirements as the data read conversion element. Thus, the servo read conversion element can be made using other methods than those described above, or the same methods described above can be used to simplify the manufacturing process. In another embodiment, the magnetic head 10 includes 32 data read transducers similar to the transducers described above, or only 32 write transducers, with the remaining substrate portion serving as a servo read transducer. It can be the magnetic head as used. By using such a servo read transducer, the magnetic head is operated between different lateral positions relative to the magnetic tape, resulting in different sets of 32 tape tracks at each read and write position. Data can be read and written. Further description of the magnetic head servo means is omitted as it is not directly related to the present invention.

Magnetic head 1 remote from the bearing surface
Although the 0 configuration is shown in FIGS. 2 and 3, this configuration is not directly relevant to the present invention. The magnetic tape 12 may be any known tape, such as audio, video, or computer magnetic tape. The working recording layer may be any such as a chromium oxide layer or a magnetic layer of metal particles. The magnetic tape 12 has a quarter inch (6.35 mm) and a half inch (12.7 mm).
Mm), or any width of 8 mm.

As a result of examining the characteristics of the nitrided and hydrogenated amorphous carbon thin film, it was found to be superior to the characteristics of all conventionally known insulating gap materials.
The nitrided, hydrogenated, amorphous carbon thin film of the present invention is harder than the conventionally used alumina gearstock material, and thus resists the wear of the magnetic head caused by the abrasive action of the magnetic tape 12. Provides greater wear resistance. Also, such thin films of the present invention have low stress and therefore can be used in magnetic heads without the use of additional deposition layers. It has been found that in non-nitrided carbon thin films, the non-nitrided carbon thin films peel off from the deposited substrate.

To test the properties of nitrided and hydrogenated amorphous carbon thin films, thin films in accordance with the present invention were fabricated on a silicon wafer substrate by plasma enhanced CVD, or sputtering deposition processes. . The hardness of this thin film is shown in FIG. In the graph of FIG. 4, it is shown that the hardness of the thin film is maximum at a certain amount of nitrogen in the thin film depending on the amount of hydrogen in the thin film. Above about 25 atomic percent nitrogen, in contrast to the figure, this film is, in fact, very vulnerable to most applications. It has been found that above about 25 atomic percent hydrogen, the film becomes too soft, and films below about 5 atomic percent hydrogen have high stress.

The stress of a thin film deposited according to the invention with a thickness of 2000 Å is shown in FIG.
Since the stress of the thin film causes the substrate to warp,
The stress was measured using a deflection gauge to determine the amount of friction), and this measurement was used to calculate the stress of the thin film. For more information on this test,
US Patent Application No. 8 filed December 16, 1991
See 08338.

The tests described in the above-referenced US patents are based on a thin film of amorphous carbon (gear layer 31) of about 2800 to 3200 angstroms, respectively, deposited on the magnetic layer.
It does not indicate whether the thin film as described above for .about.33) is low enough in stress to prevent later delamination from the adjacent magnetic head material. The ability to meet such requirements was not apparent from the tests set forth in the above-referenced U.S. Patents, so a subsequent 3000 angstrom layer of nitrided and hydrogenated amorphous carbon was used with other known insulating gap materials. Later tests were carried out to confirm that these layers had excellent material properties when compared to the material properties of. The thin films of the present invention do not delaminate from layers of nickel-iron or ferrite material. Rusherod's reverse and forward recoil and skiutter measurements on 3000 angstrom thick films of the present invention (Rutherford bac
kscattering and forward recoil scattering measurem
ent) results indicated the presence of 14 atomic percent nitrogen and 12 atomic percent hydrogen.

The thin film of the embodiment of the present invention is a plasma enhanced CV.
Made by D, or Spatta Deposition.
Hydrocarbon gas (cyclopentane) is maintained at a pressure of 6 mTorr for plasma enhanced CVD deposition in a plasma enhanced CVD chamber with 0.5 mT
It was introduced at a partial pressure of orr. The plasma was ignited at 400 watts applied to the magnetron using a low frequency (300 kilohertz). The undercoat layer was biased with a DC voltage of about -200 to -600 volts. A 1: 1 ratio of argon and nitrogen carrier gas was used for the deposition process.

For the sputter deposition process,
A high-purity DC magnetron carbon target was used with a 1.5 kilowatt DC power supply. The undercoat layer is 650 with a low frequency power supply operating at 300 kHz.
Biased by Watts. Carrier gas is argon with 4% hydrogen and 50% nitrogen.

It should be noted that the thin film of carbon nitrided and hydrogenated according to the present invention can also be used as an insulating gap material in thin film magnetic heads other than magnetic transducers for magnetic tape systems.

[0029]

The present invention provides a thin film magnetic head having improved wear resistance of the thin film magnetic head and reduced stress in the conversion gap layer.

[Brief description of drawings]

FIG. 1 is a schematic view of a juxtaposed thin film magnetic head to which the present invention is applied.

2 is a sectional view of a bearing surface of a write element of the juxtaposed thin film magnetic head of FIG.

3 is a cross-sectional view of the bearing surface of the read element of the juxtaposed thin film magnetic head of FIG.

FIG. 4 is a graph showing the hardness of nitrided and hydrogenated amorphous carbon thin films as a function of the amount of nitrogen included for films containing different amounts of hydrogen.

FIG. 5 shows the stress of thin films of nitrided and hydrogenated amorphous carbon as a function of the amount of nitrogen contained for thin films produced by plasma enhanced chemical vapor deposition (CVD) or sputter deposition. It is a graph shown.

[Explanation of symbols]

 10 thin film magnetic head 12 magnetic tape 18, 20 module 22 substrate 24 encapsulation block 26 gearup line (writing gearup area) 28 gearup line (reading gearup area) 30 first magnetic pole chip 31, 32, 33 gearup layer 35 magnetic resistance (MR) layer 38 Insulator 40 Second magnetic pole chip 42 Supporting insulator 44 Leveling layer 46 Undercoat layer 48 Additional layer

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor James Harvey Kauffman, South Zerubs Street, San Jose, California 499 (72) Inventor Sahhat Meetin, San Jose, California, Turner Court 230 (72) Inventor David Dawn Superstin Durazno Way 130, Portola Barry, California, USA 130 (72) Inventor Anthony Way Woo Briar Ranch Lane, San Jose, CA 663

Claims (7)

[Claims] 1. A thin film magnetic transducer for recording information on a storage medium adjacent to a bearing surface of the thin film magnetic transducer, comprising: a first magnetic pole chip; and amorphous carbon, hydrogen, and hydrogen on the first magnetic pole chip. A nitrogen magnetic non-magnetic gap region and a second magnetic pole on the gear magnetic region, the first magnetic pole being separated from the second magnetic pole to form a write gear on the bearing surface. Thin film magnetic transducer. 2. The thin film magnetic transducer of claim 1 wherein said gap region contains hydrogen in an amount between about 5 and 25 atomic percent. 3. The thin film magnetic transducer of claim 1 wherein said gap region contains nitrogen in an amount less than or equal to about 25 atomic percent. 4. The thin film magnetic transducer of claim 2 wherein said gap region contains nitrogen in an amount less than or equal to about 25 atomic percent. 5. The thin film magnetic transducer of claim 4 wherein said gap region is at least 2500 Angstroms thick. 6. A thin film magnetic transducer for reading information on an adjacent storage medium, comprising: a first magnetic shield, a first non-magnetic gap layer of amorphous carbon, hydrogen and nitrogen; and the first gear gap. Thin-film magnetic transducer comprising a magnetoresistive layer on a layer, a second non-magnetic gap layer of amorphous carbon, hydrogen and nitrogen on the magnetoresistive layer, and a second magnetic shield on the second gap layer . 7. A juxtaposed thin film magnetic head for reading information from and writing information to a storage medium adjacent to a bearing surface of the magnetic head, wherein the first and second modules are integrally formed. A deposited module, each module having a plurality of alternating read and / or write transducers, wherein each of the plurality of read transducers of the first module is a plurality of second modules. Opposite the different converter of the writing converter of
The plurality of write transducers of the first module oppose the different transducers of the plurality of read transducers of the second module, each module including a magnetic ferrite substrate; The substrate of each of the write transducers includes a non-magnetic undercoat layer on the substrate, a first magnetic pole chip on the non-magnetic undercoat layer, and amorphous carbon, hydrogen, and hydrogen on the first magnetic pole chip. A non-magnetic write gap region of nitrogen and a second magnetic pole chip on the write gear gap region, the first magnetic pole chip having a first magnetic pole chip for forming a magnetic write gear region on the bearing surface. Two
Being separated from the magnetic pole tip of the plurality of read transducers, and the substrate of each of the plurality of read transducers includes a first non-magnetic read gap layer of amorphous carbon, hydrogen and nitrogen on the substrate and a first read gap layer. The upper magnetoresistive layer and the amorphous carbon on the magnetoresistive layer
A non-magnetic read gear layer, a magnetic shield on the second read gear layer, a non-magnetic leveling layer on the second magnetic pole chip on the second read gear layer, and a non-magnetic enclosure on the leveling layer. A thin film magnetic head comprising: