JP2003204095A - Magnetoresistive device, its manufacturing method, magnetic reproducing device, and magnetic memory - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic micro contact which can be turned to an element, is superior in controllability, and easily manufactured, a reproducing head device which uses the magnetic micro contact and is high in sensitivity, and furthermore a magnetic memory which uses a magnetoresistive device and has a recording/producing function. <P>SOLUTION: The magnetoresistive device is equipped with a first ferromagnetic layer (1), an insulating layer (3) formed on the first ferromagnetic layer (1), and a second ferromagnetic layer (2) formed on the insulating layer (3). An opening (A) having a diameter of 20 nm or smaller is provided to the insulating layer (3), and the first ferromagnetic layer (1) and the second ferromagnetic layer (2) are connected together through the intermediary of the opening (A) for the formation of the magnetoresistive effect device. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetoresistive effect element, a method of manufacturing the same, a magnetic reproducing element and a magnetic memory, and more particularly, a magnetoresistive effect element having magnetic micro contacts showing a high magnetoresistive change rate. The present invention relates to a manufacturing method thereof, a magnetic reproducing element and a magnetic memory.

[0002]

2. Description of the Related Art Since it was found that a giant magnetoresistive effect (Giant Magnetoresistance effect) appears when a current is applied in a plane in a laminated structure of a ferromagnetic layer / nonmagnetic layer / ferromagnetic layer , A system with a larger magnetoresistance change rate has been searched. So far, the CPP that allows the ferromagnetic tunnel junction and current to flow in the direction perpendicular to the laminated structure
(Current Perpendicular to Plane) type MR elements have been developed, and these are regarded as promising as magnetic sensors and reproducing elements for magnetic recording.

In the field of magnetic recording technology, the recording density is inevitably reduced by the improvement of recording density.
As a result, it is becoming difficult to obtain sufficient signal strength. Therefore, there is a demand for a material exhibiting a magnetoresistive effect with higher sensitivity, and the need for a system exhibiting a large magnetoresistive change rate as described above is increasing.

Recently, a "magnetic microcontact" in which two needle-shaped nickel (Ni) are attached to each other or a magnetic microcontact in which two magnetites are brought into contact with each other has been disclosed as those exhibiting a magnetoresistive effect of 100% or more. (Non-Patent Document 1
And 2).

[0005]

[Non-Patent Document 1] N. Garcia, M. Munoz, and Y. -W. Zh
ao, Physical Review Letters, vol.82, p2923 (1999)

[Non-Patent Document 2] JJ Versluijs, MA Bari and J.
MD Coey, Physical Review Letters, vol.87, p26
601 -1 (2001)

Although these materials show a large rate of change in magnetic resistance, the method for producing the magnetic microcontacts is such that two needle-shaped or triangular-shaped ferromagnetic bodies are angled together. More recently, a magnetic microcontact has been disclosed in which two thin Ni wires are arranged in a T-shape and a microcolumn is grown at a contact portion by using an electrodeposition method (see Non-Patent Documents 3 and 4).

[0007]

[Non-Patent Document 3] N. Garcia et al., Appl. Phys. Lett., Vol. 8
0, p1785 (2002)

[Non-Patent Document 4] HD Chopra and SZHua, Phys. Rev.
B, vol.66, p.20403-1 (2002)

These also show a very large rate of change in magnetic resistance, but this magnetic microcontact structure cannot be used as an element. On the other hand, a magnetic microcontact made by growing Ni clusters in alumina pinholes by electrodeposition has been disclosed (see Non-Patent Document 5).

[0009]

[Non-Patent Document 5] M. Munoz, GG Qian, N. Karar, H.
Cheng, IG Saveliev, N. Garcia, TP Moffat,
PJ Chen, L. Gan, and WF Egelhoff, Jr., Appl.
Phys. Lett., Vol.79, p.2946, (2001))

With this structure, it is difficult to control the magnetic domain and the contact structure, and therefore the resistance change rate of this contact is as small as 14% or less.

[0011]

Although the magnetic microcontact has a possibility of exhibiting a large magnetoresistance change rate, in order to obtain a magnetic microcontact having a large magnetoresistive effect, it is necessary to process the magnetic microcontact into two needles or the like. Corners of magnetic material, or 2
The structure was such that precise control of the contact portion during fabrication was difficult, because it was necessary to form minute columns by electrodeposition between the wires of the book. Considering applications to magnetic heads and solid-state magnetic memories, it is necessary to develop a microcontact structure that can be manufactured with good controllability and that can be mass-produced, and a manufacturing method thereof.

The change in magnetic resistance detects the difference in the magnetization direction between the magnetic electrodes on both sides of the micro junction. Therefore, the magnetic domain control of the magnetic electrodes on both sides determines its characteristics. Therefore, a structure that facilitates magnetic domain control of both magnetic electrodes is indispensable as a magnetoresistive effect element.

The present invention has been made on the basis of the recognition of such a problem, and an object thereof is to provide a magnetic microcontact structure which can be used as an element with a structure in which the magnetic domain of a magnetic electrode can be easily controlled. At the same time, another object of the present invention is to provide a magnetic minute contact structure whose contact structure can be easily controlled during manufacturing.
Another object is to provide a highly sensitive read head element using the same. Still another object is to provide a magnetic memory having a recording / reproducing function using the magnetoresistive effect element. Still another object is to provide a method for manufacturing such a magnetic microcontact.

[0014]

In order to achieve the above object, a first magnetoresistive effect element of the present invention comprises a first ferromagnetic layer and an insulating layer provided on the first ferromagnetic layer. Layers and
A second ferromagnetic layer provided on the insulating layer, the maximum width at which the first ferromagnetic layer and the second ferromagnetic layer are connected to a predetermined position of the insulating layer. Is provided with a hole having an opening of 20 nm or less.

According to the above structure, a magnetoresistive effect element having a magnetic minute contact capable of obtaining a large magnetoresistive change can be reliably and easily realized, and since the ferromagnetic electrode has a thin film structure, the magnetic domain control of the magnetic electrode is easy. Therefore, it can be applied to various devices.

The second magnetic resistance element of the present invention is
A first ferromagnetic layer, an insulating layer provided on the first ferromagnetic layer, and a second ferromagnetic layer provided on the insulating layer. At the position of the first
A hole having an opening with a maximum width of 20 nm or less for connecting the first ferromagnetic layer and the second ferromagnetic layer is provided, and the first ferromagnetic layer and the second ferromagnetic layer are passed through the hole. It is characterized in that the electric resistance changes depending on the relative magnetization arrangement of the first ferromagnetic layer and the second ferromagnetic layer with respect to the current applied to the layer.

With the above structure, it is possible to surely and easily realize a magnetoresistive effect element having a magnetic minute contact capable of obtaining a large magnetoresistive change. Further, since the ferromagnetic electrode has a thin film structure, the magnetic domain control of the magnetic electrode becomes easy. It can be applied to various devices.

Here, if the holes in the insulating layer are cone-shaped, the opening width on the side of the first ferromagnetic layer is smaller than the opening width on the side of the second ferromagnetic layer. By forming an opening using a needle, reliable and easy manufacturing is possible.

A plurality of holes may be provided.

The resistance between the first ferromagnetic layer and the second ferromagnetic layer is 5 Ω or more and 100 kΩ or less,
If it exhibits a magnetoresistance change rate of 20% or more, it can be applied to various applications as a magnetoresistance effect element.

Here, "resistance between the first ferromagnetic layer and the second ferromagnetic layer" means an average value.
That is, the maximum resistance value observed between the first ferromagnetic layer and the second ferromagnetic layer is Rmax and the minimum resistance value is Rmin.
Then, “the resistance between the first ferromagnetic layer and the second ferromagnetic layer” is the average value of these, that is, (Rmax + R
min) / 2 is defined.

In the present specification, the "rate of change in magnetoresistance" is defined as a value obtained by dividing the change in electric resistance of the magnetoresistive effect element by application of a magnetic field by the electric resistance in the state where a magnetic field is applied. However, when the magnetic field is insufficient and the magnetization is unsaturated, it is defined as the value divided by the smallest resistance value.

The insulating layer is made of polymer or
Aluminum (Al), titanium (Ti), tantalum (T
a), cobalt (Co), nickel (Ni), silicon (Si), zirconium (Zr), hafnium (Hf)
And an oxide, a nitride, or a fluoride containing at least one element selected from the group consisting of iron (Fe), and the first and second ferromagnetic layers are made of iron (Fe), cobalt (Co). ), Nickel (Ni), or iron (F
e), an alloy, oxide, nitride or Heusler alloy containing at least one element selected from the group consisting of cobalt (Co), nickel (Ni), manganese (Mn) and chromium (Cr), or iron ( If a compound semiconductor or oxide semiconductor containing at least one element of Fe), cobalt (Co), nickel (Ni), manganese (Mn), and chromium (Cr) is used, good characteristics can be easily obtained. To be

Further, at the connection portion of the hole between the first ferromagnetic layer and the second ferromagnetic layer, the element constituting the first ferromagnetic layer and the element constituting the second ferromagnetic layer also constitute the second ferromagnetic layer. It is also possible to add a different element different from the above element and the thickness of the region to which the different element is added is 10 atomic layers or less.

If a plurality of any one of the magnetoresistive effect elements described above are connected in series, a so-called tandem type serial structure can be obtained, and a larger magnetoresistive change than that of a single element can be obtained.

On the other hand, the magnetic reproducing element of the present invention comprises any of the magnetoresistive elements described above, and the first and second ferromagnetic layers are connected in series on the path of the magnetic flux emitted from the magnetic recording medium. It is characterized in that the difference between the magnetization directions of the first and second ferromagnetic layers sandwiching the hole can be detected as a change in magnetoresistance.

According to the above structure, a highly sensitive magnetic detection element can be realized reliably and easily.

Here, of the first and second ferromagnetic layers, the magnetization of a ferromagnetic layer provided relatively far from the magnetic recording medium is fixed in one direction. With the spin filter effect, magnetic detection with high signal strength becomes possible.

Further, if the signal magnetic field from the magnetic recording medium is detected by arranging the film surface of the first ferromagnetic layer substantially perpendicular to the magnetoresistive effect element, the signal from the medium is highly sensitive. It becomes possible to reproduce.

Furthermore, the holes may be provided at positions displaced from the center of the insulating layer in the direction of the recording medium.

According to the above structure, the magnetic minute contact can be provided in the highly sensitive area, and the highly sensitive magnetic detecting element can be easily realized.

On the other hand, the magnetic memory of the present invention comprises: a magnetoresistive element according to any one of the above, a nonmagnetic intermediate layer provided on the second ferromagnetic layer, and a nonmagnetic intermediate layer provided on the nonmagnetic intermediate layer. A third ferromagnetic layer provided, wherein the magnetization direction of the first ferromagnetic layer is fixed to the first direction, and the magnetization direction of the third ferromagnetic layer is the first direction. Is fixed in a second direction substantially anti-parallel to the direction, the direction of magnetization of the second ferromagnetic layer is variable, and the direction is substantially perpendicular to the film surfaces of the first to third ferromagnetic layers. At least one of writing and reading is performed by applying a current to the device.

According to the above structure, a magnetic memory using the magnetoresistive effect element can be realized.

On the other hand, in the magnetic memory of the present invention, any one of the magnetoresistive element described above, the non-magnetic intermediate layer provided on the second ferromagnetic layer, and the non-magnetic intermediate layer provided on the non-magnetic intermediate layer are provided. And a magnetization direction of the first and third ferromagnetic layers are fixed to the first direction, and a magnetization direction of the second ferromagnetic layer is fixed to the first direction. It is variable, and at least one of writing and reading is performed by causing a current to flow in a direction substantially perpendicular to the film surfaces of the first to third ferromagnetic layers.

With the above structure, a magnetic memory using a magnetoresistive effect element can be realized.

On the other hand, the magnetic memory of the present invention includes any one of the magnetoresistive effect elements described above, and the magnetization direction of either one of the first and second ferromagnetic layers is fixed to the first method. The direction of magnetization of the other of the first and second ferromagnetic layers is variable, and a current is caused to flow in a direction substantially perpendicular to the film surfaces of the first and second ferromagnetic layers. At least one of writing and reading is performed.

With the above structure, a magnetic memory using a magnetoresistive effect element having a simple structure can be realized.

Here, the first and second electrodes for passing the current are provided so as to cover all or part of the first and second ferromagnetic layers, and the first and second electrodes are provided. The opening may be provided in a range in which the electrodes of FIG.

On the other hand, the magnetic memory of the present invention is
A plurality of memory cells are separated from each other by an insulating region 2
A current is supplied to each of the plurality of memory cells by a conductor probe or a fixed wiring arranged in a dimension, and an absolute value of a current for writing to each of the plurality of memory cells is a sense current for reading. And each of the plurality of memory cells includes any of the magnetoresistive effect elements described above, and the magnetization direction of either one of the first and second ferromagnetic layers is fixed to the first method. The direction of magnetization of the other of the first and second ferromagnetic layers is variable, and a current is caused to flow in a direction substantially perpendicular to the film surfaces of the first and second ferromagnetic layers. At least one of the writing and reading is performed.

According to the above structure, it is possible to realize a magnetic memory using the magnetoresistive effect element and capable of recording a large capacity.

On the other hand, the method of manufacturing a magnetoresistive effect element according to the present invention comprises a step of forming an insulating layer on the first ferromagnetic layer,
A step of forming a hole reaching the first ferromagnetic layer by press-fitting a needle on the surface of the insulating layer; and depositing a ferromagnetic material on the hole and the insulating layer so as to fill the hole. And a step of forming a second ferromagnetic layer.

According to the above structure, the minute opening can be surely formed by press-fitting the needle, and the small opening can be surely and easily formed by embedding the minute opening.

Here, if the current flowing between the first ferromagnetic layer and the needle is monitored and the press-fitting of the needle is stopped when the current reaches a predetermined value, a minute opening is formed. The opening width can be controlled reliably and easily.

[0044]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic view illustrating a cross-sectional structure of a main part of a magnetoresistive effect element according to an embodiment of the present invention.

That is, the magnetoresistive element of the present invention is
An insulating layer 3 having a minute opening A is formed on the first ferromagnetic layer 1 formed directly or indirectly on the substrate S, and the second ferromagnetic layer is formed so as to fill the minute opening A. Two
Are formed.

As will be described in detail later, it is desirable that the minute opening A has a minimum opening width of 20 nm or less.
This "aperture width" is the diameter of the minute aperture A if it is circular, and in the case of a polygon it is the longest of the diagonal lines, or if it is an anisotropic shape such as a flat circle. Means the longest of the opening widths.

The insulating layer 3 has a conical or circular opening, a polygonal pyramid shape, a cylindrical shape, or a polygonal columnar shape toward the first ferromagnetic layer 1, and a part of the opening is a minute opening A. Is formed. As one of the preferred embodiments of the present invention, the minute opening A is provided in the vicinity of the first ferromagnetic layer.

That is, the magnetoresistive effect element of the present invention has the magnetic minute contact in which the first ferromagnetic layer 1 and the second ferromagnetic layer 2 are connected in the minute opening A.

Furthermore, the ferromagnetic layer 1 and the ferromagnetic layer 2
Are ferromagnetic layers 1 and 2 obtained when they also act as electrodes, or electrodes connected to them are separately provided and a current is passed between these electrodes.
The electrical resistance between the two is characterized by changing depending on the relative magnetization arrangement of the first ferromagnetic layer and the second ferromagnetic layer.

That is, when the opening width of the magnetic fine contact formed in the fine opening A becomes 20 nm or less, this opening becomes a generation portion of an ultrathin domain wall, and the relative distance between the ferromagnetic layer 1 and the ferromagnetic layer 2 is increased. It is possible to change the relative arrangement of the magnetization. As a result, the electric resistance between the first ferromagnetic layer and the second ferromagnetic layer 2 changes. In the case of the magnetoresistive effect element of the present invention, basically, there is a magnetic field region in which the electric resistance is reduced by the magnetic field even if the magnetic field application direction is changed. Therefore, the magnetoresistive effect generated here is It can be said that this is a magnetoresistive effect generated by the formed domain wall. Here, this domain wall acts as a transition region of two parts having different magnetization directions. Further, in the present invention, 20 is set according to the magnetization direction and the magnitude of the applied magnetic field.
% Or more large magnetoresistive effect occurs.

FIG. 2 is a schematic diagram for explaining the relationship between the applied magnetic field and the electric resistance in the magnetoresistive effect element of the present invention. That is, FIGS. 10A and 10C show that when the minute aperture A, that is, the aperture width of the magnetic minute contact is 20 nm or less, a magnetic field is applied in a direction parallel to the film surface of the ferromagnetic layer 1 or 2. It is a graph showing the change of the electrical resistance obtained by. Similarly, FIGS. 2B and 2D are obtained when the opening width of the minute opening A is 20 nm or less and a magnetic field is applied in a direction perpendicular to the film surface of the ferromagnetic layer 1 or 2. It is a graph showing the change of the electric resistance. As shown in FIG. 1, these figures show the simplest basic structure having no exchange bias layer, and the easy magnetization domain direction of the device is in the in-plane direction in this case.

As can be seen from these graphs, when the opening width of the minute aperture A is 20 nm or less, the electric resistance is reduced by the magnetic field even if the magnetic field application direction is changed, regardless of the magnetic field application direction. Areas basically exist. However, in some cases, when a magnetic field is applied in the direction of the hard magnetic domain, the change is small and the resistance decrease cannot be found.

On the other hand, the opening width of the magnetic microcontact is 2
When it becomes larger than 0 nm, the magnetoresistive effect due to the usual anisotropic magnetoresistive effect becomes remarkable.

FIG. 3 is a conceptual diagram for explaining the change in magnetoresistance due to the usual anisotropic magnetoresistance effect. In the anisotropic magnetoresistive effect, when the magnetic field is applied perpendicularly to the current, that is, when the magnetic field is applied parallel to the film surface of the ferromagnetic layer 1 or 2, the As shown in a), the electric resistance is slightly reduced by applying the magnetic field.

On the other hand, when a magnetic field is applied in the direction parallel to the current, that is, when a magnetic field is applied in the direction perpendicular to the film surface of the ferromagnetic layer 1 or 2, the magnetization is It does not saturate easily, and as shown in Fig. 3 (b),
Although the magnetic field gradient is small, the electric resistance increases with the application of the magnetic field. However, as can be seen from FIGS. 3A and 3B,
When exhibiting the usual anisotropic magnetoresistive effect, the magnetoresistive change rate is at most a few percent at most.

On the other hand, in the case of the magnetoresistive effect element of the present invention, as illustrated in FIGS. 2A to 2D, there is a magnetic field application direction in which the resistance changes greatly with respect to the magnetic field. Moreover, it has a characteristic that the rate of change in magnetic resistance is extremely large. Hereinafter, the reason why the magnetoresistive effect element of the present invention exhibits a large magnetoresistive change rate as compared with the conventional magnetoresistive effect element will be described.

FIG. 4 is a conceptual diagram showing a comparison between the magnetoresistive effect element of the present invention and a conventional magnetoresistive effect element.

Here, in each of FIGS. 7A to 7F, a schematic diagram of the element including the magnetization direction is shown on the upper side, and a corresponding potential diagram is shown on the lower side. 7A and 7B show the case of the CPP type magnetoresistive effect element, and FIGS. 7C and 7D show the case of the magnetoresistive effect element of the present invention having minute contacts. ) And (f)
In the case of the magnetoresistive effect element having no minute contact, the case of parallel magnetization arrangement and the case of antiparallel magnetization arrangement are shown.

In the following, in these schematic diagrams, the case where the flow of electrons flows from the ferromagnetic layer 1 to the ferromagnetic layer 2 will be described.

In the case of the CPP-MR of FIGS. 4A and 4B, the intermediate layer 40 provided between the ferromagnetic layers 1 and 2 is
It is a layer made of a non-magnetic material such as copper (Cu). That is, the CPP type MR element is formed of, for example, cobalt (Co).
It has a laminated structure of / copper (Cu) / cobalt (Co). In the case of such a CPP type MR element, FIG.
When the magnetizations M of the ferromagnetic layers 1 and 2 are parallel to each other, as shown in (1), up-spin electrons flow from the ferromagnetic layer 1 to the ferromagnetic layer 2 via the intermediate layer 40. On the other hand, as shown in FIG. 4B, when the magnetizations M of the ferromagnetic layers 1 and 2 are antiparallel,
The up-spin electrons that have survived without being scattered when passing through the intermediate layer 40 from the ferromagnetic layer 1 travel toward the ferromagnetic layer 2 and are scattered by the ferromagnetic layer 2.

On the other hand, in the case of the MR element of the present invention, as shown in FIG. 6C, when the magnetization M is parallel, the up-spin electrons and the down-spin electrons are directly transferred from the ferromagnetic layer 1 to the ferromagnetic layer 2. Flow into. On the other hand, as shown in FIG. 4D, when the magnetization M is antiparallel, an extremely thin domain wall is formed at the minute contact point, and the direction of the magnetization M changes sharply (in FIG. 4D, Since the thickness of this domain wall is, for example, about the same as the thickness of the drawing line, the up-spin electrons are scattered by the ferromagnetic layer 2 and the down-spin electrons are also scattered in the ferromagnetic layer 2.
Is scattered at. As described above, in the case of the MR element of the present invention, electrons of both spins are scattered, so that a larger magnetoresistive effect can be obtained as compared with the CPP-MR element illustrated in (a) and (b). As will be described later in detail, the present inventor has found that a large magnetoresistive effect can be obtained even when a different element is added to the opening connection portion. In this case, since the thickness of the layer composed of the different element is extremely thin, the existence of the different element layer can be ignored and the approximation can be performed.

On the other hand, if the minute contact has a large size exceeding 20 nm, as shown in FIG. 4 (f), when the magnetization M is antiparallel, the domain wall between them is extremely small. Becomes thicker, and it becomes difficult for the electrons passing here to keep spin information. As a result, it becomes difficult to obtain the magnetoresistive effect due to the change in the direction of the magnetization M.

The reason why the magnetoresistive effect element of the present invention exhibits an extremely large magnetoresistance change rate has been described above.

In the present invention, since the element structure has a laminated structure so that the magnetization M of the ferromagnetic layers 1 and 2 can be easily controlled, the magnetization state shown in FIG. Can be realized. In the case of the magnetoresistive effect element of the present invention, the electric resistance is reduced by applying a magnetic field, but in the case where hysteresis is present, the maximum resistance may be shifted from the zero magnetic field as illustrated in FIG. is there. Alternatively, the resistance may drop near the zero magnetic field as shown in FIG. However, in any case, when the resistance exceeds the maximum value when a magnetic field is applied, the electric resistance decreases until the magnetizations of the elements are all aligned in parallel due to a further increase in the magnetic field.

Now, returning to FIG. 1 and continuing the description, in the magnetoresistive effect element of the present invention, the ferromagnetic layer 1 and the magnetic layer 2 sandwiching the minute contact are film-shaped so that the magnetic domain control is easy. It has a plane. By doing so, the magnetization distribution state can be made uniform, so that the domain wall width between the other ferromagnetic layer connected at the minute contact can be kept steep, and a large magnetoresistance change rate can be obtained. can get.

However, the ferromagnetic layer 1 and the insulating layer 3 do not necessarily have to be strictly flat layers, and have some uneven or curved surface as illustrated in FIG. 1B, for example. May be. Furthermore, in the present invention, FIG.
As illustrated in (a) to (d), a plurality of minute contacts may be provided. Although the MR value is reduced by using a plurality of minute contact points, it is possible to reduce the “variation” of the MR value for each element as compared with the case where a single minute contact point is provided, and to reproduce stable MR characteristics. It will be easy.

Here, as the opening shape of the minute contact, in addition to the "mortar shape" as illustrated in FIGS. 5 (a) and 5 (b), it is flat as illustrated in FIG. 6 (a). It may be composed of a convex curved surface formed on the ferromagnetic layer 1. Further, it may have a vertical wall surface as illustrated in FIG. 6 (b). Alternatively, as illustrated in FIG. 6C, on either side of the ferromagnetic layers 1 and 2,
It may be formed of a convex curved surface.

As the insulating layer 3 surrounding the magnetic micro contacts, polymer or aluminum (Al), titanium (Ti), tantalum (Ta), cobalt (Co), nickel (Ni), silicon (Si), iron (Fe) is used. It is preferable to use an oxide, a nitride or a fluoride containing at least one element of zirconium, zirconium (Zr) and hafnium (Hf), or a compound semiconductor such as aluminum arsenide (AlAs) which substantially acts as an insulator. it can.

As the ferromagnetic layer 1 and the ferromagnetic layer 2,
Is iron (Fe), cobalt (Co), nickel (Ni)
Such as, or iron (Fe), cobalt (Co),
Nickel (Ni), manganese (Mn), chromium (Cr)
Alloy containing at least one element of
-NiFe alloy called "malloy" or Co
NbZr alloy, FeTaC alloy, CoTaZr alloy
Gold, FeAlSi type alloy, FeB type alloy, CoFeB type
Soft magnetic materials such as alloys, Heusler alloys and CrO _Two, F
e_ThreeO_Four, La_1-XSr_XMnO_ThreeHalf meta such as
A magnetic material can be used. Furthermore, (Ga, C
r) N, (Ga, Mn) N, MnAs, CrAs, (G
a, Cr) As, ZnO: Fe, (Mg, Fe), etc.
Of iron (Fe), cobalt (Co), nickel (N
i), at least manganese (Mn) and chromium (Cr)
Any magnetic element and compound semiconductor or oxide semiconductor
The body can be used. That is, these materials
Choose the one with the magnetic characteristics suitable for the application.
You can use it.

Further, the ferromagnetic layer 1 or the ferromagnetic layer 2 is
Each may be a single film or a multi-layer film structure composed of a combination of a plurality of ferromagnetic layers. For example, when it is desired to detect an external magnetic field with good reactivity, a two-layer film made of CoFe / Permalloy may be used for the soft layer. That is, a combination may be appropriately selected and used according to the application.

The materials of the ferromagnetic layers 1 and 2 are
The same one may be used or different ones may be used.

Further, next to the ferromagnetic layer 1 or 2, an antiferromagnetic layer or a multi-layered film of nonmagnetic layer / ferromagnetic layer / antiferromagnetic layer is further provided, whereby the ferromagnetic layer 1
Alternatively, the magnetization direction of 2 can be fixed, and the response characteristic of the magnetoresistive effect element to the magnetic field can be controlled. As antiferromagnetic materials therefor, FeMn, P
tMn, PdMn, PdPtMn, etc. are useful.

In order to control the element resistance to obtain a desired value, it is also effective to make a small amount of a different element having the properties of a conductor, a semiconductor, or an insulator exist near the opening of the minute contact. .

FIGS. 7A and 7B are schematic views showing such a magnetoresistive effect element. That is, in these specific examples, the region D to which the different element is added is provided near the opening end of the minute opening A. In this case, the magnetoresistance change rate may be slightly sacrificed, but it can be adjusted to a value required by the system in which the magnetoresistance effect element is used. The region D to which the different element is added can be formed in a layered form, and in this case, the thickness of the region D in the minute opening A is preferably in the range of 0 atomic layer to 10 atomic layers or less on average.

These different elements have the effect of breaking the exchange coupling between the ferromagnetic layers 1 and 2, and also have the effect of facilitating the control of the magnetic domain. Furthermore, by adding different elements, the effective opening diameter can be reduced to facilitate the control of magnetic domains, and to increase the efficiency of the magnetoresistive effect of the minute contacts.

As such a different element, copper (C
u), gold (Au), silver (Ag), and other noble metals such as Ni—O, Fe—O and Co—
O, Co-Fe-O, Ni-Fe-O, Ni-Fe-C
O-O, Al-O, Cu-O, and other oxides, and complex compounds containing these oxides, such as Al-Cu-O, or so-called surfactants for growth of magnetic layers such as antimony (Sb) and tin (Sn). An element that acts as can be used.

The magnetoresistive effect element of the present invention is characterized in that it is easier to manufacture and can be surely made into a device, as compared with the magnetoresistive effect element using the minute contact which has been conventionally proposed. Hereinafter, a method for manufacturing the magnetoresistive effect element of the present invention will be described.

FIG. 8 is a process sectional view showing an essential part of the method for manufacturing a magnetoresistive effect element according to the present invention.

First, as shown in FIG. 10A, the ferromagnetic layer 1 is formed directly on a substrate (not shown) or via a single layer or a plurality of layers such as a buffer layer (not shown). Then, the insulating layer 3 is formed thereon. The insulating layer 3 may be formed by depositing or depositing a different material on the ferromagnetic layer 1, or by oxidizing the surface layer of the ferromagnetic layer 1.
It may be formed by modifying by a method such as nitriding or fluorination.

Next, as shown in FIG. 8B or 8C, the needle 1 having a spherical shape, a conical shape, or a polygonal pyramid shape whose tip has a radius of curvature of 5 nm to 1000 nm is conductive.
10 is brought into contact with each other and pressure is applied to the insulating layer 3
A minute opening A is formed in the. At this time, a predetermined voltage is applied to the conducting wire 120 provided between the needle 110 and the magnetic layer,
The needle 110 is press-fitted until the current flowing through the lead wire 120 reaches a predetermined value. That is, the opening width of the minute opening A is controlled by monitoring the current flowing between the needle 110 and the ferromagnetic layer 1 by penetrating the insulating layer 3. In this way, when the flowing current reaches a predetermined value, the needle 11
Move 0 in the opposite direction to remove it from the surface of the insulating layer 3.

The needle 110 is driven by the distance changing function section 130A (130B) as shown in FIGS. 8B and 8C. The distance changing function unit 130 has a function of moving the needle 110 in a direction perpendicular to the sample surface. As a method of movement for that purpose, for example, there is a method of bending the arm as shown in FIG. 8B or a method of moving the arm in the vertical direction as shown in FIG. 8C.

In the case of the bending method illustrated in FIG. 8 (b), the needle 110 is attached to the arm 140 provided in parallel with the sample surface,
By expanding and contracting the distance changing function part 130A provided on the upper part or the lower part of the arm 140,
The height of the needle 110 can be changed by bending 0. As the distance changing function part 130A, a film or the like that causes thermal expansion due to a temperature change caused by energization heating can be used. In the case of such electric heating,
An insulator is required between the distance changing function unit 130 and the arm 140 as appropriate.

In the case of the vertical movement system illustrated in FIG. 8C, a distance changing function section 130B such as a piezo element is provided above the needle 110, and the position of the needle 110 can be changed by the voltage applied thereto. .

As another case, it is possible to use a piezo element as the distance changing function section 130A of FIG. 8 (b). In that case, voltage is applied to the piezo element and the arm 1
Control the curvature of 40.

The hole formed by using the mechanism capable of controlling these minute distances basically has a predetermined minimum diameter, and has a spherical shape, a conical shape, or a polygonal pyramid shape which is the tip shape of the needle 110. It has a shape corresponding to.

By such a method, the minute opening A for finally obtaining the desired conductance is formed at the tip of the opening having a conical shape, a circular shape, or a polygonal cone shape depending on the shape of the tip of the needle 110. .

As the next step, as shown in FIG. 8D, the ferromagnetic layer 2 is deposited toward this hole. As a result, the ferromagnetic layer 1 and the ferromagnetic layer 2 have the desired minute opening A.
At, it will be connected with a small conductance.
Thereafter, heat treatment may be performed if necessary. In using the magnetoresistive effect element thus formed,
An electrode is provided on each ferromagnetic layer so that electricity can be supplied.

By the method described above, a magnetic microcontact excellent in reproducibility and controllability is formed between the ferromagnetic layers 1 and 2. A typical value of the voltage applied when the needle 110 is press-fitted is 0.01 V to 10 V, the predetermined current range is 0.05 μA to 100 mA, and a conical shape, a circular shape, or a polygonal pyramid shape of an insulator is used. The minimum opening width of the formed hole is 0.1 nm to 50 nm. In particular, the opening width of the minute opening is preferably 0.1 nm to 20 nm.

The material of the needle 110 used here is preferably harder than the insulating layer 3 and conductive.
For example, conductive diamond, superhard metal, silicon (Si), silicon coated with conductive diamond, or the like can be used.

Further, it is preferable that the thickness of the insulating layer 3 before forming the magnetic minute contact is thin within a range in which the function as the insulating layer 3 is maintained. Specifically, 0.5 nm to 50 n
The range is m. Further, the thicknesses of the ferromagnetic layers 1 and 2 can be appropriately determined according to the application. In particular, the ferromagnetic layer 1 may be of a sufficiently thick bulk shape without any problem.

Further, according to the present invention, as shown in FIG. 9, a structure in which a plurality of magnetoresistive effect elements are arranged on a common substrate (not shown) can be easily formed. Such a structure can be applied to, for example, a patterned medium described in detail later.

Since the magnetoresistive effect element of the present invention has a structure that can be easily made into a device, it can be applied to various uses.

First, it can be used as a reproducing element in a magnetic recording system. By using the magnetoresistive effect element of the present invention, a magnetoresistive change rate of 20% or more can be generated, so that a large reproducing sensitivity can be obtained.

FIG. 10 is a schematic diagram showing a specific example in which the magnetoresistive effect element of the present invention is used as a magnetic reproducing element.

In the case of the specific example illustrated in FIG. 10A, the ferromagnetic layer 2, the insulating layer 3 and the ferromagnetic layer of the magnetoresistive effect element are provided on the path through which the magnetic flux emitted from the surface of the magnetic recording medium 200 passes. Layer 1 is placed in series. By doing so, the difference in the magnetization directions of the ferromagnetic layers 1 and 2 facing each other with the magnetic microcontact formed in the microaperture A interposed therebetween can be detected as a change in magnetic resistance. In this case, as illustrated in FIG.
The magnetization directions M of the two ferromagnetic layers 1 and 2 may be controlled by magnetic domains as necessary.

In the case of the specific example illustrated in FIG. 10B, the ferromagnetic layer 2 of the magnetoresistive effect element is perpendicular to the surface of the magnetic recording medium 200 within an error angle of about ± 20 degrees. , The insulating layer 3 and the ferromagnetic layer 1 are arranged in series. Even in this case, the difference in the magnetization directions of the ferromagnetic layers 1 and 2 facing each other with the magnetic minute contact formed in the minute opening A interposed therebetween can be detected as a change in magnetic resistance.

In this case, it is desirable that the magnetization M of the ferromagnetic layer 1 provided at a position far from the recording medium 200 be fixed in the direction perpendicular to the surface of the recording medium 200 within a range of plus or minus 20 degrees. As a method of fixing the magnetization,
Examples thereof include a method of introducing strong shape magnetic anisotropy and a method of introducing unidirectional anisotropy by providing an antiferromagnetic layer (not shown) adjacently.

Then, the ferromagnetic layer 2 close to the recording medium 200
The direction of the magnetization M can be switched by the magnetic flux from the medium 200. In this way, the signal from the recording medium 200 can be detected from the angle formed by the ferromagnetic layer 1, the ferromagnetic layer 2, and the magnetization M.

When the magnetoresistive effect element of the present invention is used, high sensitivity can be obtained and the medium facing surface side facing the recording medium 200 can be easily formed and processed. This is because the distance from the medium 200 to the magnetic minute contact A can be basically determined by the layer thickness of the ferromagnetic layer 2. If the medium facing surface facing the recording medium 200 is easy to process, the ferromagnetic layer 1 may be arranged on the side closer to the recording medium 200 as illustrated in FIG. .

FIG. 11 is a schematic diagram showing another specific example in which the magnetoresistive effect element of the present invention is used as a magnetic reproducing element. In the case of the specific example shown in the figure, the film surface of the magnetoresistive effect element is arranged perpendicular to the medium 200. here,
The minute opening A is shifted downward (direction toward the medium 200) when viewed from the center (center of gravity) of the magnetoresistive effect element. Since the signal magnetic field from the medium 200 increases as the distance from the medium decreases, this structure has a great advantage that the magnetic field detection efficiency of the free layer 2 can be increased.

The ferromagnetic layer 2 functioning as a magnetization sensing layer (free layer) may be a single layer as illustrated in FIG. 11A, or may be two layers as illustrated in FIG. 11B. Good. In the case of the specific example of FIG. 11A, the ferromagnetic layer 1 forms a “pin layer” whose magnetization direction is fixed. The ferromagnetic layer (pin layer) 1 may have a laminated structure such as a magnetic layer / antiferromagnetic layer or a magnetic layer / nonmagnetic layer / magnetic layer / antiferromagnetic layer in this order from the minute opening A. it can.

In the case of the specific example of FIG. 11B, the ferromagnetic layer (pin layer) 1 is composed of ferromagnetic layer / antiferromagnetic layer / ferromagnetic layer, or ferromagnetic layer / nonmagnetic layer / ferromagnetic layer. A layered structure of layers / antiferromagnetic layer / ferromagnetic layer / nonmagnetic layer / ferromagnetic layer can be used. As shown in FIG. 11B, free layers 2A and 2B are provided on both sides of the pinned layer with an opening A sandwiched therebetween, and each of these senses a signal from the recording medium thereunder. At that time, as shown in FIG. 11C, when both the free layers 2A and 2B are upward signals, the magnetization is directed in the same direction as that of the pinned layer, so that the resistance change ΔR becomes 0,
When both the free layers 2A and 2B are downward signals, spin scattering occurs on both sides, and ΔR becomes 2.
When the signal directions of A and 2B are down / up or up / down, respectively, only one side is spin-scattered, and therefore ΔR becomes 1, and the distinction is made from the history of ΔR.

By providing a plurality of free layers in this way, it is possible to generate multivalued resistance changes. Since the nanohole MR can generate a resistance change of 100% or more, it is possible to reproduce a multi-valued signal by combining them.

The magnetoresistive effect element of the present invention can be applied to a so-called "patterned medium". That is, it is possible to easily form a structure in which a plurality of magnetoresistive effect elements are arranged as illustrated in FIG. As a concrete application example of this, a magnetic memory or a medium for probe storage can be cited.

FIG. 12 is a schematic view illustrating the cross-sectional structure of the main part of a magnetic memory using the magnetoresistive effect element of the present invention.

As shown in the figure, the magnetic memory of the present invention has a structure in which a plurality of magnetoresistive elements 10 are arranged in parallel on the electrode layer 20. Each magnetoresistive effect element 1
0 is electrically isolated by the insulator 30 and has a role as a recording / reproducing cell.

To access each of these recording / reproducing cells 10, for example, as shown in FIG. 13 (a), a conductive probe PR as an upper electrode may be used, or FIG. 13 (b). Fixed wiring W as shown in
R may be used. Here, in the case of the fixed wiring WR, the cell 10 is used in contact with it, but in the case of the conductive probe PR, either contact or non-contact with the cell 10 may be used. In the case of non-contact, probing is possible via the tunnel current flowing between the cell 10 and the cell 10.

14 and 15 are schematic views showing the cross-sectional structure of the magnetoresistive effect element 10 used in the magnetic memory of FIG. 14 (a) to (d) and FIG. 15 (a) to
Each of the magnetoresistive effect elements in (h) has a structure in which a magnetic layer is laminated on the second ferromagnetic layer 2 with a nonmagnetic layer 4 interposed therebetween. The electrodes 7 are connected to the top and bottom of this laminated structure. Each of these magnetoresistive elements has both recording and reproducing functions. That is, recording can be performed by applying a current of a predetermined magnitude to these magnetoresistive effect elements in a predetermined direction.
The signal of the cell can be read from the resistance value measured by passing a current weaker than this.

The cell shown in FIG. 14A has a structure in which the nonmagnetic intermediate layer 4 and the ferromagnetic layer 5 are laminated on the second ferromagnetic layer 2. Further, here, the magnetizations M of the first ferromagnetic layer 1 and the ferromagnetic layer 5 are fixed so that their magnetization directions are antiparallel to each other. When the magnetization directions are antiparallel, writing with a smaller current becomes possible, as will be described later in detail.

With respect to such a laminated structure, when a current is passed in the direction perpendicular to the film surface, recording and reproduction can be performed using the second ferromagnetic layer 2 as a recording section. That is, the current is the first
When passing through the ferromagnetic layer 1 or the ferromagnetic layer 5, the conduction electrons receive spin information according to the magnetization direction of these magnetic layers. Then, when these electrons flow into the second ferromagnetic layer 2, when the spin directions of the electrons and the spin direction corresponding to the magnetization direction of the second ferromagnetic layer 2 are the same, , The electrons easily pass through, but when they are antiparallel, the electrons are reflected and become difficult to pass through the second ferromagnetic layer 2.

At this time, the conductance between the ferromagnetic layers 1 and 2 is small and the change in magnetoresistance is large, while
The conductance between the ferromagnetic layers 2 and 5 is large, and the change in magnetoresistance is small. Therefore, in the case of FIG. 14A in which these are connected in series, the conductance between the former ferromagnetic layer 1 and ferromagnetic layer 2 becomes dominant, and the magnetization directions of the ferromagnetic layers 1 and 2 become dominant. Differences will be detected. That is, an increase or decrease in electric resistance is observed according to the magnetization direction of the second ferromagnetic layer 2, and information according to the magnetization direction can be read.

On the other hand, in recording, when a predetermined amount of current is passed in the direction perpendicular to the film surface, the conduction electrons first flow into the first ferromagnetic layer 1 and the ferromagnetic layer 5. The spin information of the magnetization M included in the magnetic layer is received. After that, the electrons flow into the second ferromagnetic layer 2. At this time, if a large amount of electrons flow into the second ferromagnetic layer 2,
The direction of the magnetization of the ferromagnetic layer 2 changes according to the spin information of these electrons. That is, the direction of the magnetization M of the layer in which the electron first flows in between the first ferromagnetic layer 1 and the ferromagnetic layer 5 is in the direction of being transferred to the second ferromagnetic layer (recording layer) 2.

The electrons that have passed through the ferromagnetic layer 2 are 1 and 5
Among them, the spin information of the layer which flows in later is received in the form of a reaction, and is directed in the opposite direction. Therefore, the magnetization direction can be controlled by the direction of the current.

FIGS. 14A to 14D show the case where the in-plane magnetization, that is, the direction of the magnetization is parallel to the film surface. FIGS. 15A, 15C, and 15J show the same. Similar effects can be obtained in the case of perpendicular magnetization as shown. Further, the cross-sectional shape of the minute opening may be narrowed downward as shown in FIGS. 14A to 14D, or FIG.
As shown in (b) to (l), it may be narrowed upward. Alternatively, it is possible to give various shapes as shown in FIGS.

In the magnetoresistive effect element shown in FIGS. 14 and 15, the direction of the magnetization M of the second ferromagnetic layer (recording layer) 2 depends on the direction of current flow when a current of a certain critical level or more flows. Change. A signal is recorded according to the magnetization direction of the ferromagnetic layer (recording layer) 2. Further, the reading can read the signal from the resistance value when a current equal to or lower than the critical current for writing is passed.

For this purpose, the ferromagnetic layers 1 and 5 are provided above and below the second ferromagnetic layer 2 having a role as a recording layer,
It is necessary to fix these magnetizations M in the antiparallel direction to each other.

14 (b)-(d) and 15 (d)-
(H) exemplifies the structure which gives this magnetization fixation.

In the case of the cell shown in FIG. 14B, the non-magnetic intermediate layer 4A, the ferromagnetic layer 5A, and the second ferromagnetic layer 2 are formed on the second ferromagnetic layer 2.
The non-magnetic intermediate layer 4B, the ferromagnetic layer 5B, and the antiferromagnetic layer 6A are laminated in this order. Further, an antiferromagnetic layer 6B is provided below the first ferromagnetic layer 1. In this way, the magnetizations M of the first ferromagnetic layer 1 and the ferromagnetic layer 5 can be fixed respectively. Here, the minute opening may be opened in the opposite direction as shown in FIG. 15D, for example. Also, there is no upper or lower default common to all of FIGS. 14 and 15. Furthermore, the magnetization is not limited to the in-plane magnetization, and
The perpendicular magnetization (perpendicular magnetization) as illustrated in (f) may be used.

In the case of the cell shown in FIG. 14C, the nonmagnetic intermediate layer 4A, the ferromagnetic layer 5A and the antiferromagnetic layer 6A are laminated in this order on the second ferromagnetic layer 2. There is.
A non-magnetic intermediate layer 4 is provided below the first ferromagnetic layer 1.
B, a ferromagnetic layer 5B, and an antiferromagnetic layer 6B are provided in this order. Even in this case, the magnetizations M of the first ferromagnetic layer 1 and the ferromagnetic layer 5 can be fixed.

Further, in the case of the cell shown in FIG. 14D, the non-magnetic intermediate layer 4A, the ferromagnetic layer 5A, the non-magnetic intermediate layer 4B, the ferromagnetic layer 5B, on the second ferromagnetic layer 2, The antiferromagnetic layer 6A is laminated in this order. Further, below the first ferromagnetic layer 1, a nonmagnetic intermediate layer 4C, a ferromagnetic layer 5C, and an antiferromagnetic layer 6B are provided in this order. Even in this case, the magnetizations M of the first ferromagnetic layer 1 and the ferromagnetic layer 5 can be fixed.

14 (a) to 14 (d) and 15 (a) to
In the case of the magnetoresistive effect element illustrated in (d), the ferromagnetic layer 1
The directions of magnetization of and 5 are antiparallel. By making them antiparallel, spin transfer and reaction effects are added, and writing to the recording layer 2 is efficiently performed.

On the other hand, considering the ease of making, FIG.
As illustrated in (f) to (h), it is preferable that the magnetizations of the ferromagnetic layers 1 and 5 are parallel. The magnitudes of the spin transfer effect and the reaction effect differ depending on the area in contact with the recording layer 2. So at the expense of one,
The magnetizations of the ferromagnetic layers 1 and 5 can be arranged in parallel at the expense of a slightly higher reversal current. By doing so, it is possible to reduce the number of layers for fixing or reduce the number of manufacturing steps.

FIG. 16 is a schematic cross-sectional view showing another specific example of the magnetoresistive effect element which can be used in the magnetic memory illustrated in FIG. That is, FIG.
In the case of the specific example shown in (e), the magnetization direction of either the first ferromagnetic layer 1 or the second ferromagnetic layer 2 is fixed to a predetermined direction, and the other magnetization direction is variable. And the first
And a pair of electrodes 7 are provided outside the second ferromagnetic layer (on the side opposite to the intermediate layer 3), and a current is supplied to these electrodes 7 from a current supply means (not shown) in a contact or non-contact manner. By doing so, recording / reproducing is performed by passing an electric current so that the electric current passes through the interface of each laminated film.

In order to fix the magnetization of the ferromagnetic layer, an antiferromagnetic layer may be provided outside the magnetic layer or nonmagnetic layer / ferromagnetic layer / antiferromagnetic layer may be laminated.

The reproduction is detected by utilizing the magnetoresistive effect of the element itself, and the recording is caused to flow a current larger than that of the reproduction, so that the spin transfer and the reaction effect are generated between the ferromagnetic layers 1 and 2 as described above. You can do it by doing between. The structure of FIG. 16 is slightly difficult to adjust the device characteristics, but has the advantage of being extremely simple in structure. Also in the case of the magnetoresistive effect element illustrated in FIG. 16, the cross-sectional shape of the minute opening is not limited to the conical shape as illustrated, and may be a cylinder, a polygonal pyramid, a polygonal prism, a curved surface or the like as described above. .

It is desirable that the position of the minute opening is between the two electrodes 7, 7 provided for flowing a current through the magnetoresistive effect element. Therefore, when the electrode 7 is provided off-center, that is, at a position deviated from the center of the element as illustrated in FIG. 16 (e), it is desirable that the minute aperture be correspondingly off-center.

[0128]

Embodiments of the present invention will be described in more detail below with reference to embodiments.

(First Embodiment) First, as a first embodiment of the present invention, nickel (Ni) covered with alumina is used.
An example of making a magnetoresistive element with a magnetic microcontact formed on it will be introduced.

First, in order to obtain the laminated structure shown in FIG. 8A, aluminum (Al) is vapor-deposited on the ferromagnetic layer 1 made of nickel, and the surface thereof is oxidized to form the insulating layer alumina. Formed.

Next, as shown in FIG. 8B, a needle 110 for forming a minute opening coated with conductive diamond was brought close to the surface. Then, a voltage of 0.1 V was applied between the nickel layer 1 and the needle 110, and the needle 110 was pressed into the alumina 3 while monitoring the flowing current. The movement of the needle 110 was controlled by utilizing the thermal expansion of the distance changing function unit 130A attached to the upper portion of the arm 140 due to electric heating.

FIG. 17 shows (a) the distance between the surface of the ferromagnetic layer 1 and the tip of the needle 110 and (b) the current flowing between them when the needle 110 is press-fitted at a constant speed. It is a graph showing time change.

Here, the distance is linearly changed with time, but the flowing current increases exponentially. The set current was set to 10 μA, and when the current reached this value, the bending of the arm 140 mounting the needle 110 was restored. Further, nickel was vapor-deposited as the ferromagnetic layer 2 so as to fill the formed hole.

Electrodes were respectively provided on the two ferromagnetic layers 1 and 2 of the magnetoresistive effect element thus formed, and the magnetoresistive effect was measured.

FIG. 18 is a graph showing the relationship between the applied magnetic field and the electric resistance in the magnetoresistive effect element of this example. Although some hysteresis was observed, the resistance decreased in general when the magnetic field was applied. The resistance of the contact portion in the minute opening A was about 3 kΩ when the magnetic field was zero, and a large MR ratio of 120% was obtained.

(Second Embodiment) Next, as a second embodiment of the present invention, a reproducing element for magnetic recording was manufactured by applying the manufacturing method used in the first embodiment described above.

That is, first, cobalt (C
A thick film of o) was formed and alumina was formed thereon. Then, after forming the minute openings A, permalloy having a thickness of 20 nm was deposited. Approximately 2 permalloys above the small aperture A
A 0 nm square pattern was processed, and the cobalt layer thereunder was cut out to 100 nm. When a conductor was provided on this and this magnetoresistive effect element was moved on the surface of the perpendicular magnetization medium, a resistance change corresponding to the medium signal change was observed.

(Third Embodiment) Next, as a third embodiment of the present invention, the magnetic memory illustrated in FIG. 12 was prepared.

That is, FIG. 14D is formed on the conductive substrate.
The laminated structure film shown in was prepared using a sputtering apparatus.
In the process, the minute openings A were also formed.

That is, the antiferromagnetic layer 6 is formed on the electrode layer 20.
B to the first ferromagnetic layer 1 were laminated and formed thereon, as the insulating layer 3, a polymer was applied to form the minute openings A.
Then, the second ferromagnetic layer 2 was deposited thereon.

Further, as shown in FIG. 14D, the nonmagnetic intermediate layer 4A to the antiferromagnetic layer 6A were formed. And
A microfabrication mask was formed by applying a polymer having a phase-separated structure on this, and the patterned medium was prepared by etching the surface by ion milling. Polymer was filled between the cell patterns to flatten the surface.

A recording / reproducing test was conducted by passing a current through one cell of the patterned medium thus manufactured using a probe as an electrode. First, plus 50
Writing was performed by passing a recording current of 0 μA. Here, the plus direction corresponds to the direction in which the current flows from top to bottom in FIG. And 10 μA
The resistance of the cell was measured with the current of. The resistance value at this time is 3
It was kΩ. Further, writing was performed by passing a recording current of −500 μA, and the resistance of the cell was measured at the same current of 10 μA. As a result, the resistance value was 7 kΩ.

That is, although some hysteresis was observed, it was confirmed from this result that current drive writing and current drive reading were possible. (Fourth Embodiment) Next, as a fourth embodiment of the present invention,
A magnetoresistive effect element in which a different element is added to the opening will be described. Here, according to the structure shown in FIG. 19, the magnetoresistive effect element in which the different element is added to the contact portion, the element in which the different element is added to the contact portion as shown in FIG. 7A, and the different element is not added. An element composed of magnetic microcontacts was produced and compared with an element having a conventional CCP-MR structure.

For each of the films, an ion beam sputter film forming apparatus was used for deposition, and reactive etching by an electron beam (details will be described with respect to an eleventh embodiment described later) was used except for sample II described below. It was made. Further, the opening diameter of the insulating layer 3 was set to 10 nm as a set target value.
The structure of each sample is as follows.

Sample I has the structure shown in FIG. 19 (a), and here, as a different element, a triatomic layer of copper (Cu) is used.
Inserted. The lower structure including the ferromagnetic layer 1 is PtMn1.
5nm / CoFe4nm / Ru1nm / CoFe4nm
The ferromagnetic layer 1 was used as a pinned layer having a laminated structure of (ferromagnetic layer 1). SiO ₂ is used as the material of the insulating layer 3,
Openings were formed after deposition to a thickness of 3 nm.

When a Cu layer is inserted as a different element, the exchange coupling between the upper and lower ferromagnetic layers 1 and 2 is promoted while maintaining the crystallinity of the contact portion, and the magnetizations of these upper and lower layers 1 and 2 are independent. That is, in this case, the magnetization of the upper ferromagnetic layer 2 can move more freely. In general, even when a Cu intermediate layer is present, interlayer exchange interaction works where the film thickness is small, so the upper and lower layers are combined.
However, when the contact area such as a magnetic microcontact is extremely small, the interlayer exchange interaction can be ignored, and therefore it is effective for disconnecting the coupling between the upper and lower magnetic layers.

The ferromagnetic layer 2 is CoFe 4 nm,
A Cu layer was deposited thereon as a protective film.

On the other hand, Sample II has the structure shown in FIG. 19B. As the different element here, an alloy of copper (Cu) and aluminum (Al) is deposited and then oxidized in oxygen. , Cu-Al-O. The substructure including the ferromagnetic layer 1 and the ferromagnetic layer 2 are the same as in the sample I,
Al ₂ O ₃ was used as the material of the insulating layer 3. Cu-
In the Al-O layer, highly insulating fine particles rich in alumina,
A place where Cu is rich and conductive is easily formed. Therefore, it is possible to substantially reduce the size of the opening of the magnetic micro-contact, thereby obtaining a larger magnetoresistive effect.

Sample III has the structure shown in FIG. The foreign element here is oxygen (O), and the oxygen element was introduced by natural oxidation. Its basic structure is
It is the same as Sample I except for the method of introducing the different element. The introduction of this oxide layer aims to substantially reduce the opening size of the magnetic microcontact, as in Sample II.

Sample IV is a minute contact made of only permalloy, and has a structure in which a different element layer does not exist in the contact portion.

Sample V has a normal CCP-MR structure,
PtMn15nm / CoFe4nm / Ru1nm / Co
It has a laminated structure of Fe4 nm / Cu2 nm / CoFe4 nm / Cu.

Table 1 summarizes the measurement results of the rate of change in magnetoresistance. Samples I to IV, which are the magnetoresistive effect elements of the present invention, all show a larger magnetoresistance change rate than the normal CCP-MR of sample V. Also, with sample I
In II, a larger magnetoresistance change rate was obtained by adding different elements.

[0153]

[Table 1] (Fifth Embodiment) Next, as a fifth embodiment of the present invention,
A so-called "tandem type" element was manufactured by stacking a plurality of magnetoresistive elements in series.

FIG. 20 is a schematic view showing the cross-sectional structure of the main part of the magnetoresistive effect element manufactured as this example.

As shown in the figure, the ferromagnetic layers 1 and the insulating layers 3 are alternately laminated, and the minute openings A are formed in each of the insulating layers 3. Connected by contacts. That is, the ferromagnetic layer 1 and the ferromagnetic layer 2 in the magnetoresistive effect element shown in FIG. 1 are shared between adjacent magnetoresistive element elements.

Here, the positions of the minute openings A formed in each insulating layer 3 do not necessarily have to be aligned on a straight line, and may be "shifted" from each other as illustrated in FIG.

The series structure as in this embodiment is advantageous in that a larger magnetoresistance change can be obtained.

Further, in such a laminated series structure,
If there are variations in the opening width of the minute opening A, the entire characteristic is defined by the portion of the minute opening A having the highest resistance, so that the disadvantage that the minute opening A tends to become large can be compensated. .

(Sixth Embodiment) Next, as a sixth embodiment of the present invention, a magnetoresistive effect element having a cylindrical minute opening will be described.

FIG. 21 is a schematic view showing the cross-sectional structure of the main part of the magnetoresistive effect element manufactured in this example.

First, on the conductive substrate S, the antiferromagnetic film 6,
A magnetic layer 1 is formed in this order, and a diameter of 5 nm is further formed on the magnetic layer 1.
Alumina 3 having a cylindrical minute opening A was formed.
Nickel (Ni) was embedded in the minute openings A by an electrochemical deposition method. Then, by depositing the magnetic layer 2 thereon, a magnetoresistive effect element having the structure shown in FIG. 21 was obtained.

FIG. 22 is a graph showing the magnetoresistance change of this magnetoresistance effect element. That is, the electric resistance in the zero magnetic field is relatively small as 100Ω or less, and
It has been found that a great reduction in resistance is obtained above G.

(Seventh Embodiment) Next, as a seventh embodiment of the present invention, a reproducing element for magnetic recording having the structure shown in FIG. 11A was manufactured. This device is a medium 200
The sectional structure (on the opening surface) viewed from the side is as shown in FIG. The materials and film thicknesses of the respective layers constituting the magnetoresistive effect element excluding a part of the electrode layers and the shield layer are as follows. Ta5nm / CoFe1nm / opening in the SiO ₂ layer / CoFe1nm / Ru1nm / CoFe1nm / Pt
Mn30nm / Ta5nm

Here, the opening is FIB (focused ion bea).
m) was used. Further, a hard magnet layer HM is provided on the side surface of the magnetoresistive effect element for controlling the magnetization of the free layer 2. A portion of the free layer 2 near the hard magnet layer HM becomes the insensitive region 2A for controlling the magnetization. Therefore, in the case of an MR element having a simple laminated structure of a simple free layer / intermediate layer / pin layer, the magnetoresistive effect of the insensitive region 2A is also included, so that the detection efficiency is reduced. Further, as the distance from the medium 200 increases, the signal magnetic field from the medium 200 decreases, so that the response of the free layer 2 deteriorates and the detection efficiency also decreases.

On the other hand, in the structure of this embodiment, the insensitive region 2A is avoided, and the medium 20 in the free layer 2 is avoided.
It is possible to detect the sense state only in the portion close to 0. That is, according to the present embodiment, the loss of sensitivity is small, and the detection efficiency can be increased to 1.5 times or more as compared with the simple free layer / intermediate layer / pin layer structure.

(Eighth Embodiment) Next, as an eighth embodiment of the present invention, magnetoresistive cells having the structure of FIG. 15G are arranged on the substrate as shown in FIG. A x32 matrix was formed. 3 more of this matrix
A total of 1 M (mega) bit recording / reproducing medium was formed by 2 × 32 arrangement.

With respect to this recording / reproducing medium, 32
Recording and reproduction were performed with a probe consisting of 32 pieces. That is, one probe was made to correspond to one set of matrix. Probing is as shown in FIG. The cell selection for each probe PR is
It was performed by an XY drive mechanism provided on the medium.

Further, these probes PR were connected in an array through the transistors TR as shown in FIG. By doing so, the bit line BL and the word line W
A probe was selected by selecting L and L and turning on a transistor TR corresponding to a predetermined probe PR. It was confirmed that such a structure enables bit selection even for a large number of bits.

(Ninth Embodiment) Next, as a ninth embodiment of the present invention, a magnetoresistive effect element having the sectional structure illustrated in FIG. It was made.

First, an ultrahigh vacuum ion beam sputtering apparatus was used to form a flat layer of the ferromagnetic layer 1 made of CoFe on the substrate, then the substrate temperature was raised to 200 ° C. and the SiO ₂ layer 3 was formed thereon. Has grown up. SiO ₂ depending on conditions
Layer 3 grows like an island.

FIGS. 25A to 25C are schematic views showing the planar form of the SiO ₂ layer 3 which changes with the growth time.

That is, the SiO ₂ layer 3 grows by connecting fine islands in the initial growth stage, large islands in the middle growth stage, and islands in the latter growth stage as shown in FIG. The end result is a continuous film.

CoFe ferromagnetic layers 2 were further deposited on the upper surfaces of the films having different growth times as described above, and the magnetoresistive effect was examined.

FIG. 26 is a graph showing the growth time of the SiO ₂ layer 3 on the horizontal axis and the MR ratio on the vertical axis. Since the ferromagnetic layers 1 and 2 are in contact with each other over a large area at the initial stage of growth, the MR
The effect is very small. However, when the growth of the SiO ₂ layer 3 progresses and the contact area of the ferromagnetic layers 1 and 2 decreases to an appropriate range, the MR ratio rapidly increases. And S
When the growth of the iO ₂ layer 3 further progresses, the MR ratio exceeds the peak and rapidly decreases to cover the surface of the ferromagnetic layer 1. It is assumed that the TMR effect appears in the state immediately after the SiO ₂ layer 3 covers the surface of the ferromagnetic layer 1. However, since the thickness of the insulating layer 3 increases as the growth proceeds, The MR ratio drops rapidly.

As described above, according to the method of this embodiment, it is possible to form a minute opening and obtain a large MR value without making full use of the fine processing technique.

(Tenth Embodiment) Next, the tenth embodiment of the present invention will be described.
16A, a cell having the relationship of the magnetization directions shown in FIG. 16A is manufactured by the same method as in the ninth embodiment, and
No. 2 magnetic recording medium was formed.

First, a PtMn layer (thickness 10 nm) is formed on the base electrode 20 using an ultra-high vacuum sputtering apparatus, then a Co layer (thickness 5 nm) 1 is grown, and further an alumina layer 3 is formed in an island shape. , And a Co layer (2.
5 nm) 2 was formed. Then, a Ta layer (3n
m) was formed. After this laminated film was annealed in a vacuum magnetic field, an EB (electron beam) exposure apparatus was used to form a cell array in which cells each having a size of 70 nm × 120 nm were regularly arranged.

Then, the change in element resistance when the probe PR was brought into contact with one of these cells and the current value was swept was examined. As a result, when a current of plus 1.2 mA or more is applied, the resistance of the element increases, and when the current is applied up to 2 mA and then reduced to reverse the current direction,
The resistance value was still large until it was close to minus 1.4 mA, and the resistance value decreased when the current value was further increased in the negative direction beyond this current value. Such a resistance change reaction was similarly reproduced in several repeated experiments. The rate of change in resistance due to the current sweep was 22% on average.

The magnetoresistive effect element and the method of manufacturing the same according to the present invention have been described above with reference to FIGS. 1 to 26. Hereinafter, with respect to another specific example related to the method for manufacturing the minute opening provided in the magnetoresistive effect element of the present invention,
A detailed description will be given with reference to the eighteenth embodiment.

(Eleventh Embodiment) Next, the eleventh embodiment of the present invention will be described.
As a practical example of the above, a specific example in which a minute opening is formed by using etching with an electron beam (EB) will be described.

FIG. 27 is a conceptual diagram for explaining the method used in this embodiment. This apparatus includes a vacuum chamber 30
An EB source 310 that supplies an electron beam installed in
It has a sample stage 320, a nozzle 340 for supplying a reaction gas to the sample, and a sample heater 330 for raising the sample temperature. Vacuum chamber 300
Is vacuum-exhausted through the exhaust port 350, and a reduced pressure atmosphere can be maintained.

The drilling of the minute openings was performed as follows.

First, the sample on which the ferromagnetic layer 1 and the insulating layer 3 are formed is fixed to the sample stage 320. Observing the scanned EB image, the position where the insulating layer 3 is drilled is determined. Further, the EB is concentrated and irradiated to the predetermined place, and the reaction gas is further sprayed in the vicinity through the nozzle 340. Further, the sample heater 330 appropriately raises the temperature of the sample in order to accelerate the reaction. By doing so, the surface of the insulating layer 3 reacts with the supplied gas by EB to become a volatile substance and evaporate. As a result, etching is promoted. Further, by raising the sample temperature, the reaction rate can be increased and the process time can be shortened. In addition, the carbon fluoride layer is EB on the surface of the magnetic layer 1 which is an end point and does not react.
Prevents formation and deposition by irradiation.

FIG. 28 is a schematic diagram showing a process of forming a magnetoresistive effect element. That is, the figure shows a step of forming the minute openings A in the SiO ₂ insulating layer 3 formed on the CoFe magnetic layer 1.

First, a base film (not shown) having a thickness of 5
PtM (not shown)
An n antiferromagnetic film (for example, thickness 15 nm) is formed.
The CoFe layer 1 is formed thereon as a pinned layer of the MR element. A SiO ₂ layer 3 having a thickness of 3 nm is formed thereon.

Next, the surface of the SiO ₂ layer 3 is irradiated with spots of EB having a beam diameter of 10 nm or less. To prevent the insulator from charging up, the EB acceleration voltage is 1
It was set to 0 kV. XeF2 is sprayed as a reaction gas there. By doing so, SiO ₂ reacts with the gas to become Si fluoride and evaporates. However, CoF
e The reaction is S because it does not form a volatile reactant with the magnetic layer 1.
It stops only by etching the iO ₂ layer 3.

In order to avoid the influence of charge-up, it is advisable to incline the sample by about 30 degrees or accelerate the emission of secondary electrons. As the reactive gas supplied from the nozzle 340, not only XeF ₂ but also CHF ₃ gas or other Freon-based gas is effective. Furthermore, as a measure against charge-up, a metal film such as an Nb (niobium) film may be formed on the SiO ₂ layer 3.

FIG. 29 shows an example in which the Nb film 400 is formed. The thickness of the Nb film 400 can be set to, for example, about 3 nm. In this case, first, as shown in FIG. 29A, EB is irradiated using CF ₄ as a reaction gas to form spot-shaped holes 400A in the Nb film 400. Next, as shown in FIG. 29B, the SiO ₂ layer 3 is etched by EB irradiation by switching to the XeF ₂ gas.

As described above, by forming the metal film 400 on the insulating layer 3, it is possible to prevent the EB irradiation diameter from increasing due to charge-up. In addition, since the metal film 400 is present on the insulating layer 3, the magnetic film 2 formed thereon is
The crystallinity is improved, and as a result, the soft magnetism and the resistance change rate are improved. That is, it contributes to the improvement of the magnetic field sensitivity of the magnetoresistive effect element.

FIG. 30 is a process sectional view showing another example of a process of forming a minute opening.

That is, the EB for each element
Since it takes time to form the minute opening A by
The minute openings A formed by B are formed only on the metal film 400 as shown in FIG.
(B) As shown in CHF ₃ gas by RIE (Reac
tive ion etching is performed on the entire wafer, and CDE (Chemical Dry Etching) with less physical damage is performed.
The process time can be shortened by etching the SiO ₂ layer 3 over the entire wafer by g).

Further, as shown in FIG. 30A, by sputter etching or ion milling the whole in the state where the hole 400A is opened in the metal film 400, as shown in FIG.
The metal hole 400A may be transferred to the insulating layer 3 as shown in FIG. Also in the case of this method, since the minute openings A can be simultaneously formed over the entire wafer, the process time can be shortened.

After forming the minute openings A in the SiO ₂ layer 3,
As shown in FIG. 31A, the magnetic layer 2 serving as a free layer.
(For example, CoFe 3 having a thickness of about 5 nm) is laminated, and further a Ta film to be the protective film 9 is laminated to have a thickness of about 5 nm, whereby an MR laminated film in which the pin layer and the free layer are in point contact can be obtained. .

Also, as shown in FIG. 31B, before forming the CoFe magnetic film 2 to be the free layer, the Cr film or Cu to be the non-magnetic intermediate layer (spacer layer) 4 in the MR element is formed.
The films may be laminated to have a thickness of about 2 nm. By doing so, as described above with reference to FIG. 14, the contact portion of the free layer 2 is easily magnetized and rotated with respect to the external magnetic field, and reacts with the low signal magnetic field.

Further, as shown in FIG. 31C, the same effect can be obtained by providing the nonmagnetic intermediate layer 4 on the pinned layer 1.

On the other hand, the upper and lower magnetic layers may be inverted so that the lower layer is a free layer and the upper layer is a pinned layer.

FIG. 32A shows an example in which the top and bottom are inverted, and after forming the minute opening A, the CoFe layer 1 serving as the pinned layer, the antiferromagnetic layer 6 for fixing the magnetization of the CoFe layer 1, and the Ta protective film 9 are formed. It is formed. Since the magnetic film 1 embedded in the minute opening A is likely to have crystal defects, it is more advantageous in terms of sensitivity to a signal magnetic field to embed a pin layer, which is not required to have soft magnetic characteristics, in a hole. Even when the magnetic film 2 to be the pinned layer is embedded, the nonmagnetic intermediate layer 4 may be embedded first as shown in FIG. Also in this case, the magnetization rotation of the free layer 1 with respect to the signal magnetic field becomes smooth, and the sensitivity to the signal magnetic field can be increased.

Further, as shown in FIG. 32C, the same effect can be obtained even if the spacer layer 4 is formed on the free layer 2.

In order to improve the crystallinity of the embedded magnetic layer 2 and obtain a high MR, it is desirable that the side surface of the minute opening A has a gentle taper shape and has a small surface roughness. In order to make a gentle taper, as shown in Fig. 33, oblique incident ion milling and oblique incident RIBE (Reactive Ion Beam Etchin) are used.
g) Etching the insulating film 3 may be performed. Further, in order to reduce the surface roughness of the tapered surface, it is desirable to use an amorphous oxide such as SiO ₂ or alumina as the material of the insulating layer 3.

As described above, EB irradiation using a reactive gas can be used to make a fine hole at an arbitrary position. The principle itself of processing the electrons by colliding with the substrate together with the reactive gas is described in J. W. It is disclosed by Coburn (see Non-Patent Document 6).

[0201]

[Non-Patent Document 6] JW Coburn (Journal of Applied Phy
sics, vol.50, no.5, pp3189-3196 (1979)

The feature of this method is that the physical damage to the collision target is extremely small because it is an electron collision. When applied to the formation of a nano-contact MR element, the insulating film can be etched by using an electron beam that is extremely finely squeezed without physically damaging the magnetic material under the insulating film. The minute partial etching can prevent EB convergence deterioration due to charge-up by covering the surface of the insulator with a metal film.

This EB irradiation etching is a particularly useful opening forming process because the contact portion of the nano-contact MR element is required to have good crystallinity. Also,
The merit of applying this method to the nano-contact MR element is that the processing time is short because the processing area of each element is extremely narrow, and the processing shape can be observed after processing and as a result process feedback is possible. Is.

Depending on the process, it is necessary to take out a sample after forming the minute openings in the insulator and before forming the upper magnetic layer, the different element layer, or the nonmagnetic intermediate layer.
Exposure to a poor quality atmosphere can cause unwanted oxidation of the openings in the underlying magnetic layer. Two methods are listed below as methods for removing the oxide layer in such a case.

First, the first method is a method of removing by ordinary sputter etching. In this case, the crystal is likely to be damaged. Therefore, if sputter etching is performed with an ion beam in the same vacuum chamber as the upper electrode or in a vacuum chamber connected by a vacuum line, the crystal may be heated locally by using an electron beam or a laser beam. It is useful for improving sex. Of course, the sample may be heated.

The second method is a method of removing surface oxygen by exposing the sample surface to atomic hydrogen in the same chamber as the vacuum chamber for forming the upper electrode or in another vacuum chamber connected by a vacuum line. .

Atomic hydrogen was heated to a high temperature provided in the vicinity of the sample (about 1400 ° C to 2 ° C as an approximate temperature).
It can be generated by introducing hydrogen gas into a tungsten (W) filament or a tantalum (Ta) tube to crack (heat decompose) hydrogen. The distance from the nozzle to the sample surface is 10
It may be about cm, but it may be longer depending on the internal structure of the chamber. It is more effective to reduce the oxygen by hydrogen and recover the crystallinity by heating.

As the heat source in this case, radiant heat from a hydrogen cracking device, electron beam heating for locally applying an electron beam, or laser beam heating for locally applying a laser beam can be used. The method of removing the oxide layer as described above can be applied to the magnetoresistive effect element of the present invention, in addition to the method of forming a minute opening of this embodiment.

(Twelfth Embodiment) Next, the twelfth embodiment of the present invention will be described.
As an example of the above, a process of forming minute openings by performing spot-like heating in the state of the MR laminated film using EB will be described.

FIG. 34 is a process sectional view showing a manufacturing process of the magnetoresistive effect element according to the present embodiment.

First, as shown in FIG. 9A, the PtMn antiferromagnetic layer 6 (thickness 15 nm), the CoFe magnetic layer 1 (thickness 2 nm) to be the pinned layer, and the SiO ₂ insulating layer 3 are arranged in this order from the bottom. (Thickness 2 nm), CoFe layer 2 to be a free layer
(Thickness 2 nm), Ta layer as protective layer 9 (thickness 5 nm)
To form.

Next, as shown in FIG. 34 (b), EB
The spot diameter is narrowed to 10 nm or less, and irradiation is performed from above the Ta protective layer 9.

Then, as shown in FIG. 34C, E
The region irradiated with B rapidly rises in temperature to cause an increase in grain size, and Si atoms and O atoms constituting the SiO ₂ insulating layer 3 are segregated at the interface, or a part of them is in the CoFe layers 1 and 2. The insulating layer 3 locally disappears in the portion that is taken in and irradiated with EB. As a result, the upper and lower magnetic layers 1 and 2 can be connected by a point contact.

As shown in FIG. 35 (a), a non-magnetic spacer layer 4A such as Cr and a chromium oxide formed by oxidizing its surface are formed between the upper and lower magnetic layers 1 and 2. A structure in which the non-magnetic spacer layer 4B is inserted is also conceivable.

Also in this case, similarly, as shown in FIG. 35B, EB irradiation is locally performed from above the Ta protective layer 9 so that local irradiation as shown in FIG. The spacer layers 4A and 4B can be effectively eliminated to obtain conduction. In this case, when electrical continuity is obtained between the upper and lower magnetic layers 1 and 2 through the minute openings formed in the non-magnetic spacers 4A and 4B, MR by point contact is obtained.
Both the merit of increase and the merit of improving the sensitivity due to the reaction of the free layer 2 with a low signal magnetic field can be obtained.

The merits of performing EB irradiation from above the Ta protective layer 9 are that since a process of forming a minute opening is not performed during the MR film laminating step, a cleaner laminating interface can be formed, and EB irradiation is performed. Since the point contact can be formed only once, the process time can be shortened.

In addition, as shown in FIG. 36, in this EB irradiation process, the pinned magnetic layer 1 is formed on the lower pinned magnetic layer 1.
37 is formed by oxidizing the oxide layer 1A (Co-Fe-O), or as shown in FIG. 37, the oxide layer 2A (Co-Fe-O) is formed below the free magnetic layer 2 on the upper side. It is effective even when the formation is formed.

Further, the nanoholes (small openings) PC formed by the EB irradiation are E-shaped as shown in FIG.
When B is irradiated in a spot shape, it is formed in the irradiated portion as shown in FIG. 38 (c), or as plural spots are formed around the irradiation spot as shown in FIG. 38 (b). In some cases. In any of these cases, it can be used as a minute contact of a magnetoresistive effect element. Note that FIG. 38 (a)
In (c) to (c), the EB irradiation region is represented by a one-dot chain line.

Further, when the EB irradiation position is mounted on a magnetic head as a magnetoresistive effect element, it is desirable to irradiate the position near the medium running surface.

FIG. 39 shows a state after the MR laminated film is formed.
Alignment mark AM is read and the center of gravity of the element (center)
9 is a conceptual diagram showing that the EB irradiation position is set closer to the medium traveling surface than point C. FIG.

FIG. 40 is a conceptual diagram showing the structure of the device. The magnetoresistive film MR is sandwiched between the upper and lower electrodes EL, and the left and right sides thereof are sandwiched by the vertical bias film HM. As can be seen from the figure, the point contact PC formed by the EB irradiation is offset in a direction closer to the medium running surface ABS than the center (center) point C of the element. By doing so, the magnetic detecting portion of the MR element can be brought close to the medium traveling surface ABS, and the sense current can be concentratedly supplied to the portion where a large signal magnetic field from the recording medium is obtained. As a result, the detection output per sense current can be increased.

Even when etching is performed using EB as described above with respect to the eleventh embodiment, it is desirable that the position where the minute opening is formed is close to the medium running surface ABS.

By the way, in this example, the crystal grain size was increased and the crystal defects were reduced in the EB-irradiated region. As a result, the element resistance was reduced and the MR change rate was improved. However, the improvement of soft magnetism was not clearly confirmed. This is because the electrical properties of the device depend on the crystallinity of only the current-carrying region, but the soft magnetic properties of the entire free layer 2 are exchange-coupled and the magnetization moves as a whole. It is considered that the above does not appear clearly.

From this, it is understood that the local annealing by the EB irradiation is a method in which the electrical properties and magnetic properties of the element can be controlled independently as compared with the method of heating the entire element in an oven or the like.

For example, FeCo having a bcc crystal structure having a large crystal magnetic anisotropy can be expected to have a large MR, but its soft magnetism deteriorates as the crystal size increases. Therefore, as shown in FIG. 41A, most of bcc-FeCo is formed of microcrystals, and EB irradiation is performed only on the current-carrying region (the EB irradiation region is indicated by a chain line). Then, as shown in FIG. 7B, the crystal size of the EB-irradiated portion slightly increases, but the crystal defects in the conduction region of the sense current decrease. By doing this, a large MR
It is possible to achieve both soft magnetic properties and soft magnetic properties. The same method is also effective when laminated with a NiFe (permalloy) alloy film for assisting soft magnetism.

Further, it is possible to promote the selective growth only in a specific crystal orientation by utilizing the annealing by the EB irradiation.

FIG. 42 is a schematic diagram showing a state in which several (eg, [111], [100], [110]) growth axes exist in the MR element. These growth axes are, for example, SI (Secondary) obtained by irradiating an ion beam.
It can be confirmed as a difference in contrast in the Ion) image. When the MR element is composed of a plurality of crystal grains having different plane orientations, it causes noise when operating as a magnetoresistive effect element. This becomes more remarkable when the element size is reduced and the number of crystal grains is small. Further, when the point contacts are formed near the grain boundaries, the influence of the current magnetic field is also added, which further causes a problem in operational reliability.

Therefore, when EB is point-irradiated,
It is desirable to avoid this grain boundary and perform irradiation. Furthermore, it is possible to grow crystal grains in a specific orientation not only by avoiding grain boundaries but by controlling EB for scanning.

For example, as illustrated in FIG. 43 (a),
The [111] -oriented portion can be widened by gradually spreading the EB irradiation in a “spiral-like” shape at the [111] -oriented crystal grain portion. Then, as shown in FIG. 43B, it is desirable that the entire region of the point contact PC be in the same orientation.

Further, in the present embodiment, the improvement of the crystallinity by the EB heating may be carried out in the middle not after laminating all the layers of the MR film.

FIG. 44A shows, in order from the substrate (not shown) side, the free magnetic layer 1 and Cr for the purpose of increasing the resistance change rate.
A state in which the contact hole CH is formed in the stacked body including the As layer 410, the SiO ₂ insulating layer 3, and the Nb conductive layer 400 is shown. This contact hole CH is irradiated with EB to Cr.
Overheat the As layer 410. By doing so, the crystallinity and crystal orientation of the CrAs layer 410 are improved, and a structure having high electronic polarization characteristics is obtained.

After this, as shown in FIG. 44B, the magnetic layer 2 to be the pinned layer, the antiferromagnetic layer 6 and the protective film 9 are formed. By performing EB irradiation in the process in the middle of lamination, only a specific layer can be heat-treated.

On the other hand, as shown in FIG. 45 (a), M
All layers of the R film (from the bottom, CoFe free layer 1, C
rAs layer 410, Cr spacer layer 4A, Cr oxide layer 4B, CoFe pinned layer 2, PtMn antiferromagnetic layer 6, Ta.
EB irradiation may be performed locally after forming the protective layer 9). As a result, the atomic arrangement of the CrAs layer 410 is rearranged due to the influence of the vertically adjacent laminated films. As described above, by performing EB irradiation on the minute contact point, the crystallinity of only that portion can be improved, and the element manufacturing method does not adversely affect the heating of other portions.

In the step of making a hole in the insulating layer 3,
Damage such as crystal defects and strain introduced into the lower magnetic layer 1 can be removed by EB irradiation.

FIG. 46A shows a state in which a damaged portion DM has been formed on the surface of the lower magnetic layer 1 in the RIE drilling step. After that, by performing EB irradiation toward the hole as shown in FIG. 46B, the damaged portion DM can be removed by local annealing (FIG. 46C).

As a process different from this, the same effect can be obtained by further forming the upper magnetic layer 2 and burying it in the hole, and then EB annealing the same, and further burying in the hole. It is also possible to reduce crystal defects of the magnetic substance that has been generated. As a result, an MR element having a high MR change rate can be obtained.

As described above, the EB local irradiation heating can achieve both the electrical properties locally required for the connection part of the magnetic layer and the overall magnetic properties of the free layer responsive to an external magnetic field in the nanohole MR element. Is a process. Local heating is effective not only by EB irradiation but also by laser light irradiation. In the case of laser light irradiation, when the surface is a transparent layer, it is possible to focus on an arbitrary place. For example, a "pillar" for electrically connecting the upper and lower magnetic layers can be formed by forming an insulating layer after forming the free layer and irradiating the insulating layer with a laser without the need for drilling. After that, a pin layer is laminated to form an MR element with point contact. Since this method does not form a hole and bury the magnetic layer there, the quality of the embedded magnetic film is improved, and as a result, the MR of the device is improved.
And soft magnetism is improved.

(Thirteenth Embodiment) Next, the thirteenth embodiment of the present invention will be described.
As an example of the above, a method of forming minute contacts by FIB (Focused Ion Beam) will be described. In the case of FIB, since the mass of collision particles (ions) is basically large, etching processing can be performed only by irradiation.

FIG. 47 is a process sectional view showing a method of forming a minute opening in the SiO ₂ insulating layer 3 formed on the CoFe magnetic layer 1.

First, an underlayer (not shown) having a thickness of 5 nm is used.
a), a PtMn antiferromagnetic layer (thickness: 15 n)
m) is formed. The CoFe layer 1 is formed thereon as a pinned layer of the MR element. On top of that, SiO with a thickness of 3 nm
_Two layers 3 are formed.

Next, as shown in FIG.
FIB with a diameter of 10 nm or less is spotted into Si.
O_TwoIrradiate the surface of layer 3. To control the dose
Therefore, as shown in FIG._TwoFine in layer 3
The small opening A can be opened. However, in general, FI
Ga ions used as a B source are also used in the CoFe layer 1.
Strict control of the dose amount is required because
Becomes Also, SiO _TwoEtching of layer 3 and CoFe layer 1
By increasing the selection ratio of the CoFe magnetic layer 1,
Overetching can be suppressed.

For example, as illustrated in FIG. 48 (a),
By performing FIB processing while spraying Freon-based gas as the reaction assist gas AG onto the processing region, the selection ratio can be increased. As a result, FIG. 48 (b)
As shown in (1), the fine openings A can be formed while suppressing the over-etching of the CoFe magnetic layer 1. CH as gas
Besides Freon gas such as F3, iodine gas can also be used.

Further, as shown in FIG. 49 (a), Si
The surface of the O ₂ layer 3 is FIB processed, but the FIB processing is Si
It may be stopped in the middle of the O ₂ layer 3 (FIG. 49B), and the remaining portion may be etched by another method (FIG. 49).
(C)).

If RIE or CDE, which makes the etching rate of the magnetic layer 1 extremely low, is used as this etching method, problems such as over-etching of the CoFe magnetic layer 1 and introduction of damage due to crystallinity deterioration can be suppressed. That is, by stopping FIB in the middle and finally etching by RIE or CDE with less damage, etching with lower damage is possible.

In this case, it is necessary to set the initial film thickness of the SiO ₂ layer 3 to a large amount by the amount etched by RIE or CDE.

Further, as illustrated in FIG. 50, SiO ₂
Forming a Ta film or the like on the surface of the layer 3 can reduce the film slip of the SiO ₂ layer 3 due to RIE or CDE. Specifically, for example, as shown in FIG. 50A, a Ta film 9 having a thickness of 3 nm is formed on the SiO ₂ layer 3. Then, a hole is drilled in the FIB.

As shown in FIG. 50B, the opening is made of SiO 2.
_{When the number of} layers reaches 3, the switching to RIE or CDE is performed as shown in FIG.

By forming a material, which can obtain a large etching selection ratio in RIE or CDE, on the SiO ₂ layer 3 as the mask layer 9, a film in RIE or CDE using a Freon-based gas such as CHF ₃ is formed. It is possible to suppress the decrease in thickness,
Further, in-plane non-uniformity of the film thickness of the SiO ₂ layer 3 due to over-etching time and in-plane non-uniformity of etching can be suppressed.

Further, in order to reduce the defects of the magnetic layer 2 embedded in the thus formed minute opening, it is effective to taper the side wall of the minute opening. For this purpose, it is also preferable to perform oblique incidence RIBE as illustrated in FIG.

By applying the metal mask layer 9, E
As in the case of B, it is possible to prevent the beam diameter from increasing due to charge-up. Further, since the metal mask layer 9 acts as a buffer layer of the magnetic layer 2 formed thereon, high output and high sensitivity can be obtained by improving the crystallinity of the magnetic layer 2.

It is also possible to perform the same process only with the FIB.

First, as shown in FIG. 51A, a laminated structure of the CoFe magnetic layer 1, the SiO ₂ oxide layer 3 and the Ta mask layer 9 is formed from the bottom and FIB irradiation is performed.

As shown in FIG. 51B, the Ta mask layer 9 is formed.
When holes are formed in, then, as represented in FIG. 51 (c), cutting the SiO ₂ layer 3 again in FIB. At this time, CH
It is possible to increase the etching rate of the SiO ₂ layer 3 by introducing an assist gas AG such as F ₃ to increase the etching rate selection ratio with the CoFe magnetic layer 1.

For simplification of the process, the assist gas AG is used during the first Ta film etching (see FIG. 51).
It does not matter if it is sprayed from (a)). However, when a material that reacts with the assist gas AG is used as the material of the mask layer 9, the etching proceeds even at the skirt portion of the FIB beam, which would not normally proceed, and as a result, a hole is formed. It can grow large. Therefore, it is desirable to select an assist gas AG gas that reacts with the insulating layer 3 but does not react with the mask layer 9 and the magnetic layer 1.

Further, as shown in FIG. 52, it is also possible to insert a spacer layer 4 (eg Cu) and use it as an etching stop layer.

In this example, gallium (Ga) was used as the ion source, but when gallium atoms remain on the processed surface, there is no fear of such residual argon (Ar) gas. It is desirable to use an ion source using a gas such as.

(Fourteenth Embodiment) Next, the fourteenth embodiment of the present invention will be described.
As an example of the above, a process of collectively forming fine openings over the entire surface of a wafer will be described. That is, it is advantageous to form the microscopic openings all over the wafer at once rather than to form the microscopic openings one by one, because the process time can be shortened.

53 and 54 are process diagrams showing the process of this embodiment.

First, as shown in FIG. 53A, a photoresist PR having a thickness of 0.1 μm is coated on the alumina insulating layer 3 (thickness 6 nm) formed on the magnetic layer (not shown). , Patterning up to the position X of the hole.

Next, as shown in FIG. 53B, a SiO ₂ film 420 having a thickness of 7 nm is formed thereon. A 5 nm SiO ₂ film 420 was formed on the sidewall of the photoresist PR. Further, as shown in FIG. 53C, a photoresist PR having a thickness of 0.1 μm is coated.

Then, the surface is subjected to ion milling or R
Etching back by IE and shaving to a thickness of about 30 nm, as shown in FIG. 53D, the SiO ₂ film 4 on the side wall of the PR is formed.
20 was exposed on the surface. That is, when viewed from above,
The SiO ₂ film 420 looks like a line with a width of 5 nm.

By RIE using CHF ₃ gas,
As shown in FIG. 54A, the SiO ₂ layer 4 having a width of 5 nm is formed.
20 is selectively etched. Furthermore, CHF ₃ -C
RIE using an F ₄ mixed gas is performed, and as shown in FIG. 54B, line etching is performed up to about half the film thickness of the alumina insulating layer 3 (about 3 nm).

Then, the pair of photoresist PR remaining on the surface is removed by RIE of O ₂ gas, and further the SiO ₂ film 420 thereunder is removed by CHF ₃ gas RIE. R for these gases with respect to the alumina insulating layer 3
Since the etching rate of the IE is 1/10 or less, the etching of the alumina insulating layer 3 is small.

Through the above process, as shown in FIG. 54C, a groove G having a width of 5 nm and a depth of 3 nm is formed at the position x on the surface of the alumina insulating layer 3.

Next, the patterning direction is rotated by 90 degrees, and the process shown in FIGS. 53A to 54B is repeated to form a groove G having a width of 5 nm and a depth of 3 nm. Then, as shown in FIG.
A hole CH of 5 nm square is formed at the intersection of the two grooves G.

By applying the process described above,
We were able to greatly reduce the time required for the drilling process. Further, the hole CH has a steep inclination angle of 80 degrees or more when RIE is used, while when CDE is used, a gentle side wall is formed in a wine cup shape. . When the magnetic film 2 to be embedded thereover is a free layer, the soft magnetic characteristics of the magnetic substance embedded in the hole are better when the side wall is gentle.

(Fifteenth Embodiment) The fifteenth embodiment of the present invention will now be described.
As an example of AFM (Atomic Force Microprove)
A method of making a hole with a needle technique represented by a technique will be described.

FIG. 55 is a conceptual diagram for explaining a process utilizing a reduction reaction in this example.

As a sample, a magnetic layer 1 on which an alumina insulating layer 3 (thickness: 5 nm) was formed was used. Then, a metal film is coated on the surface of the needle of the AFM, and an electric field is applied between the needle ND and the sample in a state where the H2 mixed forming gas is blown to reduce the generation of new oxide to create a reducing atmosphere. . Then, an electric current suddenly flows out at a certain electric field strength, a reduction reaction occurs, and the region where the needle ND is applied becomes the energization region (Al). Since the needles ND are in contact with each other, the lines of electric force are dense at the contact portion, and the reduction reaction proceeds from that portion.

Here, the spacer layer 4 may be inserted between the alumina insulating layer 3 and the magnetic layer 1. Also, the insulating layer 3
When a metal oxide is used as the material, a metal such as aluminum (Al) may be formed into a film and then the oxide may be formed by an oxidation process.

A metal oxide is desirable as the insulating layer 3 in this embodiment, but when SiO ₂ is used, Si or S is reduced by reducing the SiO ₂ by energization from the needle ND.
The i compound is formed, and thereafter, as shown in FIG. 56, the contact hole is completed by removing it by RIE.

It is also possible to process the magnetic layer 2 laminated on the insulating layer 3. That is, as illustrated in FIG. 57, by locally applying an electric field from the needle ND to the sample having the sandwich structure of the magnetic layer 1, the insulating layer 3, and the magnetic layer 2, the insulating layer 3 is locally reduced. It is also possible to form a local current-carrying region.

On the other hand, in the present invention, it is also possible to utilize an oxidation reaction.

FIG. 58 is a conceptual diagram for explaining a process utilizing an oxidation reaction.

That is, on the magnetic layer 1, silicon (S
When the layer 3A such as i) is provided and the needle ND is brought into contact with this in an oxidizing atmosphere to apply an electric field in the opposite direction, the anodizing reaction locally proceeds. As a result, a minute SiO ₂ region 3R is formed as shown in FIG.

Then, the SiO ₂ region 3R is removed by RI.
Etching is selectively removed by E or the like. At this time, it is desirable to perform the etching under the condition that the etching selection ratio to the base silicon (Si) is large.

Thereafter, the silicon layer 3A is oxidized to form Si.
The insulating layer 3 in which minute openings are formed by using O ₂
Can be formed.

When the AFM technique is used, there is an advantage that the opening position on the sample can be confirmed in advance and adjusted. In particular, when the MR element of the present invention is formed, since the current is locally applied,
I want to avoid defects, foreign substances, grain boundaries, etc. On the other hand, AF
It is possible to grasp the shape of the surface of the film in advance by M scanning and adjust the drilling position. Furthermore, it can be said that there is a remarkable merit in that the magnetic state of the surface of the sample can be confirmed by the MFM (Magnetic Force Microscope) technique by using the needle ND made of a magnetic material.

(Sixteenth Embodiment) Next, the sixteenth embodiment of the present invention will be described.
As an example, the function of the spacer layer 4 made of a non-magnetic material will be described.

In FIG. 59A, the SiO ₂ insulating layer 3 is formed on the CoFe magnetic layer 1, and the contact hole CH is formed.
Is formed, the spacer layer 4 is made of, for example, C
u (thickness 2 nm) is formed first, and CoFe is formed on top of it.
The structure for forming the magnetic layer 2 (thickness 4 nm) is shown. In the case of this structure, since the magnetic layer 1 and the magnetic layer 2 do not come into direct contact with each other, there is a decrease in soft magnetism due to exchange coupling of the free layer (for example, the magnetic layer 2) with the pinned layer (for example, the magnetic layer 1). Can be suppressed. In particular, the magnetic substance embedded in the contact hole CH contains many defects, which makes it difficult for the pinned layer and the free layer to undergo steep magnetization rotation. On the other hand, as shown in FIG. 59A, the nonmagnetic layer 4 is first formed, and then the upper magnetic layer 2 is formed. By doing so, the side surface of the contact hole CH also forms a metal film underlayer, the crystallinity of the magnetic film in the contact hole CH is improved, and the magnetic substance in the hole CH is magnetized together with the surrounding magnetic layer. It becomes rotatable and is sensitive to the signal magnetic field.
R change occurs.

Also, when the magnetic layer 1 at the bottom of the hole CH is abraded by the process of opening the hole CH or the sputter etching before the buried film formation, as shown in FIG. 59 (b), the spacer layer 4 is formed. After forming the openings and forming the openings, a similar buffer effect can be obtained by forming the upper spacer layer 4 and the magnetic layer 2 as shown in FIG.

On the other hand, the insulating layer 3 is RI with a Freon gas.
When E etching is performed, as shown in FIG.
Depending on the etching conditions, the carbon film CF may be deposited on the bottom of the hole CH (that is, the surface of the lower magnetic layer 1). This carbon film CF also functions as the spacer layer 4. That is, when forming the upper magnetic layer 2 as shown in FIG. 60B, the same buffer effect as that described above is obtained.

It is not necessary for the spacer layer 4 to cover the entire surface of CH with Cu, and it is also possible to limit the magnetic contact area in the state where Cu is pinhole-like or mesh-like and Cu is partially confined. effective. By inserting the conductor, it is possible to prevent the electric resistance from excessively increasing due to the constriction, and as a result, it is possible to supply a reproducing element corresponding to a high frequency. Moreover, the MR value can be increased by partially inserting the insulating film. This is an effective countermeasure when CH is greatly completed in the manufacturing process.

(17th Embodiment) Next, the 17th embodiment of the present invention will be described.
As an example, a process of filling a contact hole with a magnetic material by a plating method will be described.

When the magnetic layer is embedded in the contact hole, the growth of the magnetic layer starts from the bottom of the hole when the plating method is used, so that defects can be extremely suppressed and grown.

For example, as shown in FIG. 61A, the SiO ₂ insulating layer 3 is formed on the lower magnetic layer 1, and the contact hole CH is formed. Then, an electrode is connected to the magnetic layer 1 and put in the plating bath PL. For example, when it is put into the NiFe plating bath PL, as shown in FIG.
C which is the magnetic layer 1 exposed at the bottom of the contact hole CH
NiFe growth starts from the oFe surface. Further, in this case, a Cu spacer layer 4 (not shown) may be laminated on the surface of the CoFe magnetic layer 1.

NiF started from the bottom of the contact hole
The growth of the e-film 2 spreads toward the periphery at the exit of the hole CH, and the surface area starts to increase rapidly, so that the growth rate decreases at a constant plating current. Therefore, when plating is performed on the extremely small contact hole portion, the timing of stopping the plating for filling the hole can be easily controlled by the plating time. As described above, the magnetic film formed in the contact hole by plating has few defects and a large MR can appear.

After that, as shown in FIG. 61C, the antiferromagnetic layer 6 is formed to fix the pinned layer. As described above, after the holes are filled with plating, the magnetic domain can be controlled by fixing the magnetization in the antiferromagnetic layer.
noz (Applied Physics Letters vol.79, No.18, pp2946-2
It is possible to provide a reproducing element in which a large noise, which is a problem in 948 (2001)), is suppressed.

(Eighteenth Embodiment) Next, the eighteenth embodiment of the present invention will be described.
As an example of the above, a method of forming an MR element having minute contacts whose current-carrying direction is formed parallel to the film surface will be described.

FIG. 62 is a schematic diagram showing the structure of the MR element of this example. That is, from the first electrode EL1 to the second electrode
The pinned layer 1, the region PC in which the current is confined (AB), and the free layer 2 are provided while the current flows to the electrode EL2. In this configuration example, the signal magnetic field SM is generated by the second electrode EL2.
Enter Free Tier 2 from the side.

FIG. 63 is a process chart showing the process of forming such an MR element.

First, as shown in FIG.
e Magnetic layer (thickness 5 nm) FM is formed, and PtM is formed on it.
An n antiferromagnetic layer 6 (thickness 15 nm) is formed. further,
Then, a photoresist PR is patterned and formed so that an edge (end portion) is arranged at a position where the current is constricted.

Next, as shown in FIG. 63B, the PtMn layer 6 on the CoFe layer FM on the side which becomes the free layer by ion milling is removed.

Next, as shown in FIG. 63 (c), beam scanning is performed by the FIB along the edge of the photoresist PR to perform trimming to form a current constricting portion PC.

Then, after processing, a shape as shown in FIG. 63 (d) is obtained. Then, the first electrode EL1 and the second electrode EL2 are formed.

However, at this time, looking at the cross section on the free layer 2 side of the AB cross section, as shown in FIG.
The upper side is rounded under the influence of the beam profile, which makes resistance value control difficult. Therefore, as shown in FIG. 65, a protective layer PR is provided, and F is provided through the protective layer PF.
By performing the IB processing, it is possible to prevent “curl” of the magnetic layer FM. The protective film PF is preferably a high resistance film such as an insulating film from the viewpoint of current shunt with the magnetic film.

FIG. 66 shows a state in which a photoresist is further coated from the state of FIG. 63 (b) to form a protective layer PR on the free layer. If current confinement processing is performed by FIB in this state, both the pinned layer 1 and the free layer 2 are subjected to FIB etching while the upper surfaces are protected, so that variations in resistance due to "rounding" can be suppressed.

On the other hand, the current confinement width can be made narrower than the processing width by utilizing gallium (Ga) implantation.

FIG. 67 is a schematic diagram showing a state in which Ga is driven into the end portion of the FIB processed portion. In the Ga implanted region IZ, the crystals of the CoFe layers 1 and 2 are destroyed and the resistance value also increases. Therefore, a junction that is narrower on both sides by several to several tens of nm is formed effectively than the physical processing width by FIB. Thus, by implanting FIB source particles such as Ga, it is possible to form a contact that is substantially narrower than the physically processed width.

Further, the MR characteristics can be improved by heating the narrowed portion by EB irradiation to improve crystal defects.

The embodiments of the present invention have been described above with reference to specific examples. However, the present invention is not limited to these specific examples. For example, regarding the specific dimensional relationship and material of each element constituting the magnetoresistive effect film, as well as the shape and material of the electrode, the bias applying film, the insulating structure, etc., those skilled in the art can appropriately select from the known range. The present invention is included in the scope of the present invention as long as it can be carried out in the same manner and the same effect can be obtained.

As described above, the components such as the antiferromagnetic layer, the ferromagnetic layer, the non-magnetic intermediate layer and the insulating layer in the magnetoresistive effect element may be formed as a single layer, or two or more layers may be formed. It may have a structure in which the layers are laminated.

When the magnetoresistive effect element of the present invention is applied to a reproducing magnetic head, a write magnetic head is provided adjacent to the reproducing magnetic head to obtain a recording / reproducing integrated magnetic head.

In addition, based on the magnetic head and the magnetic storage / reproducing apparatus described above as the embodiments of the present invention, all magnetoresistive elements, magnetic heads, and magnetic storage / reproduction which can be appropriately modified and implemented by those skilled in the art. The device likewise falls within the scope of the invention.

[0305]

As described in detail above, according to the present invention,
It is possible to provide a magnetic minute contact which can be formed into an element, has good controllability, and is easy to manufacture, and also to provide a highly sensitive read head element using the same.

Furthermore, it is possible to provide a magnetic memory having a recording / reproducing function using this magnetoresistive effect element, which is a great industrial advantage.

[Brief description of drawings]

FIG. 1 is a schematic diagram illustrating a cross-sectional structure of a main part of a magnetoresistive effect element according to an embodiment of the present invention.

FIG. 2 is a schematic diagram for explaining a relationship between an applied magnetic field and electric resistance in the magnetoresistive effect element of the present invention.

FIG. 3 is a conceptual diagram illustrating a change in magnetoresistance due to a normal anisotropic magnetoresistance effect.

FIG. 4 is a conceptual diagram showing a comparison between the magnetoresistive effect element of the present invention and a conventional magnetoresistive effect element.

FIG. 5 is a schematic diagram showing a magnetoresistive effect element having a plurality of minute contacts.

FIG. 6 is a schematic view illustrating the cross-sectional shape of the opening of the minute contact.

FIG. 7 is a schematic diagram showing a magnetoresistive effect element in which a region D to which a different element is added is provided near the opening end of a minute opening A.

FIG. 8 is a process cross-sectional view illustrating a main part of a method of manufacturing a magnetoresistive effect element according to the present invention.

FIG. 9 is a cross-sectional view showing a structure in which a plurality of magnetoresistive effect elements are arranged on a common substrate (not shown).

FIG. 10 is a schematic view showing a specific example in which the magnetoresistive effect element of the present invention is used as a magnetic reproducing element.

FIG. 11 is a schematic view showing another specific example in which the magnetoresistive effect element of the present invention is used as a magnetic reproducing element.

FIG. 12 is a schematic view illustrating a cross-sectional structure of a main part of a magnetic memory using the magnetoresistive effect element of the present invention.

FIG. 13 is a schematic view illustrating a means for accessing each of the recording / reproducing cells 10.

14 is a schematic diagram showing a cross-sectional structure of a magnetoresistive effect element 10 used in the magnetic memory of FIG.

15 is a schematic diagram showing a cross-sectional structure of a magnetoresistive effect element 10 used in the magnetic memory of FIG.

16 is a schematic cross-sectional view showing another specific example of the magnetoresistive effect element that can be used in the magnetic memory of FIG.

FIG. 17 (a) when the needle 110 is press-fitted at a constant speed.
The distance between the surface of the ferromagnetic layer 1 and the tip of the needle 110,
(B) It is a graph figure showing the time change of the electric current which flows between these.

FIG. 18 is a graph showing a relationship between an applied magnetic field and electric resistance in the magnetoresistive effect element according to the example of the present invention.

FIG. 19 is a schematic diagram showing a cross-sectional structure of a main part of a magnetoresistive effect element manufactured as a fourth example of the present invention.

FIG. 20 is a schematic view showing a cross-sectional structure of a main part of a magnetoresistive effect element manufactured in an example of the present invention.

FIG. 21 is a schematic view showing a cross-sectional structure of a main part of a magnetoresistive effect element manufactured in an example of the present invention.

FIG. 22 is a graph showing changes in magnetoresistance of the magnetoresistive effect element according to the example of the present invention.

FIG. 23 is a schematic diagram showing a cross-sectional structure of an element formed in a seventh example of the present invention as viewed from the medium 200 side.

FIG. 24 is a schematic diagram showing a state in which a plurality of probes are connected in an array via transistors TR.

FIG. 25 is a schematic diagram showing a planar form of the SiO ₂ layer 3 which changes with the growth time.

FIG. 26 shows the growth time of the SiO ₂ layer 3 on the horizontal axis and the MR on the vertical axis.
It is a graph showing a ratio.

FIG. 27 is a schematic diagram for explaining the method of the eleventh embodiment of the present invention.

FIG. 28 is a schematic diagram showing a method of forming a magnetoresistive effect element according to an example of the present invention.

FIG. 29 is a schematic view showing a specific example of forming a niobium film 400.

FIG. 30 is a schematic view illustrating a method of forming a minute contact.

FIG. 31 is a schematic view illustrating a process following the process in FIG. 30.

FIG. 32 is a schematic diagram showing another method of forming minute contacts.

FIG. 33 is a schematic diagram showing a method by oblique incidence.

FIG. 34 is a schematic view showing a method of manufacturing a magnetoresistive effect element according to an example of the present invention.

FIG. 35 is a schematic view showing another manufacturing method of the magnetoresistive effect element in the example of the present invention.

FIG. 36 is a schematic view showing still another manufacturing method of the magnetoresistive effect element in the example of the present invention.

FIG. 37 is a schematic view showing still another manufacturing method of the magnetoresistive effect element in the example of the present invention.

FIG. 38 is a schematic diagram illustrating formation of point contacts when an electron beam is applied in spots.

FIG. 39 is a schematic view illustrating the relationship between the electron beam irradiation position and the center C of the element.

FIG. 40 is a schematic diagram showing the configuration of a device.

FIG. 41 is a schematic diagram showing a case where a plurality of growth axes exist in the MR element.

FIG. 42 is a schematic view illustrating a process of orienting the crystal orientation of crystal grains.

FIG. 43 is a schematic diagram showing an electron beam heating process inserted in the lamination process of the MR laminated film.

FIG. 44 is a schematic view showing a process of performing electron beam heating after the MR laminated film laminating process.

FIG. 45 is a schematic view showing a process of removing a defect generated in a hole making step.

FIG. 46 is a schematic view showing a method of forming a minute opening.

FIG. 47 is a schematic view showing a method for preventing overetching.

FIG. 48 is a schematic diagram showing a process of forming a minute opening by using different etching.

FIG. 49 is a schematic diagram illustrating a process of suppressing film slippage of an insulating layer.

FIG. 50 is a schematic diagram showing a formation process by FIB.

FIG. 51 is a schematic view showing a process using a spacer layer.

FIG. 52 is a schematic diagram showing the process of the fourteenth embodiment of the present invention.

FIG. 53 is a schematic diagram showing the process of the fourteenth embodiment of the present invention.

FIG. 54 is a schematic view showing the process of the fifteenth embodiment of the present invention.

FIG. 55 is a schematic view showing a process of the fifteenth embodiment of the present invention.

FIG. 56 is a schematic diagram showing the process of the fifteenth embodiment of the present invention.

FIG. 57 is a schematic diagram showing a process utilizing an oxidation reaction.

FIG. 58 is a schematic view showing the process of the 16th example of the present invention.

FIG. 59 is a schematic view showing a process using a spacer layer.

FIG. 60 is a schematic diagram showing a state in which a carbon film is deposited on the bottom of a hole.

FIG. 61 is a schematic diagram showing a seventeenth embodiment of the present invention.

FIG. 62 is a schematic view showing an MR element according to the 18th embodiment of the present invention.

FIG. 63 is a schematic view showing the process of forming the MR element of the eighteenth embodiment of the present invention.

FIG. 64 is a schematic diagram showing that “rounding” occurs in the magnetic layer due to the profile of the FIB beam.

FIG. 65 is a schematic diagram showing a state in which a protective layer PF is used.

FIG. 66 is a schematic view showing a specific example using a photoresist.

FIG. 67 is a schematic view showing a state where Ga is driven into the end portion of the FIB processed portion.

[Explanation of symbols]

1 and 2 ferromagnetic layers 3 insulating layers 4, 4A to 4C non-magnetic intermediate layer 5, 5A-5C ferromagnetic layer 6, 6A, 6B Antiferromagnetic layer 7 electrodes 10 Magnetoresistive element 20 electrode layers 30 insulator 110 needles 120 conductors 130A, 130B Distance change function unit 140 arms A micro aperture S substrate

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H01F 10/32 H01F 10/32 H01L 27/105 H01L 43/12 43/12 27/10 447 (72) Invention Person Shigeru Haneda 1 Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa Within the Toshiba Research and Development Center, a stock company (72) Inventor Yuzo Ueguchi 1 Komukai-shiba-cho, Saiwai-ku, Kawasaki-shi, Kanagawa Toshiba Research & Development Center (72) Inventor Tatsuya Kishi 1 Komukai Toshiba Town, Kawasaki City, Kanagawa Prefecture F-term in Toshiba Research and Development Center, a stock company (reference) 5D034 BA03 5E049 AA01 AA04 AA07 AC05 BA12 DB11 5F083 FZ10 GA27 JA36 JA37 JA38 JA39 PR03 PR04

Claims (23)

[Claims] 1. A first ferromagnetic layer, an insulating layer provided on the first ferromagnetic layer, and a second ferromagnetic layer provided on the insulating layer, A magnetoresistive device characterized in that a hole having an opening with a maximum width of 20 nm or less for connecting the first ferromagnetic layer and the second ferromagnetic layer is provided at a predetermined position of the insulating layer. Effect element. 2. The electric resistance of the first ferromagnetic layer and the second ferromagnetic layer with respect to a current flowing through the hole between the first ferromagnetic layer and the second ferromagnetic layer. The magnetoresistive effect element according to claim 1, wherein the magnetoresistive effect element changes depending on the relative magnetization arrangement of the layers. 3. The holes of the insulating layer are cone-shaped, with the opening width on the side of the first ferromagnetic layer being smaller than the opening width on the side of the second ferromagnetic layer. Item 3. The magnetoresistive effect element according to Item 1 or 2. 4. The magnetoresistive effect element according to claim 1, wherein a plurality of the holes are provided. 5. The resistance between the first ferromagnetic layer and the second ferromagnetic layer is 5 Ω or more and 100 kΩ or less, and is 20%.
The above-mentioned magnetoresistance change rate is shown, The claim 1 characterized by the above-mentioned.
The magnetoresistive effect element as described in any one of 4-4. 6. The insulating layer is made of polymer, aluminum (Al), titanium (Ti), tantalum (Ta),
Cobalt (Co), Nickel (Ni), Silicon (S
i), an oxide, a nitride, or a fluoride containing at least one element selected from the group consisting of zirconium (Zr), hafnium (Hf), and iron (Fe). The magnetic layer is made of iron (Fe), cobalt (Co), nickel (Ni), or iron (Fe), cobalt (Co), nickel (Ni), manganese (Mn).
And alloys, oxides, nitrides or Heusler alloys containing at least one element selected from the group consisting of chromium and chromium (Cr), or iron (Fe), cobalt (C)
o), nickel (Ni), manganese (Mn) and chromium (Cr), which is a compound semiconductor or oxide semiconductor containing at least one element.
The magnetoresistive effect element as described in any one of Claims 1-3. 7. The second ferromagnetic layer is formed with the element forming the first ferromagnetic layer at the connection between the first ferromagnetic layer and the second ferromagnetic layer in the hole. 7. The magnetoresistive effect element according to claim 1, wherein a different element different from the element described above is added, and the thickness of the region to which the different element is added is 10 atomic layers or less. 8. A magnetoresistive effect element comprising a plurality of magnetoresistive effect elements according to any one of claims 1 to 7 coupled in series. 9. A magnetoresistive effect element according to claim 1, wherein the first and second ferromagnetic layers are connected in series on a path of a magnetic flux emitted from a magnetic recording medium. A magnetic reproducing element, which is provided so that a difference between the magnetization directions of the first and second ferromagnetic layers sandwiching the hole can be detected as a change in magnetoresistance. 10. Of the first and second ferromagnetic layers,
10. The magnetic reproducing element according to claim 9, wherein the magnetization of a ferromagnetic layer provided relatively far from the magnetic recording medium is fixed in one direction. 11. A magnetoresistive effect element according to claim 1, wherein the film surface of the first ferromagnetic layer is arranged substantially perpendicular to a magnetic recording medium. A magnetic reproducing element characterized by detecting a signal magnetic field from a magnetic recording medium. 12. The magnetic reproducing element according to claim 11, wherein the hole is provided at a position displaced from the center of the insulating layer toward the recording medium. 13. A magnetoresistive effect element according to claim 1, a nonmagnetic intermediate layer provided on the second ferromagnetic layer, and a nonmagnetic intermediate layer provided on the nonmagnetic intermediate layer. A third ferromagnetic layer provided on the first ferromagnetic layer, the magnetization direction of the first ferromagnetic layer is fixed to the first direction, and the magnetization direction of the third ferromagnetic layer is the first direction. Is fixed in a second direction substantially antiparallel to the direction of, the direction of magnetization of the second ferromagnetic layer is variable, and is substantially perpendicular to the film surfaces of the first to third ferromagnetic layers. A magnetic memory characterized in that at least one of writing and reading is performed by passing a current in a direction. 14. A magnetoresistive effect element according to claim 1, a non-magnetic intermediate layer provided on the second ferromagnetic layer, and a non-magnetic intermediate layer provided on the non-magnetic intermediate layer. And a magnetization direction of the second ferromagnetic layer is fixed to the first direction, and a magnetization direction of the second ferromagnetic layer is fixed to the first direction. A magnetic memory, which is variable and which performs at least one of writing and reading by passing a current in a direction substantially perpendicular to the film surfaces of the first to third ferromagnetic layers. 15. The magnetoresistive effect element according to claim 1, wherein the magnetization direction of one of the first and second ferromagnetic layers is fixed to the first method. The direction of magnetization of the other of the first and second ferromagnetic layers is variable, and a current is passed in a direction substantially perpendicular to the film surfaces of the first and second ferromagnetic layers. A magnetic memory characterized by performing at least one of writing and reading. 16. The first and second electrodes for flowing the current are provided so as to cover all or part of the first and second ferromagnetic layers, and the first and second electrodes are provided. The magnetic memory according to any one of claims 13 to 15, wherein the opening is provided within a range where the electrodes face each other. 17. A plurality of memory cells are separated from each other by an insulating region and arranged two-dimensionally, and a current is supplied to each of the plurality of memory cells by a conductor probe or a fixed wiring. The absolute value of the current for writing to each is larger than the sense current for reading, and each of the plurality of memory cells includes the magnetoresistive effect element according to claim 1. The direction of magnetization of one of the first and second ferromagnetic layers is fixed to the first method, and the direction of magnetization of the other one of the first and second ferromagnetic layers is variable. The magnetic memory is characterized in that at least one of the writing and reading is performed by passing a current in a direction substantially perpendicular to the film surfaces of the first and second ferromagnetic layers. 18. A step of forming an insulating layer on the first ferromagnetic layer, a step of press-fitting a needle on the surface of the insulating layer to form a hole reaching the first ferromagnetic layer, A step of forming a second ferromagnetic layer by depositing a ferromagnetic material on the hole and the insulating layer so as to fill the hole, and a method for manufacturing a magnetoresistive effect element, comprising: 19. The current flowing between the first ferromagnetic layer and the needle is monitored, and when the current reaches a predetermined value, the press-fitting of the needle is stopped.
A method for manufacturing the magnetoresistive effect element described. 20. A magnetoresistive effect element comprising a step of substantially regulating the electrical conduction between upper and lower magnetic layers sandwiching an insulating layer in the irradiation region by converging irradiation of a charged particle beam. Forming method. 21. A step of etching a surface of an insulating layer by supplying a reaction gas, which is a volatile gas synthesized by a reaction between the converged electron beam and the insulating layer, to the surface of the insulating layer; A method of forming a magnetoresistive effect element, comprising the step of embedding a magnetic layer which is a part of the effect element constituent layer. 22. A step of etching the surface of the insulating layer with a focused ion beam, and a step of burying a magnetic layer which is a part of the magnetoresistive effect element constituent layer in the etching region. Method of forming magnetoresistive element. 23. A first ferromagnetic layer, an insulating layer provided on the first ferromagnetic layer, and a second ferromagnetic layer provided on the insulating layer, A method of manufacturing a magnetoresistive effect element, wherein a hole is provided in the insulating layer, and the first ferromagnetic layer and the second ferromagnetic layer are connected to each other through the hole. A method of manufacturing a magnetoresistive effect element, characterized in that the crystal arrangement of at least one of the first and second ferromagnetic layers is changed by irradiation.