JP2003197872A - Memory using magneto-resistance effect film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a memory which has a large readout signal and high recording density. <P>SOLUTION: One bit is recorded to two magneto-resistance effect film which are stacked so that one is a magnetism array with large resistance and the other is a magnetism array with small resistance. Here, a magnetic body is a vertically magnetized film. The two magneto-resistance effect films can share recording wires. Magnetism fixed layers 011 and 014 are reversely parallel, so the resistance is large when the magnetization directions of magnetism free layers 012 and 015 are reversely parallel with the direction of a storage magnetic field and small when parallel. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a memory using a magnetoresistive effect film.

[0002]

2. Description of the Related Art In recent years, semiconductor memories, which are solid-state memories, have been widely used in information equipment, and DRAM, FeRAM, flash EEP
There are various types such as ROM. The characteristics of these semiconductor memories have advantages and disadvantages, and there is no memory that meets all of the specifications required in current information devices. For example, DRAM has a high recording density and a large number of rewritable times,
It is volatile and loses information when the power is turned off. Also,
Flash EEPROM is non-volatile, but it takes a long time to erase,
It is not suitable for high-speed processing of information.

In contrast to the current state of the semiconductor memory as described above, a memory (MRAM) using the magnetoresistive effect is
It is promising as a memory that meets all the specifications required by many information devices in terms of read time, recording density, number of rewritable times, power consumption, and the like. In particular, MRAM using the spin tunneling magnetoresistance (TMR) effect is advantageous for high recording density or high-speed read because a large read signal can be obtained.
The feasibility as is proved.

The basic structure of the magnetoresistive film used as an element of the MRAM is a sandwich structure in which magnetic layers are formed adjacent to each other with a nonmagnetic layer interposed therebetween. Cu and Al ₂ O ₃ are examples of materials that are often used as the non-magnetic film. A magnetoresistive film that uses a conductor such as Cu for the nonmagnetic layer is called a giant magnetoresistive film (GMR film), and a film that uses an insulator such as Al ₂ O ₃ is a spin tunneling film ( TMR
Membrane). Generally, the TMR film exhibits a larger magnetoresistive effect than the GMR film.

When the magnetization directions of the two magnetic layers are parallel as shown in FIG. 21 (a), the electric resistance of the magnetoresistive film is relatively small, and the magnetization directions are antiparallel as shown in FIG. 21 (b). Then, the electric resistance becomes relatively large. Therefore, it is possible to read information by using one of the magnetic layers as a recording layer and the other as a reading layer and utilizing the above properties. For example, the magnetic layer 003 located above the non-magnetic layer 002 is used as a recording layer, and the magnetic layer 004 located below is used as a reading layer. The magnetization direction of the recording layer is “1” when the magnetization direction is rightward, and “0” when the magnetization direction is leftward. And When the magnetization directions of both magnetic layers are rightward as shown in FIG. 22A, the electric resistance of the magnetoresistive film is relatively small,
As shown in FIG. 22B, when the magnetization direction of the read layer is rightward and the magnetization direction of the recording layer is leftward, the electric resistance is relatively large. Further, as shown in FIG. 22 (c), when the magnetization direction of the read layer is leftward and the magnetization direction of the recording layer is rightward, the electric resistance is relatively large, and as shown in FIG. When the magnetization direction is leftward, the electric resistance is relatively small. In other words, if the magnetization direction of the readout layer is fixed to the right, if the electric resistance is large, then "0" is recorded in the recording layer, and if the electric resistance is small, then "1" is recorded. Has been done. Alternatively,
When the magnetization direction of the readout layer is fixed to the left, if the electric resistance is large, then "1" is recorded in the recording layer, and if the electric resistance is small, "0" is recorded. Will be there.

In-plane magnetized films of Co, CoFe, NiFe and the like are mentioned as materials mainly used as the magnetic material of the magnetoresistive effect film. It is known that among these materials, NiFe reverses the magnetization in a relatively small magnetic field, and CoFe exhibits a large magnetoresistive effect. Therefore, for example, a magnetic film in which NiFe and CoFe are exchange-coupled and a film structure in which a nonmagnetic layer is sandwiched by CoFe can be used as a magnetoresistive film in which a large magnetoresistance change occurs with a small magnetic field.

By the way, as disclosed in ISSCC2000, a method has been proposed in which 1-bit information is recorded on two magnetoresistive films using in-plane magnetized films to obtain a large read signal. FIG. 23 shows a circuit diagram of the reading section of this method. Since one memory cell uses two magnetoresistive films and two transistors, it is called a 2T2R type. Of the two magnetoresistive films that record 1 bit, the magnetization is oriented so that the resistance becomes small, and the other is oriented so that the resistance becomes large. By doing so, a relatively high voltage is input to one of the inputs of the sense amplifier, and a relatively low voltage is input to the other, so that it is twice as large as when one magnetoresistive film is used. A read signal can be obtained, and it is possible to reduce the influence of device manufacturing variations and noise.

[0008]

As described above, the 2T2R type uses a transistor to select a memory element at the time of reading. However, since the transistor requires a large area, the memory cell size depends on the size of the transistor. The current situation is that it has been decided. 2T2 at ISSCC2000
The cell size of R type is reported to be about 50F ^{2 when the} design rule is F, and 2T2R is required to achieve high recording density.
Difficult to type.

On the other hand, by connecting the memory element and the diode in series as proposed in USP 5640343, it is possible to reduce the memory cell size and select the memory element. In a magnetoresistive effect film that uses an in-plane magnetized film as a magnetic material, if the shape is square, the phenomenon that the magnetization direction cannot be maintained due to the effect of the demagnetizing field occurs, so the shape must be rectangular. The membrane size should be at least 2F ² . Therefore, 1
If one magnetoresistive film and one diode are stacked on top of each other to make one cell, the cell size will be 6F ² . But,
When this method is applied to the conventional 2T2R type, since the two magnetoresistive effect films are arranged side by side, the size of the memory cell is doubled to 12F ² .

In view of this point, an object of the present invention is to provide a memory having a large read signal and a high recording density.

[0011]

A memory using a magnetoresistive effect film of the present invention comprises a pair of magnetoresistive effect films having a structure in which a nonmagnetic film is sandwiched between magnetic films, and a pair of magnetoresistive effect films. First magnetic field applying means for applying a magnetic field to each of the magnetoresistive films so that the resistances of the magnetoresistive films are different from each other, and a bit line for detecting a potential generated by the resistance value of the magnetoresistive film. And a pair of magnetoresistive effect films are laminated in the direction normal to the film surface.

A plurality of pairs of magnetoresistive films are arranged on the substrate, diodes are connected in series to the magnetoresistive films, and word lines are connected to the other terminals of the diodes to form memory cells. Information recorded in a specific memory cell may be selectively read.

Further, the first magnetic field applying means is a conductor,
A magnetic field induced by passing a current through the conductor may be applied to the magnetoresistive film to change the magnetization state.

Further, it further comprises a second magnetic field applying means for applying a magnetic field to the magnetoresistive effect film from a direction different from the magnetic field applied by the first magnetic field applying means.
Recording may be performed by selecting a specific magnetoresistive effect film from a plurality of magnetoresistive effect films by causing a magnetic field applied from the second magnetic field applying means to act on an arbitrary magnetoresistive effect film.

Further, the magnetic film may be an in-plane magnetized film.

Further, the magnetic field by the first magnetic field applying means is a magnetic field in the in-plane direction of the film, and the magnetic field by the second magnetic field applying means is orthogonal to the magnetic field by the first magnetic field applying means and is oriented in the in-plane direction of the film. May be.

Further, one of the magnetic films may be a magnetization free layer which is reversible by a magnetic field applied during recording, and the other may be a magnetization fixed layer which is not reversible.

In addition, at the time of initialization, the net magnetizations of the magnetization fixed layers of the pair of magnetoresistive films may be parallel by applying a magnetic field in one direction.

Also, two magnetoresistive films for recording 1 bit may be provided above and below the conducting wire for generating the recording magnetic field.

Further, one of the two magnetoresistive films may have a laminated ferri structure.

The magnetic film may be a perpendicular magnetization film.

Further, the magnetic field by the first magnetic field applying means is in the direction normal to the film surface, and the magnetic field by the second magnetic field applying means is
It may be a magnetic field in the in-plane direction of the film.

Further, one of the magnetic films may be a magnetization free layer which is reversible by a magnetic field applied during recording, and the other may be a magnetization fixed layer which is not reversible.

In addition, at the time of initialization, the net magnetizations of the magnetization fixed layers of the pair of magnetoresistive films may be parallel by applying a magnetic field in one direction.

Further, the magnetization fixed layer may be ferromagnetism made of a material containing a transition metal, and the magnetization direction of the magnetization fixed layer may be antiparallel between the two magnetoresistive films.

Further, the magnetization fixed layer is a ferromagnet made of a material containing a transition metal, the magnetization direction of the magnetization fixed layer is parallel between the two magnetoresistive films, and the magnetization free layer is The magnetization free layer of one magnetoresistive film of ferrimagnetism composed of a rare earth and a transition metal may have a rare earth sublattice magnetization dominance and the magnetization free layer of the other magnetoresistive film may have a transition metal sublattice magnetization dominance.

The magnetic film may be ferrimagnetic composed of a rare earth metal and a transition metal.

Further, the magnetic film has a transition metal sublattice magnetization predominant, and the magnetization direction of the magnetization pinned layer of one magnetoresistance effect film is antiparallel to the magnetization direction of the magnetization pinned layer of the other magnetoresistance effect film. You may face.

The magnetic film has a rare earth metal sublattice magnetization predominant, and the magnetization direction of the magnetization pinned layer of one magnetoresistance effect film is antiparallel to the magnetization direction of the magnetization pinned layer of the other magnetoresistance effect film. You may face.

The magnetization pinned layer of one magnetoresistive film has a rare earth metal sublattice magnetization predominance, and the magnetization pinned layer of the other magnetoresistive film has a transition metal sublattice magnetization predominant.
The magnetization directions of the two magnetization fixed layers are parallel to each other, and the magnetization free layers of the two magnetoresistive films may both have the transition metal sublattice magnetization dominant.

The magnetization fixed layer of one magnetoresistive effect film has a rare earth metal sublattice magnetization predominant, and the magnetization fixed layer of the other magnetoresistive effect film has a transition metal sublattice magnetization predominant. The magnetization directions are parallel to each other, and the magnetization free layers of the two magnetoresistive films may both have a rare earth metal sublattice magnetization predominant.

Further, both of the two magnetization pinned layers are dominant in the transition metal sublattice magnetization, and their magnetization directions are parallel to each other, and the magnetization free layer of one magnetoresistive film is dominant in the rare earth metal sublattice magnetization. The magnetization free layer of the other magnetoresistive film may have a transition metal sublattice magnetization dominant.

Further, both of the two magnetization fixed layers have a rare earth metal sub-lattice magnetization dominant and their magnetization directions are parallel, and the magnetization free layer of one of the magnetoresistive films has a rare earth metal sub-lattice magnetization dominant. The magnetization free layer of the other magnetoresistive film may have a transition metal sublattice magnetization dominant.

Further, two magnetoresistive films are formed on the substrate.
In a memory in which a plurality of elements in which bits are formed are arranged in a matrix, at least one write line is formed between magnetoresistive films, and the write line has a film normal to a desired element. Recording may be performed by passing an electric current so that a magnetic field is applied in the direction.

Further, a write line is formed between the elements only in the row direction, and a conductive wire is further provided above or below the element, and the write line is opposite to the two adjacent elements in the film normal direction. A current is applied so that a magnetic field is applied to the device, and a magnetic field is applied to the desired device in the in-plane direction by applying a current to a conductor provided above or below the desired device for recording. You can go.

Further, the conducting wire for applying the magnetic field in the in-plane direction of the film may be a bit line or a word line.

The magnetoresistive film may be a spin tunnel magnetoresistive film.

Therefore, by stacking two magnetoresistive films whose resistance changes with respect to the applied magnetic field are opposite to each other and recording 1 bit on the two magnetoresistive films, a read signal is large and a recording density is high. By using it as a memory and sharing the recording means of the two magnetoresistive films, it is possible to reduce the power consumption during recording.

Further, by using a perpendicular magnetization film and stacking two magnetoresistive effect films whose resistance changes with respect to an applied magnetic field are opposite to each other and recording 1 bit on the two magnetoresistive effect films, a read signal is obtained. By making the memory large and having high recording density, and sharing the recording means of the two magnetoresistive films, it is possible to reduce power consumption during recording. Further, it is possible to share the conductive wire for generating the recording magnetic field.

[0040]

BEST MODE FOR CARRYING OUT THE INVENTION (First Embodiment) In this embodiment, an in-plane magnetized film whose magnetization is oriented in the in-plane direction is used as the magnetic film. As shown in FIG. 21, the low resistance state and the high resistance state of the magnetoresistive film depend on whether the magnetizations of the magnetic layers on both sides of the nonmagnetic layer are parallel or antiparallel. The memory of the present embodiment needs to have a pair of magnetoresistive films in the memory cells forming one bit so that they have different resistance values depending on the recording operation.

FIG. 1 shows a conceptual diagram of the magnetization state of this embodiment. The magnetization of one of the two magnetic films of the magnetoresistive film is a magnetization fixed layer 022, 025 which is not reversed by the recording magnetic field, and the other magnetic film is a magnetization free layer 021, 024 capable of reversing the magnetization. The magnetization directions of 022 and 025 are set to be antiparallel between the two magnetoresistive films. For example, as shown in FIG. 1A, the magnetization of the magnetization fixed layer 022 is directed to the left,
025 is to the right. When a magnetic field in the same direction is applied to both magnetoresistive films in such a state, the magnetizations of the magnetization free layers 021 and 024 are inverted and oriented in the direction of the applied magnetic field. For example, in FIG. 1A, the magnetization directions of the magnetization free layer 021 and the magnetization fixed layer 022 are antiparallel, and the magnetization free layer 0
The magnetizations of 24 and the magnetization fixed layer 025 are parallel to each other. That is, the resistance of one magnetoresistive film is low and the resistance of the other is high.

Here, in the initial setting, the magnetization fixed layer 02
The antiparallel magnetization of 2,025 can be achieved by applying a magnetic field in a desired direction when forming the magnetic film. That is, the direction of the magnetic field applied when forming one magnetoresistive effect film is opposite to the direction of the magnetic field applied when forming the other magnetoresistive effect film.

Alternatively, the coercive forces of the two magnetization fixed layers 022 and 025 are made different from each other, and a magnetic field in which the magnetizations of the two magnetic layers are reversed is applied to bring the magnetizations of the two magnetization fixed layers into a parallel state. After that, one of the magnetizations is reversible and the other is not reversed, and a magnetic field is applied in the direction opposite to the direction of the previous magnetic field, and only one of the magnetizations is reversed, and the magnetization directions of the two magnetization fixed layers are reversed. Can be antiparallel.

When the magnetization directions of the magnetization fixed layers 022 and 025 are initially set to be parallel, as shown in FIG. 2, one magnetoresistive film is provided above and below the conducting wire 801, respectively. When a current is passed through 801 the recording magnetic fields in opposite directions are applied to the two magnetoresistive films, so that the resistance of one magnetoresistive film is low and the other is high.

Further, when the magnetizations of the respective magnetization pinned layers are initialized to be parallel, it is also effective to use a magnetoresistive film using the laminated ferri structure 030 for one of the magnetization free layers as shown in FIG. Is. The laminated ferri structure is a multilayer film such as Fe / Ru / Fe, and is characterized in that the magnetizations of the two ferromagnetic films are antiferromagnetically coupled. One of the two magnetoresistive films is a magnetoresistive film using the laminated ferri structure 030 for the magnetization free layer, and the other is a basic structure of the magnetoresistive film. It is possible to lower the resistance of the magnetoresistive film and increase the other.

Next, to record information only in a desired cell among a plurality of memory cells formed on the substrate, "1",
A magnetic field applied in the direction corresponding to "0" and a magnetic field in the in-plane direction orthogonal to the magnetic field are simultaneously applied only to a desired cell. By doing so, only the magnetization of the magnetization free layer of the memory cell to which a magnetic field is applied in two directions can be reversed, and selective recording is performed. The recording magnetic field causes a current to flow in the conductor,
It is preferable to utilize the magnetic field generated by this.
Further, it is preferable to use a bit line or a word line arranged above or below the memory element as a conducting wire for generating a magnetic field because it is not necessary to newly provide a magnetic field applying means for generating a recording magnetic field.

(Second Embodiment) In this embodiment, a perpendicular magnetization film is used as the magnetic film. When the element size is reduced in order to increase the recording density of MRAM, MRAM using an in-plane magnetized film may have a problem that it cannot retain information due to the influence of demagnetizing field or curling of end surface magnetization. There is. In order to avoid this problem, for example, the shape of the magnetic film may be made rectangular. However, since the element size cannot be reduced by this method, improvement in recording density is not expected so much. Therefore, for example, as described in Japanese Patent Laid-Open No. 11-213650, a proposal has been made to avoid the above problem by using a perpendicular magnetization film. With this method, the demagnetizing field does not increase even when the element size is reduced.
It is possible to realize a magnetoresistive film having a size smaller than that of AM.

As the perpendicular magnetization film, at least one element selected from rare earth metals such as Gd, Dy, Tb and Co, Fe,
An alloy film or artificial lattice film of at least one element selected from transition metals such as Ni, an artificial lattice film of a transition metal such as Co / Pt and a noble metal, an alloy such as CoCr having a crystal magnetic anisotropy in the direction perpendicular to the film surface. Membranes are mainly mentioned.

Among these materials, the alloy film of rare earth metal and transition metal and the artificial lattice film show a magnetization curve having a squareness ratio of 1, and a sharp magnetization reversal occurs when a magnetic field is applied. Further, since spins of rare earth metal atoms and spins of transition metal atoms are coupled antiparallel to each other, the saturation magnetization is smaller than that of Fe, Co, Ni or their alloys which are mainly used for in-plane magnetized films, and nonmagnetic films are Since the magnetostatic coupling force acting between the two magnetic films laminated via the thin film is small, an alloy of rare earth metal and transition metal or an artificial lattice film is suitable for a magnetoresistive film used as a memory element.

First, FIG. 9 shows the magnetization state when all the magnetic films used for the magnetoresistive film exhibit ferromagnetism. 012 and 015 are magnetization free layers, 011 and 014 are magnetization fixed layers, and 013 and 016 are nonmagnetic layers, and when a spin tunnel magnetoresistive film is used, they are insulators. Also, 800
Is the direction of the recording magnetic field.

The magnetizations of the two magnetization free layers are oriented in the direction of the recording magnetic field. In the initial setting, the magnetization pinned layer is anti-parallel in the pair of magnetoresistive films, so that
As described above, when the recording magnetic field is upward, the upper magnetoresistive effect film is in an antiparallel state and the resistance is high, and the lower magnetoresistive effect film is in parallel magnetization and the resistance is low. Further, when the recording magnetic field is directed downward, the state is as shown in FIG. 9B, which is the reverse of the state shown in FIG. Therefore, by applying a magnetic field in one direction, the pair of magnetoresistive effect films can have different resistances.

Next, an example in which a ferromagnetic material is used as the magnetization fixed layer and a ferrimagnetic material is used as the magnetization free layer is shown in FIG.
Shown in 0 and 11.

The composition of the ferrimagnetic material is roughly classified into a rare earth metal sublattice magnetization dominant and a transition metal sublattice magnetization dominant. As shown in FIG. 10, when the magnetization direction of the magnetization fixed layer is initially set to be antiparallel between the two magnetoresistive films, the magnetization free layer has a rare earth metal sublattice magnetization in both magnetoresistive films. Either the dominant or the transition metal sublattice magnetization is dominant.
821 indicates a transition metal sublattice magnetization, and 822 indicates a rare earth metal sublattice magnetization. Therefore, as shown in FIG. 10, the transition metal sublattice magnetization is dominant in the magnetization free layer. Since the magnetoresistive effect largely depends on the spin direction of the transition metal atom, if the magnetization of the magnetization fixed layer is due to the transition metal atom and the magnetization free layer has the transition metal sublattice magnetization dominant, The resistance is small when the net magnetization directions of the magnetizations of the rare earth metals are parallel, and is large when they are antiparallel. If the magnetization free layer is predominantly a rare earth metal, the resistance is large when the net magnetization directions are parallel, and the resistance is small when the net magnetization directions are antiparallel. As shown in FIG. 10, by applying a recording magnetic field in one direction, different resistance states can be created in the pair of magnetoresistive films.

Further, as shown in FIG. 11, when the magnetization direction of the magnetization fixed layer is made parallel between the two magnetoresistive effect films, the composition of the magnetization free layer is adjusted and the two magnetoresistive effect films are adjusted. One of the magnetization free layers is made to have a rare earth metal sublattice magnetization dominant, and the other is made to be a transition metal sublattice magnetization dominant. By doing so, even if a magnetic field in the same direction is applied, one of the magnetoresistive effect films can have a high resistance, and the other magnetoresistive effect film can have a low resistance, so that different resistance states can be created. In FIGS. 11A and 11B, the composition of the upper magnetoresistive film is dominated by the transition metal sublattice magnetization 821, and the composition of the lower magnetoresistive film is dominated by the rare earth metal sublattice magnetization 822.
11 (c) and (d) are the opposite.

Further, it is possible to adopt a structure in which both the magnetization fixed layer and the magnetization free layer are ferrimagnetic layers.

First, FIG. 12 shows a structure in which the magnetization fixed layer is antiparallel with a composition in which the transition metal sublattice magnetization is dominant. Figure 12
In (a) and (b), the magnetization free layer has a composition in which the transition metal sublattice magnetization 821 is dominant. Further, in FIGS. 12C and 12D, the magnetization free layer has a composition in which the rare earth metal sublattice magnetization is dominant. In such a composition, since the transition metal sublattice magnetizations of the magnetization fixed layer are antiparallel in the initial state, the composition is adjusted so that the transition metal sublattice magnetizations of the magnetization free layer are parallel to each other. do it. By doing so, by applying a magnetic field in one direction, magnetization states having different resistance values are achieved.

Next, in FIG. 13, the composition of the magnetization fixed layer is such that one of the magnetizations of the transition metal sublattice is dominant and the other of the magnetizations of the rare earth metal sublattice is dominant, and the magnetizations of the magnetization pinned layers are antiparallel to each other. The configuration is shown. 13 (a) and 13 (b) show a composition in which the magnetization free layers are both dominant in the transition metal sublattice.
(C) and (d) show compositions in which the magnetization free layers are both dominant in the rare earth metal sublattice. However, in the two magnetoresistive films, the net magnetization directions of the magnetization fixed layers 011 and 014 are set to be parallel. Here, the net magnetization direction refers to a composite magnetization of a rare earth metal sublattice magnetization and a transition metal sublattice magnetization. Even in such a configuration, since the transition metal sublattice magnetization is antiparallel in the initial setting, the composition is such that the transition metal sublattice magnetization of the magnetization free layer is parallel. As is clear from the figure, by applying one magnetic field, magnetization states having different resistance values are achieved.

Next, FIG. 14 shows a configuration in which the magnetization fixed layers of the two magnetoresistive films both have the transition metal sublattice magnetization dominant or the rare earth metal sublattice magnetization dominant and the transition metal sublattice magnetizations are parallel. Show. In FIGS. 14 (a) and 14 (b), the magnetization fixed layer has the transition metal sublattice magnetization predominant.
In (c) and (d), the composition has a rare earth metal sublattice magnetization dominant. The magnetization free layer is shown in FIGS.
(C) (d) In both of the above magnetoresistive films,
The composition of the transition metal sublattice magnetization is dominant, and the magnetoresistive film below has a composition of the rare earth metal sublattice magnetization predominant. However, the net magnetization direction of the magnetization fixed layer is set to be parallel between the two magnetoresistive films. In such a configuration, since the transition metal sublattice magnetization of the magnetization fixed layer is parallel in the initial setting, the transition metal sublattice magnetization of the magnetization free layer is antiparallel due to the application of the recording magnetic field in one direction. The composition may be such that As is clear from the figure, magnetization states having different resistance values are achieved by applying a magnetic field in one direction.

In summary, in the configuration in which the ferrimagnetic material is used for the magnetization free layer, when the transition metal sublattice magnetizations of the magnetization fixed layers of the two magnetoresistive films are parallel in the initial setting, at the time of recording. When the composition is such that the transition metal sublattice magnetizations of the magnetization free layers of the two magnetoresistive effect elements are antiparallel due to the application of the magnetic field, and the transition metal sublattice magnetizations of the magnetization fixed layer are antiparallel, the recording is also performed. The composition may be adjusted so that the magnetization of the transition metal in the magnetization free layer becomes parallel by applying the magnetic field. Further, the magnetic field at the time of recording is appropriately applied in two directions to record 0 and 1, but as shown in the figure, for example, an upward magnetic field causes the resistance of one magnetoresistive film to be increased. In the high state, the resistance of the other magnetoresistive film is low state, the composition of the magnetization free layer, the magnetization fixed layer, so that the opposite state by the downward magnetic field application,
Specifies the magnetization direction in the initial setting.

Next, a method of selectively recording only desired ones out of a plurality of memory cells arranged on the substrate will be described. FIG. 15 shows a plan view of the memory as viewed from above. A conductor wire is arranged between the memory cells to induce a recording magnetic field, and a current is applied to the conductor wire around the desired magnetoresistive film so that the recording magnetic field is generated in the same direction as the film surface perpendicular direction. Shed. By doing so, a strong magnetic field is applied only to the desired memory cell, and recording is selectively performed. For example, Figure 15
When recording to the memory cell 150 in the
Current is applied to 12,723 in the direction of the arrow shown in the figure. Then, a recording magnetic field is applied to the memory element 150 toward the back side of the paper. In addition, additional conductors are provided above and below each conductor.
The magnetic field may be applied using four or more conducting wires.

Alternatively, as shown in FIG. 16, conductors are arranged between the memory cells and above, and a magnetic field is applied to the magnetoresistive film in the direction perpendicular to the film surface by the conductors between the memory cells. A magnetic field is applied to the memory element in the in-plane direction of the film by the conductive wire on the memory. By doing so, recording can be performed only in the memory cell to which the magnetic field is applied in both the in-plane direction and the direction perpendicular to the film plane, and the recording density can be increased as compared with the configuration of FIG. is there.

As described above, a conductive wire for generating a magnetic field may be separately provided, but a bit line or word line used for reading may be used.

[0063]

EXAMPLES The present invention will be described in more detail with reference to examples.

(Embodiment 1) FIG. 4 shows a schematic sectional view of a memory of this embodiment.

On the surface-oxidized Si wafer 001,
Bit line 642, spin tunnel magnetoresistive film 124-12
6, memory cell selection diodes 224-226, word line 6
Form 21-623. Then, an insulator 700 made of Al ₂ O ₃
To form word lines 611 to 613 and diodes 214 to 2
16, spin tunnel magnetoresistive films 114 to 116 and bit line 632 are formed. 114 and 124, 115 and 125, and 116 and 126 are paired to form one bit. A memory cell is formed by a pair of spin tunnel magnetoresistive film, a bit line, a diode, and a word line. Bit lines and word lines were made of Al. The diode may be made of, for example, amorphous silicon.

FIG. 5 shows the film structure of the spin tunnel magnetoresistive film. The pair of spin tunnel magnetoresistive films have the same film structure. A Ni ₈₀ Fe ₂₀ film 005 with a film thickness of ₃₀ nm and a Co ₇₀ Fe ₃₀ film 006 with a film thickness of 20 nm are used to form an Al ₂ O ₃ thin film with a film thickness of 1.5 nm. 007
It is a multi-layered film sandwiching. At this time, the magnetization direction is the in-plane direction. A magnetic field is applied at the time of forming the magnetic film to give uniaxial magnetic anisotropy. The magnetization reversal field of Ni ₈₀ Fe ₂₀ film 005 is about 800 A / m in the direction of uniaxial magnetic anisotropy and Co ₇₀ Fe is
The magnetization reversal magnetic field of the _30th film 006 was about 5 kA / m. Therefore, the magnitude of the recording magnetic field applied in the direction having the uniaxial magnetic anisotropy of the two magnetoresistive films is larger than 800 A / m and
With less than 5 kA / m, it is possible to reverse only the magnetization of the Ni _{8 0} Fe ₂₀ film 005. Alternatively, when a further magnetic field is applied in the in-plane direction and in the direction orthogonal to the direction of uniaxial magnetic anisotropy, the magnitude of the magnetic field applied in the direction of uniaxial magnetic anisotropy is smaller than the above magnetic field range. The magnetization can be reversed.

The magnetization of the Co ₇₀ Fe ₃₀ film 006, which is the magnetization fixed layer of the two magnetoresistive films, is initially set to be parallel. Further, in the present embodiment, the magnetization direction of the magnetization free layer is determined by the magnetic field generated by passing a current through the word line.

At the time of recording, an electric current is applied to the word line and the bit line to apply a magnetic field in a direction having uniaxial magnetic anisotropy of the magnetic film and in a direction perpendicular to the direction having uniaxial magnetic anisotropy and in the film plane. Recording is performed by selecting a specific memory cell. In this embodiment, the magnetic field generated from the bit line is applied to the magnetic film in a direction orthogonal to the uniaxial magnetic anisotropy, and the magnetic field generated from the word line is applied in the uniaxial magnetic anisotropy direction. At this time, the recording magnetic fields generated from the two word lines stacked above and below act on both of the two spin tunnel magnetoresistive films stacked above and below. For example, the recording magnetic field generated from the word line 611 acts on both the spin tunnel magnetoresistive films 114 and 124, and the word line 62
The same applies to the recording magnetic field generated from 1. By doing so, it is possible to perform recording with a smaller current than when recording is performed only with the magnetic field generated from one word line. By changing the direction of the current flowing through the word line, "0" and "1" are recorded separately.

FIG. 6 is an equivalent circuit diagram of this embodiment. In this embodiment, as described above, the spin tunnel magnetoresistive effect film is used as the magnetoresistive effect film. In FIG. 6, for the sake of explanation, the spin tunnel magnetoresistive effect films 111 and 121 and the like which form a 1-bit memory cell in pairs are shown separately. First, the spin tunnel magnetoresistive effect films 121 to 129 are formed on the substrate, and the spin tunnel magnetoresistive effect elements 111 to 119 are laminated in the film surface normal direction. Pairs form a 1-bit memory cell. For example, when recording is performed in the memory cell having the spin tunnel magnetoresistive films 115 and 125, the transistors 333, 3
25, 322, 337, 332, 312, 315, 336, 363, 355, 352, 3
Turn on 68, 362, 342, 345, and 366, and turn off other transistors. By doing so, a current flows through the bit line 632 by the power supply 402 and through the bit line 642 by the power supply 406, and the directions of the uniaxial magnetic anisotropy of the spin tunnel magnetoresistive films 114, 115, 116 and 124, 125, 126. A magnetic field is applied in the vertical direction. At the same time, a current flows through the word line 612 by the power supply 401 and through the word line 622 by the power supply 405, and the spin tunnel magnetoresistive films 112, 115, 118 and 122,
A magnetic field is applied in the direction of uniaxial magnetic anisotropy of 125 and 128.
However, the currents flow so that the magnetic fields generated from the word lines 612 and 622 are in the same direction. Of the plurality of spin tunnel magnetoresistive films, only 115 and 125 are applied with magnetic fields in two directions at the same time, so that recording is selectively performed. Further, the potential of the word line is set higher than that of the bit line in order to prevent current from flowing through the spin tunnel magnetoresistive films 115 and 125.

If the above-mentioned recording is an operation of recording "1", for example, when recording "0", the transistors 333, 325, 322, 337, 335, 315, 312, 331, 363, 35 are used.
Turn on 5, 352, 368, 365, 345, 342, 361, and turn off other transistors. By doing so, a magnetic field is generated from the bit lines 632 and 642 as in the previous case, a magnetic field in the opposite direction from the word lines 612 and 622 is generated, and “0” is generated in the spin tunnel magnetoresistive films 115 and 125. Is recorded.

Reading is accomplished by connecting a fixed resistance and a spin tunneling magnetoresistive film in series and detecting the potential at the connection point of these two resistances. For example, to read the information recorded on the spin tunneling magnetoresistive films 115 and 125, the transistors 334, 325, 322, 338, 315, and 3 are used.
Turn on 36, 364, 355, 352, 367, 345, 366, and turn off other transistors. By doing so, the power supply 403, the fixed resistance 101, the spin tunnel magnetoresistive effect film 11 are formed.
5 are connected in series, and the power supply voltage is divided into these two resistors. That is, the spin tunnel magnetoresistive film 115
The potential at the connection point of the two resistors is different depending on whether the resistance value of is high or low. Further, the power supply 407, the fixed resistance 102, and the spin tunnel magnetoresistive effect film 125 are also connected in series,
Similar to the above, the potential at the connection point of these two resistors differs depending on the resistance value of the spin tunnel magnetoresistive film 125.

As described above, in the pair of spin tunnel magnetoresistive films for recording 1 bit, when one resistance is high, the other resistance is low. The high voltage is input to one side and the low voltage is input to the other side, and it is possible to read the recorded information by detecting which voltage is higher.

Example 2 FIG. 7 schematically shows a cross section of the memory of this embodiment. Surface oxidized Si wafer 001
The bit line 642 and the spin tunnel magnetoresistive film 124 are formed on the upper surface.
~ 126, diodes 224-226, and word lines 621-623 are formed. After that, the insulator 700 is formed of Al ₂ O ₃ , and the bit line 632 and the spin tunnel magnetoresistive effect film 1 are further formed thereon.
14-116, diodes 214-216 and word lines 611-613
To form. Bit lines and word lines are made of Al. The diode was made of amorphous silicon. The spin tunnel magnetoresistive film has the same film structure as that of the first embodiment shown in FIG. However, the two spin tunneling magnetoresistive films that form one memory cell are initialized by changing the direction of the magnetic field applied during film formation so that the magnetization directions of the Co ₇₀ Fe ₃₀ film 006 are antiparallel to each other. I am creating it.

FIG. 8 is an equivalent circuit diagram of this embodiment. Spin tunnel magnetoresistive films 111 and 121, 1 as in Example 1
12 and 122, 113 and 123, 114 and 124, 115 and 125, 116 and 126, 1
17 and 127, 118 and 128, and 119 and 129 are formed by stacking in the film surface normal direction, respectively, and form a 1-bit memory cell.

Recording is performed by passing a current through the bit line and the word line to generate a magnetic field. For example, spin magnetoresistive film 11
When recording to a memory cell having 5 and 125, transistors 332, 312, 315, 336, 363, 355, 352, 368, 36
Turn on 2, 341, 342, 343, and other transistors are OF
Leave it at F. In this way, the spin tunnel magnetoresistive film 112, 115, 118 is generated by the current flowing through the word line 612.
And 122, 125, 128 a magnetic field is applied in the direction of uniaxial magnetic anisotropy, and the current flowing in the bit line 642 causes spin tunnel magnetoresistive films 114, 115, 116 and 124, 12
A magnetic field is applied in a direction perpendicular to the uniaxial magnetic anisotropy direction of 5,126. Therefore, recording is performed only on the spin tunnel magnetoresistive films 115 and 125 to which the magnetic fields from the bit lines and the word lines are simultaneously applied. Furthermore, in order to record the reverse information, the direction of the magnetic field generated from the word line may be reversed. That is, transistors 331, 312, 31
Turn ON 5, 335, 363, 355, 352, 368, 362, 341, 342, 343
The other transistors are turned off, and a current in the reverse direction is passed through the word line 612.

At this time, the voltage of the word line is set to a value higher than the voltage of the bit line so that no current flows in the spin tunnel magnetoresistive film.

Further, the spin tunnel magnetoresistive effect film 115.
And the information recorded in 125 is read by transistors 325, 312, 331, 322, 364, 355, 342, 361, 352, 367.
Is turned on, and other transistors are turned off. In this way, the power supply 403, the fixed resistance 101 and the spin tunnel magnetoresistive effect film 115 are connected in series, and the voltage of the power supply 403 is the fixed resistance 101 and the spin tunnel magnetoresistive effect film 115.
Is divided into. The same applies to the power supply 407, the fixed resistor 102, and the spin tunnel magnetoresistive effect film 125.
After the information is recorded, the pair of spin tunnel magnetoresistive effect films are magnetically oriented so that one has a high resistance and the other has a magnetic orientation so as to have a low resistance. Therefore, the two voltage values input to the sense amplifier 500 are different, and it is possible to read by detecting this difference.

Example 3 In this example, Example 2 is used.
Recording is performed using one word line and one bit line in the same manner as in. The film structure of the magnetoresistive film of this example will be described with reference to FIG. The spin tunnel magnetoresistive films 121 to 129 are
30 nm Ni ₈₀ Fe ₂₀ film 024 and 20 nm Co ₇₀ Fe ₃₀ film 0
25 by a configuration sandwiching the Al ₂ O ₃ thin film 026 having a thickness of 1.5 nm, TMR element 111-119 is the 50nm film thickness Ni ₈₀ Fe ₂₀ film, the Ru film further 10nm of 0.7nm Ni ₈₀ Fe
A laminated ferri structure 030 in which ₂₀ films were laminated was further formed, and an Al ₂ O ₃ thin film 023 having a film thickness of 1.5 nm and a Co ₇₀ Fe ₃₀ film 022 having a film thickness of ₂₀ nm were sequentially laminated. In the laminated ferri structure, the two Ni ₈₀ Fe ₂₀ films are antiferromagnetically coupled, and the magnetization directions are antiparallel. In addition, a thick Ni film against the applied magnetic field
The magnetization of the ₈₀ Fe ₂₀ film becomes parallel, and the thin Ni ₈₀ Fe ₂₀ film becomes antiparallel to the applied magnetic field due to antiferromagnetic coupling. That is, at the time of recording, the spin tunnel magnetoresistive films 121-1
When the magnetization of 29 is oriented so as to have a low resistance, the magnetizations of the spin tunnel magnetoresistive effect films 111 to 119 are oriented so as to have a high resistance.

(Embodiment 4) FIG. 17 schematically shows a cross section of a memory of this embodiment. In this embodiment, the perpendicular magnetic film is used as the magnetic film. Surface oxidized
Bit line 642, spin tunnel magnetoresistive films 124 to 126, and diode 22 for memory cell selection on Si wafer 001.
4 to 226 and word lines 621 to 623 are formed. Then Al ₂ O ₃
To form an insulator 700 on which a word line 611 is formed.
˜613, diodes 214˜216, spin tunnel magnetoresistive films 114˜116 and bit line 632. Also,
Between the magnetoresistive film formed as a pair, the X-direction conducting wires 711, 712, 713 and the Y-direction conducting wire 7 for generating the recording magnetic field are formed.
21 to 728 are provided. The bit line, the word line, and the conducting wire for magnetic field generation were made of Al. The two spin tunneling magnetoresistive films have the same film structure, and Pt (4nm) / Co (1.4
(nm) / Pt (1.5 nm) / Co (0.4 nm) artificial lattice film is formed, and then a nonmagnetic insulating film consisting of an Al ₂ O ₃ thin film with a thickness of 1.5 nm is formed, and Co is further formed on it. (0.6nm) / Pt (1.5nm) / Co (1.4nm) /
An artificial lattice film of Pt (5 nm) was created. That is, both the magnetic pinned layer and the magnetic free layer are ferromagnetic.

All films were formed by magnetron sputtering. Both artificial lattice films are perpendicular magnetization films, and the coercive force of the lower artificial lattice film is about 32 kA / m and the coercive force of the upper artificial lattice film is about 23 kA / m. In this embodiment, the lower artificial lattice film is the magnetization fixed layer and the upper artificial lattice film is the magnetization free layer. At the time of recording, recording can be performed by applying a magnetic field smaller than 32 kA / m and larger than 23 kA / m to the desired memory cell in the direction perpendicular to the film surface. The recording magnetic field can be applied in a desired direction by changing the direction of the current flowing through the conductor. The magnetization direction of the magnetization fixed layer is antiparallel between the two magnetoresistive films. However, in order to direct the magnetization in such a direction, a magnetic field was applied in the direction desired to be initially set when the magnetization fixed layer was formed. FIG. 9 shows the magnetization states of the pair of magnetoresistive films forming one bit in this example.

FIG. 18 is an equivalent circuit diagram mainly relating to reading in this embodiment. Spin tunnel magnetoresistive film 111 is 1
21 bits are stacked in the direction normal to the film surface, and a pair of spin tunnel magnetoresistive films are made to have different magnetization states, and 1 bit is recorded. In addition, spin tunnel magnetoresistive films 112 and 122, 113 and 123, 114 and 124, 115 and 125, 11
The same applies to 6 and 126, 117 and 127, 118 and 128, and 119 and 129.

Reading is accomplished by connecting a fixed resistance and a spin tunneling magnetoresistive film in series and detecting the potential at the connection point of these two resistances. For example, to read the information recorded in the spin tunnel magnetoresistive films 115 and 125, the transistors 325, 322, 312, 345, 342, 3 are used.
Turn on 32 and turn off other transistors.
By doing so, the power supply 401, the fixed resistance 101, and the spin tunnel magnetoresistive effect film 115 are connected in series, and the power supply voltage is divided into these two resistances. That is, the potential at the connection point of the two resistors is different depending on whether the resistance value of the spin tunnel magnetoresistive effect film 115 is high or low. Also power 40
2. The fixed resistor 102 and the spin tunnel magnetoresistive effect film 125 are also connected in series, and the potential at the connection point of these two resistors differs depending on the resistance value of the spin tunnel magnetoresistive effect film 125. The two spin tunnel magnetoresistive films for recording one bit have a lower resistance when the resistance of one is higher, so that one side always has a high voltage on the input side of the sense amplifier 500. A low voltage is input to the other, and it is possible to read the recorded information by detecting which voltage is higher.

(Embodiment 5) In this embodiment, as shown in FIG. 19, a pair of magnetoresistive films that form one bit and adjacent bits share a conductor for applying a magnetic field. There is. Components having the same functions as those in FIG. 17 are designated by the same reference numerals, and detailed description thereof will be omitted. The two spin tunnel magnetoresistive films have the same film structure, the magnetization fixed layer uses the same artificial lattice film as in Example 4, and the magnetization free layer has a thickness of 10 nm of Gd _{2 0} (Fe ₅₀ Co ₅₀ ). _A ferrimagnetic material consisting of ₈₀ is used. Where Gd ₂₀ (Fe ₅₀ Co
₅₀ ) ₈₀ film is dominant in transition metal sublattice magnetization and has coercive force of about 2.4 kA
/ m. The non-magnetic film is an Al ₂ O ₃ thin film with a thickness of 1.5 nm.
The magnetization direction of the magnetization fixed layer is oriented antiparallel between the two magnetoresistive films. Fig. 10 (a) shows a schematic diagram of the magnetization state.
It shows in (b).

FIG. 20 is an equivalent circuit diagram of this embodiment. Figure 1
Those having the same function as 8 are given the same numbers. Detailed explanation is omitted. In this embodiment, the bit line is also used as a conductor for applying a magnetic field in the in-plane direction of the magnetoresistive effect film to the magnetization free layer formed of the perpendicular magnetization film.

The recording method will be described with reference to FIGS. Recording is performed by passing a current through a conductor wire for applying a magnetic field perpendicular to the film surface to a desired magnetoresistive film and a bit line connected to a memory element to generate a magnetic field. For example, when recording is performed on the spin tunnel magnetoresistive films 115 and 125, an electric current is passed through the recording lines 722 and 723 to generate spin tunnel magnetoresistive films 112, 115, 118, 122 and 12.
A magnetic field is applied to 5 and 128 in the direction perpendicular to the film surface. At the same time, the transistors 311, 312, 313, 322, 325, 351, 353, 356,
Turn on 331, 332, 333, 342, 345, 361, 363, 366, and turn off other transistors. In this way, a current flows through the bit lines 632 and 642, and a magnetic field is applied in the in-plane direction of the spin tunnel magnetoresistive effect films 114, 115, 116 and 124, 125, 126. When the magnetization of the perpendicular magnetization film is reversed in the direction perpendicular to the film surface while the magnetic field is applied in the direction of the film surface, the coercive force becomes smaller than that in the case where the in-plane magnetization film is not applied. Further, in the spin tunnel magnetoresistive effect film, only 115 and 125 to which both the magnetic field in the in-plane direction and the magnetic field in the direction perpendicular to the film plane are applied can be recorded. However, the power supplies 405 and 406 prevent current from flowing in the spin magnetoresistive film during recording, and have a voltage having a magnitude such that a reverse voltage is applied to each diode.

Information reading may be performed in the same manner as in the fourth embodiment.

(Embodiment 6) The composition of one magnetization free layer of the pair of spin tunnel magnetoresistive films constituting one bit used in Embodiment 5 is Gd ₂₅ (Fe ₅₀ Co ₅₀ ) ₇₅ , and the other is the same. And Here, the Gd ₂₅ (Fe ₅₀ Co ₅₀ ) ₇₅ film has a rare earth metal sublattice magnetization dominant and a coercive force of about 3.1 kA / m. A schematic diagram showing the magnetization state is shown in FIG. Also in this embodiment, by applying a magnetic field in one direction, a pair of magnetoresistive effect films forming one bit can have different magnetization states and different resistance values.

(Example 7) The magnetization fixed layer of the spin tunnel magnetoresistive film used in Example 5 was formed of Tb ₂₂ (Fe) with a film thickness of 10 nm.
Others are the same as ₆₀ Co ₄₀ ) ₇₈ . Where Tb
_{The 22} (Fe ₆₀ Co ₄₀ ) ₇₈ film is dominated by the transition metal sublattice magnetization and has a coercive force of about 1.5 MA / m. 12 (a) and 12 (b) show schematic views of the magnetization state. As shown in FIG. 12, the net magnetization directions of the magnetization fixed layer are antiparallel. Also in this embodiment, by applying a magnetic field in one direction, each of the pair of magnetoresistive films can have a different resistance value.

(Example 8) Spin tunnel used in Example 7
Gd of the composition of the magnetization free layer of the magnetoresistive film_{twenty five}(Fe ₅₀Co₅₀)
₇₅Others are the same. The magnetization free layer,
Gd_{twenty five}(Fe₅₀Co₅₀)_{7 Five}Is a rare earth metal sublattice magnetization predominant composition and
Has become. FIG. 12C and FIG. 12D show the magnetization state of this example.
The schematic diagram of is shown. Also in this embodiment, the magnetic field in one direction
Is applied, the pair of magnetoresistive films are different from each other.
Can have a resistance value of

(Example 9) The magnetization fixed layer of the spin tunnel magnetoresistive film used in Example 7 was formed of Tb ₂₄ (Fe) with a film thickness of 10 nm.
Others are the same as ₆₀ Co ₄₀ ) ₇₆ . Where Tb
_{The 24} (Fe ₆₀ Co ₄₀ ) ₇₆ film has a predominantly rare earth metal sublattice magnetization and a coercive force of about 1.2 MA / m. In the magnetization states of FIGS. 12C and 12D described in the eighth embodiment. The transition metal sublattice magnetization and the rare earth metal sublattice magnetization are interchanged. Also in this embodiment, by applying a magnetic field in one direction, each of the pair of magnetoresistive films can have a different resistance value.

(Example 10) The composition of the magnetization free layer of the spin tunnel magnetoresistive film used in Example 9 was the same except that the rare earth metal sublattice magnetization dominant Gd ₂₅ (Fe ₅₀ Co ₅₀ ) ₇₅ was used. . It can be considered that the magnetization state of the present embodiment is such that the transition metal sublattice magnetization and the rare earth metal sublattice magnetization in the magnetization states shown in FIGS. 12A and 12B are exchanged. Also in this embodiment, by applying a magnetic field in one direction, each of the pair of magnetoresistive films can have a different resistance value.

(Example 11) Of the spin tunnel magnetoresistive effect films used in Example 5, 121, 122, 123, 124, 125, 1
For 26, 127, 128, and 129, the composition of the magnetization free layer was set to Gd ₂₅ (Fe ₅₀ Co ₅₀ ) ₇₅ with the rare earth metal predominant, and 111, 112, 113, 1
The composition of the magnetization free layer of 14, 115, 116, 117, 118, and 119 was set to Gd ₂₀ (Fe ₅₀ Co ₅₀ ) ₈₀ having a transition metal dominant. In addition, the magnetization directions of the magnetization fixed layers were parallel, and the other directions were the same. FIG. 11 is a schematic diagram showing the magnetization state of this example. Also in this embodiment, by applying a magnetic field in one direction, each of the pair of magnetoresistive films can have a different resistance value.

(Example 12) The magnetization fixed layer of the spin tunnel magnetoresistive film used in Example 11 was Tb ₂₂ (Fe ₆₀ Co ₄₀ ) ₇₈ , which has a dominant magnetization of the transition metal sublattice, and the others were the same. . FIG. 14 is a schematic diagram showing the magnetization state of this example. Also in this embodiment, by applying a magnetic field in one direction, each of the pair of magnetoresistive films can have a different resistance value.

(Example 13) The magnetization fixed layer of the spin tunnel magnetoresistive film used in Example 12 was Tb ₂₄ (Fe ₆₀ Co ₄₀ ) ₇₆ which has a dominant rare earth metal sublattice magnetization, and the others were the same. . The magnetization state of the present embodiment is a configuration in which the magnetization state of the magnetization fixed layer in FIG. 14 has a rare earth metal sublattice magnetization dominant. Also in this embodiment, by applying a magnetic field in one direction, each of the pair of magnetoresistive films can have a different resistance value.

Example 14 Of the spin tunnel magnetoresistive effect films used in Example 5, 121, 122, 123, 124, 125, 1
For 26, 127, 128, and 129, the composition of the magnetization fixed layer was set to Tb ₂₄ (Fe ₆₀ Co ₄₀ ) ₇₆ with the rare earth metal predominant, and 111, 112, 113, 1
The composition of the magnetization fixed layers of 14, 115, 116, 117, 118, and 119 was Tb ₂₂ (Fe ₆₀ Co ₄₀ ) ₇₈ with a transition metal dominant. In addition, the magnetization directions of the magnetization fixed layers were parallel, and the other directions were the same. FIG. 13 shows a schematic view of the magnetization state of this example. Also in this embodiment, by applying a magnetic field in one direction, each of the pair of magnetoresistive films can have a different resistance value.

(Example 15) The composition of the magnetization free layer of the spin tunnel magnetoresistive film used in Example 14 was the same except that the rare earth sublattice magnetization predominant Gd ₂₅ (Fe ₅₀ Co ₅₀ ) ₇₅ was used. Also in this embodiment, by applying a magnetic field in one direction, each of the pair of magnetoresistive films can have a different resistance value.

[0097]

As described above, the present invention has the following effects.

By stacking two magnetoresistive films whose resistance changes with respect to the applied magnetic field are opposite to each other and recording 1 bit on the two magnetoresistive films, a memory having a large read signal and a high recording density can be obtained. Along with
By sharing the recording means of the two magnetoresistive films, it is possible to reduce the power consumption during recording.

Further, by using a perpendicular magnetization film and stacking two magnetoresistive effect films whose resistance changes with respect to an applied magnetic field are opposite to each other and recording 1 bit on the two magnetoresistive effect films, a read signal is obtained. By making the memory large and having high recording density, and sharing the recording means of the two magnetoresistive films, there is an effect of reducing power consumption during recording. Further, it is possible to share the conductive wire for generating the recording magnetic field.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing a magnetization direction and a recording magnetic field direction in an example of a magnetoresistive effect film of the present invention.

FIG. 2 is a diagram schematically showing a magnetization direction and a recording magnetic field direction in an example of the magneto-resistive effect film of the present invention.

FIG. 3 is a diagram schematically showing a magnetization direction and a recording magnetic field direction in an example of the magneto-resistive effect film of the present invention.

FIG. 4 is a diagram schematically showing a cross section of a memory of Example-1.

FIG. 5 is a diagram showing a spin tunnel magnetoresistive film of Example-1.

FIG. 6 is a simplified diagram of an electric circuit of the memory of the first embodiment.

FIG. 7 is a diagram schematically showing a cross section of a memory of Example-2.

FIG. 8 is a simplified diagram of an electric circuit of the memory of Example-2.

FIG. 9 is a schematic view schematically showing the magnetization state of a magnetoresistive film used in the memory of the present invention, in which ferromagnetism is used for both the magnetization fixed layer and the magnetization free layer. (a) shows the magnetization state when a recording magnetic field is applied upward, (b)
Indicates the magnetization state when the recording magnetic field is applied downward.

FIG. 10 is a schematic diagram schematically showing a magnetization state of a magnetoresistive film used in the memory of the present invention, in which ferromagnetism is used for the magnetization fixed layer and ferrimagnetism composed of a rare earth metal and a transition metal is used for the magnetization free layer. Used. (a) and (b) show that the ferrimagnetic composition is dominant in the transition metal sublattice magnetization, (a) shows the magnetization state when the recording magnetic field is applied upward, and (b) shows the recording magnetic field when applied downward. Shows the magnetization state of. Further, (c) and (d) show that the ferrimagnetic composition is dominant in the rare earth metal sublattice magnetization, (c) shows the magnetization state when the recording magnetic field is applied upward, and (d) shows the recording magnetic field applied downward. The magnetization state in the case of doing is shown.

FIG. 11 is a schematic view schematically showing a magnetization state of a magnetoresistive effect film used in the memory of the present invention, in which ferromagnetism is used for the magnetization fixed layer and ferrimagnetism composed of a rare earth metal and a transition metal is used for the magnetization free layer. Used. In (a) and (b), the composition of the magnetization free layer of the upper magnetoresistive effect film is dominant in the transition metal sublattice magnetization, and the composition of the magnetization free layer of the lower magnetoresistive effect film is dominant in the rare earth metal sublattice magnetization. (a) shows the magnetization state when the recording magnetic field is applied upward, and (b) shows the magnetization state when the recording magnetic field is applied downward. Also,
In (c) and (d), the composition of the magnetization free layer of the upper magnetoresistive film is the rare earth metal sublattice magnetization dominant and the composition of the magnetization free layer of the lower magnetoresistive film is the transition metal sublattice magnetization dominant. (c) shows the magnetization state when the recording magnetic field is applied upward, and (d) shows the magnetization state when the recording magnetic field is applied downward.

FIG. 12 is a schematic view schematically showing a magnetization state of a magnetoresistive effect film used in the memory of the present invention, in which ferrimagnetism is used for both the magnetization fixed layer and the magnetization free layer. (a) and (b) show the transition metal sublattice magnetization dominant in both the magnetization free layer and the magnetization fixed layer, (a) shows the magnetization state when a recording magnetic field is applied upward, and (b) shows the recording state. The magnetization state when a magnetic field is applied downward is shown. Further, (c) and (d) are both the rare earth metal sublattice magnetization dominant in both the magnetization free layer and the magnetization fixed layer, and (c) shows the magnetization state when the recording magnetic field is applied upward, (d) Indicates the magnetization state when the recording magnetic field is applied downward.

FIG. 13 is a schematic view schematically showing a magnetization state of a magnetoresistive film used in the memory of the present invention, in which ferrimagnetism is used for both the magnetization fixed layer and the magnetization free layer. In (a) and (b), the composition of the magnetization fixed layer of the upper magnetoresistive effect film is dominant in the transition metal sublattice magnetization and the composition of the magnetization fixed layer of the lower magnetoresistive effect film is dominant in the rare earth metal sublattice magnetization. ,
Both of the magnetization free layers are dominant in the transition metal sublattice magnetization.
(a) shows the magnetization state when the recording magnetic field is applied upward, and (b) shows the magnetization state when the recording magnetic field is applied downward. Also, (c) and (d) show that the composition of the magnetization fixed layer of the upper magnetoresistive effect film is dominant in the transition metal sublattice magnetization and the composition of the magnetization fixed layer of the lower magnetoresistive effect film is dominant in the rare earth metal sublattice magnetization. And both of the magnetization free layers have the rare earth metal sublattice magnetization predominant. (c) shows the magnetization state when the recording magnetic field is applied upward, and (d) shows the magnetization state when the recording magnetic field is applied downward.

FIG. 14 is a schematic diagram schematically showing a magnetization state of a magnetoresistive film used in the memory of the present invention, in which ferrimagnetism is used for both the magnetization fixed layer and the magnetization free layer. In (a) and (b), the composition of the magnetization free layer of the upper magnetoresistive effect film is dominant in the transition metal sublattice magnetization, and the composition of the magnetization free layer of the lower magnetoresistive effect film is dominant in the rare earth metal sublattice magnetization. ,
Both of the magnetization pinned layers are dominant in the transition metal sublattice magnetization.
(a) shows the magnetization state when the recording magnetic field is applied upward, and (b) shows the magnetization state when the recording magnetic field is applied downward. Also, (c) and (d) show that the composition of the magnetization free layer of the upper magnetoresistive effect film is dominant in the transition metal sublattice magnetization and the composition of the magnetization free layer of the lower magnetoresistive effect film is dominant in the rare earth metal sublattice magnetization. And both of the magnetization pinned layers have the rare earth metal sublattice magnetization predominant. (c) shows the magnetization state when the recording magnetic field is applied upward, and (d) shows the magnetization state when the recording magnetic field is applied downward.

FIG. 15 is a schematic view schematically showing the arrangement of a memory element and a conductor for generating a recording magnetic field, and the direction of a current flowing during recording.

FIG. 16 is a schematic view schematically showing the arrangement of a memory element and a conductor for generating a recording magnetic field and the direction of a current flowing during recording.

FIG. 17 is a cross-sectional view schematically showing the memory of Example-1.

FIG. 18 is a schematic diagram of a read circuit according to a first embodiment.

FIG. 19 is a cross-sectional view schematically showing the memory of Example-2.

FIG. 20 is a simplified diagram of a read circuit and a circuit for generating an in-plane magnetic field according to the second embodiment.

21A is a sectional view schematically showing a state where the magnetizations of the magnetoresistive effect film are parallel, and FIG. 21B is a sectional view schematically showing a state where the magnetizations of the magnetoresistive effect film are antiparallel. .

FIG. 22 is a diagram for explaining the recording / reproducing principle in the conventional magnetoresistive film, and is a cross-sectional view schematically showing the magnetization state when (a) and (c) the recording information “1” is read. , (B) and (d) are cross-sectional views schematically showing the state of magnetization when the recorded information "0" is read.

FIG. 23 is a simplified diagram of a read circuit in a 2T2R type configuration of a memory using a magnetoresistive effect film.

[Explanation of symbols]

001 Surface oxidized Si substrate 002, 013, 016, 023, 026 Non-magnetic layer 003, 004 Magnetic layer 005 Ni ₈₀ Fe ₂₀ film 006 Co ₇₀ Fe ₃₀ film 007 Al ₂ O ₃ thin film 011, 014, 021, 024 Magnetization Free layer 012, 015, 022, 025 Magnetization fixed layer 030 Laminated ferri structure 101, 102 Fixed resistance 110, 120, 130, 140, 150, 160, 170, 180, 190 Memory element 111-119, 121-129 Magnetoresistive effect Membranes 211-219, 221-229 Diodes 311-316, 321-326, 331-338, 341-346, 351-356,
361 to 368 Transistor 401 to 408 Power supply 500 Sense amplifier 611 to 613, 621 to 623 Word line 631 to 633, 641 to 643 Bit line 700 Insulator 711 to 714, 721 to 728 Recording magnetic field generating conductor 800 Recording magnetic field 801 Conductor 810 Magnetization 821 Transition metal sublattice magnetization 822 Rare earth metal sublattice magnetization

Claims (27)

[Claims] 1. A pair of magnetoresistive effect films having a structure in which a nonmagnetic film is sandwiched between magnetic films, and a magnetic field is applied to the pair of magnetoresistive effect films so that the magnetoresistive effect films have different resistances. A pair of magnetoresistive effect films, wherein the pair of magnetoresistive effect films is a memory having first magnetic field applying means for performing 1-bit recording in a state and a bit line for detecting a potential generated by a resistance value of the magnetoresistive effect film. A memory characterized by being stacked in a direction normal to a film surface. 2. A plurality of the pair of magnetoresistive films are arranged on a substrate, a diode is connected in series to the magnetoresistive film, and a word line is connected to the other terminal of the diode to form a memory cell. A device configured to selectively read information recorded in a specific memory cell.
Memory described in 1. 3. The first magnetic field applying means is a conductive wire,
2. The memory according to claim 1, wherein a magnetic field induced by passing a current through the conductor is applied to the magnetoresistive film to change the magnetization state. 4. Further comprising a second magnetic field applying means for applying a magnetic field to the magnetoresistive film from a direction different from the magnetic field applied by the first magnetic field applying means, By applying a magnetic field applied from the second magnetic field applying means to any of the magnetoresistive effect films, a specific magnetoresistive effect film is selected from a plurality of magnetoresistive effect films to perform recording. A memory according to any one of claims 1 to 3, characterized in that it is a memory. 5. The memory according to claim 4, wherein the magnetic film is an in-plane magnetized film. 6. The magnetic field produced by the first magnetic field applying means is an in-plane magnetic field, and the magnetic field produced by the second magnetic field applying means is orthogonal to the magnetic field produced by the first magnetic field applying means and is in the film plane. The memory according to claim 8, wherein the memory is oriented in a direction. 7. The memory according to claim 5, wherein one of the magnetic films is a magnetization free layer that is reversible by a magnetic field applied during recording, and the other is a magnetization fixed layer that is not reversible. . 8. The memory according to claim 5, wherein at the time of initialization, the net magnetizations of the magnetization fixed layers of the pair of magnetoresistive films become parallel by applying a magnetic field in one direction. 9. The magnetoresistive effect film for recording one bit is provided above and below the conducting wire for generating the recording magnetic field, respectively.
8. The memory according to any one of 8. 10. The memory according to claim 5, wherein one of the two magnetoresistive films has a laminated ferri structure. 11. The memory according to claim 4, wherein the magnetic film is a perpendicular magnetization film. 12. The magnetic field produced by the first magnetic field applying means is in a film surface normal direction, and the magnetic field produced by the second magnetic field applying means is a magnetic field in a film surface in-plane direction. Memory described in. 13. The magnetic free layer, one of which is reversible by a magnetic field applied during recording, and the other is a non-reversible magnetization fixed layer.
The memory according to 1 or 12. 14. The memory according to claim 11, wherein the net magnetization of the magnetization fixed layers of the pair of magnetoresistive films becomes parallel by applying a magnetic field in one direction during initialization. 15. The magnetization pinned layer is ferromagnetic made of a material containing a transition metal, and the magnetization direction of the magnetization pinned layer is antiparallel between the two magnetoresistive films. The memory of claim 13, wherein the memory is a memory. 16. The magnetization pinned layer is ferromagnetic made of a material containing a transition metal, and the magnetization direction of the magnetization pinned layer is parallel between the two magnetoresistive films, and The free layer is ferrimagnetic consisting of rare earth and transition metal, and the magnetization free layer of one magnetoresistive film has a rare-earth sublattice magnetization dominant and the magnetization free layer of the other magnetoresistive film has a transition metal sublattice dominant magnetization. 14. The method according to claim 13,
Memory described in. 17. The memory according to claim 13, wherein the magnetic film is ferrimagnetic composed of a rare earth metal and a transition metal. 18. The magnetization direction of the magnetic pinned layer of one of the magnetoresistive effect films is antiparallel to the magnetization direction of the pinned layer of one of the magnetoresistive effect films. 18. The memory according to claim 17, which is suitable for. 19. The magnetization direction of the magnetization pinned layer of one magnetoresistive effect film is antiparallel to the magnetization direction of the magnetization pinned layer of the other magnetoresistive film. 18. The memory according to claim 17, which is suitable for. 20. The magnetization pinned layer of one magnetoresistive effect film has a rare earth metal sub-lattice magnetization predominant, and the magnetization pinned layer of the other magnetoresistive film has a transition metal sublattice magnetization predominant.
The magnetization directions of the two magnetization fixed layers are parallel to each other,
18. The magnetization free layers of the two magnetoresistive films are both dominant in transition metal sublattice magnetization.
Memory described in. 21. The magnetization pinned layer of one magnetoresistive effect film has a rare earth metal sublattice magnetization predominance, and the magnetization pinned layer of the other magnetoresistive effect film has a transition metal sublattice magnetization predominant.
The magnetization directions of the two magnetization fixed layers are parallel to each other,
2. The rare-earth metal sublattice magnetization predominant in both magnetization free layers of the two magnetoresistive films.
7. The memory according to 7. 22. The two magnetization pinned layers are both dominant in transition metal sublattice magnetization, and their magnetization directions are parallel to each other, and the magnetization free layer of one magnetoresistive film is a rare earth metal sublattice. The memory according to claim 17, wherein the magnetization free layer of the other magnetoresistive film has a transition metal sublattice magnetization dominant. 23. Both of the two magnetization fixed layers have a rare earth metal sublattice magnetization dominant and their magnetization directions are parallel to each other, and the magnetization free layer of one magnetoresistive film is a rare earth metal sublattice. The memory according to claim 17, wherein the magnetization free layer of the other magnetoresistive film has a transition metal sublattice magnetization dominant. 24. A memory in which a plurality of elements in which one bit is formed by two magnetoresistive films on a substrate are arranged in a matrix, and at least one write line is provided between the magnetoresistive films. Is formed, and recording is performed by applying a current to the write line so that a magnetic field is applied to a desired element in the film normal direction. 25. A write line is formed between the elements only in a row direction, and a conductive wire is further provided above or below the element, and the write line is formed in a film normal direction with respect to two adjacent elements. By applying an electric current in such a way that a magnetic field is applied in the opposite direction, and by applying an electric current to a conducting wire provided above or below the desired element in the in-plane direction of the desired element, The memory according to claim 24, wherein recording is performed. 26. The memory according to claim 25, wherein the conducting wire for applying a magnetic field in the in-plane direction of the film is a bit line or a word line. 27. The magnetoresistive effect film is a spin tunnel magnetoresistive effect film.
The memory according to any one of 1.