JP2002124717A - Magnetoresistance effect element, its manufacturing method, and magnetic thin film memory using the magnetoresistance effect element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid electric short-circuit by reducing adhesion of constituent material of a magnetic layer and an electrode under a tunnel barrier layer to a side part of the tunnel barrier layer, in the case of etching process. SOLUTION: After a substrate side electrode layer 1, a first magnetic layer 2, the tunnel barrier layer 3 and a second magnetic layer 4 are laminated in this order, a resist pattern 21 is formed on an element part 22 of the second magnetic layer 4, and the second magnetic layer 4 except the element part 22 is etched and eliminated while leaving a part. The second magnetic layer 4 which is left without being etched and eliminated is oxidized reaching as far as the tunnel barrier layer 3, and resistance is increased to form an oxide layer 6. The whole surface is subjected to sputtering and an insulating layer 7 is formed for sufficient electrical isolation. After that, a window is formed on the upper surface of the element part 22, and an upper electrode 5 is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetoresistive element for recording information according to the direction of magnetization and reproducing information by a magnetoresistance effect, a method for manufacturing the same, and a magnetic thin film memory using the magnetoresistive element.

[0002]

2. Description of the Related Art Like a semiconductor memory, a magnetic thin film memory is a solid-state memory having no moving parts, but does not lose information even when power is cut off, and has an infinite number of rewrites.
There is an advantage in comparison with a semiconductor memory, for example, there is no danger of erasing recorded contents even when radiation is incident.

A magnetic thin film memory element using a magnetic tunnel junction (hereinafter referred to as a magnetoresistive effect element) is formed of a thin insulator having a thickness of several nm between two magnetic layers formed of a ferromagnetic material. It has a structure with an intervening tunnel barrier layer.

In this type of magnetoresistive element, when an external magnetic field is applied to the surface of a magnetic layer with a constant current flowing between two magnetic layers, the resistance changes according to the relative angle of magnetization of the two magnetic layers. The magnetoresistance effect phenomenon appears. When the magnetization directions are parallel, the resistance value is minimum, and when the magnetization directions are antiparallel, the resistance value is maximum. Therefore, by providing a coercive force difference between the two magnetic layers, a parallel state or an anti-parallel state of magnetization can be realized according to the strength of the magnetic field, so that the magnetization state can be detected by a change in resistance value. Becomes

In recent years, by using an Al surface oxide film for the tunnel barrier layer, a magnetoresistive element exhibiting a magnetoresistance change rate of nearly 20% has been obtained. The possibility of application of the magnetoresistive effect element has increased. As a representative example of a document reporting a magnetoresistance effect element exhibiting such a large magnetoresistance change rate, "April 1996, Journal of Applied Physics, Vol. 79, pp. 4724-4729 (Journa
l of Applied Physics, vol. 79, 4724-4729, 1996) "
There is.

[0006]

In order to manufacture the above-described magnetoresistive element at a high density, dry etching in the step of forming an element portion (portion where a tunnel current flows) is indispensable. When the lower magnetic layer and the substrate electrode located closer to the substrate than the tunnel barrier layer are etched, the magnetic material and the metal material constituting the lower magnetic layer and the metal material adhere to the etched side wall of the tunnel barrier layer, thereby causing an electrical problem. A short circuit will occur.

In order to solve such a problem, for example, Japanese Patent Application Laid-Open No. 10-163544 proposes a configuration in which a lower magnetic layer and a substrate electrode are not etched.

However, since the tunnel barrier layer has a very small thickness of about several nm, it has been difficult to stop the etching with good reproducibility in the vicinity of the tunnel barrier layer.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and the constituent materials of the magnetic layer and the substrate-side electrode located under the tunnel barrier layer during the etching step are different from those of the prior art. It is an object of the present invention to provide a magnetoresistive element capable of reducing adhesion to a layer side portion and avoiding an electric short circuit, a method for manufacturing the same, and a magnetic thin film memory using the magnetoresistive element.

[0010]

According to the present invention, there is provided a magnetic recording medium comprising a first magnetic layer, a tunnel barrier layer formed of a thin insulator, and a second magnetic layer. In a magnetoresistive element having a tunnel junction and flowing a tunnel current between the first magnetic layer and the second magnetic layer via the tunnel barrier layer, an oxide of a material forming the second magnetic layer And an insulating layer formed of an insulator and disposed on the oxide layer so as to limit a region of the second magnetic layer through which the tunnel current flows. It is characterized by.

Also, a magnetic tunnel junction is provided in which a first magnetic layer, a tunnel barrier layer formed of a thin-film insulator, and a second magnetic layer are sequentially laminated, and the first magnetic layer and the second magnetic layer are formed. In a magnetoresistive element in which a tunnel current flows between the magnetic layer and the magnetic layer via the tunnel barrier layer, a nitride layer formed of a nitride of a material constituting the second magnetic layer; An insulating layer formed of an insulator is provided so as to limit an area of the second magnetic layer through which the tunnel current flows.

Further, the first magnetic layer and the second magnetic layer may include:
It is formed of a magnetic material having perpendicular magnetic anisotropy and is magnetized in the layer thickness direction.

Further, the first magnetic layer and the second magnetic layer have different coercive forces from each other.

The second magnetic layer is joined to the second magnetic layer on the side opposite to the side joined to the tunnel barrier layer, and has an area larger than the area of the second magnetic layer; And a third magnetic layer magnetically coupled to the second magnetic layer at a junction with the second magnetic layer.

Further, an antiferromagnetic layer joined to the first magnetic layer is provided on a surface of the first magnetic layer opposite to a side joined to the tunnel barrier layer.

In the method of manufacturing a magnetoresistive element, a step of sequentially laminating the first magnetic layer, the tunnel barrier layer, and the second magnetic layer; Etching the remaining portion of the second magnetic layer that is not etched away, forming the oxide layer by oxidizing a region of the second magnetic layer remaining without being removed, Forming the insulating layer.

In the method for manufacturing a magnetoresistive element, a step of sequentially laminating the first magnetic layer, the tunnel barrier layer, and the second magnetic layer; A step of etching and removing a portion other than a region where the gas flows, forming a nitride layer by nitriding a region of the second magnetic layer remaining without being etched, and forming a nitride layer on the nitride layer. Forming the insulating layer.

A magnetic thin film memory using a magnetoresistive element according to the present invention is characterized in that information is recorded and reproduced using the magnetoresistive element.

(Function) In the present invention having the above-described structure, a magnetic tunnel junction in which a first magnetic layer, a tunnel barrier layer formed of a thin insulator, and a second magnetic layer are sequentially laminated. Wherein a tunnel current flows between the first magnetic layer and the second magnetic layer via a tunnel barrier layer. The magnetoresistive element is formed of an oxide or nitride of a material constituting the second magnetic layer. An oxide layer or a nitride layer, and an insulating layer formed on the oxide layer or the nitride layer and formed of an insulator are arranged so as to limit a region of the second magnetic layer through which a tunnel current flows. I have.

According to the present invention, the tunnel barrier layer comprises
Since the insulating layer is in contact with the insulating layer via the oxide layer or the nitride layer of the magnetic layer, even if a leak current occurs along the interface of the insulating layer, there is no path reaching the first magnetic layer.
This leak current does not actually flow through the first magnetic layer. Therefore, good magnetoresistance characteristics corresponding to whether the magnetization directions of the first magnetic layer and the second magnetic layer are parallel or antiparallel can be obtained.

Further, according to the present invention, in the magnetoresistive element configured as described above, a step of sequentially laminating a first magnetic layer, a tunnel barrier layer and a second magnetic layer, A step of etching away leaving a part other than a region where a tunnel current flows, and a step of oxidizing or nitriding a region of the second magnetic layer that is not etched away to form an oxide layer or a nitride layer; Forming an insulating layer on the oxide layer or the nitride layer.

As described above, the second magnetic layer is etched away while leaving a part other than the region where the tunnel current flows, and the remaining second magnetic layer is oxidized or nitrided to increase the resistance, thereby increasing the second magnetic layer. The tolerance when etching the layer is
Whereas in the prior art, the thickness of the tunnel barrier layer was
Since the sum of the thickness of the second magnetic layer and the thickness of the tunnel barrier layer is obtained, and the allowable range is greatly widened, the first magnetic layer and the substrate-side electrode are not etched.

This makes it possible to manufacture the magnetoresistive element without the constituent materials of the first magnetic layer and the substrate-side electrode adhering to the tunnel barrier layer during the etching step. It is possible to avoid an electric short circuit caused by the adhered substance. Further, since the allowable range of the etching is widened, the etching can be performed with good reproducibility, and the yield at the time of manufacturing the magnetoresistive element can be greatly improved.

The second magnetic layer has an area larger than the area of the second magnetic layer, and is magnetically coupled to the second magnetic layer at a junction with the second magnetic layer. In the case where the three magnetic layers are provided, the coercive force required for storing data can be covered by the combined coercive force of the second magnetic layer and the third magnetic layer.
As a result, the second magnetic layer can be formed thin. Therefore, since the etching amount of the second magnetic layer is reduced, the accuracy of controlling the etching depth is improved, and the yield during manufacturing can be significantly improved.

In the case where the above-mentioned third magnetic layer is provided, even if the second magnetic layer is miniaturized in order to realize a high-density memory, the second magnetic layer and the third magnetic layer are magnetically separated. Due to the coupling, it is possible to suppress the occurrence of magnetization curling due to miniaturization in the second magnetic layer. Therefore,
Even if the second magnetic layer is miniaturized, the magnetization direction can be made parallel or anti-parallel between the first magnetic layer and the second magnetic layer which are opposed via the tunnel barrier layer. An effect element and a magnetic thin film memory (MRAM) can be realized.

The third magnetic layer is larger than the area of the junction between the second magnetic layer and the tunnel barrier layer, and this large portion can overlap with the element isolation region and the wiring portion. Therefore, high integration can be achieved substantially.

[0027]

Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) FIG. 1 is a sectional view showing a first embodiment of a magnetoresistive element according to the present invention.

As shown in FIG. 1, in this embodiment,
A substrate-side electrode 1 made of a material having a low electric resistance, a first magnetic layer 2 made of a magnetic material such as a ferromagnetic metal, and a tunnel barrier formed of a thin insulator on a substrate (not shown). Layer 3, second magnetic layer 4 formed of a magnetic material such as ferromagnetic metal
And an oxide (or nitride) of a magnetic material constituting the second magnetic layer 4 in a configuration in which the second magnetic layer 4 and the upper electrode 5 are sequentially laminated.
The oxide layer (or nitride layer) 6 formed by the above and the insulating layer 7 formed of an insulator on the oxide layer (or nitride layer) 6 limit the tunnel current of the second magnetic layer 4. It is provided as follows.

Specifically, a Cu layer (50 nm thick) as the substrate-side electrode layer 1, a NiFe layer (20 nm thick) as the first magnetic layer 2, and an AlOx layer (1.2 nm thick) as the tunnel barrier layer 3 A Co layer (film thickness 30) as the second magnetic layer 4.
nm), Cu layer (100 nm thick) as upper electrode layer 5
Are formed, and regions other than the element portion are formed in the second magnetic layer 4.
An oxide layer 6 formed of an oxide of a Co layer,
It is electrically separated by an insulating layer 7 made of 2O3, SiO2, Si3N4 or the like.

Here, in the present embodiment, the first magnetic layer 2 and the second magnetic layer 4 are formed of a magnetic material such as a ferromagnetic metal. In this ferromagnetic metal, conduction electrons are spin-polarized. Since the pole is raised, the electronic states of the upward spin and the downward spin on the Fermi surface are different from each other.
When a magnetic tunnel junction is formed by sandwiching the tunnel barrier layer 3 formed of an insulator between the first magnetic layer 2 and the second magnetic layer 4 formed of such a ferromagnetic metal, When a voltage is applied to the tunnel barrier layer 3, the conduction electrons tunnel from the first magnetic layer 2 to the second magnetic layer 4 (or from the second magnetic layer 4 to the first magnetic layer 2) while maintaining their spins,
Tunnel barrier layer 3 between first magnetic layer 2 and second magnetic layer 4
, A tunnel phenomenon occurs, and the tunnel probability changes depending on the magnetization state of both magnetic layers, and the change in the tunnel probability appears as a change in the tunnel resistance. Accordingly, when the magnetizations of the first magnetic layer 2 and the second magnetic layer 4 are parallel, the resistance value is small, and when the magnetizations are antiparallel, the resistance value is large. Is larger, the resistance value of the tunnel resistance becomes larger, and a larger reproduction signal can be obtained.

Therefore, it is desirable that the first magnetic layer 2 and the second magnetic layer 4 are formed of a magnetic material having a high spin polarizability. As a magnetic material having a high spin polarizability, Fe having a large amount of polarization of the upper and lower spins on the Fermi surface is selected as the first component, and Co is selected as the second component.
Specifically, it is desirable to be formed of a material containing Fe, Co, and Ni as main components, and more desirably, Fe, Co, and Ni.
FeCo, NiFe, NiFeCo and the like are preferable. Note that N
When iFe is used, its elemental composition is NixFe100
-x, x is preferably from 0 to 82, and more specifically, Ni72Fe23, Ni51Fe49, Ni42Fe58, Ni
25Fe75, Ni9Fe91 and the like are desirable.

The second magnetic layer 4 is provided for recording magnetization information of "0" and "1" as a magnetization direction.
The magnetization direction is determined according to the magnetization information. The second magnetic layer 4 needs to be able to stably store the magnetization state and to have a higher coercive force than the first magnetic layer 2. For this reason, the second magnetic layer 4 is made of the composition described above.
It is desirable to be formed of a material containing Fe and Co as main components, and specifically, it is desirable to be formed of a magnetic film such as Fe, FeCo, and Co.

Further, an element such as Pt may be added to the second magnetic layer 4 for the purpose of controlling coercive force and improving corrosion resistance. When Fe is added to Co, the coercive force decreases, and when Pt is added, the coercive force increases. Therefore, when a material having an elemental composition of Co100-x-yFexPty is used for the second magnetic layer 4, for example, x And y may be adjusted to control the coercive force. Further, since the coercive force can be increased by increasing the substrate temperature during film formation, another method of controlling the coercive force may be a method of adjusting the substrate temperature during film formation. May be combined with the method for adjusting the element composition described above. Also, the coercive force of the first magnetic layer 2 can be adjusted by the element composition and the substrate temperature at the time of film formation, as described above.

The thickness of the second magnetic layer 4 needs to be a thickness having a sufficient coercive force for efficiently generating a magnetoresistance effect and storing and holding magnetization information, and is preferably 20 ° or more. More preferably, the angle is 80 ° or more. On the other hand, if the thickness is too large, there is a problem that the distance from the word electrode is too large to cause the magnetization reversal to occur easily.

The first magnetic layer 2 is provided for reading out the magnetization information “0” and “1” recorded by the second magnetic layer 4 by utilizing the magnetoresistance effect by spin tunneling. The first magnetic layer 2 has a coercive force lower than the coercive force of the second magnetic layer, and the direction of magnetization of only the first magnetic layer is reversed during reproduction. Note that a magnetoresistive element in which the coercive force of the first magnetic layer 2 and the coercive force of the second magnetic layer 4 are different from each other is called a coercive force difference type magnetoresistive element.

For this reason, the first magnetic layer 2 is desirably formed of a soft magnetic material containing Ni of the above-described composition, and specifically, is formed of a material mainly containing NiFe and NiFeCo. Is desirable. Note that NiFe
When x is used, if the element composition is NixFe100-x, x is desirably 30 to 82. Also, NiFeCo
When Ni is used, the element composition is changed to Nix (Fe100-yC
oy) If 100-x, x is preferably 30 to 82 and y is preferably 0 to 90.

The thickness of the first magnetic layer 2 depends on the coercive force of the second magnetic layer 4, but is preferably 20 ° or more, more preferably 80 ° or more. Also, it is preferably 5000 ° or less, more preferably 1000 ° or less.

The magnetic material as described above mainly has a magnetization axis in a plane, but is made of a ferrimagnetic material such as GdFe or TbFe which is a magnetic material having perpendicular magnetic anisotropy. And the second magnetic layer 4 may be formed. First magnetic layer 2
By forming the second magnetic layer 4 with a ferrimagnetic material, a magnetoresistive element having a magnetization axis in the thickness direction of the magnetic layer can be realized. Such a perpendicular magnetoresistance effect element has an advantage that even if the area of the magnetic layer is reduced, curling of magnetization such as in-plane magnetization does not occur. Furthermore, in the present embodiment, the oxide layer (or nitride layer) 6 is formed of the oxide (or nitride) of the magnetic material constituting the second magnetic layer 4, and in particular, ferrimagnetic The oxide of the material has higher resistance than oxides of Co, NiFe, etc., and is more effective in reducing leakage current and separating elements.

The tunnel barrier layer 3 is formed of a thin insulator as described above. In order for conduction electrons to tunnel while holding spin, the insulator must be nonmagnetic. Further, by minimizing the thickness of a part thereof, the magnetoresistance effect can be further enhanced. Also,
The tunnel barrier layer 3 may be an oxide layer obtained by oxidizing a nonmagnetic metal film. An example of forming the oxide layer is an example in which a part of an Al film is oxidized in air to form an Al2O3 layer. . This Al2O3 layer is desirable because it has high insulating properties and is dense. Also, the tunnel barrier layer 3
Means AlNx, SiO2 other than AlxOy such as Al2O3
It is desirable to be formed of a material containing x, SiNx and NiOx as main components. The thickness of the tunnel barrier layer 3 is 4
Å25 ° is desirable, and preferably uniform.

Hereinafter, the manufacturing process of the magnetoresistance effect element of the present invention will be described.

FIG. 2 is a view for explaining a manufacturing process of the magnetoresistive element shown in FIG. 1 and shows a cross section of the magnetoresistive element.

First, a substrate-side electrode layer 1, a first magnetic layer 2, a tunnel barrier layer 3, and a second magnetic layer 4 are formed on a substrate (not shown).
Are sequentially laminated (FIG. 2A).

The substrate-side electrode layer 1, the first magnetic layer 2, and the second magnetic layer 4 can be formed by, for example, an ion beam sputtering method. The tunnel barrier layer 3 is formed by forming a metal aluminum film by ion beam sputtering and oxidizing the metal aluminum film by oxygen plasma.

Next, the second photolithography method is used.
A resist pattern 21 is formed on the element portion 22 of the magnetic layer 4 (FIG. 2B).

Next, the second magnetic layer 4 other than the element portion 22 is dry-etched by Ar ion milling or the like.
Is partially removed by etching (FIG. 2C). Here, the distance was controlled based on the etching time so that the distance from the etching surface to the tunnel barrier layer 3 was about 5 nm or less. When the etching is performed up to the tunnel barrier layer 3 as in the conventional technique, the allowable range of the etching is the film thickness (1.2 nm) of the tunnel barrier layer 3, but in the present embodiment, the allowable range of the etching is limited. About 5
About 6 nm.

Next, the second magnetic layer 4 remaining without being etched away is oxidized by exposure to oxygen plasma (30 W: 20 min) in an oxygen atmosphere (1 Pa or less) until it reaches the tunnel barrier layer 3. The oxide layer 6 is formed by increasing the resistance (FIG. 2 (d)). Further, the entire surface is sputtered to perform Al 2 O 3 and SiO
2. An insulating layer 7 of Si3N4 or the like is formed.

Thereafter, a window is opened on the upper surface of the element portion 22 by the lift-off method, and the upper electrode 5 is formed, whereby a magnetoresistive element having a cross-sectional structure as shown in FIG. it can.

As described above, in this embodiment, the etching for forming the element portion 22 of the magnetoresistive element is performed halfway through the second magnetic layer 4 and the remaining second magnetic layer 4 is oxidized. Therefore, the allowable range of etching is widened, so that the first magnetic layer 2 and the substrate-side electrode 1 are not etched. Therefore,
Since the material of the first magnetic layer 2 and the material of the substrate-side electrode material 1 do not adhere to the side of the tunnel barrier layer 3 during etching, a magnetoresistive element can be manufactured, so that an electrical short circuit is avoided. Can be.

(Second Embodiment) FIG. 3 is a sectional view showing a second embodiment of the magnetoresistance effect element of the present invention.

As shown in FIG. 3, the present embodiment is different from the first embodiment shown in FIG. 1 in that a portion larger than the second magnetic layer 4 is provided between the second magnetic layer 4 and the upper electrode 5. Have an area,
And third magnetic layer 31 magnetically coupled to second magnetic layer 4
Is provided. Other configurations and operations are the same as those of the first embodiment.

In the magnetoresistive effect element configured as described above, the coercive force required for holding the data may be covered by the combined coercive force of the second magnetic layer 4 and the third magnetic layer 31. The magnetic layer 4 can be formed thin. Further, by forming the second magnetic layer 4 thin, the amount of etching of the second magnetic layer 4 is reduced, so that the accuracy of controlling the etching depth is improved, and the yield at the time of manufacturing is significantly improved. it can.

In order to realize a high-density memory, the second
Even if the magnetic layer 4 is miniaturized, since the third magnetic layer 31 having a larger area than the second magnetic layer 4 and the second magnetic layer 4 are magnetically coupled, the fineness of the second magnetic layer 4 is reduced. Curling of magnetization due to the formation can be suppressed. Therefore, even if the second magnetic layer 4 is miniaturized, the magnetization direction can be made parallel or anti-parallel between the first magnetic layer 2 and the second magnetic layer 4 opposed via the tunnel barrier layer 3. An integrated magnetoresistive element and a magnetic thin film memory (MRAM) can be realized.

In this embodiment, since the third magnetic layer 31 is provided, the thickness of the second magnetic layer 4 can be reduced as described above. Is preferably 5 to 20 °.

The required function, thickness, material and the like of the third magnetic layer 31 are the same as those of the second magnetic layer 4 alone except that the required coercive force is a combined coercive force with the second magnetic layer. Of the second magnetic layer 4.

(Third Embodiment) FIG. 4 is a sectional view showing a magnetoresistive element according to a second embodiment of the present invention.

As shown in FIG. 4, this embodiment is different from the first embodiment shown in FIG. 1 in that the first magnetic layer 2 is replaced between the substrate side electrode 1 and the first magnetic layer 2. The difference is that an antiferromagnetic layer 41 (for example, FeMn having a thickness of 20 nm) is provided. Other configurations and operations are the same as those of the first embodiment.

In the magnetoresistive element constructed as described above, the magnetization direction of the first magnetic layer 2 is changed by the antiferromagnetic layer 41 provided between the substrate-side electrode 1 and the first magnetic layer 2. The information is read out depending on the element resistance depending on whether the magnetization direction of the second magnetic layer 4 (corresponding to the recorded information) is “parallel” or “anti-parallel” with the magnetization of the first magnetic layer 2.

The configuration of a magnetic thin film memory using the above-described magnetoresistive effect element of the present invention will be described below.

First, a 1-bit configuration of a magnetic thin film memory in which the magnetoresistive element of the present invention is combined with an element selecting diode or transistor will be described.

FIG. 5 shows the magnetoresistance effect element of the present invention and the MO.
FIG. 3 is a diagram illustrating a configuration example of a magnetic thin film memory in which an S transistor (MOS-FET) is combined. In FIG. 5, one magnetoresistive element and one MOS-F
One bit of the magnetic thin film memory is configured in combination with ET.

As shown in FIG. 5, in this configuration example, one end of a magnetoresistive element 51 of the present invention is connected to the drain electrode of a MOS-FET 52 formed on a Si substrate (not shown), and the other end is connected. It is connected to the bit line 53. In writing to the magnetoresistive element 51, a current is applied to the bit line 53 and the word line 54 at the same time.
This is performed for one memory layer as the magnetization direction. On the other hand, reading from the magnetoresistive element 51 is performed by the MOS-FET 52.
, The magnetization direction recorded in the memory layer of the magnetoresistive element 51 is read from the resistance value.

Next, a description will be given of an array structure of memory cells when the magnetoresistive elements of the present invention are arranged in a matrix to form a magnetic thin film memory.

FIG. 6 is a diagram showing an example of the configuration of a magnetic thin film memory in which the magnetoresistance effect elements of the present invention are arranged in a matrix. In FIG. 6, the MOS-FET section is omitted.

As shown in FIG. 6, in the present configuration example, one set of conductive lines functioning as parallel word lines 601 to 603 in a horizontal plane and a parallel sense line 6 in another horizontal plane are provided.
A set of conductive lines functioning as 11 to 613 and a set of conductive lines functioning as word lines 604 to 606 are provided below sense lines 611 to 613 via an insulating layer (not shown). The magnetoresistance effect element of the present invention,
Word line 6 in the crossing region vertically spaced between word lines 601 to 603 and sense lines 611 to 613
It is located at each intersection between 01-603 and sense lines 611-613. Note that the word lines 601 to 603 and the sense lines 611 to 613 are arranged to cross each other when viewed from above, for example, to be perpendicular to each other when viewed from above.

Word lines 601 to 606 are provided mainly for recording signals, and sense lines 611 to 613 are provided.
Is provided mainly for extracting a reproduction signal.

The memory cell array configured as described above can be formed on a substrate such as a silicon substrate on which other circuits exist. Although not shown, a bit line (not shown) and a word line 6
Usually, a layer of an insulating material is provided between 01 and 603.

[0068]

As described above, in the present invention,
A magnetic tunnel junction in which a first magnetic layer, a tunnel barrier layer formed of a thin insulator, and a second magnetic layer are sequentially stacked, and a tunnel is provided between the first magnetic layer and the second magnetic layer. In a magnetoresistive element in which a tunnel current flows through a barrier layer, an oxide layer or a nitride layer formed of an oxide or a nitride of a material constituting a second magnetic layer, and an oxide layer or a nitride layer on the oxide layer or a nitride layer And an insulating layer formed of an insulator is arranged so as to limit a region of the second magnetic layer through which a tunnel current flows.

Further, according to the present invention, the magnetoresistive element having the above-described configuration includes a step of sequentially laminating a first magnetic layer, a tunnel barrier layer, and a second magnetic layer; A step of etching away leaving a part other than a region where a tunnel current flows, and a step of oxidizing or nitriding a region of the second magnetic layer that is not etched away to form an oxide layer or a nitride layer; Forming an insulating layer on the oxide layer or the nitride layer.

As described above, the second magnetic layer is etched away while leaving a portion other than the region where the tunnel current flows, and the remaining second magnetic layer is oxidized or nitrided to increase the resistance, thereby increasing the second magnetic layer. Since the allowable range when etching the layer is greatly expanded as compared with the related art, the first magnetic layer and the substrate-side electrode are not etched.

This makes it possible to manufacture the magnetoresistive element without the constituent materials of the first magnetic layer and the substrate-side electrode adhering to the tunnel barrier layer side during the etching step. It is possible to avoid an electrical short circuit caused by the deposits. In addition, since the allowable range when etching is widened, etching can be performed with good reproducibility, and the yield at the time of manufacturing the magnetoresistive element can be greatly improved. It can be manufactured with good reproducibility.

The second magnetic layer has an area larger than the area of the second magnetic layer on the second magnetic layer, and is magnetically coupled to the second magnetic layer at the junction with the second magnetic layer. In the case where the three magnetic layers are provided, the coercive force required for storing data can be covered by the combined coercive force of the second magnetic layer and the third magnetic layer.
As a result, the second magnetic layer can be formed thin. Therefore, since the etching amount of the second magnetic layer is reduced, the accuracy of controlling the etching depth is improved, and the yield during manufacturing can be significantly improved.

When the third magnetic layer is provided, even if the second magnetic layer is miniaturized to realize a high density memory,
Since the second magnetic layer and the third magnetic layer are magnetically coupled, it is possible to suppress the occurrence of curling of magnetization due to miniaturization in the second magnetic layer. Therefore, even if the second magnetic layer is miniaturized, the first magnetic layer which is opposed via the tunnel barrier layer is formed.
Since the magnetization direction can be made parallel or anti-parallel with the magnetic layer, a highly integrated magnetoresistive element and magnetic thin film memory (MRAM) can be realized.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a first embodiment of a magnetoresistive element according to the present invention.

FIG. 2 is a diagram for explaining a manufacturing process of the magnetoresistance effect element shown in FIG.

FIG. 3 is a sectional view showing a second embodiment of the magnetoresistive element of the present invention.

FIG. 4 is a sectional view showing a third embodiment of the magnetoresistive element of the present invention.

FIG. 5 is a diagram showing a configuration example of a magnetic thin film memory in which a magnetoresistive element of the present invention and a MOS transistor (MOS-FET) are combined.

FIG. 6 is a diagram showing a configuration example of a magnetic thin film memory in which the magnetoresistive elements of the present invention are arranged in a matrix.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate side electrode 2 1st magnetic layer 3 Tunnel barrier layer 4 2nd magnetic layer 5 Upper electrode 6 Oxide layer 7 Insulating layer 21 Resist pattern 22 Element part 31 Third magnetic layer 41 Antiferromagnetic layer 601-606 Word line 611 ~ 613 Sense line

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01F 10/32 H01F 10/32 H01L 43/12 H01L 43/12

Claims (10)

[Claims] 1. A magnetic tunnel junction comprising a first magnetic layer, a tunnel barrier layer formed of a thin-film insulator, and a second magnetic layer, which are sequentially stacked, wherein the first magnetic layer and the second magnetic layer In a magnetoresistive effect element that causes a tunnel current to flow between the magnetic layer and the magnetic layer via the tunnel barrier layer, an oxide layer formed of an oxide of a material forming the second magnetic layer; A magnetoresistive element, wherein the magnetoresistance effect element is arranged so as to limit an area of the second magnetic layer through which the tunnel current flows, and an insulating layer formed of an insulator. 2. A magnetic tunnel junction comprising a first magnetic layer, a tunnel barrier layer formed of a thin-film insulator, and a second magnetic layer sequentially stacked, wherein the first magnetic layer and the second magnetic layer A magnetoresistive effect element that allows a tunnel current to flow between the magnetic layer and the tunnel barrier layer via the tunnel barrier layer; a nitride layer formed of a nitride of a material forming the second magnetic layer; A magnetoresistive element, wherein the magnetoresistance effect element is arranged so as to limit an area of the second magnetic layer through which the tunnel current flows, and an insulating layer formed of an insulator. 3. The method according to claim 1, wherein the first magnetic layer and the second magnetic layer are formed of a magnetic material having perpendicular magnetic anisotropy, and are magnetized in a layer thickness direction. The magnetoresistive effect element according to the above. 4. The first magnetic layer and the second magnetic layer,
4. The coercive force is different from each other.
The magnetoresistive element according to any one of the above items. 5. The second magnetic layer is joined to the second magnetic layer on a surface opposite to a side joined to the tunnel barrier layer, and has an area larger than an area of the second magnetic layer; 5. The magnetoresistive device according to claim 1, further comprising a third magnetic layer magnetically coupled to the second magnetic layer at a junction with the second magnetic layer. Effect element. 6. The semiconductor device according to claim 1, further comprising an antiferromagnetic layer joined to said first magnetic layer on a surface of said first magnetic layer opposite to a side joined to said tunnel barrier layer. 2. The magnetoresistive element according to claim 1. 7. The method according to claim 1, wherein the first magnetic layer, the tunnel barrier layer, and the second magnetic layer are sequentially stacked; and the second magnetic layer. A step of etching and removing a part of the second magnetic layer that is not removed by etching, leaving a portion other than a region where the tunnel current flows; and a step of forming the oxide layer by oxidizing a region of the second magnetic layer that is not removed by etching. Forming the insulating layer on an oxide layer. 8. The method for manufacturing a magnetoresistive element according to claim 2, wherein the first magnetic layer, the tunnel barrier layer, and the second magnetic layer are sequentially stacked, and the second magnetic layer is formed. Forming a nitride layer by etching a portion of the second magnetic layer that has not been removed by etching, leaving a portion other than the region through which the tunnel current flows; Forming the insulating layer on a nitride layer. 9. A magnetic thin film memory for recording and reproducing information by using the magnetoresistive element according to claim 1. Description: 10. A magnetic thin film memory which records and reproduces information using a magnetoresistive element manufactured by the method of manufacturing a magnetoresistive element according to claim 7.