JPS63299219A - Magnetically soft thin film - Google Patents

Abstract

PURPOSE:To obtain the magnetically soft thin film having highly saturated magnetic flux density, low coercive force and high permability and these characteristics are not deteriorated greatly when a heat treatment is conducted by a method wherein a magnetically soft thin film, on which a prescribed percentage of ternary element is added to iron nitride, is used independently or it is used together with a non-magnetic nitrogen film in laminated form. CONSTITUTION:A magnetically soft thin film is indicated by the compositional formula of FexNyAz (provided that the compositional ratio of x, y and z is shown in terms of atomic %, and A indicates at least a kind of Si, Al, Ta, B, Mg, Ca, Sr, Ba, Cr, Mn, Zr, Nb, Ti, Mo, V, W, Rf, Ga, Ge and rare-earth element). A main magnetic layer having the range of composition of 0.5<=y<=5.0, 0.5<=z<=7.5 and x+y+z=100, and a nonmagnetic nitride film are laminated. An Fe96.5Si2N15 film 1, which is a main magnetic layer of about 1000Angstrom in thickness, and an Si3N4 film 2, which is a nonmagnetic nitride film of about 9Angstrom in thickness, are laminated alternately by conducting a sputtering operation while a substrate is being rotated, and a magnetically soft laminated film is formed. The soft magnetic characteristics which are highly excellent in practical use can be accomplished on the above-mentioned laminated film.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a soft magnetic thin film, and in particular to a soft magnetic ill! Regarding.

[Summary of the invention]

In the soft magnetic rII film used as the core of a magnetic head, the present invention uses a soft magnetic 'FR film in which 0.5 to 7.5% of a third element is added to iron nitride, either alone or with a non-magnetic nitride. By stacking with the film, high saturation magnetic flux density,
The present invention provides a soft magnetic thin film that has core characteristics of low coercive force and high magnetic permeability, and these core characteristics do not deteriorate significantly due to heat treatment.

[Conventional technology]

For example, in magnetic recording and reproducing devices such as audio tape recorders and VTRs (video tape recorders), the recording signal density and quality are increasing, and so-called magnetic Tapes and so-called vapor-deposited tapes, in which ferromagnetic metal materials are directly wave-deposited onto a base film using vacuum thin film formation technology, have been put into practical use.

By the way, in order to make good use of the characteristics of magnetic edge media with such high coercive force for good recording and reproducing, the core material of the magnetic head must have a high saturation magnetic flux density as well as the same magnetic head. In the case of attempting to reproduce the magnetic material, it is also required to have high magnetic permeability.

Iron nitride is known as a soft magnetic material that meets these demands. This material is formed into a thin film by performing ion beam evaporation or sputtering using iron as a target in a nitrogen atmosphere, and has an extremely high saturation magnetic flux density.

In addition, instead of the single-layer iron nitride film mentioned above, a soft magnetic laminated film in which a main magnetic layer mainly composed of iron and an insulating material such as silicon oxide are alternately laminated is also used for the purpose of reducing eddy current loss. It has been successfully developed to achieve both high saturation magnetic flux density and high magnetic permeability, which were not possible with single-layer films.

[Problem that the invention seeks to solve]

Incidentally, in the manufacturing process of a magnetic head, a fusing process using high-melting point glass is essential, and this process requires high-temperature heat treatment. However, the conventionally developed 2
A soft magnetic thin film with an extremely high saturation magnetic flux density exceeding 0 kG does not have a sufficiently low coercive force after film formation, and the coercive force increases even after heat treatment at about 400°C, resulting in a good film. It could not be said that it exhibited soft magnetic properties.

Even in laminated soft magnetic thin films, improving the soft magnetic properties of the soft magnetic thin film that serves as the main magnetic layer is fundamental to improving the properties.

Therefore, an object of the present invention is to provide a soft magnetic fi)II whose soft magnetic properties do not deteriorate even after heat treatment.

[Means for solving problems]

The soft magnetic thin film of the present invention has been proposed to achieve the above-mentioned conventional object, and is composed of FeIINVAll (where X+L+Z each represents the composition ratio as atomic %, and A
are St, AI, Ta, B, Mg, Ca, S
r.

Ba, Cr, Mn, Zr, Nb, Ti, Mo, V.

represents at least one of W, Hf, Ga, Ge, and rare earth elements, and the composition range is 0.5≦
y≦2.5.0.5≦2≦7.5. x+y+z-10
It is characterized by being 0.

Furthermore, the soft magnetic thin film of the present invention is made of Fe8NyAg (wherein, L Y+ 2 represents each composition ratio as atomic %, and A
are Si, AI, Ta, B, Mg, Ca.

Sr, Ba, Cr, Mn, Zr, Nb, Ti, Mo.

At least one of V, W, Hr, Ga, Ge, and rare earth elements
), which represents a species, and whose composition range is 0.
5≦y≦2.5.0.5≦2≦7.5. x+y+z=1
00, and a non-magnetic nitride film are laminated.

The main magnetic layer of the soft magnetic GL film or laminated soft magnetic thin film according to the present invention is made of iron nitride to which the various elements described above are added at a ratio of 0.5 to 7.5 atomic percent. but,
It is also possible to combine two or more types of additive elements.The soft magnetic thin film according to the present invention is created by sputtering in an atmosphere containing nitrogen. A possible method is to prepare an alloy of iron and iron and use this alloy as a target.

However, for metals such as alkaline earth metals that do not form a solid solution with iron, a chip is prepared and sputtering is performed by placing the chip on an iron target.

When the above-mentioned soft magnetic thin film is used as the main magnetic layer and is laminated with other non-magnetic nitride films, examples of non-magnetic nitrides that can be used include S1iNa, BN, and AIN.

TaN, ZrN, NbN, TiN, GaN, MgN.

There are MoN, VN, etc. Two or more types of these nitrides may be combined together.

In a laminated soft magnetic thin film using the above-mentioned materials, the nonmagnetic nitride film is formed by sputtering in the same way as the main magnetic layer. At this time, the film thicknesses of the main magnetic layer and the non-magnetic nitride film may be set appropriately depending on the desired characteristics, but first, the film thickness of each main magnetic layer should be 100 to 1.000 μm from the viewpoint of magnetic properties. desirable. In addition, it is desirable that the thickness of the non-magnetic nitride film per 111 is in the range of 3 to 500 people.If the thickness is less than 3 people, it is difficult to form a uniform film, and there is no point in forming a layered film. Further, above the above range, the saturation magnetic flux density decreases. Furthermore, the number of laminated layers of the main magnetic layer and the nonmagnetic nitride film may be selected as appropriate.

[Effect]

In the soft magnetic thin film according to the present invention, high saturation magnetic flux density and high magnetic permeability are achieved by adding various elements to iron nitride. These various added elements form stable nitrides in the iron nitride film, so nitrogen is not released from the iron nitride film even at high temperatures. Even after heat treatment, the coercive force does not increase significantly, making it possible to maintain good soft magnetic properties.

In addition, in a laminated soft magnetic thin film in which the above-mentioned soft magnetic thin film is laminated with a nonmagnetic nitride film, the coercive force is actually reduced after heat treatment, and further improvement in soft magnetic properties can be expected.

〔Example〕

Hereinafter, preferred embodiments of the present invention will be described based on experimental results.

First Embodiment This embodiment is an example of a soft magnetic thin film as a single layer film using aluminum, thallium, and silicon as additive elements.

F eqqA l! ＋Fe! ?
T a 3+ and F e *tS l
An iron alloy target having a composition of s (all values are atomic %) was prepared, and high frequency magnetron sputtering was performed under the conditions of a gas pressure of 3 mTorr and an output of 300 W in an argon atmosphere containing 2.5 mol% nitrogen. conducted, aluminum-containing iron nitride thin film (summer), thallium-containing iron nitride thin film (I[), and silicon-containing iron nitride thin film (I[I)]
were created respectively. After annealing each of these iron nitride thin films at 550° C. for 1 hour, the coercive force was measured and compared with the coercive force before annealing. The results are summarized in Table 1.

According to Table 1, although the coercive force of all iron nitride thin films is slightly higher after annealing than before annealing, the thermal stability is far superior to that of the conventional soft magnetic first surface film. It turns out that it has sex. In addition, the saturation magnetic flux density of all soft magnetic thin films was around 20 kG, which was extremely high.

Note that the conditions for high-frequency magnetron sputtering employed in this example are not limited to those described above; for example, the nitrogen content is in the range of 0.5 to 5 mol%, and the gas pressure is in the range of 1.0 to 5 mol%. These conditions may be changed within the range of aTorr, but since these conditions affect the composition of the obtained iron nitride, they may be appropriately selected depending on the desired soft magnetic properties.

In addition, the sputtering method is also based on the high frequency magnetron mentioned above.
Not limited to sputtering, e.g.
DC sputtering, facing target sputtering, ion beam sputtering, etc. can also be used.
Again, the process is carried out in a nitrogen-argon atmosphere with a nitrogen content of 0.5 to 5 mol%. An example of the gas pressure at this time is 1.0 to 5 mTorrs in the case of DC sputtering.
0.2 to 5 m for facing target sputtering
Torr, 0.1 for ion beam sputtering
~1.0 mTorr.

Comparative Example As a comparative example to the above experiment, an example in which the amount of added element is outside the range limited in the present invention is shown.
As an example in which the added amount of the element is less than the above range, a thin iron nitride Wa (IV) was prepared under the same conditions using pure iron as a target without using the added element, and the coercive force was similarly measured. In addition, as an example of a large amount of added elements, F ems, s
A silicon-containing iron nitride thin film (
V) was prepared and the coercive force was measured in the same manner. The results are shown in Table 2. Looking at this table, the coercive force of the produced iron nitride mH is higher in all cases than the soft magnetic thin films shown in Table 1 above, and the soft magnetic properties are inferior. It dawned on me that something was going on.

Second Example In this example, silicon or thallium is used as the additive element of the main magnetic film, silicon nitride is used as the non-magnetic nitride film, and both are laminated by so-called simultaneous binary sputtering to create a soft magnetic thin film. (Hereinafter, it will be referred to as a soft magnetic laminated film.

) is an example.

First, a case where silicon is used as an additive element will be explained.

First, the target Fe*tS is placed inside the chamber.
ls (atomic %) and 5iiNa were juxtaposed.

Next, a substrate made of crystallized glass or the like was placed on a movable mounting table so as to face one of these targets. Subsequently, after deaerating the inside of the chamber, argon containing 2.5 mol% nitrogen was filled, and the gas pressure was increased to 2.5 W.
Torr.

While rotating the substrate, sputtering was performed at an output of 300 -, resulting in a film thickness of 1,000 mm as shown in Figure 1.
Fe*h, ss itN+, s film (1), which is the main magnetic layer of humans, and 5isN-, which is a non-magnetic nitride film with a film thickness of about 9
11! (2) and are alternately laminated to form a soft magnetic N film (■).
It was created.

When using thallium as the additive element, the same procedure as above when using silicon is performed except that FewtTas (atomic %) is used as the target, and F e qh, sT a tN 1. A 1 m (■) soft magnetic tank containing the S film was obtained.

Soft magnetic laminated film (■) created in this way.

For (■), after annealing at 550°C for 1 hour, the coercive force and magnetic permeability at 5 MHz were measured and compared with the coercive force and magnetic permeability before annealing. The results are shown in Table 3.

According to Table 3, the coercive force was lower after annealing than before annealing in all soft magnetic tanks Fillll. In addition, the magnetic permeability shows a slight decrease when Table 3 silicon is used as an additive element, and a slight increase when thallium is used as an additive element, but in either case, it is a very good soft magnetic material for practical use. characteristics have been achieved.

As an example of data showing these good soft magnetic properties,
Figure 2 (A) and Figure 2 (B) show the soft magnetic laminated film ('1
The hysteresis curve of ll) is shown. Figure 2 (A) shows the hysteresis curve before annealing, and Figure 2 (B) shows the hysteresis curve after annealing. From these figures, the saturation magnetic flux density after annealing is almost 20 kG compared to before annealing. It can be seen that the coercive force is lowered by 0.1 (Oe) and the width of the hysteresis curve in the lateral direction is narrower.

Further, FIGS. 3(A) and 3(B) similarly show the frequency dependence of the magnetic permeability of the soft magnetic laminated layer III (V[). FIG. 3(A) shows the characteristics before annealing, and FIG. 3(B) shows the characteristics after annealing.

In these figures, the vertical axis represents magnetic permeability, and the horizontal axis represents frequency. Looking at this, it was found that after annealing, the magnetic permeability decreased slightly over the entire measured frequency band compared to before annealing, but the magnetic permeability was still sufficiently high for practical use.

〔Effect of the invention〕

As is clear from the above description, the first aspect of the present invention is to add an element capable of forming a stable nitride to iron nitride within a predetermined range, so that it can be included in the manufacturing process of a magnetic head. This makes it possible to maintain stable soft magnetic properties even after undergoing high-temperature annealing treatment. Therefore, by using this soft magnetic thin film, it is possible to suppress the increase in coercive force after annealing, which has been a problem in the past.

In addition, in the second aspect of the present invention, since the above-mentioned soft magnetic thin film is combined with a non-magnetic nitride film to form a laminated soft magnetic thin film, the coercive force is reduced after annealing, resulting in a further improvement effect. You can get it.

If such a soft magnetic thin film with a sufficiently low coercive force is applied to a magnetic head, the magnetic head will be prevented from becoming magnetized, and good recording and reproduction with less distortion and a high S/N ratio will be possible.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view schematically showing a configuration example of a laminated soft magnetic thin film to which the present invention is applied. Figure 2 (A) and 2
Figure 2 (B) is a characteristic diagram showing the hysteresis curve of the soft magnetic laminated film when silicon is used as an additive element, and Figure 2 (A)
shows the characteristics before annealing, and FIG. 2 CB) shows the characteristics after annealing. Figure 3 (A) and Figure 3 (B)
is a characteristic diagram showing the frequency dependence of magnetic permeability of a soft magnetic laminated film when silicon is used as an additive element, and FIG. 3(A) shows the characteristics before annealing and FIG. 3(B) shows the characteristics, respectively. be. 1-・-F ewa, ss txN+, s membrane 2...5
isNn membrane patent applicant Sony Corporation representative Patent attorney Koike Mimi Ei Tamura Masaru Sato Figure 1 Figure 2 (A> Figure 2 (B) Delivered counter number (MHz) Figure 3 (A') ) 7. Contents of the amendment Procedural Authorization (spontaneous) July 10, 1988 Director General of the Patent Office Kunio Ogawa 1. Indication of the case 1988 Patent Application No. 133996 2. Name of the invention Soft magnetic thin film 3. Person making the amendment 4, agent 6, subject of amendment Attachment (1) Amend the claims of the specification as shown in the attachment. (2) Page 5, line 13, and page 6 of the specification "0.5≦y≦2.5" in the second line is corrected to "2.5≦y≦5.O". Claim r(1) F e, INyA- (However, X+ L Z
represents the composition ratio as atomic %, and A is Si, AI, T
a. B, Mg, Ca, Sr, Ba, Cr, Mn, Zr. Nb, Ti, Mo, V, W, Hr, Ga, Ge. Represents at least one rare earth element. ), and the composition range is 2.5≦≦5.0 0.5≦2°≦7.5″+3′+Z=100. (2) Fe, NyA, (however, L V + Z represents the composition ratio as atomic %, A is Si, AI, Ta, B. M g , Ca + S r + B a , Cr
+Mn+Zr+Nb. Represents at least one of Ti, Mo, V, W, Hf, Ga, Ge, and rare earth elements. ), and the composition range is 2.5≦≦5.0 0.5≦2≦7.5 x+y+z=100 A main magnetic layer and a nonmagnetic nitride film are laminated. Characteristic soft magnetic thin film. j Procedures (Hoshosho (spontaneous) July 14, 1988 Case 13 Indication of Patent Application No. 133996 of 1988 2, Name of invention Soft magnetic thin film 3, Person making amendment 4, Agent 6, Name of amendment Target 7, Contents of amendment (1) The scope of claims in the specification is amended as shown in the attached sheet. (2) “0.5≦y≦ 2.5" is changed to "0.5≦y≦
5.0”. Attachment Claims r(1) FexN, A, (wherein X+ Y+ 2 each represents the composition ratio as atomic %, A is Si, Al, Ta. B, Mg, Ca, Sr, Ba, Cr, Mn , Zr. Nb, Ti, Mo, V, W, Hf, Ga, Ge. represents at least one rare earth element. A soft magnetic thin film characterized in that 5≦2≧7.5 X+y+z=100. (2) F ellN y A - (However, L V
+ z represents the composition ratio as atomic %, and A is Si, A
I, Ta, B. Mg, Ca, -3r, Ba, Cr, Mn, Zr, Nb. Ti, Mo, V, W, Hf, Ga, Ge,
Represents at least one rare earth element. ), and its composition range is 0.5≦≦5.0 0.5≦2≦7.5 x+y+z=], OO

Claims (1)

[Claims] (1) Fe_xN_yA_z (where x, y, and z each represent the composition ratio as atomic %, and A is Si, Al, Ta,
B, Mg, Ca, Sr, Ba, Cr, Mn, Zr, Nb
, Ti, Mo, V, W, Hf, Ga, Ge, and a rare earth element. ), and has a composition range of 0.5≦y≦2.5, 0.5≦z≦7.5 x+y+z=100. (2) Fe_xN_yA_z (where x, y, and z each represent the composition ratio as atomic %, and A is Si, Al, Ta,
B, Mg, Ca, Sr, Ba, Cr, Mn, Zr, Nb
, Ti, Mo, V, W, Hf, Ga, Ge, and a rare earth element. ), the main magnetic layer having a composition range of 0.5≦y≦2.5, 0.5≦z≦7.5 x+y+z=100 and a nonmagnetic nitride film are laminated. A soft magnetic thin film characterized by: