JP2005353819A - Magnetoresistive effect element and storage device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a memory device using a BMR element that is miniaturized. <P>SOLUTION: In the magnetoresistance effect (BMR) element, first and second magnetic bodies 201 and 202 provided in an insulating layer to face each other in the direction perpendicular to the surface of the layer are connected to each other in a connection. The first and second magnetic bodies 201 and 202 contain at least one kind of element selected from among transition metal elements, and the area of the contacting surfaces of the magnetic bodies 201 and 202 in the connection is smaller than the cross-sectional area parallel to the plane forming at least the connection of the magnetic bodies 201 and 202. In addition. the electric resistance of the magnetoresistance effect element varies depending upon the angle between the directions of magnetization of the magnetic bodies 201 and 202. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a magnetoresistive effect element and a memory device using the magnetoresistive effect element.

  In recent years, MRAM (Magnetic Random Access Memory) has attracted attention as a storage device (hereinafter abbreviated as a memory) that replaces many of the currently used solid-state storage devices. The MRAM is a non-volatile memory that can be accessed at high speed. In particular, the MRAM using the TMR (Tunnel Magnetoresistivity) effect has been actively researched and developed because a large read signal can be obtained.

  The TMR film has a sandwich structure in which magnetic layers are formed adjacent to each other through a tunnel barrier layer. The tunnel barrier layer used has a very thin film thickness of about 1 nm to 2 nm, and alumina is preferably used.

  In order to increase the recording density of the MRAM, a proposal has been made to use a perpendicular magnetization film as described in Patent Document 1, for example. In this method, the demagnetizing field does not increase even when the element size is reduced. Therefore, a magnetoresistive film having a size smaller than that of the MRAM using the in-plane magnetization film can be realized.

  When the magnetic film of the magnetoresistive film is a perpendicularly magnetized film, a magnetic field perpendicular to the film surface, that is, an upward or downward magnetic field is applied, and two of the magnetic films formed in contact with the nonmagnetic film Only the magnetization direction of one magnetic film is directed to the direction corresponding to the information.

  As another method of reversing the magnetization direction, there is a method of passing a spin-polarized current through the magnetic film. This is called spin injection and is a magnetization reversal method proposed by Non-Patent Documents 1 and 2. In order to generate a spin-polarized current, it is common to use a multilayer film of a magnetic metal and a non-magnetic metal. However, when an electric field is applied to a semiconductor made of p-type gallium arsenide, a spin current is generated in a direction perpendicular thereto. It has been recently reported by Murakami et al. According to Non-Patent Document 3 that this can be used for magnetization reversal.

  When the TMR film is used as a memory element, it is preferable that the resistance value of the element is small in order to shorten the information reading time. The resistance value of the TMR film is dominated by the resistance value of the tunnel barrier film. In order to reduce the resistance value, it is necessary to reduce the resistance of the tunnel barrier film.

  One way to reduce the resistance of the tunnel barrier film is to reduce the thickness. However, as the area of the memory element decreases, the resistance value of the element increases. Therefore, it is necessary to make the tunnel barrier film thinner. For a memory element of submicron square size, a tunnel barrier film having a thickness of 1 nm or less is required. It is not easy to form such an alumina tunnel barrier film uniformly. Therefore, there is a limit to reducing the resistance by thinning the tunnel barrier film, and there is a limit to miniaturization of the size of the memory element, so that it is said that it is difficult to manufacture a large capacity memory of, for example, 1 Gbit or more.

  Another method is to use a material having a low energy barrier height for the tunnel barrier film. However, various materials such as nickel oxide and aluminum nitride have been studied so far, but no material capable of obtaining a sufficient magnetoresistance change rate has been found.

In 1999, Garcia et al. Reported a BMR (Ballistic Magnetoresistance) effect which is a new magnetoresistance effect (Non-patent Document 4). In this research, two nickel thin wires having a diameter of 2 mm are fixed to a Teflon tube using a resin, and a tip is pressed against each other, thereby producing a magnetoresistive effect element having a local contact. When the magnetization directions of the two nickel thin wires are antiparallel, a domain wall is formed at the contact, and when the magnetization directions are parallel, the domain wall disappears. When a voltage is applied to both ends of two nickel wires and an electric current is passed so that electrons pass through the contacts, the electrical resistance when the domain wall is formed is larger than when there is no domain wall, and the rate of change in resistance Is as large as 280% as shown in Non-Patent Document 4. In subsequent studies, Non-Patent Document 5 reports a larger magnetoresistance change rate of 100,000%.
Japanese Patent Laid-Open No. 11-213650 J. et al. C. Slonzewski (J. Magn. Magn. Mater. 159, L1 (1996)) L. Berger (Phys. Rev. B 54, 9353 (1996)) Murakami et al. , Science 301 1348 (2003) N. Garcia, M.M. Munoz, and Y.M. W. Zhao, Phys. Rev. Lett. 82, 2923 (1999) S. Z. Hua and H.H. D. Chopra, Phys. Rev. B 67, 060401 (R) (2003))

  However, in the reports so far, the BMR element uses a magnetic wire having a diameter of about several millimeters to several hundreds of micrometers, and is extremely large as a memory element.

  For example, in the current mainstream DRAM (Random Access Memory), the 90 nm rule is adopted, and even in an MRAM using a TMR element currently being commercialized, a wiring rule of 0.6 μm or less is used. As a result, the miniaturization of memory elements is progressing.

  Therefore, in order to realize a memory using a BMR element, it is necessary to study further miniaturization of the memory element.

  In order to solve the above-described problems, the configuration of the present invention is such that a first magnetic body and a second magnetic body containing at least one element selected from transition metal elements are disposed on the surface of a layer in an insulating layer. The first magnetic body and the second magnetic body are provided so as to face each other in a vertical direction, and are connected at a connection portion. An area of a contact surface between the first magnetic body and the second magnetic body at the connection portion. Is smaller than the cross-sectional area parallel to the plane forming the connection part of the first magnetic body and the second magnetic body at least in contact with the connection part, and when a voltage is applied so that a current flows through the connection part, The electrical resistance varies depending on the angle formed by the magnetization directions of the first magnetic body and the second magnetic body (magnetic resistance change rate (MR ratio)).

  According to the present invention, since the memory element has a high MR ratio, it is possible to read and write stable information, and a small configuration, a high recording density, and a high-speed memory are realized with a simple configuration. it can.

  Fabrication of a fine BMR element is necessary for miniaturization of the memory. To achieve this, the BMR element of the present invention is formed by laminating a first magnetic body and a second magnetic body in the insulator film in a direction perpendicular to the film surface of the insulator film. The magnetic body and the second magnetic body are connected at a connection portion, and the area of the contact surface between the first magnetic body and the second magnetic body of the connection portion is at least the first magnetic body in contact with the connection portion, and A fine magnetoresistive film can be realized by making it smaller than the cross-sectional area parallel to the plane forming the connecting portion of the second magnetic body.

  The first magnetic body and the second magnetic body may be directly connected at the connection portion, or may be in contact with each other in a connection region made of the magnetic body. When the first magnetic body and the second magnetic body are directly connected at the connection portion, the cross-sectional area of the first magnetic body and the second magnetic body in which the area of the contact surface is parallel to these contact surfaces. Need to be smaller than.

  The magnetic body located at the upper part of the connecting portion and the magnetic body located at the lower part are designed so that their magnetization directions can be controlled in two states, parallel or antiparallel. For example, when the magnetization direction is controlled by applying a magnetic field, the magnetization reversal magnetic fields (coercive force) of the two magnetic bodies have different magnitudes. Alternatively, when magnetization reversal is performed by spin injection, it is possible to reverse the magnetization of only one of the two magnetic bodies by setting the two magnetic bodies to different volumes.

  When the magnetization reversal of the magnetoresistive effect element of the present invention is performed by spin injection, it is not necessary to arrange a conducting wire for generating a magnetic field beside the element, so that a higher-density and high-speed memory element can be realized.

  In order to realize a smaller BMR element, the magnetic material is preferably a perpendicular magnetization film rather than an in-plane magnetization film. Examples of the perpendicular magnetization film include an amorphous alloy film made of a rare earth metal such as gadolinium or terbium and a transition metal such as iron or cobalt. In particular, when the magnetization is reversed by applying a magnetic field, it is preferable to use an alloy of gadolinium and a transition metal having a relatively small coercive force.

  When the magnetic material is elongated in the direction perpendicular to the film surface, such as a columnar shape or a needle shape, the magnetization is directed in the direction perpendicular to the film surface due to shape anisotropy. In this case, a transition metal such as iron, cobalt or nickel can be used as the magnetic material.

  As described above, the BMR element has a large magnetoresistance change rate and does not require the formation of a remarkably thin tunnel barrier film. Therefore, the BMR element is useful as a magnetoresistive effect element. Application to is possible.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
(First embodiment)
A first embodiment of the present invention will be described with reference to the schematic sectional view of FIG. A resist pattern is formed so as to cover a region other than the rectangular region to be etched whose one side is in the (110) direction on the front and back surfaces of the substrate 100 made of crystalline silicon having a substrate surface orientation of (100) and an orientation flat of (110). And is etched by immersing in a tetramethylammonium hydroxide solution which is an etching solution having a (111) plane orientation dependency to form a sawtooth-shaped groove. At this time, the apex of the groove formed from the front side of the substrate 100 is connected to the apex of the groove formed from the back side.

  Thereafter, the resist is removed, and the surface of the substrate 100 is oxidized to form an insulating film (not shown) on the surface of the substrate 100. In the case of a configuration having a tapered shape as shown in the figure, it is preferable to perform the wet etching as in this embodiment.

  The insulating film can be formed by a normal thermal oxidation method or a vapor phase growth method. Thereafter, an amorphous alloy film made of gadolinium, iron, and cobalt is sputtered on one surface of the substrate 100, and an amorphous alloy film made of terbium, iron, and cobalt is sputtered on the other surface of the substrate 100. First magnetic body 201 and second magnetic body 202 are formed (FIG. 1A). As a result, the first magnetic body 201 and the second magnetic body 202 are formed in a groove surrounded by an insulating film and are connected at the apex of the groove.

  The first magnetic body 201 made of gadolinium, iron, and cobalt has a smaller coercive force than the second magnetic body 202 made of terbium, iron, and cobalt. Therefore, when an external magnetic field larger than the coercive force of the first magnetic body 201 and smaller than the coercive force of the second magnetic body 202 is applied, only the magnetization direction of the first magnetic body can be directed in a desired direction. Is possible.

  As a result, a magnetoresistive element having an easy axis of magnetization in the direction perpendicular to the substrate surface can be obtained.

  In addition to applying a magnetic field, the magnetization can be reversed by spin injection. However, in this case, it is preferable that the two magnetic bodies have different volumes, and the volume of the magnetic body to be reversed is smaller than the volume of the magnetic body that is not reversed.

As a method for making the first magnetic body 201 and the second magnetic body 202 have different volumes, for example, a side perpendicular to the (110) plane of the rectangular etched region of the resist pattern formed on one surface Is shorter than the side of the rectangular etched region formed on the other surface, the smaller the etched region, the smaller the volume etched due to the nature of the etching, and therefore in the groove. It is possible to reduce the volume of the formed magnetic material.
(Second embodiment)
This embodiment will be described with reference to FIG. A first aluminum film having a thickness of 1.2 μm is formed on a substrate 100 (not shown) made of silicon, and a hollow is formed at a desired position by using FIB (Focused Ion Beam). And By subjecting the entire first aluminum film to anodization, holes having a diameter of several tens of nanometers are formed and aluminum is used as the first insulator (layer) 101. A conventional method can be used for the anodizing treatment. An aluminum film is placed in an oxalic acid solution, and this is used as an anode to apply a pulse voltage to electrolyze water. Oxygen generated from the anode reacts with the aluminum film to form an aluminum oxide film. At this time, fine holes are formed with the depression formed by FIB as a base point.

  Thereafter, the holes are filled with cobalt by electrodeposition, the surface of the obtained structure is polished, the cobalt protruding from the holes is removed, and the first magnetic body 201 having a columnar structure is formed. Further, aluminum and silicon were simultaneously sputtered to form a 20 nm thick eutectic thin film 121 in which an aluminum columnar structure having a diameter of several nm was formed in the silicon film.

  In the present invention, since a greater change in magnetoresistance can be expected by forming the domain wall as thin as possible, it is preferable to form the eutectic thin film on which the aluminum columnar structure is formed thin. According to the current technology, it is said that if the film thickness is 5 nm or more, a Kyochang thin film is formed.

  Further, a second aluminum film having a thickness of 400 nm is formed, and the second aluminum film is formed on the surface of the second aluminum film by using the above-described FIB so that the second aluminum film is positioned immediately above the first magnetic body 201. A recess serving as a base point of a hole is formed, and a hole is formed in the second aluminum film by anodic oxidation, and the second aluminum film is anodized to form a second insulator (layer) 102.

  At this time, the aluminum is removed from the thin film 121 made of aluminum and silicon, and a plurality of fine holes penetrating the thin film 121 are formed.

  Thereafter, the silicon remaining in the thin film 121 is oxidized to form an insulator, and then filled with cobalt by electrodeposition, and the surface of the obtained structure is polished to remove cobalt protruding from the holes. As a result, the columnar second magnetic body 202 and the fine columnar magnetic body formed on the thin film 121 are formed on the second insulator 102. A magnetoresistive element film having a structure in which the first magnetic body 201 and the second magnetic body 202 are locally coupled by a plurality of fine columnar magnetic bodies formed on the thin film 121 is formed (FIG. 2). ).

  The magnetic bodies 201 and 202 have a shape in which the length in the direction perpendicular to the surface of the layer is longer than the length in the in-plane direction of the film of the insulator (layer). Due to this shape anisotropy, both have magnetic anisotropy in the direction perpendicular to the plane of the layer, and have different magnetization reversal fields due to the difference in shape. Therefore, it is possible to reverse only the magnetization direction of one magnetic body by applying an external magnetic field, and when the magnetization directions of the two magnetic bodies are antiparallel, a domain wall is formed at a local coupling portion. As described above, when the magnetization directions of two magnetic bodies are antiparallel, the electric resistance is higher than when they are parallel.

In this embodiment, cobalt is used as the magnetic material. However, any magnetic material exhibiting a magnetoresistive effect may be used. For example, iron or nickel can be used.
(Third embodiment)
This embodiment will be described with reference to FIG. A first aluminum film having a thickness of 1 μm is formed on a substrate 100 (not shown) made of silicon, and a dent is formed by pressing a needle at a desired position to be a starting point of a hole. Of course, the starting point may be formed by FIB as described in the second embodiment.

  Next, the first aluminum film is anodized to open holes with a diameter of several tens of nanometers, and aluminum is used as the first insulator (layer) 101. Thereafter, the holes are filled with cobalt by electrodeposition, the surface of the obtained structure is polished, the cobalt protruding from the holes is removed, and the first magnetic body 201 having a columnar structure is formed. Thereafter, as in the second embodiment, aluminum and silicon are simultaneously sputtered to form a 20 nm-thick eutectic thin film 121 in which an aluminum columnar structure having a diameter of several nm is formed in the silicon film, and further to a thickness of 1 μm. A second aluminum film is formed.

  When a hole is provided in the first aluminum film, a hole is formed by anodization so that the hole is located immediately above the first magnetic body 201 of the second aluminum film, and the aluminum film is anodized. The second insulator (layer) 102 is used. At this time, in the thin film 121 made of aluminum and silicon, the aluminum is removed and fine pores are formed. After the remaining silicon is oxidized to form an insulator, cobalt is filled by electrodeposition, and the surface of the resulting structure is polished to remove cobalt protruding from the holes. Through the above steps, a structure in which the columnar structure magnetic bodies 201 and 202 are locally coupled by the plurality of fine columnar magnetic bodies formed in the thin film 121 is formed in the insulating layer film.

  Next, the magnetization direction of the second magnetic body 202 is aligned in either the upper or lower direction perpendicular to the layer surface.

  Thereafter, an antiferromagnetic material 211 made of manganese and platinum is formed on the second magnetic material 202. By forming the antiferromagnetic material 211, the unidirectional anisotropy of the antiferromagnetic material 211 is induced. As a result, the magnetoresistive effect element shown in FIG. 3 is formed.

When the magnetization directions of the first magnetic body 201 and the second magnetic body 202 are aligned in the direction of unidirectional anisotropy of the antiferromagnetic body 211, the second magnetic body 202 is separated from the antiferromagnetic body 211. When an external magnetic field is applied in a direction that is exchange coupled and antiparallel to the magnetization direction, the magnetization direction of the first magnetic body can be reversed by a magnetic field smaller than the magnetization direction of the second magnetic body. .
(Fourth embodiment)
In the magnetoresistive effect element described in the second embodiment, since the volumes of the first magnetic body 201 and the second magnetic body 202 are different, magnetization reversal by spin injection is also possible.

  In order to perform spin injection, the nonmagnetic metal film 103 is formed on the second magnetic film 202, and the fourth magnetic body 204 is formed continuously.

  Similarly to the third embodiment, a eutectic thin film 121 made of silicon and aluminum is formed, and then a sufficiently thick second aluminum film is formed. A second magnetic body 202, a nonmagnetic metal 103, and a fourth magnetic body 204 are successively formed in the holes of the second insulator 202 produced by anodizing the aluminum film. At this time, the film thickness of the nonmagnetic metal 103 is set to be thinner than the thickness at which spin is not reversed, that is, the spin relaxation length. Since the film thickness varies depending on the magnetic body 202 and the non-magnetic metal 103, it is necessary to appropriately change the thickness depending on the material.

  The first magnetic body 201 and the fourth magnetic body 204 have large volumes so that magnetization is not reversed at the time of spin injection. For example, the thickness of the second aluminum film is 3 μm, and this is anodized to form holes in the upper portion of the first magnetic body 201 and simultaneously oxidize the aluminum film. Next, as the second magnetic body 202, 300 nm of cobalt is electrodeposited by electrodeposition, 5 nm thick copper is filled as the nonmagnetic metal 103, and cobalt as the second magnetic body 202 is filled up to the film surface (FIG. 4).

  The magnetization direction of the fourth magnetic body 204 is parallel to the magnetization direction of the first magnetic body 201. When the magnetization direction of the fourth magnetic body 204 and the magnetization direction of the second magnetic body 202 are antiparallel, the magnetization direction of the second magnetic body 202 is aligned with the magnetization direction of the fourth magnetic body 204. The spin-polarized electrons from the magnetic body 204 are injected into the second magnetic body 202 through the nonmagnetic metal 103. Then, due to the interaction between the spin of electrons and the magnetization of the second magnetic body 202, the magnetization of the second magnetic body 202 is parallel to the magnetization direction of the fourth magnetic body 204. Conversely, when the magnetization direction of the second magnetic body 202 is directed antiparallel to the magnetization direction of the fourth magnetic body 204, electrons are injected from the second magnetic body 202. The injected electrons are spin-polarized, and electrons having a spin parallel to the magnetization direction of the fourth magnetic body 204 pass through the fourth magnetic body 204 through the nonmagnetic metal 103.

However, electrons having spins antiparallel to the fourth magnetic body 204 are reflected at the interface between the fourth magnetic body 204 and the nonmagnetic metal 103 and are injected into the second magnetic body 202 again. The magnetization of the second magnetic body 202 is reversed by this electron injection. Since the fourth magnetic body 204 and the first magnetic body 201 have a large volume, the magnetization is not reversed, and a domain wall is formed at the interface between the first magnetic body 201 and the second magnetic body 202. The amount of current required for the magnetization reversal in the spin injection method is determined so that the first magnetic body 201 and the fourth magnetic body 204 can be reversed, and the second magnetic body 202 does not reverse the magnetization. The information recording circuit is almost the same as the conventional simple matrix method, but since the magnetic recording method is common in the conventional simple matrix method, the detection circuit and the recording circuit are separated. On the other hand, in the case of using spin injection recording, there is a shared portion between the detection circuit and the recording circuit, and even the selection transistor of the detection circuit of the magnetic field recording simple matrix system is the shared portion. A detection circuit and a power source are connected to the tip of the selection transistor, and these may be switched by a switch.
(Fifth embodiment)
This embodiment will be described with reference to FIG. A first aluminum film is formed to a thickness of 1.5 μm, and a dent is formed as a starting point of etching by pressing a needle at a desired position. Anodizing forms columnar holes and oxidizes aluminum.

  Next, cobalt is filled in the holes as the first magnetic body 201 by electrodeposition, and the cobalt protruding from the holes is removed. Thereafter, a second aluminum film is further formed to a thickness of 500 nm on the sample surface. By shifting the distance slightly shorter than the diameter of the first magnetic body 201, a dent is formed on the surface of the second aluminum film by pressing a needle to form an etching starting point, and holes are formed by anodization. The vacancies are filled with cobalt to be the second magnetic body 202 by electrodeposition, and the cobalt protruding from the vacancies is removed.

  The first magnetic body 201 is shifted by a distance slightly shorter than the diameter of the first magnetic body 201, a dent is formed on the surface of the second aluminum film by pressing a needle to form an etching start point, and vacancy is formed by anodization. The magnetic body 201 and the second magnetic body 202 are formed so as to be locally coupled as shown in FIG. Any material can be used for the first magnetic body 201 and the second magnetic body 202 as long as they exhibit a magnetoresistive effect. Examples of the first magnetic body 201 and the second magnetic body 202 include iron and nickel other than cobalt.

  The first magnetic body 201 has a magnetization reversal magnetic field (coercive force) larger than that of the second magnetic body 202. Assuming that the magnetization directions of the first magnetic body 201 and the second magnetic body 202 are parallel in the initial state, when the magnetic field is applied in antiparallel to the magnetization direction, only the magnetization of the second magnetic body 202 is reversed, and the first magnetic body A domain wall is formed at the interface between the body 201 and the second magnetic body 202. Further, when the magnetization is antiparallel, the electric resistance is larger than when the magnetization is parallel.

Further, in the magnetoresistive effect element having the film configuration of the present embodiment, since the first magnetic body 201 and the second magnetic body 202 have different volumes, only the magnetization direction of the second magnetic body 202 is reversed by spin injection. Is possible.
(Sixth embodiment)
A nonvolatile memory can be realized using the magnetoresistive effect element of the present invention as a memory element. n-type diffusion regions 105 and 106 to be source and drain regions formed on the surface of the p-type silicon wafer 104, and a gate formed between the n-type diffusion regions 105 and 106 via the silicon wafer 104 and a gate insulating film An n-type MOS (NMOS) transistor having an electrode 107 is included.

  The switch transistor for element selection is preferably formed by a CMOS process simultaneously with the peripheral circuit. A contact plug 108 is formed on the n-type diffusion region 105 to electrically connect the selection transistor and the magnetoresistive element. In the same manner as the manufacturing method described in the third embodiment, a structure in which the first magnetic body 201 made of cobalt and the second magnetic body 202 are locally coupled is formed. Further, an amorphous alloy perpendicular magnetization film 203 that is a third magnetic body 203 made of terbium, iron, and cobalt is formed on the second magnetic body, and the magnetization direction of the second magnetic body 202 is fixed. However, the composition of the third magnetic body 203 is in the vicinity of the compensation composition so as to have a large coercive force so that it is not easily reversed by external magnetization.

The write lines 111 and 112 are arranged in the vicinity of the first magnetic body 201, and a current is allowed to flow therethrough so that a magnetic field perpendicular to the film surface can be applied to the first magnetic body 201. However, when recording is performed in a desired memory element, a current is also passed through the write lines 111 and 112 and simultaneously a current is passed through the bit line 113 connected to the desired memory element. By applying a magnetic field in the in-plane direction, the magnetization of the first magnetic body 201 is reversed, and only a desired memory element is selectively recorded. The write lines 111 and 112 are connected to a power source capable of flowing a current (not shown) bidirectionally, and the information recording means is constituted by the write lines and the power source. A circuit for detecting the resistance of the magnetoresistive effect element is connected to one end of the bit line, and the bit line and the circuit constitute information detection means. A differential amplifier or the like may be used as a circuit for detection.
The gate electrode 107 is connected to a word line for selecting a desired element when reading information.
(Seventh embodiment)
By using the magnetoresistive effect element according to the fourth embodiment of the present invention as a memory element and using spin injection for the information recording method, the magnetoresistive effect element of the present invention is obtained as shown in FIG. A cross-point structure in which the magnetoresistive effect element of the present invention is sandwiched between a bit line and a word line can be taken.

  Information is recorded by passing a current in a direction corresponding to information recorded on the bit line and the word line connected to the desired magnetoresistive element. In addition, information is read by passing a small current that does not reverse the magnetization of the magnetoresistive effect element to the bit line and the word line as in the recording operation, and detecting a difference in the resistance value of the element.

  The BMR magnetoresistive element of the present invention performs the same configuration and operation as a cross-point type memory using a TMR element, for example, Japanese Patent Laid-Open No. 2000-315382. Compared with the TMR element, the BMR element of the present invention has an MR ratio of 10 times or more and the cell area can be reduced to 1/10 or less, so that the configuration of the detection circuit can be simplified and a memory with a high storage density can be obtained. Can be obtained.

It is sectional drawing which shows typically the structure of the magnetoresistive effect element of this invention. It is sectional drawing which shows typically the structure of the magnetoresistive effect element of this invention. It is sectional drawing which shows typically the structure of the magnetoresistive effect element of this invention. It is sectional drawing which shows typically the structure of the magnetoresistive effect element of this invention. It is sectional drawing which shows typically the structure of the magnetoresistive effect element of this invention. It is sectional drawing which shows typically the Example of the memory element which used the magnetoresistive effect element of this invention as a memory element. It is a bird's-eye view which shows typically the structure of the memory which used the magnetoresistive effect element of this invention as a memory element. It is sectional drawing which shows typically the basic film structure and magnetization direction of a magnetoresistive effect film | membrane.

Explanation of symbols

100 substrate 101 first insulator 102 second insulator 103 nonmagnetic metal film 104 p-type silicon substrate 105 n-type diffusion region 106 n-type diffusion region 107 gate electrode (word line)
108 contact plug 109 contact plug 110 source electrode 111 write line 112 write line 113 bit line 114 word line 121 eutectic thin film 200 magnetoresistive effect element 201 first magnetic body 202 second magnetic body 203 third magnetic body 204 third 4 Magnetic material 211 Antiferromagnetic material 301 Magnetic film 302 Magnetic film 303 Nonmagnetic film

Claims (13)

A first magnetic body and a second magnetic body provided in the insulating layer so as to face each other in a direction perpendicular to the surface of the layer are connected at a connection portion, and the first magnetic body and the second magnetic body are , Including at least one element selected from transition metal elements,
An area of a contact surface between the first magnetic body and the second magnetic body of the connection portion is parallel to at least a plane that forms the connection portion of the first magnetic body and the second magnetic body. Smaller than the cross-sectional area,
A magnetoresistive effect element, wherein an electric resistance varies depending on an angle formed by magnetization directions of the first magnetic body and the magnetic body of the second magnetic body.   2. The magnetoresistance according to claim 1, wherein both of the first magnetic body and the second magnetic body have a length in a direction perpendicular to a film surface longer than a length in a film surface direction of the insulator film. Effect element.   The magnetoresistive effect element according to claim 1, wherein the magnetic film has an easy axis of magnetization in a direction perpendicular to the film surface of the insulating film.   The at least one of the first magnetic body and the second magnetic body is an alloy of at least one element selected from rare earths and at least one element selected from transition metals. The magnetoresistive effect element of any one of 1-3.   5. The switch according to claim 1, wherein either the first magnetic body or the second magnetic body is exchange coupled with an antiferromagnetic body having unidirectional anisotropy. 2. The magnetoresistive effect element according to item 1.   Either the first magnetic body or the second magnetic body is exchange-coupled with a third magnetic body having a coercive force larger than that of the first magnetic body and the second magnetic body. The magnetoresistive effect element according to any one of claims 1 to 4, wherein the magnetoresistive effect element is provided.   The magnetoresistive effect element according to any one of claims 1 to 6, wherein a joint portion between the first magnetic body and the second magnetic body is a eutectic thin film.   The first magnetic body and the second magnetic body are formed so as to be shifted in the film plane direction, and an upper end portion of the first magnetic body and a lower end portion of the second magnetic body are coupled to each other. Item 8. The magnetoresistive element according to any one of Items 1 to 7.   9. A magnetoresistive element according to claim 1, wherein the magnetoresistive element is a memory element, recording means for directing magnetization of the memory element in a desired direction in accordance with information to be recorded, and a current to the memory element A memory having detection means for detecting a magnetization direction of the memory element by flowing the memory element.   10. A memory, wherein the recording circuit according to claim 9 is a mechanism for recording in a desired direction of a magnetization direction of a memory element by applying a magnetic field generated by passing a current through a conducting wire to the memory element.   The recording circuit according to claim 9 has a portion that spin-polarizes a current, and records the magnetization direction of the memory element in a desired direction by flowing the spin-polarized current through the memory element. Memory.   The memory according to claim 11, wherein the portion for spin-polarizing the current comprises a multilayer film of a nonmagnetic film and a magnetic film. The memory according to claim 11, wherein the mechanism for spin-polarizing the current includes a semiconductor and a mechanism for applying an electric field to the semiconductor.

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