JP2001156357A - Magneto-resistance effect element and magnetic recording element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magneto-resistance effect element wherein the increase of an applied voltage for a desired output voltage value causes less decrease in magneto-resistance change ratio, no writing rotates the magnetic moment of a part of the magnetization adhesion layer for gradual drop of an output, and an inversion magnetic field is designed at will. SOLUTION: A magneto-resistance effect element having a ferromagnetic double tunnel joint is provided where first anti-ferromagnetic layer 11/first ferromagnetic layer 12/first dielectrics layer 13/second ferromagnetic layer 14/second dielectrics layer 15/third ferromagnetic layer 16/second anti- ferromagnetic layer 17 are laminated. Here, the second ferromagnetic layer 14 of a free layer comprises a Co base alloy or a 3-layer film comprising Co base alloy/Ni-Fe alloy/Co base alloy, with first or third ferromagnetic layer applied with a tunnel current.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a magnetoresistance effect element having a ferromagnetic double tunnel junction and a magnetic recording element using the same.

[0002]

2. Description of the Related Art The magnetoresistance effect is a phenomenon in which the electric resistance changes when a magnetic field is applied to a ferromagnetic material. A magnetoresistive effect element (MR element) using this effect has excellent temperature stability and a wide operating temperature range. Therefore, it is used for a magnetic head or a magnetic sensor. Effect memories, MRAM) and the like are also being prototyped. These magnetoresistive elements are required to have high sensitivity to an external magnetic field and a high response speed.

In recent years, a magnetoresistance effect element having a sandwich film in which a dielectric layer is inserted between two ferromagnetic layers and utilizing a tunnel current flowing perpendicularly to the film surface, a so-called ferromagnetic tunnel junction element (tunnel junction) Type magnetoresistive element,
TMR) has been found. A ferromagnetic tunnel junction device exhibits a magnetoresistance ratio of 20% or more (J. Appl.
hys. 79, 4724 (1996)), the possibility of application to magnetic heads and magnetoresistive memories has been increasing. However, this ferromagnetic single tunnel junction device has a problem that when the applied voltage is increased to obtain a desired output voltage value, the rate of change in magnetoresistance is considerably reduced (Phy).
s. Rev .. Lett. 74, 3273 (199
5)).

Further, there has been proposed a ferromagnetic single tunnel junction device having a structure in which an antiferromagnetic layer is provided in contact with one ferromagnetic layer constituting a ferromagnetic single tunnel junction and this ferromagnetic layer is used as a magnetization fixed layer. (Japanese Patent Laid-Open No. 10-4227).
However, in this ferromagnetic single tunnel junction device,
When the applied voltage is increased to obtain a desired output voltage value, there is a problem that the rate of change in magnetoresistance is considerably reduced.

On the other hand, in a magnetoresistive effect element having a ferromagnetic double tunnel junction having a laminated structure of Fe / Ge / Fe / Ge / Fe, a large MR ratio can be obtained due to the spin-polarized resonance tunnel effect. Is theoretically expected (Phys. Rev. B56, 5484).
(1997)). However, these are the results at low temperatures (8K), and it is not expected that the above-mentioned phenomenon will occur at room temperature. In this example, Al ₂ O ₃ , SiO ₂ ,
No dielectric such as AlN is used. Further, the ferromagnetic double tunnel junction device having the above structure does not have a ferromagnetic layer pinned by an antiferromagnetic layer. As a result of the rotation, there is a problem that the output gradually decreases.

Further, a ferromagnetic multi-tunnel junction device including a dielectric layer in which magnetic particles are dispersed has been proposed (P.
hys. Rev .. B56 (10), R5747 (199
7)); Journal of the Japan Society of Applied Magnetics 23, 4-2, (1999);
Appl. Phys. Lett. 73 (19), 282
9 (1998)). Since these elements can achieve a magnetoresistance ratio of 20% or more, application to magnetic heads and magnetoresistance memories is expected. In particular, the ferromagnetic double tunnel junction element has an advantage that the decrease in the magnetoresistance ratio is small even when the applied voltage is increased.
However, even in these devices, since there is no ferromagnetic layer pinned by an antiferromagnetic layer, when used in an MRAM or the like, the magnetic moment of a part of the magnetization fixed layer is rotated by several writings, so that the output gradually increases. There is a problem of lowering. Further, a ferromagnetic double tunnel junction device using a ferromagnetic layer composed of a continuous film (Appl. Phys. Lett. 73 (1)
9), 2829 (1998)), since the ferromagnetic layer sandwiched between the dielectric layers is formed of a single layer film of Co, Ni ₈₀ Fe ₂₀ or the like, the reversal magnetic field for reversing the magnetic moment by the current magnetic field can be freely set. In addition, there is a problem that the coercive force is increased when Co or the like having large magnetostriction is processed.

When a ferromagnetic tunnel junction device is applied to an MRAM or the like, a current is applied to a wiring (bit line or word line) to externally connect a ferromagnetic layer (free layer, magnetic recording layer) whose magnetization is not fixed. A magnetic field (current magnetic field) is applied to reverse the magnetization of the magnetic recording layer. However, the magnetic field (switching magnetic field) required for reversing the magnetization of the magnetic recording layer increases as the memory cell shrinks, and a large current needs to flow through the wiring for writing. For this reason, the power consumption at the time of writing increases as the storage capacity of the MRAM increases. For example, in a high-density MRAM device of 1 Gb or more, there is a possibility that the current density flowing through the wiring at the time of writing by the current magnetic field increases, and the wiring may be melted.

As one method for dealing with such a problem, an attempt has been made to inject a spin-polarized spin current to perform magnetization reversal (J. Mag. Mag. Ma.
t. , 159 (1996) L1; Mag. Mag.
Mat. , 202 (1999) 157). However, in the method of performing magnetization reversal by injecting a spin current, the current density flowing through the TMR element increases, and the tunnel insulating layer may be broken. Moreover, an element structure suitable for spin injection has not yet been proposed.

[0009]

SUMMARY OF THE INVENTION It is an object of the present invention to increase the applied voltage in order to obtain a desired output voltage value, but the magnetoresistance ratio does not decrease so much. To provide a tunnel-junction magnetoresistive element and a magnetic recording element capable of freely designing a reversal magnetic field for reversing a moment of a ferromagnetic layer without causing a problem that a moment rotates and an output gradually decreases. is there.

Another object of the present invention is to provide a tunnel junction type magnetoresistive element and a magnetic recording element capable of suppressing an increase in a reversal magnetic field for reversing the magnetization of a magnetic recording layer accompanying a reduction in a memory cell. It is in.

Still another object of the present invention is to provide a magnetic recording element having a structure suitable for spin injection and capable of suppressing a current density flowing through wiring and a TMR element, and a method for writing to the magnetic recording element. It is in.

[0012]

The first magnetoresistance effect element according to the present invention comprises a first antiferromagnetic layer / first ferromagnetic layer / first ferromagnetic layer.
A magnetoresistive effect element having a ferromagnetic double tunnel junction in which a dielectric layer of a second type / second ferromagnetic layer / second dielectric layer / third ferromagnetic layer / second antiferromagnetic layer is laminated The second ferromagnetic layer is made of a Co-based alloy or a Co-based alloy / Ni-F
It is formed of a three-layer film of an e-alloy / Co-based alloy, and is characterized in that a tunnel current flows through the first to third ferromagnetic layers.

[0013] The second magnetoresistive element of the present invention comprises a first magnetoresistive element.
Ferromagnetic layer / first dielectric layer / second ferromagnetic layer / first antiferromagnetic layer / third ferromagnetic layer / second dielectric layer / fourth ferromagnetic layer Wherein the first and fourth ferromagnetic layers are a Co-based alloy or a Co-based alloy / Ni-Fe alloy /
It comprises a three-layered film of a Co-based alloy, and is characterized in that a tunnel current flows through the first to fourth ferromagnetic layers.

A third magnetoresistive element according to the present invention comprises a first magnetoresistive element.
Antiferromagnetic layer / first ferromagnetic layer / first dielectric layer / second
Ferromagnetic layer / second antiferromagnetic layer / third ferromagnetic layer / second
A magnetoresistive effect element having a ferromagnetic double tunnel junction in which a dielectric layer, a fourth ferromagnetic layer, and a third antiferromagnetic layer are stacked, wherein the first and fourth ferromagnetic layers or The second and third ferromagnetic layers are made of a Co-based alloy or a three-layered film of a Co-based alloy / Ni-Fe alloy / Co-based alloy, and a tunnel current flows through the first to fourth ferromagnetic layers. It is characterized by.

[0015] The fourth magnetoresistive element of the present invention comprises a first magnetoresistive element.
Ferromagnetic layer / first dielectric layer / second ferromagnetic layer / first nonmagnetic layer / third ferromagnetic layer / second nonmagnetic layer / fourth ferromagnetic layer / second A magnetoresistive element having a ferromagnetic double tunnel junction in which a dielectric layer / fifth ferromagnetic layer is stacked, wherein second, third and fourth ferromagnetic layers adjacent to each other form a nonmagnetic layer. The first and fifth ferromagnetic layers are made of a Co-based alloy or a Co-based alloy / Ni-
A three-layer film of an Fe alloy / Co-based alloy is provided, and a tunnel current flows through the first to fifth ferromagnetic layers.

In the magnetoresistance effect element according to the present invention, the Co-based alloy or the Co-based alloy / Ni--Fe alloy / Co
The thickness of the three-layer film of the base alloy is preferably 1 to 5 nm.

The magnetic recording element of the present invention is characterized by comprising a transistor or a diode and any one of the first to fourth magnetoresistive elements.

According to a magnetic recording element of the present invention, in a magnetic recording element including a transistor or a diode and a first or third magnetoresistive element, at least an uppermost antiferromagnetic layer of the magnetoresistive element is formed. It is characterized by forming a part of a bit line.

According to another magnetic recording element of the present invention, there is provided a first magnetization fixed layer having a fixed magnetization direction, a first dielectric layer, a magnetic recording layer whose magnetization direction is reversible, and a second dielectric layer. Body layers,
A second magnetization fixed layer having a fixed magnetization direction, wherein the magnetic recording layer includes a three-layer film of a magnetic layer, a non-magnetic layer, and a magnetic layer, and two magnetic layers forming the three-layer film. The layers are antiferromagnetically coupled, and the magnetizations of regions of the two pinned layers that are in contact with the dielectric layer are substantially antiparallel.

Still another magnetic recording element of the present invention comprises a first magnetization fixed layer having a fixed magnetization direction, a first dielectric layer, a magnetic recording layer whose magnetization direction is reversible, and a second magnetization fixed layer. A dielectric layer and a second magnetization fixed layer having a fixed magnetization direction, wherein the magnetic recording layer includes a three-layer film of a magnetic layer, a non-magnetic layer, and a magnetic layer; The constituent two magnetic layers are antiferromagnetically coupled, and the second magnetization pinned layer includes a three-layer film of a magnetic layer, a non-magnetic layer, and a magnetic layer. The magnetic layer is antiferromagnetically coupled, and the length of the first magnetization fixed layer is formed longer than the lengths of the second magnetization fixed layer and the magnetic recording layer. The magnetization of a region of the layer in contact with the dielectric layer is substantially antiparallel.

In the method for writing to the magnetic recording element, a spin current is supplied to the magnetic recording layer through the first or second magnetization pinned layer constituting the magnetic recording element, and a current is supplied to the write wiring. And applying a current magnetic field to the magnetic recording layer.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The basic structure of a magnetoresistive element according to the present invention will be described below with reference to FIGS.

FIG. 1 shows a first magnetoresistive element according to the present invention. In this magnetoresistance effect element 10, the first antiferromagnetic layer 11 / first ferromagnetic layer 12 / first dielectric layer 13 / second ferromagnetic layer 14 / second dielectric layer 15 / second The three ferromagnetic layers 16 / the second antiferromagnetic layers 17 are stacked to form a ferromagnetic double tunnel junction. In this element, a tunnel current flows through the first to third ferromagnetic layers. In this element,
The first and third ferromagnetic layers 12 and 16 are pinned layers (magnetic pinned layers), and the second ferromagnetic layer 14 is a free layer (magnetic recording layer in the case of MRAM). In the first magnetoresistance effect element, the second ferromagnetic layer 14 as a free layer is made of a Co-based alloy (for example, Co-Fe, Co-Fe-Ni, etc.) or a Co-based alloy / Ni-Fe alloy / Co-based alloy. Consisting of three layers.

FIG. 2 shows a second magnetoresistive element according to the present invention. In this magnetoresistive element 20, the first ferromagnetic layer 21 / first dielectric layer 22 / second ferromagnetic layer 23 / first ferromagnetic layer 23
The antiferromagnetic layer 24 / third ferromagnetic layer 25 / second dielectric layer 26 / fourth ferromagnetic layer 27 are stacked to form a ferromagnetic double tunnel junction. In this element, a tunnel current flows through the first to fourth ferromagnetic layers. In this element, the second and third ferromagnetic layers 23 and 25 are pin layers, and the first and fourth ferromagnetic layers 21 and 27 are free layers (magnetic recording layers in the case of MRAM). In the second magnetoresistance effect element, the first and fourth ferromagnetic layers 2 which are free layers
1, 27 are Co-based alloys (for example, Co-Fe, Co-F
e-Ni) or Co-based alloy / Ni-Fe alloy / C
It consists of a three-layer film of an o-based alloy.

FIG. 3 shows a third magnetoresistive element according to the present invention. In the magnetoresistive element 30, the first antiferromagnetic layer 31 / first ferromagnetic layer 32 / first dielectric layer 33 / second ferromagnetic layer 34 / second antiferromagnetic layer 35 / Third ferromagnetic layer 36 / second dielectric layer 37 / fourth ferromagnetic layer 38 /
The third antiferromagnetic layer 39 is stacked to form a ferromagnetic double tunnel junction. In this element, a tunnel current flows through the first to fourth ferromagnetic layers. In this device, when the second and third ferromagnetic layers 34 and 36 are designed as pinned layers, the first and fourth ferromagnetic layers 32 and 38 are free layers (magnetic recording layers in the case of MRAM). become. Meanwhile, the first
When the fourth and fourth ferromagnetic layers 32 and 38 are designed as pinned layers, the second and third ferromagnetic layers 34 and 36 become free layers (magnetic recording layers in the case of MRAM). In the third magnetoresistive element, the first and fourth ferromagnetic layers 32 and 38 or the second
And any pair of the third ferromagnetic layers 34 and 36 is made of Co.
Base alloy (for example, Co-Fe, Co-Fe-Ni, etc.)
Alternatively, it is formed of a three-layer film of a Co-based alloy / Ni-Fe alloy / Co-based alloy.

FIG. 4 shows a fourth magnetoresistive element according to the present invention. In this magnetoresistive element 40, the first ferromagnetic layer 41 / first dielectric layer 42 / second ferromagnetic layer 43 / first ferromagnetic layer 43
Non-magnetic layer 44 / third ferromagnetic layer 45 / second non-magnetic layer 46 / fourth ferromagnetic layer 47 / second dielectric layer 48 / fifth
Are laminated to form a ferromagnetic double tunnel junction. In this element, a tunnel current flows through the first to fifth ferromagnetic layers. The second, third, and fourth ferromagnetic layers 43, 45, and 47 adjacent to each other include a nonmagnetic layer 44,
Antiferromagnetic coupling is provided via 46. In this device, the second to fourth ferromagnetic layers 43, 45, and 47 are pinned layers, and the first and fifth ferromagnetic layers 41 and 49 are free layers (MRA).
M, the magnetic recording layer). In the fourth magnetoresistance effect element, the first and fifth ferromagnetic layers 4 which are free layers
1, 49 are Co-based alloys (eg, Co-Fe, Co-F
e-Ni) or Co-based alloy / Ni-Fe alloy / C
It consists of a three-layer film of an o-based alloy.

FIG. 5 shows a modification of the fourth magnetoresistive element. The magnetoresistive element of FIG. 5 has a structure in which an antiferromagnetic layer is provided in the middle of the third ferromagnetic layer 45 instead of the third ferromagnetic layer 45 of FIG.
/ A three-layer film of the ferromagnetic layer 45b is formed.

An antiferromagnetic layer may be provided in contact with at least one of the second and fourth ferromagnetic layers 43 and 47 constituting the fourth magnetoresistance effect element.

Since the magnetoresistance effect element having the ferromagnetic double tunnel junction according to the present invention has at least two dielectric layers, the voltage effectively applied to one tunnel junction is small. For this reason, there is an advantage that the voltage dependence of the magnetoresistance change rate is not remarkable, and the decrease in the magnetoresistance change rate is small even if the applied voltage is increased to obtain a desired output voltage value.

In the magnetoresistive element having a ferromagnetic double tunnel junction according to the present invention, in any of the above four basic structures, the magnetization fixed layer (pin layer) has an antiferromagnetic layer or an antiferromagnetic coupling spin. Therefore, the problem that the magnetic moment of the magnetization fixed layer does not rotate even when writing is repeated and the output gradually decreases can be prevented.

In the magnetoresistive element according to the present invention, the free layer (magnetic recording layer) has a Co-based alloy (Co-Fe, Co-Fe-Ni, etc.) or a Co-based alloy / Ni-Fe alloy with small magnetostriction. A three-layer film of / Co-based alloy is used.
The free layer is the second ferromagnetic layer 14 in FIG. 1, the first and fourth ferromagnetic layers 21 and 27 in FIG. 2, the first and fourth ferromagnetic layers 32 and 38 in FIG.
4 and any pair of the third ferromagnetic layers 34 and 36, FIG.
And the first and fifth ferromagnetic layers 41, 4 in FIG.
9 For this reason, the reversal magnetic field can be suppressed small, and the current flowing through the wiring for applying the current magnetic field can be reduced. Co-based alloy / Ni-Fe alloy / C for free layer
When a three-layered film of an o-based alloy is used, the magnitude of the switching magnetic field can be freely designed by changing the thickness ratio of each layer.

In particular, in the magnetoresistive element having the structure shown in FIG. 3, the reversal magnetic field is determined not by the coercive force of the magnetic material but by the exchange magnetic field generated at the interface between the magnetic material and the antiferromagnetic material. The exchange magnetic field is applied to the first and third antiferromagnetic layers 3.
1, 39 and the type and thickness of the second antiferromagnetic layer 35;
There is an advantage that it can be freely designed by changing the alloy composition. For this reason, the basic structure of FIG.
It shows favorable characteristics among the three basic structures. Further, the structure shown in FIG. 3 is particularly effective when the processing size is submicron and the bonding area is very small. That is, when the processing dimension becomes submicron, the write magnetic field tends to fluctuate due to processing damage and the influence of the domain of the free layer (magnetic recording layer). On the other hand, when the antiferromagnetic layer is provided in contact with the free layer (magnetic recording layer) as in the structure of FIG. 3, the write magnetic field can be designed based on the exchange magnetic field. Can be avoided. For this reason, the yield of the element can be significantly improved.

On the other hand, when the magnetoresistance effect element of the present invention is finely processed, it is preferable that the entire film thickness is small in order to increase the processing accuracy. In this regard, FIG. 2, FIG. 4 or FIG.
It is preferable that the structure has as few antiferromagnetic layers as possible.

Next, the materials used for each layer constituting the magnetoresistance effect element of the present invention will be described. As described above, the free layer (magnetic recording layer) has a Co-based alloy (Co
-Fe, Co-Fe-Ni, etc.) or Co-based alloy / Ni
-A three-layer film of an Fe alloy / Co-based alloy is used. Also,
Ag, Cu, Au, Al, Mg, Si,
Bi, Ta, B, C, O, N, Si, Pd, Pt, Z
Some non-magnetic elements such as r, Ir, W, Mo, and Nb may be added. The magnetoresistive element of the present invention can be applied to a magnetoresistive magnetic head, a magnetic recording element, a magnetic field sensor, and the like. In these applications, it is preferable to impart uniaxial anisotropy to the free layer.

The thickness of the free layer is 0.1 nm to 100 n
m is preferable, and 0.5 to 50 nm is more preferable.
5 nm is most preferred. If the thickness of the free layer is less than 1 nm, the free layer may not be a continuous film, and may have a so-called granular structure in which ferromagnetic particles are dispersed in the dielectric layer. As a result, it becomes difficult to control the junction characteristics and the switching magnetic field may vary. In addition, depending on the size of the fine particles, the particles become superparamagnetic at room temperature and the MR change rate is extremely reduced. On the other hand, when the thickness of the free layer exceeds 5 nm, the magnetoresistive element is
For example, when an element is designed in accordance with the 0.25 μm rule, the switching magnetic field exceeds 100 Oe, so that a large current needs to flow through the wiring. When the thickness of the free layer exceeds 5 nm, the so-called bias dependency, in which the MR change rate decreases as the bias voltage increases, becomes remarkable. If the thickness of the free layer is in the range of 1 to 5 nm, the increase in the switching field and the bias dependency of the MR ratio due to miniaturization are suppressed. If the thickness of the free layer is within this range, the processing accuracy will be good.

The material of the pinned layer is not particularly limited.
o, Ni or an alloy thereof, magnetite having a large spin polarizability, CrO ₂ , RXMnO _3-y (R; rare earth,
X; oxides such as Ca, Ba, Sr), NiMnSb,
A Heusler alloy such as PtMnSb can be used. The pinned layer must have a thickness that does not cause superparamagnetism, and is preferably 0.4 nm or more. Also,
Unless the ferromagnetism is lost, Ag, Cu,
Au, Al, Mg, Si, Bi, Ta, B, C, O,
Some non-magnetic elements such as N, Si, Pd, Pt, Zr, Ir, W, Mo, and Nb may be added.

When the pinned layer is strongly fixed by the antiferromagnetic layer, a three-layered film of a ferromagnetic layer / nonmagnetic layer / ferromagnetic layer is used as the pinned layer, and the two layers laminated via the nonmagnetic layer are used. May be antiferromagnetically coupled. The material of the nonmagnetic layer is not particularly limited, and metals such as Ru, Ir, Cr, and Cu can be used. By adjusting the thickness of the nonmagnetic layer, antiferromagnetic coupling occurs between the magnetic layers. The thickness of the nonmagnetic layer is preferably 0.5 to 2.5 nm.
In consideration of heat resistance and the strength of antiferromagnetic coupling, the thickness of the nonmagnetic layer is more preferably 0.7 to 1.3 nm. Specifically, Co (or Co-Fe) / Ru
/ Co (or Co-Fe), Co (or Co-F)
e) A three-layer film such as / Ir / Co (or Co-Fe).

As a material for the antiferromagnetic layer, Fe--Mn,
Pt-Mn, Pt-Cr-Mn, Ni-Mn, Ir-M
n, NiO, Fe ₂ O ₃ or the like can be used.

As a material of the dielectric layer, Al ₂ O ₃ , Si
O ₂ , MgO, AlN, Bi ₂ O ₃ , MgF ₂ , CaF ₂ ,
SrTiO ₂ , AlLaO ₃ or the like can be used.
The dielectric layer may be deficient in oxygen, nitrogen or fluorine. The thickness of the dielectric layer is not particularly limited, but is preferably thinner, preferably 10 nm or less, and more preferably 5 nm or less.

Base on which the magnetoresistive element of the present invention is formed
The plate is not particularly limited, and Si, SiO _Two, Al_TwoO_Three, Spy
Various substrates such as tunneling and AlN can be used. Departure
In the light source, the magnetoresistive effect element is
May be stacked on top of each other.
A protective layer may be provided. Materials for these underlayers and protective layers
As materials, Ta, Ti, W, Pt, Pd, Au, Ti
/ Pt, Ta / Pt, Ti / Pd, Ta / Pd, or
It is preferable to use a nitride such as TiNx.

The magnetoresistive effect element according to the present invention can be manufactured by forming each layer using a normal film forming method such as various sputtering methods, vapor deposition methods, molecular beam epitaxy methods and the like.

Next, a magnetic recording element (MRAM) to which the magnetoresistance effect element of the present invention is applied will be described. The MRAM to which the magnetoresistive element of the present invention is applied can obtain the effect that the current flowing through the wiring for applying the above-described current magnetic field can be reduced in both nondestructive readout and destructive readout.

As a specific form of the MRAM, a structure in which a ferromagnetic double tunnel junction element is stacked on a transistor or a structure in which a diode and a ferromagnetic double tunnel junction element are stacked is considered. As described below, in these structures, it is particularly preferable to apply the first or third ferromagnetic double tunnel junction element and use at least the uppermost antiferromagnetic layer as a part of the bit line.

Referring to FIGS. 6 and 7, an MRAM having a structure in which, for example, a first ferromagnetic double tunnel junction element (FIG. 1) is stacked on a MOS transistor will be described.
FIG. 6 is an equivalent circuit diagram of a 3 × 3 cell MRAM, and FIG. 7 is a sectional view of a 1 cell MRAM.

As shown in the equivalent circuit diagram of FIG. 6, the transistor 60 and the ferromagnetic double tunnel junction device (TM
R) 10 are arranged in a matrix. A read word line (WL1) 62 composed of the gate electrode of the transistor 60 and a write word line (WL2) 71 are arranged in parallel. The bit line (BL) 74 connected to the other end (upper part) of the TMR 10 is connected to a word line (WL1) 62.
And the word line (WL 2) 71.

As shown in FIG. 7, a transistor 60 including a silicon substrate 61, a gate electrode 62, source and drain regions 63 and 64 is formed. Gate electrode 62
Constitutes a read word line (WL1). A word line (WL2) 71 for writing is formed on the gate electrode 62 via an insulating layer. The contact metal 7 is formed in the drain region 64 of the transistor 60.
2 is connected, and a contact metal 72 is connected to a base layer 73. A ferromagnetic double tunnel junction device (TMR) 10 as shown in FIG. 1 is formed on the underlayer 73 at a position corresponding to above the write word line (WL2) 71. That is, the underlayer 7
3, a first antiferromagnetic layer 11 / first ferromagnetic layer (pinned layer) 12 / first dielectric layer 13 / second ferromagnetic layer (free layer) 14 / second dielectric Layer 15 / third ferromagnetic layer (pinned layer) 16a, 16b / second antiferromagnetic layer 17 are laminated. In this example, the pinned layer is composed of two layers 16a and 16b. The second antiferromagnetic layer 1 of this TMR 10
The metal layer of the bit line (BL) 74 is formed on the gate electrode 7.

As shown in FIG. 7, the area of the second ferromagnetic layer 14, which is a free layer, is different from the areas of the upper antiferromagnetic layer 17 and the pinned layer 16b.
7 and the pin layer 16b constitute a part of the bit line 74. That is, the bit line 74 is connected to the pin layer 16b.
/ An antiferromagnetic layer 17 / a metal layer. Note that the bit line 74 may be configured by the antiferromagnetic layer 17 / metal layer without providing the pinned layer 16b having the same area as the antiferromagnetic layer 17 below the antiferromagnetic layer 17.

In this structure, the spins of the pinned layers 16b and 16a can be more stably fixed by the antiferromagnetic layer 17 having a large area, and the magnetic moment of the pinned layers 16b and 16a rotates even if writing is repeated. Therefore, a decrease in output can be effectively prevented.

The structure above the free layer 14 of the TMR 10 includes the formation and patterning of the free layer 14 / second dielectric layer 15 / pinned layer 16a and the pinned layer 16b / antiferromagnetic layer 17 / metal layer Is formed by film formation and patterning. Conventionally, the structure above the free layer 14 of the TMR 10 includes film formation and patterning of the free layer 14 / second dielectric layer 15 / pinned layer 16 / antiferromagnetic layer 17,
It was formed by forming and patterning a bit line metal layer. Therefore, if the structure of FIG. 7 is adopted,
Since the patterning step of the relatively thick antiferromagnetic layer 17 is separated into separate steps, the film thickness to be finely processed at once can be reduced in the first patterning. For this reason,
The processing damage of the ferromagnetic tunnel junction can be reduced and the processing accuracy can be improved.

An MRAM having a structure in which a diode and, for example, a first ferromagnetic tunnel junction device (FIG. 1) are stacked will be described with reference to FIGS. FIG. 8 is an equivalent circuit diagram of a 3 × 3 cell MRAM, and FIG. 9 is a perspective view of the MRAM.

As shown in the equivalent circuit diagram of FIG. 8, the recording cells composed of a stacked body of the diode 80 and the TMR 10 are arranged in a matrix. Diode 80 and TMR
10 is formed on a word line (WL) 91, and one end of the diode 80 and the word line (WL) 91 are formed.
And are connected. The other end of the TMR 10 is connected to a bit line (BL) 92 arranged orthogonally to the word line (WL) 91.

As shown in FIG. 9, the word line (WL)
A silicon diode 80 is formed on the metal layer 91,
An underlayer 81 is formed thereon. A nitride film such as TiNx may be provided between the metal layer and the silicon diode to prevent atomic diffusion. On this underlayer 81, FIG.
Ferromagnetic double tunnel junction device (TMR) as shown in
10 are formed. That is, the first antiferromagnetic layer 11 / first ferromagnetic layer (pinned layer) 12 /
First dielectric layer 13 / second ferromagnetic layer (free layer) 14
/ Second dielectric layer 15 / third ferromagnetic layer (pinned layer) 16
a, 16b / second antiferromagnetic layer 17 are laminated.
In this example, the pinned layer is composed of two layers 16a and 16b. On the second antiferromagnetic layer 17 of the TMR 10, a metal layer of a bit line (BL) 92 is formed.

With the MRAM having such a structure, the same effect as that described with reference to FIG. 7 can be obtained. That is,
The pinned layer 16 is formed by the antiferromagnetic layer 17 having a large area.
The spins of b and 16a can be fixed more stably,
Even if writing is repeated, the magnetic moments of the pinned layers 16b and 16a do not rotate, and a decrease in output can be effectively prevented. Further, since the patterning step of the relatively thick antiferromagnetic layer 17 is separated into separate steps, processing damage to the ferromagnetic tunnel junction can be reduced and processing accuracy can be improved.

In the application of the MRAM, a ferromagnetic layer / non-magnetic layer / ferromagnetic layer may be used as the free layer, and the ferromagnetic layer may be antiferromagnetically coupled via the non-magnetic layer. . In such a configuration, since the magnetic flux is closed in the three-layer film, when the magnetic field of the free layer is reversed by the current magnetic field, the influence of the static magnetic field on the pinned layer is eliminated, and the leakage from the recording layer is prevented. Since the magnetic flux can be reduced, the switching magnetic field can be reduced. For this reason, the problem that the magnetic moment of a part of the magnetization fixed layer is rotated by writing and the output gradually decreases does not occur. In this configuration, of the ferromagnetic layer / non-magnetic layer / ferromagnetic layer, the ferromagnetic layer closer to the word line for applying a current magnetic field is formed of a softer ferromagnetic material or has a smaller thickness. It is preferable to make it thicker. When the thicknesses of the two ferromagnetic layers constituting the three-layer film are made different, it is preferable that the difference between the thicknesses is in the range of 0.5 to 5 nm.

Next, another MRAM according to the present invention will be described. In this MRAM, a first magnetization fixed layer having a fixed magnetization direction, a first dielectric layer, a magnetic recording layer whose magnetization direction can be reversed, a second dielectric layer, and a magnetization direction fixed to each other. And a ferromagnetic double tunnel junction element having a second magnetization fixed layer. The magnetic recording layer includes a magnetic layer, a non-magnetic layer,
And a three-layer film of a magnetic layer.
The two magnetic layers are antiferromagnetically coupled. Since the two magnetic layers are antiferromagnetically coupled and the magnetic flux is closed in the magnetic recording layer, the switching magnetic field can be reduced, and the current density flowing through the wiring can be reduced. Further, the magnetizations of the regions of the two magnetization fixed layers that are in contact with the dielectric layer are substantially antiparallel. For this reason, by selecting which of the two magnetization fixed layers the current flows to the magnetic recording layer, it is possible to select whether to supply an up spin current or a down spin current to the magnetic recording layer. For this reason, the magnetization of the magnetic recording layer can be easily reversed by changing the supply direction of the spin current, and the current flowing through the TMR element can be reduced. in this way,
This MRAM has a structure suitable for supplying a spin current to the magnetic recording layer and for applying a current magnetic field, and can suppress the current density flowing through the wiring and the TMR element.

The antiferromagnetically coupled magnetic recording layer constituting the ferromagnetic double tunnel junction device can be easily manufactured by alternately laminating ferromagnetic layers and nonmagnetic metal layers. The antiferromagnetically-coupled magnetic recording layer is preferably a three-layer film composed of a ferromagnetic layer / a nonmagnetic metal layer / a ferromagnetic layer because the thinner the film thickness, the easier it can be microfabricated. In addition, a ferromagnetic layer / soft magnetic layer /
A three-layer film composed of a ferromagnetic layer may be used. In particular, when Co _x Fe _1-x (0.5 ≦ x <1.0) is used as the ferromagnetic layer, a thin soft magnetic layer made of, for example, a Ni—Fe alloy is provided between the two Co _x Fe _1-x layers. By inserting a layer, the switching magnetic field can be significantly reduced. This is Ni
-Fe alloy layer is fcc (111) orientation, Co _x Fe _{1 -x} layer thereon also becomes fcc (111) orientation, Co _x
This is because the switching magnetic field of Fe _1-x itself is reduced and the total magnetization value of the ferromagnetic layer is reduced.

Therefore, examples of the anti-ferromagnetically coupled magnetic recording layer include (a) ferromagnetic layer / non-magnetic layer / ferromagnetic layer,
(B) (ferromagnetic layer / soft magnetic layer / ferromagnetic layer) / nonmagnetic layer / ferromagnetic layer, (c) (ferromagnetic layer / soft magnetic layer / ferromagnetic layer) / nonmagnetic layer / (ferromagnetic layer) / Soft magnetic layer / ferromagnetic layer). In this case, the strength of the antiferromagnetic coupling is preferably as large as 0.5 erg / cm ² or more. The magnetization fixed film may have a laminated structure similar to the magnetic recording layer, and may be antiferromagnetically coupled.

Referring to FIGS. 10 to 12, this MRAM
An example of a ferromagnetic double tunnel junction element used for the following will be described.

The ferromagnetic double tunnel junction device shown in FIG.
Underlayer 101 / first antiferromagnetic layer 102 / first magnetization pinned layer 103 / first dielectric layer 104 / ferromagnetic layer 105
a, the magnetic recording layer 105 / the second dielectric layer 106 / the second magnetization pinned layer 107 / the second antiferromagnetic layer 108 / the protective layer 109, which is a three-layer film of the nonmagnetic layer 105b and the ferromagnetic layer 105c. Are laminated.

The ferromagnetic layers 105a and 105c of the magnetic recording layer 105 are antiferromagnetically coupled. A first magnetization fixed layer 103 in contact with the first dielectric layer 104;
The second magnetization fixed layer 107 in contact with the dielectric layer 106 of
Each magnetization is antiparallel.

The ferromagnetic double tunnel junction device shown in FIG.
Underlayer 111 / first antiferromagnetic layer 112 / first magnetization pinned layer 113 / first dielectric layer 114 / ferromagnetic layer 115
a, a magnetic recording layer 115 / second dielectric layer 116 / ferromagnetic layer 117a, a nonmagnetic layer 117b, and a ferromagnetic layer 11 comprising a three-layer film of a nonmagnetic layer 115b and a ferromagnetic layer 115c.
7c has a structure in which a second magnetization fixed layer 117 / second antiferromagnetic layer 118 / protective layer 119 composed of a three-layer film is laminated.

The ferromagnetic layers 115a and 115c of the magnetic recording layer 115 are antiferromagnetically coupled. Ferromagnetic layer 117a and ferromagnetic layer 11 of second magnetization pinned layer 117
7c is antiferromagnetically coupled. A first magnetization fixed layer 113 in contact with the first dielectric layer 114 and a second dielectric layer 11
The magnetization of each of the ferromagnetic layers 117a constituting the second magnetization pinned layer 117 in contact with No. 6 is antiparallel.

In this case, it is preferable that the length of the first magnetization fixed layer 113 is formed longer than the lengths of the second magnetization fixed layer 117 and the magnetic recording layer 115 so that they also serve as metal wiring. In such a configuration, the magnetic flux is closed in both the second magnetization fixed layer 117 and the magnetic recording layer 115, and the leakage magnetic flux from the long first magnetization fixed layer 113 has almost no effect. The effect of the static magnetic field on the recording layer can be reduced.

The ferromagnetic double tunnel junction device shown in FIG.
Underlayer 121 / first antiferromagnetic layer 122 / ferromagnetic layer 12
3a, first magnetic pinned layer 123 / first dielectric layer 1 comprising a three-layer film of nonmagnetic layer 123b and ferromagnetic layer 123c
24 / magnetic recording layer 125 composed of a three-layered film of ferromagnetic layer 125a, nonmagnetic layer 125b and ferromagnetic layer 125c / second
Dielectric layer 126 / ferromagnetic layer 127a, non-magnetic layer 127
b, ferromagnetic layer 127c, nonmagnetic layer 127d, ferromagnetic layer 1
27e / second magnetic pinned layer 127 / second
Has a structure in which the antiferromagnetic layer 128 / protective layer 129 are stacked.

The ferromagnetic layers 125a and 125c of the magnetic recording layer 125 are antiferromagnetically coupled. Ferromagnetic layer 123a and ferromagnetic layer 12 of first magnetization pinned layer 123
3c is antiferromagnetically coupled. Second magnetization fixed layer 127
The ferromagnetic layers 127a, 127c, and 127e are antiferromagnetically coupled. First dielectric layer 11
4 and the ferromagnetic layer 127a forming the second magnetization fixed layer 127 that is in contact with the second dielectric layer 126, the respective magnetizations are antiparallel. It has become. Also in this case, similarly to FIG. 11, the length of the first magnetization fixed layer 123 may be formed longer than the lengths of the second magnetization fixed layer 117 and the magnetic recording layer 115.

FIG. 13 is a sectional view of an MRAM using the ferromagnetic double tunnel junction device of FIG. Si substrate 15
A groove is formed in the SiO ₂ insulating layer 1 above, and a word line 152 made of metal embedded in the groove is formed. An SiO ₂ insulating layer is formed on the word line 152, and a metal wiring 153 and a ferromagnetic double tunnel junction element (TMR element) are formed thereon. As shown in FIG. 11, the TMR element includes a base layer 111 / first antiferromagnetic layer 112 / first magnetization pinned layer 113 / first dielectric layer 114 / ferromagnetic layer 115a, a nonmagnetic layer 115b, Magnetic recording layer 115 composed of three layers of ferromagnetic layer 115c / second dielectric layer 116 / ferromagnetic layer 117a, nonmagnetic layer 11
Magnetization fixed layer 117 / second antiferromagnetic layer 118 / protective layer 11 composed of a three-layered film of ferromagnetic layer 7b and ferromagnetic layer 117c
9 are laminated. The TMR element is processed so as to have a predetermined bonding area, and an interlayer insulating film is formed around the TMR element. On this interlayer insulating film, TM
A bit line 154 connected to the protection layer 119 of the R element is formed.

In this MRAM, a current is applied to the word line 152 to apply a current magnetic field (for example, in the hard axis direction) to the magnetic recording layer 115, and a down spin current is injected from the bit line 154 to the magnetic recording layer 115 through each layer. Alternatively, by injecting an up-spin current from the metal wiring 153 to the magnetic recording layer 115 through each layer, the magnetization of the magnetic recording layer 115 is inverted to perform writing. As described above, when the spin current is injected into the magnetic recording layer 115 and the current magnetic field is applied to perform the writing, the T
The spin current flowing through the MR element can be reduced, and the current density flowing through the wiring (word line) can be reduced.
Therefore, even in the MRAM of 1 Gb or more, the melting of the wiring or the destruction of the tunnel barrier layer (dielectric layer) of the TMR element can be suppressed, and the reliability can be improved.

In the MRAM shown in FIG. 13, the current flowing through the bit line 154 is applied to the magnetic recording layer 115 so as to apply a current magnetic field having a direction different from the current magnetic field from the word line 152 (for example, in the easy axis direction). Works. In order to increase the current magnetic field in this direction and improve its controllability, while further reducing the spin current injected into the magnetic recording layer 115, as shown in FIG. And a second word line 156 extending parallel to the bit line 154. In the MRAM shown in FIG. 14, the change in the direction of the current flowing through the TMR element and the change in the direction of the current flowing through the second word line 156 are used together, so that the magnetic recording layer 115 can be reduced with a smaller current.
Can be repeated.

Next, a magnetoresistive head to which the magnetoresistive element of the present invention is applied will be described.

FIG. 15 is a perspective view of a magnetic head assembly equipped with a magnetoresistive head including a ferromagnetic double tunnel junction element according to the present invention. Actuator arm 2
Reference numeral 01 is provided with a hole for fixing to a fixed shaft in the magnetic disk drive, and has a bobbin and the like for holding a drive coil (not shown). A suspension 202 is fixed to one end of the actuator arm 201. At the tip of the suspension 202, a head slider 203 mounted with a magnetoresistive head including the above-described ferromagnetic double tunnel junction element is mounted. A lead wire 204 for writing and reading signals is wired to the suspension 202, and one end of the lead wire 204 is connected to each electrode of the magnetoresistive head incorporated in the head slider 203. The end is connected to the electrode pad 205.

FIG. 16 is a perspective view showing the internal structure of a magnetic disk drive on which the magnetic head assembly shown in FIG. 15 is mounted. The magnetic disk 211 is mounted on a spindle 212 and is rotated by a motor (not shown) which responds to a control signal from a drive controller (not shown). An actuator arm 201 shown in FIG. 15 is fixed to a fixed shaft 213, and a suspension 202 and a head slider 20 at the tip thereof are provided.
3 is supported. When the magnetic disk 211 rotates,
The medium facing surface of the head slider 203 is
1 is held in a state of floating a predetermined amount from the surface of the recording medium 1 to record and reproduce information. At the base end of the actuator arm 201, a voice coil motor 214, which is a kind of linear motor, is provided. The voice coil motor 214 includes a drive coil (not shown) wound around a bobbin portion of the actuator arm 201, and a magnetic circuit including a permanent magnet and an opposed yoke which are arranged to face each other so as to sandwich the coil. The actuator arm 201 is held by ball bearings (not shown) provided at two positions above and below the fixed shaft 213.
This allows the slide to rotate freely.

For use of the magnetoresistive head, it is preferable to use first, second and fourth ferromagnetic double tunnel junction elements (FIGS. 1, 2 and 4). It is more preferable to use a tunnel junction element. In addition, in the application of the magnetoresistive head, it is preferable that the spins of the adjacent pin layer and the free layer are made almost orthogonal by film formation in a magnetic field or heat treatment in a magnetic field. In this way, a linear response to a magnetic field leaking from the magnetic disk can be obtained, and any head structure can be used.

[0073]

Embodiments of the present invention will be described below. Example 1 An example in which two types of ferromagnetic double tunnel junction devices (sample A and sample B) having a structure as shown in FIG. 1 are formed on a Si / SiO ₂ substrate or a SiO ₂ substrate will be described.

Sample A was made of a Ta underlayer, Fe--Mn / Ni
A first antiferromagnetic layer made of a two-layered film of Fe, a first ferromagnetic layer made of CoFe, a first dielectric layer made of Al ₂ O _3, and a _second ferromagnetic layer made of Co ₉ Fe , A _second dielectric layer composed of Al ₂ O _{3, a} third ferromagnetic layer composed of CoFe, a second antiferromagnetic layer composed of a Ni—Fe / Fe—Mn bilayer, and a Ta protective layer. It has a laminated structure.

Sample B was composed of a Ta underlayer, a first antiferromagnetic layer of Ir—Mn, a first ferromagnetic layer of Co—Fe, a first dielectric layer of Al ₂ O ₃ , / Ni
A second ferromagnetic layer comprising a three-layer film of Fe / CoFe, A
a _second dielectric layer made of l ₂ O ₃ and a _third dielectric layer made of CoFe
Ferromagnetic layer, a second antiferromagnetic layer made of Ir-Mn, T
a has a structure in which protective layers are sequentially laminated.

Sample A was prepared as follows. The substrate is placed in a sputtering apparatus, and the initial degree of vacuum is set to 1 × 10 ⁻⁷ Torr.
After setting to r, Ar was introduced and set to a predetermined pressure. On the substrate, Ta 5 nm / Fe ₅₄ Mn ₄₆ 20 nm
/ Ni ₈ Fe ₂ 5 nm / CoFe 3 nm / Al ₂ O ₃
1.7 nm / Co ₉ Fe 3 nm / Al ₂ O ₃ 2 nm /
CoFe 3 nm / Ni ₈ Fe ₂ 5 nm / Fe ₅₄ Mn ₄₆
20 nm / Ta 5 nm were sequentially laminated. In addition, Al
₂ O ₃ was formed by forming an Al film using an Al target in pure Ar gas, introducing oxygen without breaking vacuum, and exposing the film to plasma oxygen.

After forming the above laminated film, a first resist pattern defining a lower wiring shape having a width of 100 μm was formed on the uppermost Ta protective layer by a photolithography technique, and processed by an ion milling technique. .

Next, after removing the first resist pattern, a second resist pattern for defining a junction size is formed on the uppermost Ta protective layer by a photolithography technique, and the first resist pattern is formed by an ion milling technique. Co ₉ than the Al ₂ O ₃ in the upper _{Fe / Al 2 O 3 / CoFe} / Ni-Fe / F
e-Mn / Ta was processed. With the second resist pattern left, 300 nm thick A was deposited by electron beam evaporation.
After depositing l ₂ O ₃ , the second resist pattern and the Al ₂ O ₃ thereon were lifted off, and an interlayer insulating film was formed at a portion other than the junction.

Next, after forming a third resist pattern covering an area other than the electrode wiring forming area, the surface was reverse-sputtered and cleaned. After depositing Al on the entire surface, the third resist pattern and the Al thereon were lifted off to form an Al electrode wiring. Thereafter, the pin layer was introduced into a heat treatment furnace in a magnetic field to introduce unidirectional anisotropy.

Sample B was prepared as follows. The substrate is placed in a sputtering apparatus, and the initial degree of vacuum is set to 1 × 10 ⁻⁷ Torr.
After setting to r, Ar was introduced and set to a predetermined pressure. On the substrate, Ta 5 nm / Ir ₂₂ Mn ₇₈ 20 nm
/ CoFe 3 nm / Al ₂ O ₃ 1.5 nm / CoFe
1 nm / Ni ₈ Fe ₂ t (t = 1, 2 or 3 nm) /
CoFe 1 nm / Al ₂ O ₃ 1.8 nm / CoFe
3 nm / Ir ₂₂ Mn ₇₈ 20 nm / Ta 5 nm were sequentially laminated. Al ₂ O ₃ was formed by the same method as described above.

After forming the above-mentioned laminated film, a first resist pattern defining a lower wiring shape having a width of 100 μm was formed on the uppermost Ta protective layer by photolithography, and processed by ion milling. . Next, the first
After removing the resist pattern, a second resist pattern defining the junction size is formed on the uppermost Ta protective layer by photolithography, and the upper part of the first Al ₂ O ₃ is formed by ion milling. CoFe / Ni ₈ F
e ₂ / CoFe / Al ₂ O ₃ / CoFe / Ir ₂₂ Mn ₇₈ /
Ta was processed. Then, in the same manner as above, Al ₂ O ₃
Formation of an interlayer insulating film, formation of an Al electrode wiring, and introduction of unidirectional anisotropy into a pin layer were performed.

For comparison, the following sample C was used.
And sample D was produced. Sample C is a ferromagnetic single tunnel junction device, and Ta / Ir—Mn / CoFe / Al ₂
It has a laminated structure of O ₃ / CoFe / Ni-Fe / Ta.

Sample D is a ferromagnetic double tunnel junction not containing an antiferromagnetic layer, and is made of Ta 5 nm / CoPt 20n.
m / Al ₂ O ₃ 1.5 nm / CoFe 1 nm / Ni _{8
Fe 2 3nm / CoFe 1nm / Al} 2 O 3 1.8n
It has a laminated structure of m / CoPt 20 nm / Ta 5 nm.

FIG. 17 shows the magnetoresistance effect curves of Samples A and B. Sample A has an MR ratio of 27% with a small magnetic field of 25 Oe. In sample B, it can be seen that the reversal magnetic field can be controlled by changing the film thickness ratio between Ni ₈ Fe ₂ and CoFe in the free layer (magnetic recording layer). That is, when the film thickness of Ni ₈ Fe ₂ is 1 nm, 2 nm, and 3 nm, the resistance greatly changes with a small magnetic field of 16 Oe, 36 Oe, and 52 Oe, respectively, and a large MR of 26% or more.
The rate of change is obtained.

FIG. 18 shows the MR of samples A, B and C.
4 shows the applied voltage dependence of the rate of change. In this figure, MR
The rate of change is normalized by a value at a voltage of 0 V.
From this figure, it can be seen that the samples A and B have a large voltage V _1/2 at which the value of the magnetoresistance change is halved compared to the sample C, and the decrease in the MR change with an increase in the voltage is small.

Next, the samples A, B and D were placed in a solenoid coil, and a fatigue test of the magnetic recording state of the magnetization fixed layer was performed in a pulse magnetic field of 70 Oe. FIG. 19 shows the relationship between the number of reversals of the pulse magnetic field and the output voltage for samples A, B, and D. In this figure, the output voltage is normalized by the initial output voltage value. As apparent from this figure, the sample D
In the figure, the output voltage is remarkably reduced with an increase in the number of reversals of the pulse magnetic field. On the other hand, in the samples A and B, no fatigue of the magnetic recording state of the magnetization fixed layer is observed.

As described above, it can be seen that the ferromagnetic double tunnel junction device having the structure shown in FIG. 1 exhibits suitable characteristics when applied to a magnetic recording device and a magnetic head.

Note that SiO ₂ , AlN,
When MgO, LaAlO ₃ or CaF ₂ was used, the same tendency as above was observed.

Example 2 An example in which two types of ferromagnetic double tunnel junction devices (sample A2 and sample B2) having a structure as shown in FIG. 2 were formed on a Si / SiO ₂ substrate or a SiO ₂ substrate will be described. .

Sample A2 was made of a Ta underlayer, Ni—Fe / C
a first ferromagnetic layer composed of a two-layer film of oFe, a first dielectric layer composed of Al ₂ O _{3, a} second ferromagnetic layer composed of CoFe, an antiferromagnetic layer composed of Ir—Mn, and composed of CoFe A third ferromagnetic layer, a second dielectric layer of Al ₂ O ₃ , C
a fourth ferromagnetic layer comprising a two-layer film of oFe / Ni-Fe,
It has a structure in which Ta protective layers are sequentially laminated.

Sample B2 was made of a Ta underlayer, Ni--Fe / R
a first ferromagnetic layer composed of a three-layer film of u / CoFe, Al ₂
A first dielectric layer composed of O _3, a second ferromagnetic layer composed of a two-layer film of CoFe / Ni—Fe, a first antiferromagnetic layer composed of Fe—Mn, and a two-layer of Ni—Fe / CoFe A third ferromagnetic layer made of a film, a second dielectric layer made of Al ₂ O ₃ ,
A fourth ferromagnetic layer made of CoFe / Ru / Ni-Fe,
It has a structure in which Ta protective layers are sequentially laminated.

The sample A2 was manufactured as follows. The substrate is placed in a sputtering apparatus, and the initial degree of vacuum is 1 × 10 ⁻⁷ To.
After setting to rr, Ar was introduced and set to a predetermined pressure. On the substrate, Ta 3 nm / Ni ₈₁ Fe ₁₉ t (t =
3, 5 or 8 nm) / CoFe 1 nm / Al ₂ O ₃
1.2 nm / CoFe 1 nm / Ir ₂₂ Mn ₇₈ 17n
m / CoFe 1 nm / Al ₂ O ₃ 1.6 nm / CoF
e 1 nm / Ni ₈₁ Fe ₁₉ t (t = 3, 5 or 8n
m) / Ta 5 nm. In addition, Al ₂ O
_3, after forming the Al using an Al target in pure Ar gas, was formed by exposure to plasma of oxygen introduced oxygen without breaking the vacuum.

After the formation of the above-mentioned laminated film, a first resist pattern defining a lower wiring shape having a width of 100 μm was formed on the uppermost Ta protective layer by photolithography and processed by ion milling. .

Next, after removing the first resist pattern, a second resist pattern for defining a junction size is formed on the uppermost Ta protective layer by a photolithography technique, and the first resist pattern is formed by an ion milling technique. of Al ₂ O ₃ from the top of CoFe / Ir-Mn / CoFe / Al 2 O 3 / Co
Fe / Ni-Fe / Ta was processed. With the second resist pattern remaining, a thickness of 300
After depositing ₂ nm of Al ₂ O ₃ , the second resist pattern and the Al ₂ O ₃ thereon were lifted off to form an interlayer insulating film in portions other than the junction.

Next, after forming a third resist pattern covering a region other than the region for forming the electrode wiring, the surface was cleaned by reverse sputtering. After depositing Al on the entire surface, the third resist pattern and the Al thereon were lifted off to form an Al electrode wiring. Thereafter, the pin layer was introduced into a heat treatment furnace in a magnetic field to introduce unidirectional anisotropy.

Sample B2 was prepared as follows. Base
The plate was placed in a sputtering apparatus, and the initial vacuum was 1 × 10^-7To
After setting to rr, Ar was introduced and set to a predetermined pressure.
Was. On the substrate, Ta 2 nm / Ni₈₁Fe₁₉ 6 nm /
Ru 0.7nm / Co_FourFe₆ 3 nm / Al_TwoO_Three 
1.5 nm / CoFe 1 nm / Ni₈₁Fe₁₉ 1 nm
/ Fe₅₄Mn₄₆ 20nm / Ni₈₁Fe₁₉ 1 nm / C
oFe 1nm / Al _TwoO_Three 1.7 nm / Co_FourFe₆ 
3nm / Ru 0.7nm / Ni₈₁Fe₁₉ 6nm / T
a 5 nm was sequentially laminated. Al_TwoO_ThreeIs the same as above
It was formed by a method.

After forming the above-mentioned laminated film, a first resist pattern defining a lower wiring shape having a width of 100 μm was formed on the uppermost Ta protective layer by photolithography and processed by ion milling. . Next, the first
After removing the resist pattern, a second resist pattern defining the junction size is formed on the uppermost Ta protective layer by photolithography, and the upper part of the first Al ₂ O ₃ is formed by ion milling. CoFe / Ni ₈₁ F
e ₁₉ / Fe ₅₄ Mn ₄₆ / Ni ₈₁ Fe ₁₉ / CoFe / Al ₂
O ₃ / Co ₄ Fe ₆ / Ru / Ni ₈₁ Fe ₁₉ / Ta was processed. Next, in the same manner as described above, formation of an Al ₂ O ₃ interlayer insulating film, formation of an Al electrode wiring, and introduction of unidirectional anisotropy into a pin layer were performed.

For comparison, the following sample C was used.
2 and sample D2 were produced. Sample C2 is a single ferromagnetic
It is a tunnel junction element, and Ta 3 nm / Ni₈₁Fe₁₉5
nm / CoFe 1 nm / Al_TwoO_Three 1.2 nm / Co
Fe 1nm / Ir _{twenty two}Mn₇₈ 17 nm / CoFe 1
nm / Ta 5 nm.

Sample D2 is a ferromagnetic double tunnel junction containing no antiferromagnetic layer, and has a thickness of Ta 3 nm / Ni ₈₁ Fe ₁₉
5 nm / CoFe 1 nm / Al ₂ O ₃ 1.2 nm / C
oFe 1 nm / Al ₂ O ₃ 1.6 nm / CoFe 1
It has a laminated structure of nm / Ni ₈₁ Fe ₁₉ 5 nm / Ta 5 nm.

FIG. 20 shows the magnetoresistance effect curves of Samples A2 and B2. It can be seen that in sample A2, the reversal magnetic field can be controlled by changing the film thickness ratio between Ni ₈ Fe ₂ and CoFe in the free layer (magnetic recording layer). That is, Ni ₈
When the film thickness of Fe ₂ is 3 nm, 5 nm, and 8 nm, the resistance changes greatly with a small magnetic field of 15 Oe, 26 Oe, and 38 Oe, respectively, and a large MR change rate of 26% or more is obtained. The sample B2 has a small magnetic field of 39 Oe,
An R change rate of 26% is obtained.

FIG. 21 shows the applied voltage dependency of the MR ratio for samples A2, B2 and C2. Note that in this figure, the MR change rate is normalized by a value at a voltage of 0 V. From this figure, it can be seen that, in Samples A2 and B2, the voltage V _1/2 at which the value of the magnetoresistance change rate is halved is larger than that in Sample C2, and the decrease in MR change rate with increasing voltage is small.

Next, the samples A2, B2 and D2 were placed in a solenoid coil, and a fatigue test of the magnetically fixed state of the magnetization fixed layer was performed in a pulse magnetic field of 70 Oe. FIG. 22 shows sample A.
2 shows the relationship between the number of reversals of the pulse magnetic field and the output voltage for B2 and D2. In this figure, the output voltage is normalized by the initial output voltage value. As is clear from this figure, in the sample D2, the output voltage is remarkably reduced as the number of reversals of the pulse magnetic field is increased. On the other hand, in the samples A2 and B2, the fatigue of the magnetic recording state of the magnetization fixed layer is not observed. In comparison between Samples A2 and B2, it was found that Co ₄ Fe ₆ / Ru / Ni ₈₁ Fe ₁₉ antiferromagnetically coupled to the free layer.
The sample B2 using the three-layer structure has less fatigue.

As described above, it can be seen that the ferromagnetic double tunnel junction device having the structure shown in FIG. 2 exhibits suitable characteristics when applied to a magnetic recording device and a magnetic head.

Note that SiO ₂ , AlN,
When MgO, LaAlO ₃ or CaF ₂ was used, the same tendency as above was observed.

Example 3 FIG. 3 was formed on a Si / SiO ₂ substrate or a Si / Al ₂ O ₃ substrate.
An example in which two types of ferromagnetic double tunnel junction devices (sample A3 and sample B3) having the structures shown in FIGS.

Sample A3 includes a Ta underlayer, a first antiferromagnetic layer made of Ir—Mn, a first ferromagnetic layer made of Co—Fe, a first dielectric layer made of Al ₂ O ₃ , -Fe-
A second ferromagnetic layer made of Ni, a second ferromagnetic layer made of Fe-Mn
Composed of the antiferromagnetic layer, a third ferromagnetic layer of Co-Fe-Ni, a second dielectric layer of Al ₂ O _3, fourth ferromagnetic layer of Co-Fe, the Ir-Mn It has a structure in which a third antiferromagnetic layer and a Ta protective layer are sequentially laminated.

Sample B3 was a Ta underlayer, a first antiferromagnetic layer made of Ir—Mn, Co—Fe / Ru / Co—Fe
A first ferromagnetic layer consisting of a three-layer film, a first dielectric layer consisting of Al ₂ O ₃ , a second ferromagnetic layer consisting of a two-layer film of CoFe / Ni—Fe, and a second ferromagnetic layer consisting of Fe—Mn. 2 antiferromagnetic layer, a third ferromagnetic layer composed of a two-layer film of Ni—Fe / CoFe, a second dielectric layer composed of Al ₂ O _3,
A fourth ferromagnetic layer composed of a Ru / Co—Fe three-layer film;
It has a structure in which a third antiferromagnetic layer made of r-Mn and a Ta protective layer are sequentially laminated.

The sample A3 was manufactured as follows. The substrate is placed in a sputtering apparatus, and the initial degree of vacuum is 1 × 10 ⁻⁷ To.
After setting to rr, Ar was introduced and set to a predetermined pressure. On the substrate, Ta 5 nm / Ir ₂₂ Mn ₇₈ 18 nm
/ CoFe 2 nm / Al ₂ O ₃ 1.7 nm / Co ₅ F
e ₁ Ni ₄ 2 nm / Fe ₁ Mn ₁ 17 nm / Co ₅ Fe ₁
Ni ₄ 2 nm / Al ₂ O ₃ 2 nm / CoFe 2 nm
/ Ir ₂₂ Mn ₇₈ 18 nm / Ta 5 nm. Note that Al ₂ O ₃ was formed by depositing Al in a pure Ar gas using an Al target, introducing oxygen without breaking vacuum, and exposing the film to plasma oxygen.

After forming the above-mentioned laminated film, a first resist pattern for defining a lower wiring shape having a width of 100 μm was formed on the uppermost Ta protective layer by photolithography, and processed by ion milling. .

Next, after removing the first resist pattern, a second resist pattern for defining a junction size is formed on the uppermost Ta protective layer by a photolithography technique, and the first resist pattern is formed by an ion milling technique. Co ₅ than the Al ₂ O ₃ of the upper _{Fe 1 Ni 4 / Fe 1 Mn} 1 / Co 5 Fe 1 Ni 4 /
Al ₂ O ₃ / CoFe / Ir ₂₂ Mn ₇₈ / Ta was processed.
After depositing Al ₂ O ₃ with a thickness of 350 nm by electron beam evaporation while leaving the second resist pattern, the second resist pattern and the Al ₂ O ₃ thereon are lifted off to form a portion other than the joint. An interlayer insulating film was formed.

Next, after forming a third resist pattern covering a region other than the region where the electrode wiring was formed, the surface was cleaned by reverse sputtering. After depositing Al on the entire surface, the third resist pattern and the Al thereon were lifted off to form an Al electrode wiring. Thereafter, the pin layer was introduced into a heat treatment furnace in a magnetic field to introduce unidirectional anisotropy.

The sample B3 was prepared as follows. The substrate is placed in a sputtering apparatus, and the initial degree of vacuum is 1 × 10 ⁻⁷ To.
After setting to rr, Ar was introduced and set to a predetermined pressure. On the substrate, Ta 3 nm / Ir-Mn 14 nm /
Co-Fe 1.5 nm / Ru 0.7 nm / Co-F
e 1.5 nm / Al ₂ O ₃ 1.7 nm / CoFe1n
m / Ni ₈₁ Fe ₁₉ 2 nm / Fe ₄₅ Mn _{55 19} nm /
Ni ₈₁ Fe ₁₉ 2 nm / CoFe 1 nm / Al ₂ O ₃
2.1 nm / Co ₉ Fe 2 nm / Ru 0.8 nm /
Co ₉ Fe 2 nm / Ir-Mn 14 nm / Ta 5
nm were sequentially laminated. Al ₂ O ₃ was formed by the same method as described above.

After forming the above-mentioned laminated film, a first resist pattern defining a lower wiring shape having a width of 100 μm was formed on the uppermost Ta protective layer by photolithography and processed by ion milling. . Next, the first
After removing the resist pattern, a second resist pattern defining the junction size is formed on the uppermost Ta protective layer by photolithography, and the upper part of the first Al ₂ O ₃ is formed by ion milling. CoFe / Ni ₈₁ F
e ₁₉ / Fe ₄₅ Mn ₅₅ / Ni ₈₁ Fe ₁₉ / CoFe / Al ₂
O ₃ / Co ₉ Fe / Ru / Co ₉ Fe / Ir-Mn / Ta
Was processed. Next, in the same manner as described above, formation of an Al ₂ O ₃ interlayer insulating film, formation of an Al electrode wiring, and introduction of unidirectional anisotropy into a pin layer were performed.

For comparison, the following sample C was used.
Sample No. 3 and Sample D3 were made. Sample C3 is a ferromagnetic single tunnel junction device, and Ta 3 nm / Ir-Mn14
nm / Co-Fe 1.5 nm / Ru 0.7 nm / C
o-Fe 1.5 nm / Al ₂ O ₃ 1.7 nm / CoF
e 1 nm / Ni ₈₁ Fe ₁₉ 2 nm / Fe ₄₅ Mn ₅₅ 1
It has a laminated structure of 9 nm / Ta 5 nm.

[0115] Sample D3 is a ferromagnetic double tunnel junction without the antiferromagnetic _{layer, Ta 5nm / Co 8 Pt 2} 1
5 nm / CoFe 2 nm / Al ₂ O ₃ 1.7 nm / C
o ₅ Fe ₁ Ni ₄ 2 nm / Al ₂ O ₃ 2 nm / CoFe
It has a laminated structure of ₂ nm / Co ₈ Pt ₂ 15 nm / Ta 5 nm.

FIG. 23 shows the magnetoresistance effect curves of Samples A3 and B3. The sample A3 has an MR ratio of 26% with a small magnetic field of 57 Oe. Sample B3 is 63 Oe
With a small magnetic field, an MR change rate of 27% is obtained.

FIG. 24 shows the dependency of the MR ratio on the applied voltage for samples A3, B3 and C3. Note that in this figure, the MR change rate is normalized by a value at a voltage of 0 V. From this figure, it can be seen that, in Samples A3 and B3, the voltage V _1/2 at which the value of the magnetoresistance change rate is halved is larger than that of Sample C3, and the decrease in MR change rate with increasing voltage is small.

Next, the samples A3, B3 and D3 were placed in a solenoid coil, and a fatigue test of the magnetic recording state of the magnetization fixed layer was performed in a pulse magnetic field of 75 Oe. FIG. 25 shows sample A.
3, the relationship between the number of reversals of the pulse magnetic field and the output voltage is shown for B3 and D3. In this figure, the output voltage is normalized by the initial output voltage value. As is clear from this figure, in the sample D3, the output voltage is remarkably reduced as the number of reversals of the pulse magnetic field is increased. On the other hand, in the samples A3 and B3, no fatigue of the magnetic recording state of the magnetization fixed layer is observed. In comparison between Samples A3 and B3, Sample B3 using a three-layer structure of Co ₉ Fe / Ru / Co ₉ Fe antiferromagnetically coupled to the free layer has less fatigue.

As described above, it can be seen that the ferromagnetic double tunnel junction device having the structure shown in FIG. 3 exhibits suitable characteristics when applied to a magnetic recording device and a magnetic head.

Note that SiO ₂ , AlN,
When MgO, LaAlO ₃ or CaF ₂ was used, the same tendency as above was observed.

Example 4 Two types of ferromagnetic double tunnel junction devices (sample A4 and sample B4) having a structure as shown in FIG. 4 or FIG. 5 were fabricated on a Si / SiO ₂ substrate or a Si / AlN substrate. An example will be described.

Sample A4 was made of a Ta underlayer, Ni—Fe / C
a first ferromagnetic layer composed of a two-layer film of o-Fe, a first dielectric layer composed of Al ₂ O ₃ , a _second ferromagnetic layer composed of Co—Fe, and a first nonmagnetic layer composed of Ru , A third ferromagnetic layer made of Co—Fe, a second nonmagnetic layer made of Ru, Co
The fourth ferromagnetic layer of -fe, second of Al ₂ O ₃
, A fifth ferromagnetic layer consisting of a two-layered film of Co—Fe / Ni—Fe, and a Ta protective layer.

The sample B4 was made of a Ta underlayer, Ni—Fe / C
a first ferromagnetic layer composed of a two-layer film of o-Fe, a first dielectric layer composed of Al ₂ O ₃ , a _second ferromagnetic layer composed of Co—Fe, and a first nonmagnetic layer composed of Ru , Co—Fe ferromagnetic layer / Ir—Mn antiferromagnetic layer / Co—Fe ferromagnetic layer, Ru
A second nonmagnetic layer made of, a fourth ferromagnetic layer made of Co—Fe, a second dielectric layer made of Al ₂ O ₃ , Co—Fe
/ Ni—Fe has a structure in which a fifth ferromagnetic layer composed of a two-layer film and a Ta protective layer are sequentially laminated.

Sample A4 was prepared as follows. Base
The plate was placed in a sputtering apparatus, and the initial vacuum was 1 × 10^-7To
After setting to rr, Ar was introduced and set to a predetermined pressure.
Was. On the substrate, Ta 5 nm / Ni₈₁Fe₁₉ 16nm
/ Co_FourFe₆ 3 nm / Al _TwoO_Three 1.7 nm / CoF
e 2 nm / Ru 0.7 nm / CoFe 2 nm / R
u 0.7 nm / CoFe 2 nm / Al_TwoO_Three 2 nm
/ Co_FourFe₆ 3nm / Ni₈₁Fe₁₉ 16 nm / Ta
 5 nm was sequentially laminated. In addition, Al_TwoO_ThreeIs pure Arga
After forming an Al film using an Al target in the
To introduce oxygen and expose it to plasma oxygen without breaking
Therefore, it was formed.

After forming the above-mentioned laminated film, a first resist pattern defining a lower wiring shape having a width of 100 μm was formed on the uppermost Ta protective layer by photolithography, and processed by ion milling. .

Next, after removing the first resist pattern, a second resist pattern for defining a junction size is formed on the uppermost Ta protective layer by a photolithography technique, and the first resist pattern is formed by an ion milling technique. CoFe / Ru / CoFe / Ru / CoFe / Al above Al ₂ O _3
2 O ₃ / Co ₄ Fe ₆ / Ni ₈₁ Fe ₁₉ / Ta was processed. After depositing Al ₂ O ₃ with a thickness of 300 nm by electron beam evaporation while leaving the second resist pattern, the second resist pattern and the Al ₂ O ₃ thereon are lifted off to remove portions other than the joint. An interlayer insulating film was formed.

Next, after forming a third resist pattern covering a region other than the region for forming the electrode wiring, the surface was cleaned by reverse sputtering. After depositing Al on the entire surface, the third resist pattern and the Al thereon were lifted off to form an Al electrode wiring. Thereafter, the pin layer was introduced into a heat treatment furnace in a magnetic field to introduce unidirectional anisotropy.

Sample B4 was prepared as follows. The substrate is placed in a sputtering apparatus, and the initial degree of vacuum is 1 × 10 ⁻⁷ To.
After setting to rr, Ar was introduced and set to a predetermined pressure. On the substrate, Ta 5 nm / Ni ₈₁ Fe ₁₉ 15 nm
/ Co ₉ Fe 2 nm / Al ₂ O ₃ 1.5 nm / CoF
e 1.5 nm / Ru 0.7 nm / CoFe 1.5
nm / Ir-Mn 14 nm / CoFe 1.5 nm /
Ru 0.7 nm / CoFe 1.5 nm / Al ₂ O ₃
2 nm / Co ₉ Fe 2 nm / Ni ₈₁ Fe ₁₉ 15 nm /
5 nm of Ta was sequentially laminated. Al ₂ O ₃ was formed by the same method as described above.

After forming the above-mentioned laminated film, a first resist pattern defining a lower wiring shape having a width of 100 μm was formed on the uppermost Ta protective layer by photolithography, and processed by ion milling. . Next, the first
After removing the resist pattern, a second resist pattern defining the junction size is formed on the uppermost Ta protective layer by photolithography, and the upper part of the first Al ₂ O ₃ is formed by ion milling. CoFe / Ru / C
oFe / Ir-Mn / CoFe / Ru / CoFe / Al
₂ O ₃ / Co ₉ Fe / Ni ₈₁ Fe ₁₉ / Ta was processed. Next, in the same manner as above, formation of an Al ₂ O ₃ interlayer insulating film,
Formation of Al electrode wiring and introduction of unidirectional anisotropy into the pin layer were performed.

For comparison, the following sample C was used.
4 and sample D4 were produced. Sample C4 is a ferromagnetic single tunnel junction device, and Ta 5 nm / Ni ₈₁ Fe ₁₉ 1
6 nm / Co ₄ Fe ₆ 3 nm / Al ₂ O ₃ 1.7 nm /
CoFe 2 nm / Ru 0.7 nm / CoFe 2n
m / Ru 0.7 nm / CoFe 2 nm / Ta 5n
m.

Sample D4 was a ferromagnetic double tunnel junction without antiferromagnetic coupling, and was made of Ta 5 nm / Ni ₈₁ Fe ₁₉ 1
6 nm / Co ₄ Fe ₆ 3 nm / Al ₂ O ₃ 1.7 nm /
_{CoFe 6nm / Al 2 O 3 2nm} / Co 4 Fe 6 3
It has a laminated structure of nm / Ni ₈₁ Fe ₁₉ 16 nm / Ta 5 nm.

FIG. 26 shows the magnetoresistance effect curves of Samples A4 and B4. The sample A4 has an MR ratio of 28% with a small magnetic field of 33 Oe. Sample B4 is 18 Oe
An MR change rate of 26% is obtained with such a small magnetic field.

FIG. 27 shows the dependency of the MR ratio on the applied voltage for samples A4, B4 and C4. Note that in this figure, the MR change rate is normalized by a value at a voltage of 0 V. From this figure, it can be seen that, in Samples A4 and B4, the voltage V _1/2 at which the value of the magnetoresistance change is halved is larger than that in Sample C4, and the decrease in MR change with increasing voltage is small.

Next, the samples A4, B4 and D4 were placed in a solenoid coil, and a fatigue test of the magnetically fixed state of the magnetization fixed layer was performed in a pulse magnetic field of 40 Oe. FIG. 28 shows sample A.
4, the relationship between the number of reversals of the pulse magnetic field and the output voltage is shown for B4 and D4. In this figure, the output voltage is normalized by the initial output voltage value. As is clear from this figure, in the sample D4, the output voltage is remarkably reduced as the number of reversals of the pulse magnetic field is increased. On the other hand, in the samples A4 and B4, no fatigue of the magnetic recording state of the magnetization fixed layer is observed. In comparison between Samples A4 and B4, CoFe / Ir / CoFe in which an antiferromagnetic layer was inserted into the magnetization fixed layer was used.
Sample B4 using a seven-layer structure of / Ir-Mn / CoFe / Ir / CoFe has less fatigue.

As described above, it is understood that the ferromagnetic double tunnel junction device having the structure shown in FIG. 4 exhibits suitable characteristics when applied to a magnetic recording element and a magnetic head.

Note that SiO ₂ , AlN,
When MgO, LaAlO ₃ or CaF ₂ was used, the same tendency as above was observed.

Embodiment 5 Assuming the MRAM shown in FIG. 7 or FIG.
An example in which ferromagnetic double tunnel junction devices (samples A5 and B5) having a structure as shown in FIG. 29 are formed on an iO ₂ or SiO ₂ substrate will be described.

The sample A5 was composed of a Ta underlayer, a first antiferromagnetic layer composed of Fe—Mn, a first ferromagnetic layer composed of a Ni—Fe / Co—Fe bilayer, and Al ₂ O _3. A first dielectric layer, a second ferromagnetic layer of Co ₉ Fe, Al ₂ O ₃
, A third ferromagnetic layer made of Co—Fe, a bit line (a third ferromagnetic layer made of Ni—Fe, a second antiferromagnetic layer made of Fe—Mn, Al (A metal layer made of).

The sample B5 was composed of an underlayer made of Ta, Ir-
A first antiferromagnetic layer made of Mn, a first ferromagnetic layer made of Co—Fe, a first dielectric layer made of Al ₂ O ₃ ,
-Fe / Ni-Fe / Co-Fe three-layer film
Ferromagnetic layer, a second dielectric layer of Al ₂ O _3, Co-
It has a structure in which a third ferromagnetic layer made of Fe and a bit line (a third ferromagnetic layer made of Co, a second antiferromagnetic layer made of Ir-Mn, and a metal layer made of Al) are sequentially stacked.

As shown in FIG. 29, in each of samples A5 and B5, the area of the second antiferromagnetic film is larger than the junction area.

The sample A5 was manufactured as follows. The substrate is placed in a sputtering apparatus, and the initial degree of vacuum is 1 × 10 ⁻⁷ To.
After setting to rr, Ar was introduced and set to a predetermined pressure. On the substrate, Ta 5 nm / Fe ₅₄ Mn ₄₆ 18 nm
/ Ni ₈ Fe ₂ 5 nm / CoFe 2 nm / Al ₂ O ₃
1.7 nm / Co ₉ Fe 3 nm / Al ₂ O ₃ 2 nm /
CoFe 2 nm / Ta 5 nm were sequentially laminated. Note that Al ₂ O ₃ was formed by depositing Al in a pure Ar gas using an Al target, introducing oxygen without breaking vacuum, and exposing the film to plasma oxygen.

After forming the above-mentioned laminated film, a first resist pattern defining a lower wiring shape having a width of 50 μm was formed on the uppermost Ta layer by a photolithography technique, and processed by an ion milling technique.

Next, the first resist pattern was removed.
Then, an electron beam resist is applied on the uppermost Ta layer, and EB
First Al using a drawing apparatus_TwoO_ThreeFiner in each layer above
Processing and joining area 1 × 1μm^Two, 0.5 × 0.5μ
m^Two, 0.15 × 0.15μm ^TwoFerromagnetic tunnel junction
Produced. While leaving the electron beam resist pattern,
300nm thick Al by beam evaporation_TwoO_ThreeDeposited
After that, an electron beam resist pattern and Al_TwoO_ThreeTo
Lift off and form an interlayer insulating film in the area other than the joint.
Was.

Next, after forming a third resist pattern covering a region other than the region for forming the electrode wiring, the surface was reverse-sputtered and cleaned, and the Ta layer was further removed.
Then, Ni ₈ Fe ₂ 5 as the electrode wiring of the bit line
nm / Fe ₅₄ Mn ₄₆ 18 nm / Al 5 nm. The third resist pattern and the electrode wiring thereon were lifted off. Thereafter, the pin layer was introduced into a heat treatment furnace in a magnetic field to introduce unidirectional anisotropy.

The sample B5 was manufactured as follows. The substrate is placed in a sputtering apparatus, and the initial degree of vacuum is 1 × 10 ⁻⁷ To.
After setting to rr, Ar was introduced and set to a predetermined pressure. On the substrate, Ta 5 nm / Ir ₂₂ Mn ₇₈ 18 nm
/ CoFe 3 nm / Al ₂ O ₃ 1.5 nm / CoFe
1 nm / Ni ₈ Fe ₂ 3 nm / CoFe 1 nm / A
l ₂ O ₃ 1.8 nm / CoFe 3 nm / Ta 5 nm
Were sequentially laminated. Al ₂ O ₃ was formed by the same method as described above.

After forming the laminated film, a first resist pattern defining a lower wiring shape having a width of 50 μm was formed on the uppermost Ta layer by a photolithography technique, and processed by an ion milling technique.

Next, the first resist pattern was removed.
Then, an electron beam resist is applied on the uppermost Ta layer, and EB
First Al using a drawing apparatus_TwoO_ThreeFiner in each layer above
Processing and joining area 1 × 1μm^Two, 0.5 × 0.5μ
m^Two, 0.15 × 0.15μm ^TwoFerromagnetic tunnel junction
Produced. While leaving the electron beam resist pattern,
300nm thick Al by beam evaporation_TwoO_ThreeDeposited
After that, an electron beam resist pattern and Al_TwoO_ThreeTo
Lift off and form an interlayer insulating film in the area other than the joint.
Was.

Next, after forming a third resist pattern covering a region other than the region for forming the electrode wiring, the surface was reverse-sputtered and cleaned, and the Ta layer was further removed.
Thereafter, Co / Ir ₂₂ M is used as the electrode wiring of the bit line.
n ₇₈ 18 nm / Al 5 nm were sequentially laminated. The third resist pattern and the electrode wiring thereon were lifted off. Thereafter, the pin layer was introduced into a heat treatment furnace in a magnetic field to introduce unidirectional anisotropy.

For comparison, the following sample C was used.
5, Sample D5 and Sample E5 were produced. Sample C5 is a ferromagnetic single tunnel junction device, and Ta 5 nm / Ir
₂₂ Mn ₇₈ 18 nm / CoFe 3 nm / Al ₂ O ₃
5 nm / CoFe 1 nm / Ni ₈ Fe ₂ 3 nm / Co
It has a laminated structure of Fe 1 nm / Ta 5 nm.

The sample D5 has the same laminated structure as the sample B5,
That is, Ta 5 nm / Ir_{twenty two}Mn ₇₈ 18nm / Co
Fe 3nm / Al_TwoO_Three 1.5 nm / CoFe 1n
m / Ni₈Fe_Two 3 nm / CoFe 1 nm / Al_TwoO_Three
 1.8 nm / CoFe 3 nm / Ir_{twenty two}Mn₇₈ 18
nm / Ta 5 nm. But,
Unlike the structure of FIG. 29, the second
The area of the antiferromagnetic layer (and the Ta protective layer) is also
Processed to be identical. In addition, bit line
Is made of only an Al layer.

The sample E5 has a ferromagnetic layer containing no antiferromagnetic layer.
Heavy tunnel junction, Ta 5 nm / CoFePt
13nm / Al_TwoO_Three 1.5 nm / CoFe 1 nm /
Ni ₈Fe_Two 3 nm / CoFe 1 nm / Al_TwoO_Three 
1.8 nm / CoFePt 13 nm / Ta 5 nm
Having a laminated structure.

FIG. 30 shows the magnetoresistance effect curves of Samples A5 and B5. Sample A5 has an MR ratio of 28% with a small magnetic field of 29 Oe. Sample B5 is 39 Oe
With a small magnetic field, an MR change rate of 27% is obtained.

FIG. 31 shows the dependency of the MR ratio on the applied voltage for samples A5, B5 and C5. Note that in this figure, the MR change rate is normalized by a value at a voltage of 0 V. From this figure, it can be seen that, in Samples A5 and B5, compared to Sample C5, the voltage V _1/2 at which the value of the magnetoresistance ratio is halved is large, and the decrease in MR ratio with the increase in voltage is small.

Next, the samples A5, B5, D5 and E5 were placed in a solenoid coil, and a fatigue test of the magnetic recording state of the magnetization fixed layer was performed in a pulse magnetic field of 70 Oe. FIG. 32 shows the relationship between the number of reversals of the pulse magnetic field and the output voltage for samples A5, B5, D5, and E5. In this figure, the output voltage is normalized by the initial output voltage value. As is clear from this figure, in the sample E5, the output voltage is remarkably reduced with an increase in the number of reversals of the pulse magnetic field. Also,
Sample D5 showed a tendency that the smaller the joint area was, the more the fatigue became. This is considered to be because if the bonding area was small, the upper magnetization pinned layer deteriorated due to processing damage or the like. On the other hand, in the samples A5 and B5, no fatigue of the magnetic recording state of the magnetization fixed layer is observed. From this, FIG.
As shown in FIG. 9, it can be seen that it is advantageous to configure the upper antiferromagnetic layer as part of the bit line.

As described above, it can be seen that the ferromagnetic double tunnel junction device having the structure shown in FIG. 29 exhibits suitable characteristics particularly when applied to a magnetic recording device.

Note that SiO ₂ , AlN,
When MgO, LaAlO ₃ or CaF ₂ was used, the same tendency as above was observed.

Example 6 A ferromagnetic double tunnel junction device having the basic structure shown in FIGS. 1 to 4 was fabricated on a Si / SiO ₂ substrate or a SiO ₂ substrate in the same manner as in Examples 1 to 4. . Table 1 shows the laminated structure of these elements. Note that Ta, Ti, Ti / Pt, Pt, Ti /
One of Pd, Ta / Pt, Ta / Pd, and TiNx is used.

For these samples, the MR ratio was １ ／.
Table 1 shows the ratio between the output value when the free layer (magnetic recording layer) is inverted 100000 times and the initial output value when the voltage value V _1/2 decreases to 100 V. In each of the samples, a large MR ratio was obtained, and the degree of decrease in the voltage-dependent MR ratio was smaller than that of the ferromagnetic single tunnel junction device. Further, even if the magnetization reversal of the free layer (magnetic recording layer) is repeated, the output voltage hardly decreases and the fatigue is small.

Therefore, it can be seen that these elements are effective when used as a magnetoresistive head, sensor, and magnetic storage element.

[0160]

[Table 1]

In the present invention, atomic diffusion and mixing between the layers may occur. For example, if the sputtering strength is increased during sputtering, the NiFe alloy layer, C
It is considered that diffusion of atoms occurs between the o-based alloy layer and the non-magnetic layer or the antiferromagnetic layer. Although it depends on the temperature and the time, it is considered that the same atomic diffusion occurs even in the heat treatment. Even if such an atomic diffusion occurs, the material constituting each layer is within the scope of the present invention as long as it exhibits the magnetic properties required in the present invention and is included in the range of the specified material.

Example 7 Three types of ferromagnetic double tunnel junction devices (samples T1 and T2) having a structure as shown in FIG. 1 on a Si / SiO ₂ substrate or SiO ₂ substrate and having different free layer thicknesses And T3) will be described.

The sample T1 was made of a Ta underlayer, Fe--Mn / N
a first antiferromagnetic layer comprising a two-layer film of i-Fe, CoFe
A first ferromagnetic layer made of Al ₂ O ₃ , a _second ferromagnetic layer made of Co ₉ Fe, a second dielectric layer made of Al ₂ O ₃ , made of CoFe It has a structure in which a third ferromagnetic layer, a second antiferromagnetic layer composed of a Ni—Fe / Fe—Mn two-layer film, and a Ta protective layer are sequentially laminated, and a third layer composed of Co ₉ Fe, which is a free layer. The thickness of the ferromagnetic layer of No. 2 is set to 2.5 nm.

The sample T1 was manufactured as follows. The substrate is placed in a sputtering apparatus, and the initial degree of vacuum is 1 × 10 ⁻⁷ To.
After setting to rr, Ar was introduced and set to a predetermined pressure. On the substrate, Ta 5 nm / Fe ₅₄ Mn ₄₆ 20 nm
/ Ni ₈ Fe ₂ 5 nm / CoFe 3 nm / Al ₂ O ₃
1.7 nm / Co ₉ Fe 2.5 nm / Al ₂ O ₃ 2n
m / CoFe 3 nm / Ni ₈ Fe ₂ 5 nm / Fe ₅₄ M
n ₄₆ 20 nm / Ta 5 nm were sequentially laminated. Note that A
l ₂ O ₃ is converted to Al by using an Al target in pure Ar gas.
Was formed by introducing oxygen without breaking the vacuum and exposing the film to plasma oxygen.

After forming the above-mentioned laminated film, a resist pattern defining a lower wiring shape having a width of 100 μm was formed on the uppermost Ta protective layer by photolithography, and processed by ion milling.

Next, after removing the resist pattern, the photoresist is removed.
Photolithography technology or electron beam lithography technology
And RIE to define the junction size on the top Ta protective layer.
Forming a Ti hard mask to define the ion milling technology
Using the first Al_TwoO_ThreeCo above₉Fe / Al_TwoO
_Three/ CoFe / Ni-Fe / Fe-Mn / Ta
Was. The bonding width was variously changed by this process. Joint width
When an element having a thickness of 1 μm or less is formed, electron beam lithography
The technology was used. Form a resist pattern on the joint
And a thickness of 30 by sputtering or plasma CVD.
0 nm SiO _TwoAfter depositing the resist pattern,
And SiO on it_TwoLift off the non-joint parts
Then, an interlayer insulating film was formed.

Next, after forming a resist pattern covering a region other than the region where the electrode wiring was formed, the surface was cleaned by reverse sputtering. After depositing Al on the entire surface, the resist pattern and the Al thereon are lifted off, and A
1 electrode wiring was formed. Thereafter, the pin layer was introduced into a heat treatment furnace in a magnetic field to introduce unidirectional anisotropy.

The sample T2 was manufactured in the same manner as the sample T1 except that the thickness of the second ferromagnetic layer made of Co ₉ Fe as a free layer was changed to 7 nm.

The sample T3 was manufactured in the same manner as the sample T1, except that the thickness of the second ferromagnetic layer made of Co ₉ Fe as a free layer was changed to 17 nm.

FIG. 33 shows the relationship between the junction width of the element and the reversal magnetic field of the free layer for samples T1, T2 and T3. In this figure, the horizontal axis is the reciprocal (1 / W) of the joining width W. As shown in FIG. 33, the reversal magnetic field increases as the bonding width is reduced in any of the samples. This means that in MRAM applications, the power consumption during writing increases as the junction width is reduced. However, in the sample T1 in which the thickness of the free layer is small, the inclination of the straight line is small, and the increase of the switching magnetic field accompanying the reduction of the junction width is suppressed. On the other hand, in the samples T2 and T3 in which the thickness of the free layer is relatively large, the reversal magnetic field increases remarkably as the junction width decreases, and there is a possibility that the power consumption during writing in the MRAM application will increase significantly. Here, the inversion magnetic field is compared, focusing on the element having a junction width of 0.25 μm (1 / W = 4) obtained by the current processing technology. In the sample T1, the reversal magnetic field is smaller than 100 Oe, which can cope with further miniaturization in the future. On the other hand, in the samples T2 and T3, the reversal magnetic field is 10
Since it exceeds 0 Oe, power consumption at the time of writing is already high in MRAM applications, and it is difficult to cope with further miniaturization.

FIG. 34 shows the dependency of the MR ratio on the applied voltage for samples T1, T2 and T3. Note that in this figure, the MR change rate is normalized by a value at a voltage of 0 V. In the sample T1 having a thin free layer, the bias voltage V _1/2 at which the value of the MR change rate is halved exceeds 0.9 V, and the bias dependency is suppressed. On the other hand, in the samples T2 and T3 having a relatively thick free layer, the bias dependency is smaller than that of the ferromagnetic single tunnel junction device, but V _1/2 is less than 0.8 V, which is smaller than that of the sample T1. Obviously inferior.

FIGS. 33 and 34 show that as the thickness of the free layer is smaller, the increase in the switching field due to the miniaturization of the junction is suppressed, and the bias dependency is also improved.
If the thickness of the free layer is 5 nm or less, the switching field can be suppressed to 100 Oe or less in the element of the 0.25 μm rule, and the bias dependency of the MR ratio can be improved. But,
If the thickness of the free layer is less than 1 nm, the free layer may not be a continuous film, and may have a so-called granular structure in which ferromagnetic particles are dispersed in the dielectric layer. As a result,
It becomes difficult to control the bonding characteristics, and depending on the size of the fine particles, there is also a problem that the particles become superparamagnetic at room temperature and the MR ratio is extremely reduced. Therefore, the thickness of the free layer is 1 to
Preferably it is 5 nm.

[0173] M having a structure as in Example 8 Si / SiO ₂ 14 on a substrate
An example in which a RAM is manufactured will be described. SiO ₂ was formed on the Si substrate 151 by plasma CVD. The word line 152 was formed using a damascene process. That is, a resist is applied, a resist pattern is formed by photolithography, a groove is formed in SiO ₂ by RIE,
After Cu was buried in the trenches by plating, planarization was performed by CMP to form word lines 152. Thereafter, a 250 nm thick SiO ₂ interlayer insulating film was formed on the word line 152 by plasma CVD.

This sample was put into a sputtering apparatus, and an initial vacuum was applied.
Degree 3 × 10^-8After setting to Torr, introduce Ar
A predetermined pressure was set. SiO_TwoTa on the interlayer insulating film
Underlayer / Cu (50 nm) / Ni₈₁Fe₁₉(5 nm) /
Ir_{twenty two}Mn₇₈(12 nm) / Co₅₀Fe₅₀(3 nm) /
Al_TwoO_Three(1 nm) / Co₉₀Fe_Ten(2 nm) / Ni ₈₁
Fe₁₉(1 nm) / Co₉₀Fe_Ten(2 nm) / Ru
(0.9 nm) / Co₉₀Fe_Ten(2 nm) / Ni₈₁Fe
₁₉(1 nm) / Co₉₀Fe_Ten(2 nm) / Al_TwoO_Three(1
nm) / Co₈₀Fe₂₀(3 nm) / Ru (0.9 nm)
/ Co₈₀Fe₂₀/ Ir_{twenty two}Mn₇₈(12 nm) / Ni₈₁F
e₁₉(5 nm) / Au protective film was laminated. Al_TwoO_ThreeIs
Al film was formed using Al target in pure Ar gas
After that, introduce oxygen without breaking vacuum and expose to plasma oxygen.
Formed by

After forming Si ₃ N ₄ on the laminated film, applying a resist, forming a resist pattern by photolithography, forming a hard mask for defining the metal wiring 153 by RIE, and performing ion milling. Then, the laminated film was processed. After that, the resist pattern was removed.

Next, a resist is applied, a resist pattern for defining a junction size is formed by photolithography, and a laminated film above the first Al ₂ O ₃ is processed by ion milling technology to form a TMR element. Formed. All the cell sizes of the TMR elements were 0.4 × 0.4 μm ² . After that, the resist pattern was removed.

Next, an SiO ₂ interlayer insulating film was formed by plasma CVD, and was flattened by CMP to a thickness of 250 nm. Cu, an insulating film, and Cu were stacked on the entire surface. A Si ₃ N ₄ film is formed on the laminated film, a resist is applied, a resist pattern is formed by photolithography, a hard mask is formed by RIE, ion milling is performed, and a bit line 154 and an interlayer insulating layer 155 are formed. , And a second word line 156 are formed. Thereafter, the sample was introduced into a heat treatment furnace in a magnetic field, and uniaxial anisotropy was introduced into the magnetic recording layer, and unidirectional anisotropy was introduced into the magnetization fixed layer.

Writing was performed on the obtained MRAM by the following three methods.

(1) While injecting a spin current of 1 mA into the TMR element, a current pulse of 10 nsec is applied to the word line 152 and the second word line 156 to cause a current magnetic field in the easy axis direction and the hard axis direction of the magnetic recording layer 115. How to apply.

(2) A method in which only spin current is injected into the TMR element.

(3) A method of applying a current pulse of 10 nsec to the word line 152 and the second word line 156 to apply a current magnetic field in the easy axis direction and the hard axis direction of the magnetic recording layer 115.

The current pulse for applying a current magnetic field in the hard axis direction of the magnetic recording layer 115 is 10 nsec.
mA was constant.

The magnetization reversal of the magnetic recording layer 115 was determined based on whether or not the output voltage was changed by applying a DC current to the TMR cell after writing.

For the TMR element having a size of 0.4 × 0.4 μm ² in this embodiment, the current value is increased to 10 mA in the method (2) in which only the spin current is injected into the TMR element. However, no magnetization reversal was observed. In the method (3) of applying a current magnetic field in the easy axis direction and the hard axis direction of the magnetic recording layer 115, the magnetic recording layer 11
5, the current for applying a current magnetic field in the easy axis direction of the magnetic recording layer 115 is 4.3 mA.
Had to be increased.

On the other hand, in the method (1), while applying a spin current of 1 mA and increasing the current for applying a current magnetic field in the easy axis direction of the magnetic recording layer 115, the current was increased to 2.6 mA. The magnetization reversal of the magnetic recording layer 115 was confirmed by the current value. Further, by changing the direction of the current for applying the current magnetic field in the easy axis direction of the magnetic recording layer 115 and the direction of the spin current flowing through the TMR element, the magnetic recording layer 115 can be maintained at the small current value as described above. Can be repeated.

As described above, if the structure and the writing method of the MRAM of the present embodiment are adopted, the structure has a structure suitable for spin injection, and the current flowing to the wiring for applying a current magnetic field and the current flowing to the TMR element are reduced. Can be smaller. Therefore, even if the wiring width and the TMR element size become smaller as the density of the MRAM increases, melting of the wiring or breakage of the tunnel barrier layer can be suppressed, and the reliability can be improved.

[0187]

As described in detail above, in the magnetoresistance effect element having the ferromagnetic double tunnel junction of the present invention, the magnetoresistance change rate is not so large even if the applied voltage value is increased to obtain a desired output voltage value. It does not decrease, there is no problem that the magnetic moment of a part of the magnetization fixed layer is rotated by writing and the output gradually decreases, and the reversal magnetic field can be designed freely. In addition, the wiring width and T
Even if the size of the MR element is reduced, it is possible to suppress the melting of the wiring or the destruction of the tunnel barrier layer, thereby improving the reliability. Therefore, it is possible to provide a fine magnetoresistive element capable of stably obtaining a large output voltage, and it can be suitably used for a magnetoresistive head, a magnetic field sensor, a magnetic storage element, and the like.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a basic structure of a first magnetoresistive element of the present invention.

FIG. 2 is a sectional view showing a basic structure of a second magnetoresistance effect element according to the present invention.

FIG. 3 is a sectional view showing a basic structure of a third magnetoresistive element of the present invention.

FIG. 4 is a sectional view showing a basic structure of a fourth magnetoresistance effect element according to the present invention.

FIG. 5 is a sectional view showing a basic structure of a modification of the fourth magnetoresistive element of the present invention.

FIG. 6 is an equivalent circuit diagram of an MRAM in which a MOS transistor and a ferromagnetic double tunnel junction element are combined.

7 is a cross-sectional view of the MRAM of FIG. 6, in which a pin layer of the ferromagnetic double tunnel junction device forms a part of a bit line.

FIG. 8 is an equivalent circuit diagram of an MRAM in which a diode and a ferromagnetic double tunnel junction element are combined.

FIG. 9 is a cross-sectional view of the MRAM of FIG. 8, in which a pin layer of the ferromagnetic double tunnel junction device forms a part of a bit line.

FIG. 10 is a sectional view of a ferromagnetic double tunnel junction element used in another MRAM of the present invention.

FIG. 11 is a sectional view of a ferromagnetic double tunnel junction element used in another MRAM of the present invention.

FIG. 12 is a sectional view of a ferromagnetic double tunnel junction device used in another MRAM of the present invention.

FIG. 13 is a sectional view showing an example of an MRAM according to the present invention.

FIG. 14 is a sectional view showing another example of the MRAM according to the present invention.

FIG. 15 is a perspective view of a magnetic head assembly equipped with a magnetoresistive head including a tunnel junction type magnetoresistive element according to the present invention.

FIG. 16 is a perspective view showing the internal structure of a magnetic disk drive on which the magnetic head assembly shown in FIG. 15 is mounted.

FIG. 17 is a view showing the magnetoresistance effect curves of Samples A and B of Example 1.

FIG. 18 is a diagram showing the applied voltage dependence of the magnetoresistance ratio for samples A, B, and C of Example 1.

FIG. 19 is a diagram showing the relationship between the number of reversals of the pulse magnetic field and the output voltage for samples A, B, and D of Example 1.

FIG. 20 is a diagram showing magnetoresistance effect curves of Samples A2 and B2 of Example 2.

FIG. 21 is a diagram showing the applied voltage dependence of the magnetoresistance change rate for samples A2, B2, and C2 of Example 2.

FIG. 22 is a diagram showing the relationship between the number of reversals of the pulse magnetic field and the output voltage for samples A2, B2, and D2 of Example 2.

FIG. 23 is a diagram showing magnetoresistance effect curves of Samples A3 and B3 in Example 3.

FIG. 24 is a diagram showing the applied voltage dependence of the magnetoresistance ratio for samples A3, B3, and C3 of Example 3.

FIG. 25 is a diagram showing the relationship between the number of reversals of the pulse magnetic field and the output voltage for samples A3, B3, and D3 of Example 3.

FIG. 26 is a diagram showing magnetoresistance effect curves of Samples A4 and B4 in Example 4.

FIG. 27 is a diagram showing the applied voltage dependence of the magnetoresistance ratio for samples A4, B4, and C4 of Example 4.

FIG. 28 is a diagram showing the relationship between the number of reversals of the pulse magnetic field and the output voltage for samples A4, B4, and D4 of Example 4.

FIG. 29 is a sectional view of a magnetoresistive element in which a pinned layer forms a part of a bit line in a fifth embodiment.

FIG. 30 is a view showing a magnetoresistance effect curve of Samples A5 and B5 of Example 5.

FIG. 31 is a diagram showing the applied voltage dependence of the rate of change in magnetoresistance for samples A5, B5, and C5 of Example 5.

FIG. 32 shows samples A5, B5, D5 and E5 of Example 5.
FIG. 4 is a diagram showing a relationship between the number of reversals of the pulse magnetic field and the output voltage for the case of FIG.

FIG. 33 is a diagram showing the relationship between the junction width and the rate of change in magnetoresistance for samples T1, T2, and T3 of Example 7.

FIG. 34 is a diagram showing the applied voltage dependence of the magnetoresistance change rate for samples T1, T2 and T3 of Example 7.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Magnetoresistance effect element 11 ... 1st antiferromagnetic layer 12 ... 1st ferromagnetic layer 13 ... 1st dielectric layer 14 ... 2nd ferromagnetic layer 15 ... 2nd dielectric layer 16 ... 3 ferromagnetic layer 17 second antiferromagnetic layer 20 magnetoresistive element 21 first ferromagnetic layer 22 first dielectric layer 23 second ferromagnetic layer 24 first antiferromagnetic layer Ferromagnetic layer 25 Third ferromagnetic layer 26 Second dielectric layer 27 Fourth ferromagnetic layer 30 Magnetoresistive element 31 First antiferromagnetic layer 32 First ferromagnetic layer 33 first dielectric layer 34 second ferromagnetic layer 35 second antiferromagnetic layer 36 third ferromagnetic layer 37 second dielectric layer 38 fourth ferromagnetic layer 39 ... Third antiferromagnetic layer 40... Magnetoresistive element 41. First ferromagnetic layer 42. First dielectric layer 43. Second ferromagnetic layer 44. Third ferromagnetic layer 46 Second nonmagnetic layer 47 Fourth ferromagnetic layer 48 Second dielectric layer 49 Fifth ferromagnetic layer 50 Antiferromagnetic layer 60 Transistor 61 Silicon Substrate 62 ... gate electrode (read word line) 62, 63 ... source and drain regions 71 ... write word line 72 ... contact metal 73 ... underlayer 74 ... bit line 80 ... diode 81 ... underlayer 91 ... word line 92 ... Bit line 101: Underlayer 102: First antiferromagnetic layer 103: First magnetization pinned layer 104: First dielectric layer 105: Magnetic recording layer 106: Second dielectric layer 107: Second magnetization Fixed layer 108 Second antiferromagnetic layer 109 Protective layer 111 Underlayer 112 First antiferromagnetic layer 113 First magnetic pinned layer 114 First dielectric layer 115 Magnetic Recording layer 116 second dielectric layer 117 second magnetization fixed layer 118 second antiferromagnetic layer 119 protective layer 121 underlayer 122 first antiferromagnetic layer 123 first magnetization Pinned layer 124 First dielectric layer 125 Magnetic recording layer 126 Second dielectric layer 127 Second magnetic pinned layer 128 Second antiferromagnetic layer 129 Protective layer 151 Si substrate 152 Word line 153 Metal wiring 154 Bit line 155 Insulating layer 156 Second word line 201 Actuator arm 202 Suspension 203 Head slider 204 Lead wire 205 Electrode pad 211 Magnetic disk 212 Spindle 213 Fixed axis 214 ... voice coil motor

Continuation of the front page (51) Int.Cl. ⁷ Identification FI FI Theme Court II (Reference) H01L 43/12 G01R 33/06 R (72) Inventor Koichiro Inomata 1 Kosuka Toshiba-cho, Sai-ku, Kawasaki-shi, Kanagawa Stock Company (72) Inventor Masayuki Sunai 1st location, Komukai Toshiba-cho, Saisaki-ku, Kawasaki-shi, Kanagawa Prefecture Inside Toshiba Research & Development Center Co., Ltd. (72) Inventor Tatsuya Kishi Toshiba Komukai-shi, Kawasaki-shi, Kanagawa No. 1 town Toshiba R & D Center

Claims (11)

[Claims] 1. A first antiferromagnetic layer / a first ferromagnetic layer / a first dielectric layer / a second ferromagnetic layer / a second dielectric layer / a third dielectric layer
Wherein the second ferromagnetic layer is formed of a Co-based alloy or a Co-based alloy / Ni-
A magnetoresistive element comprising a three-layered film of an Fe alloy / Co-based alloy, wherein a tunnel current flows through the first to third ferromagnetic layers. 2. The first ferromagnetic layer / first dielectric layer / second ferromagnetic layer
Ferromagnetic layer / first antiferromagnetic layer / third ferromagnetic layer / second
Wherein the first and fourth ferromagnetic layers are formed of a Co-based alloy or a Co-based alloy. A magnetoresistance effect element comprising a three-layer film of a Ni-Fe alloy / Co-based alloy, wherein a tunnel current flows through the first to fourth ferromagnetic layers. 3. The first antiferromagnetic layer / first ferromagnetic layer / first dielectric layer / second ferromagnetic layer / second antiferromagnetic layer / third ferromagnetic layer / third ferromagnetic layer 2nd dielectric layer / 4th ferromagnetic layer / 3rd
Wherein the first and fourth ferromagnetic layers or the second and third ferromagnetic layers are Co-based alloys. A magnetoresistive element comprising a three-layered film of a Co-based alloy / Ni-Fe alloy / Co-based alloy, wherein a tunnel current flows through the first to fourth ferromagnetic layers. 4. A first ferromagnetic layer / first dielectric layer / second ferromagnetic layer
Ferromagnetic layer / first nonmagnetic layer / third ferromagnetic layer / second nonmagnetic layer / fourth ferromagnetic layer / second dielectric layer / fifth ferromagnetic layer A magnetoresistive effect element having a ferromagnetic double tunnel junction, wherein a second, third,
The fourth ferromagnetic layer is antiferromagnetically coupled via a non-magnetic layer, and the first and fifth ferromagnetic layers are formed of a Co-based alloy or a Co-based alloy / Ni-Fe alloy / Co-based alloy. A magnetoresistive effect element comprising a layer film, wherein a tunnel current flows through the first to fifth ferromagnetic layers. 5. The Co-based alloy or Co-based alloy / Ni
The thickness of the three-layer film of the Fe alloy / Co-based alloy is 1 to 5 nm;
The magnetoresistive element according to any one of claims 1 to 4, wherein 6. A magnetic recording element comprising: a transistor or a diode; and the magnetoresistive element according to claim 1. 7. A magnetic recording element comprising a transistor or a diode and the magnetoresistive element according to claim 1 or 2, wherein at least the uppermost antiferromagnetic layer of the magnetoresistive element is a bit line. A magnetic recording element comprising a magnetic recording element. 8. A first magnetization fixed layer having a fixed magnetization direction, a first dielectric layer, a magnetic recording layer whose magnetization direction is reversible, a second dielectric layer, and a magnetization direction fixed to the first and second dielectric layers. A second magnetic pinned layer, wherein the magnetic recording layer includes a three-layer film of a magnetic layer, a non-magnetic layer, and a magnetic layer, and the two magnetic layers constituting the three-layer film are anti-strong. A magnetic recording element magnetically coupled, wherein the magnetizations of regions of the two magnetization fixed layers that are in contact with the dielectric layer are substantially antiparallel. 9. A first magnetization pinned layer having a fixed magnetization direction, a first dielectric layer, a magnetic recording layer whose magnetization direction is reversible, a second dielectric layer, and a magnetization direction fixed to each other. A second magnetic pinned layer, wherein the magnetic recording layer includes a three-layer film of a magnetic layer, a non-magnetic layer, and a magnetic layer, and the two magnetic layers constituting the three-layer film are anti-strong. Magnetically coupled, the second magnetization pinned layer includes a three-layer film of a magnetic layer, a non-magnetic layer, and a magnetic layer, and two magnetic layers constituting the three-layer film are antiferromagnetically coupled. The length of the first magnetization fixed layer is
The magnetic recording element is formed to be longer than the lengths of the magnetization fixed layer and the magnetic recording layer, and the magnetizations of regions of the two magnetization fixed layers that are in contact with the dielectric layer are substantially antiparallel. . 10. A spin current is supplied to the magnetic recording layer through the first or second magnetization pinned layer constituting the magnetic recording element according to claim 8, and a current is supplied to a write wiring to supply the spin current. A method for writing to a magnetic recording element, wherein a current magnetic field is applied to a recording layer. 11. A magnetic sensor or a magnetic head comprising the magnetoresistive element according to claim 1.