JP2003209227A - Magnetic memory - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic memory element which has high integrity, lower power consumption and high reliability by applying a magnetic field to a magnetic recording layer by a lower write current efficiently. <P>SOLUTION: This magnetic memory includes a magnetoresistance effect element (21) having a magnetic recording layer, and first write wiring (22) extending above or below the magnetoresistance effect element in a first direction. The direction of magnetization of the magnetic recording layer can be changed by a magnetic field formed by allowing a current to flow in the first write wiring. The first write wiring has a coating layer (SM) composed of a magnet at least on one of its two side faces. In the covered layer, the thickness of an end portion closest to the magnetoresistance effect element is made thinner than the thickness of any other portion. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic memory, and more particularly to a magnetic memory capable of reducing power consumption by efficiently applying a magnetic field to a recording layer of a magnetoresistive effect element with a small write current.

[0002]

2. Description of the Related Art Recently, a magnetic random access memory using a magnetic element having a giant magnetoresistive effect has been proposed as a solid-state magnetic memory, and in particular, a "ferromagnetic tunnel junction" is used as a magnetoresistive effect element. Attention is focused on the magnetic memory that was used.

The ferromagnetic tunnel junction is mainly based on a three-layer structure of (first ferromagnetic layer) / (nonmagnetic insulating layer) / (second ferromagnetic layer), and the nonmagnetic insulating layer is tunneled. Then the current flows. In this case, the junction resistance value changes in proportion to the cosine of the relative angle of magnetization in the first and second ferromagnetic layers. Therefore, the resistance value has a minimum value when the magnetizations of the first and second ferromagnetic layers are parallel, and a maximum value when the magnetizations are antiparallel. This is "Tunneling MagnetoR
esistance: TMR) effect ”. For example,
Appl. Phys. Lett. Vol. 77, (2
000) p. 283, it is reported that the resistance change due to the TMR effect reaches 49.7% at room temperature.

In a magnetic memory having a ferromagnetic tunnel junction as a memory cell, the magnetization of one ferromagnetic layer is fixed to serve as a "reference layer", and the other ferromagnetic layer is used as a "storage layer". In this cell, information can be stored by associating binary information, that is, "0" and "1" with the directions of magnetization of the reference layer and the storage layer being parallel or antiparallel.

Recording information is written by reversing the magnetization of the storage layer by applying a magnetic field generated by passing a current through the write wiring to the cell. At this time, a write current is simultaneously applied to two write wirings that intersect each other and are not in contact with each other, and a synthetic magnetic field is applied in a direction having a non-zero angle with respect to the easy axis of magnetization of the storage layer, thereby reversing the magnetization Often do. Further, at the time of this writing operation, an "asteroid curve" representing the relationship between the applied magnetic field direction and the reversal magnetic field is considered.

On the other hand, reading is performed by passing a current through the ferromagnetic tunnel junction and detecting the resistance change due to the TMR effect. The magnetic memory is configured as a large capacity memory by arranging a large number of such memory cells.

When such memory cells are arranged in a matrix to form an actual magnetic memory, for example, a semiconductor DRA can be selected so that any one memory cell can be selected.
Similarly to M (Dynamic Random Access Memory), a switching transistor or the like is arranged for each cell and peripheral circuits are incorporated. On the other hand, a structure in which a diode and a ferromagnetic tunnel junction element are provided at a position where a word line and a bit line intersect with each other is also proposed (US Pat. Nos. 5,640,343, 5,650,958). .

In order to increase the integration density of the magnetic memory using the magnetoresistive effect element as a memory cell, the size of each memory cell is reduced and the size of the ferromagnetic material forming the cell is necessarily reduced. There is a need. However, generally, the smaller the ferromagnetic material, the larger its coercive force. Since the magnitude of the coercive force is a measure of the magnitude of the switching magnetic field necessary for reversing the magnetization, this means an increase in the switching magnetic field. Therefore, when writing bit information, a larger current has to be passed through the write wiring, resulting in unfavorable results such as increased power consumption and shortened wiring life. Therefore, writing bit information with a smaller write current is an important issue in the practical application of a highly integrated magnetic memory.

In order to solve this problem, a magnetic memory element having a thin film made of a high magnetic permeability material around a write wiring has been proposed (US Pat. No. 5,659,499).
U.S. Pat. No. 5,956,267, U.S. Pat. No. 5,
940, 319 and International Patent Application WO 00/101
72). In these elements, the magnetic flux generated by the write current can be converged by the high magnetic permeability thin film around the write wiring. Therefore, the magnetic field generated at the time of writing can be strengthened, and as a result, bit information can be written with a smaller current. At the same time, since the magnetic flux leaking to the outside of the high magnetic permeability thin film can be greatly reduced, the effect of suppressing crosstalk can be obtained.

[0010]

However, in the case of the structure disclosed in US Pat. No. 5,659,499, a magnetic field cannot be applied uniformly over the entire magnetic recording layer. Further, in the structures disclosed in US Pat. No. 5,956,267 and US Pat. No. 5,940,319, the distance between the high magnetic permeability thin film and the magnetic recording layer is long,
Particularly in the case of a magnetic memory element having a plurality of magnetization pinned layers capable of obtaining a high output, the distance becomes large, and a magnetic field cannot be efficiently applied to the magnetic recording layer.

On the other hand, international patent application WO00 / 10172
In the case of the structure disclosed in, the structure has such a structure that the high magnetic permeability thin film and the magnetic recording layer are close to each other, but it is difficult to concentrate a sufficient magnetic flux in the magnetic recording layer.

The present invention has been made based on the recognition of such a problem, and an object thereof is to efficiently apply a magnetic field to a magnetic recording layer with a smaller write current to achieve high integration and power consumption. It is an object to provide a magnetic memory device that is reduced in reliability and has high reliability.

To achieve the above object, a first magnetic memory of the present invention comprises a magnetoresistive effect element having a magnetic recording layer and a first magnetoresistive effect element above or below the magnetoresistive effect element. A first write wiring extending in a direction, the direction of magnetization of the magnetic recording layer is made variable by a magnetic field formed by passing a current through the first write wiring, and the first write wiring is formed. The wiring has a coating layer made of a magnetic material on at least one of both side surfaces thereof, and the coating layer is provided at a tip portion closest to the magnetoresistive effect element in a cross section perpendicular to the first direction. It is characterized in that the thickness is smaller than the thickness in other portions.

According to the above structure, write crosstalk to the adjacent memory cells can be prevented and the magnetic field can be effectively concentrated on the magnetic recording layer.

A second magnetic memory of the present invention comprises a magnetoresistive effect element having a magnetic recording layer, and a first write wiring extending above or below the magnetoresistive effect element in a first direction. And a direction of magnetization of the magnetic recording layer is made variable by a magnetic field formed by passing a current through the first write wiring, and the first write wiring is provided on at least one of both side surfaces thereof. It has a coating layer made of a magnetic material, and the coating layer has a width, as viewed in the first direction, which is narrower at a tip portion closest to the magnetoresistive effect element than at other portions. Is characterized by.

Also with the above structure, the write crosstalk to the adjacent memory cells can be prevented and the magnetic field can be effectively concentrated on the magnetic recording layer.

Further, a third magnetic memory of the present invention comprises a magnetoresistive effect element having a magnetic recording layer, and a first write wiring extending above or below the magnetoresistive effect element in a first direction. And a direction of magnetization of the magnetic recording layer is made variable by a magnetic field formed by passing a current through the first write wiring, and the first write wiring is provided on at least one of both side surfaces thereof. A coating layer made of a magnetic material, wherein the coating layer has a thickness at a tip portion closest to the magnetoresistive effect element smaller than thicknesses at other portions in a cross section perpendicular to the first direction. Further, the width of the coating layer as viewed in the first direction is narrower at the tip portion closest to the magnetoresistive effect element than at the other portions. That.

According to the above structure, write crosstalk to the adjacent memory cells can be prevented and the magnetic field can be more effectively concentrated on the magnetic recording layer.

Here, the coating layer may have a taper portion whose thickness is gradually reduced toward the magnetoresistive element in a cross section perpendicular to the first direction. .

Further, the coating layer may have a taper portion in which the width is gradually narrowed toward the magnetoresistive effect element.

Further, if the covering layer has a protruding portion protruding from the first write wiring toward the magnetoresistive effect element, write crosstalk to an adjacent memory cell is prevented, The magnetic field can be more efficiently concentrated on the magnetic recording layer.

If the protrusion is provided so as to be inclined from the side surface of the first write wiring toward the magnetoresistive effect element, the coating layer that functions as a magnetic yoke. It is possible to write more efficiently by making the protruding portion of (3) closer to the magnetic recording layer.

At least a part of the protruding portion may have a taper portion whose thickness is gradually reduced toward the magnetoresistive element.

At least a part of the projecting portion may have a taper portion in which the width is gradually narrowed toward the magnetoresistive effect element.

Further, a second write wiring extending in a second direction intersecting with the first write wiring is further provided, and these are provided at an intersection of the first write wiring and the second write wiring. Wherein the magnetoresistive effect element is disposed so as to be sandwiched between the first and second write wirings, and the direction of the magnetization of the magnetic recording layer can be changed by a magnetic field formed by applying a current to each of the first and second write wirings. Then, the current flowing through each write wiring can be lowered to solve the problems such as wiring fatigue and electromigration.

Here, "intersect" includes dispositions that do not intersect in space and are not parallel to each other.

If the second write wiring has a coating layer made of a magnetic material on at least one of both side surfaces of the second write wiring and the surface opposite to the magnetoresistive effect element, the second write wiring is formed. Also in the wiring, write crosstalk to adjacent memory cells can be suppressed, and efficient writing can be performed.

In the first to third magnetic memories of the present invention, the first write wiring also has a coating layer made of a magnetic material on the surface opposite to the magnetoresistive effect element. Although it may or may not be provided, when the coating layer is provided, write crosstalk to an adjacent memory cell can be further suppressed and more efficient writing can be performed.

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

FIG. 1A is a conceptual diagram showing a cross-sectional structure of a main part of a magnetic memory according to the first embodiment of the present invention, and FIG. 1B is an A- of FIG. It is an A'line sectional view.

FIG. 2 is a perspective view of the main part of this magnetic memory.

That is, the structures shown in these drawings are
Corresponds to the memory cell of the 1-bit portion of the magnetic memory that operates as a random access memory. This memory cell comprises a storage element portion 11 and an address selection transistor portion 12.

The memory element portion 11 is the magnetoresistive effect element 2.
1 and a pair of wirings 22 and 24 connected thereto. The magnetoresistive effect element 21 may have, for example, a laminated structure of magnetic layer / nonmagnetic layer / magnetic layer or magnetic layer / insulating tunnel layer / magnetic layer, and may have a GMR effect or a TMR effect.

In the case of having the GMR effect, a sense current may be passed through the magnetoresistive effect element 21 at the time of reading bit information to detect the resistance change.

In particular, magnetic layer / nonmagnetic tunnel layer /
Including a ferromagnetic double tunnel junction having a structure of magnetic layer / non-magnetic tunnel layer / magnetic layer is advantageous in that a high magnetoresistive effect can be obtained due to a resistance change due to the tunnel magnetoresistive (TMR) effect.

In these structures, one of the magnetic layers can act as a magnetically pinned layer and any of the other magnetic layers can act as a magnetic recording layer.

The magnetization fixed layer and the magnetic recording layer are made of iron (Fe),
It includes a ferromagnetic layer made of cobalt (Co), nickel (Ni), or an alloy containing any of these, or nickel manganese antimony (N
iMnSb), platinum manganese antimony (PtMnS)
b), cobalt manganese germanium (Co ₂ Mn
It is desirable to include a half metal magnetic layer such as Ge).

As the magnetization pinned layer, one having a thicker film thickness of these magnetic layers to increase the coercive force can be used, or a structure in which antiferromagnetic layers are laminated adjacent to each other can be used. As a result, the magnetization can be fixed by the exchange interaction acting between the magnetic layer and the antiferromagnetic layer.

In the magnetoresistive effect element 21 used in the present invention, the direction of the magnetic field generated when a current is applied to the wiring 22 (or 23, or both of them) and the easy axis of magnetization of the magnetic recording layer are almost the same. It is desirable that they match. This can be easily realized by performing annealing in a state in which a magnetic field is applied after forming the magnetoresistive effect element 21. Further, shape anisotropy may be imparted by processing into a flat shape such as a rectangle, a rhombus, or an ellipse having a long axis in the direction of the magnetic field generated when a current is applied to the wiring 22.

On the other hand, in the selection transistor portion 12,
A transistor 30 connected via the via 26 and the embedded wiring 28 is provided. This transistor 30
Performs a switching operation according to the voltage applied to the gate 32, and controls the opening / closing of the current path between the magnetoresistive effect element 21 and the wiring 34. Further, a write wiring 23 is provided below the magnetoresistive effect element in a direction substantially orthogonal to the wiring 22. These write wirings 22 and 23 are
For example, it can be formed of aluminum (Al), copper (Cu), tungsten (W), tantalum (Ta), or an alloy containing any of these.

In the memory cell having such a structure, when the bit information is written in the magnetoresistive effect element 21, a write pulse current is passed through the wirings 22 and 23, and a synthetic magnetic field induced by these currents is applied to the magnetic field. The magnetization of the recording layer of the resistance effect element is appropriately reversed.

When the bit information is read, a sense current is passed through the wiring 22, the magnetoresistive effect element 21 including the magnetic recording layer, and the lower electrode 24 to change the resistance value or the resistance value of the magnetoresistive effect element 21. This is done by measuring the change.

In the present embodiment, the coating layer SM made of a magnetic material is provided on the side surfaces of the write wirings 22 and 23 and on the back surface side facing the magnetic recording layer. Further, the coating layer SM provided on the side wall of the wiring 22 is
Toward the magnetoresistive effect element 21, there is a tapered portion T whose tip portion is gradually thinned.

The coating layer SM made of a magnetic material prevents the current magnetic field generated in the write wirings 22 and 23 from leaking to the surroundings. That is, the write wirings 22, 2
A write magnetic field generated by applying a write current to the magnetic field 3 forms a magnetic circuit around the wirings 22 and 23 with the inside of the coating layer SM as a magnetic path. As a result, it is possible to effectively prevent "write crosstalk" with respect to the magnetoresistive effect element of another memory cell adjacent in the left-right direction or on the back surface side.

Further, by providing the tapered portion T at the tip of the coating layer SM of the wiring 22, the magnetic flux M passing through the coating layer SM can be converged and concentrated on the magnetic recording layer of the magnetoresistive effect element 21. That is, by providing the taper portion T at the tip of the coating layer SM that acts as a “magnetic yoke”, the write magnetic field generated around the write wiring 22 is concentrated in the magnetic recording layer, and high-efficiency writing is possible. .

According to this embodiment, the coating layer S is thus formed.
By giving M a unique characteristic, it is possible to reduce the power consumption of the magnetic memory associated with writing. Further, in order to increase the integration degree of the magnetic memory, the magnetoresistive effect element 21
Even if the recording layer is miniaturized and the coercive force of the recording layer is increased, stable writing is possible.

Furthermore, by reducing the write current flowing in the write wiring, the occurrence of electromigration of the wiring can be suppressed, the reliability of the magnetic memory can be improved, and the life can be extended.

In order to obtain such an action, the coating layer SM
As the material of (1), it is generally desirable to use a high magnetic permeability material having a large relative magnetic permeability. Particularly, the relative magnetic permeability is preferably 5 or more, more preferably 100 or more. Also,
Higher saturation magnetization is preferable, 500 or more is preferable, and 1000 or more is more preferable.

As such a material, iron (Fe), iron aluminum (Fe--Al) alloy, iron silicon (Fe--)
Si) alloy, iron-silicon-aluminum (Fe-Si-Al) alloy such as sendust, nickel iron (NiFe)
Alloy, soft ferrite containing iron oxide (Fe ₂ O ₃ ) as a main component, iron (Fe), cobalt (Co), nickel (Ni) and boron (B), silicon (Si), phosphorus (P), etc. Various high-permeability materials such as an amorphous alloy of and can be used.

In the case of the specific example shown in FIGS. 1 and 2, the coating layer SM is provided on both the side walls of the write wirings 22 and 23 and the back surface side as viewed from the magnetoresistive effect element 21. Even if the covering layer SM is provided only on the side walls of the wirings 22 and 23, some effect can be obtained.

Further, in FIGS. 1 and 2, the covering layer S
Although the case where M is provided in close contact with the wirings 22 and 23 has been illustrated, the present invention is not limited to this, and even if the covering layer SM is arranged in such a state that it is separated from the writing wirings 22 and 23 to some extent, a magnetic field is generated. The effect of preventing leakage of magnetic field and converging magnetic flux to the magnetic recording layer can be obtained.

Further, in FIGS. 1 and 2, the coating layer SM provided around the write wirings 22 and 23 is provided only in the intersection region of these wirings, that is, in the vicinity of the region where the magnetoresistive effect element 21 is provided. , Formed. In this case, it is desirable that the lengths of the wires 22 and 23 of the coating layer SM viewed in the longitudinal direction are 1.2 times or more the lengths of the magnetoresistive effect element 21 in the wire longitudinal direction, respectively. It is more preferable that the length is twice or more, and the length may be further increased to include a plurality of magnetoresistive effect elements. Further, such a covering layer SM may be provided over the entire memory region formed in a matrix.

Furthermore, the coating layers SM provided on both side surfaces of the wirings 22 and 23 do not have to have the same thickness. In other words, the left side surface and the right side surface of the wirings 22 and 23 may have different thicknesses of these covering layers SM.

Further, in FIG. 1, the tapered portion T is formed only on the coating layer SM provided on the wiring 22, but the same tapered portion T is formed on the coating layer SM provided on the wiring 23. Needless to say, the effect of can be obtained. Needless to say, a greater effect can be obtained by forming the tapered portion T on both the covering layers SM of the upper and lower wirings 22 and 23.

Next, a second embodiment of the present invention will be described.

FIG. 3A is a conceptual diagram showing the cross-sectional structure of the main part of the magnetic memory according to the second embodiment of the present invention, and FIG. 3B is the line A- of FIG. It is an A'line sectional view.

FIG. 4 is a perspective view of the main part of this magnetic memory.

In these drawings, elements similar to those described above with reference to FIGS. 1 and 2 are designated by the same reference numerals, and detailed description thereof will be omitted. Also in this embodiment, both side surfaces of the write wirings 22 and 23 and the magnetoresistive effect element 2 are
A coating layer SM made of a magnetic material is provided on the back surface side as viewed from 1.

Further, the coating layer SM provided on both side surfaces of the wiring 22 has a protruding portion P protruding toward the magnetoresistive effect element 21. The protrusion P can be provided so as to extend to the vicinity of the magnetic recording layer of the magnetoresistive effect element 21. That is, the protrusion P is provided at the tip of the coating layer SM that functions as a “magnetic yoke”. By doing so, the magnetic flux generated by passing a current through the wiring 22 is induced to the vicinity of the magnetoresistive effect element 21, and the write magnetic field in the magnetic recording layer can be further increased.

Further, in the present embodiment, as shown in FIG. 4, a tapered portion TW may be provided so that the width W of the protruding portion P is gradually narrowed toward the tip thereof. By providing such a tapered portion TW, it is possible to more efficiently concentrate the write magnetic flux induced in the coating layer SM, which acts as a magnetic yoke, in the magnetoresistive effect element 21.

On the other hand, such a taper portion T in the width direction
W may not be provided on the protrusion P, but may be provided on a portion of the coating layer SM adjacent to the wirings 22 and 23.

FIG. 5 is a perspective view showing an essential part of the magnetic memory in which the tapered portion TW is provided in the portion of the coating layer adjacent to the wiring as described above. Also in this figure, elements similar to those described above with reference to FIGS. 1 to 4 are marked with the same reference numerals and not described in detail.

In the case of the specific example shown in FIG. 5, the taper portion TW in the width direction is formed in the portion of the covering layer SM adjacent to the wiring 22.
Is provided. Even in this case, the magnetic flux generated by passing an electric current through the wiring 22 is induced to the vicinity of the magnetoresistive effect element 21, and the write magnetic field in the magnetic recording layer can be further increased.

Next, a third embodiment of the present invention will be described.

FIG. 6A is a conceptual diagram showing the cross-sectional structure of the main part of the magnetic memory according to the second embodiment of the present invention, and FIG. 6B is a section A- of FIG. It is an A'line sectional view.

FIG. 7 is a perspective view of the main part of this magnetic memory.

Also in these drawings, elements similar to those described above with reference to FIGS. 1 to 4 are designated by the same reference numerals, and detailed description thereof will be omitted. Also in this embodiment, both side surfaces of the write wirings 22 and 23 and the magnetoresistive effect element 2 are
A coating layer SM made of a magnetic material is provided on the back surface side as viewed from 1.

Further, the covering layer SM provided on both side surfaces of the wiring 22 has the protruding portion P protruding toward the magnetoresistive effect element 21 as in the second embodiment. further,
The protrusion P has a tapered portion TT whose thickness gradually decreases toward the tip thereof. Such a taper portion T
T has the same action as the tapered portion T described in the first embodiment. That is, the magnetic flux generated by passing a current through the wiring 22 can be more efficiently gathered in the vicinity of the magnetic recording layer of the magnetoresistive effect element 21, and the generated magnetic field can be strengthened.

Further, this effect is as shown in FIG.
It becomes more remarkable by combining with the taper TW in the width W direction.

Next, a fourth embodiment of the present invention will be described.

FIG. 8A is a conceptual diagram showing a cross-sectional structure of a main part of the magnetic memory according to the second embodiment of the present invention, and FIG. 8B is a view of A- in FIG. 8A. It is an A'line sectional view.

FIG. 9 is a perspective view of the main part of this magnetic memory.

Also in these drawings, elements similar to those described above with reference to FIGS. 1 to 7 are designated by the same reference numerals, and detailed description thereof will be omitted. Also in this embodiment, both side surfaces of the write wirings 22 and 23 and the magnetoresistive effect element 2 are
A coating layer SM made of a magnetic material is provided on the back surface side as viewed from 1.

Further, the covering layer SM provided on both side surfaces of the wiring 22 has the protruding portion P protruding toward the magnetoresistive effect element 21 as in the second and third embodiments.
However, in the present embodiment, the protrusion P is the wiring 2
It is provided so as to bend from a root portion adjacent to 2 or a portion in the middle of the distance from the root to change the direction and approach toward the magnetic recording layer of the magnetoresistive effect element 21 at a predetermined angle. With this configuration, the tip of the protrusion P can be brought closer to the magnetic recording layer of the magnetoresistive effect element 21, and the write magnetic flux can be efficiently concentrated on the magnetic recording layer.

Also in the present embodiment, the write magnetic flux can be more efficiently used by combining with the widthwise taper portion TW described in the second embodiment and the thickness taper portion TT described in the third embodiment. Can be converged to.

The structure of the memory cell of the magnetic memory of the present invention has been described above as the first to fourth embodiments of the present invention.

A magnetic memory can be formed by arranging these memory cells in a matrix.

FIG. 10 is a conceptual diagram illustrating the matrix configuration of the magnetic memory of the present invention.

That is, this figure shows a circuit configuration of an embodiment in which the memory cells described above with reference to FIGS. 1 to 9 are arranged in an array. A column decoder 50 and a row decoder 51 are provided for selecting one bit in the array, and the switching transistor 30 is turned on by the bit line 34 and the word line 32 to be uniquely selected and detected by the sense amplifier 52. As a result, the bit information recorded in the magnetic recording layer forming the magnetoresistive effect element 21 can be read.

Bit information is written by a magnetic field generated by passing a write current through a specific write word line 23 and bit line 22.

In this structure, the bit line 22 and the word line 23 are each provided with a coating layer SM, and the coating layer SM has a unique feature as illustrated in any one of FIGS. 1 to 9. Writing on the magnetic recording layer of the magnetoresistive effect element 21 can be efficiently performed.

FIG. 11 is a conceptual diagram showing another specific example of the matrix configuration of the magnetic memory of the present invention. That is, in the case of this example, the bit lines 22 and the word lines 34 arranged in a matrix form the decoder 60,
Selected by 61, a particular memory cell in the array is selected. Each memory cell has a structure in which the magnetoresistive effect element 21 and the diode D are connected in series. Here, the diode D has a role of preventing the sense current from bypassing in the memory cells other than the selected magnetoresistive effect element 21.

Writing is performed by a magnetic field generated by applying a write current to each of the specific bit line 22 and write word line 23.

Also in this matrix structure, the bit line 22 and the word line 23 are each provided with a coating layer SM, and these coating layers SM have unique characteristics as illustrated in any of FIGS. 1 to 9. Thus, the writing of the magnetoresistive effect element 21 to the magnetic recording layer can be efficiently performed.

[0083]

Embodiments of the present invention will be described in more detail below with reference to embodiments. That is, here, the effect of the coating layer SM provided on the write wirings 22 and 23 of the magnetic memory of the present invention will be described with reference to specific examples and the results of quantitatively examining the magnetic field generated by the wirings.

(First Embodiment) First, as a first embodiment of the present invention, a memory cell having the structure shown in FIGS. 1 and 2 will be described.

Transistor portion 11 of this memory cell
Can be produced on a silicon wafer in the same manner as a normal silicon process. Further, in order to produce the magnetic recording portion 12, the surface thereof is planarized by etching or chemical mechanical polishing (CMP), and then the magnetoresistive effect element 2 is formed.
1 was produced. For its fabrication, sputtering method, vapor deposition method, etc.
A commonly used thin film deposition method can be used. Further, the production of the oxide tunnel film for obtaining the TMR structure is
A plasma oxidation method was used.

Further, the magnetoresistive effect element was finely processed by photolithography and ion milling.
Similarly, the upper wiring 22 can be formed by fine processing. However, the coating layer SM added around the wirings 23 and 22 used in the present invention was manufactured by using the damascene method.

FIG. 12 is a graph showing the distribution of the magnetic field generated from the write wiring 22 in this embodiment. That is, the horizontal axis of the drawing represents the distance from the wiring 22 on the central axis of the magnetoresistive effect element 21 provided below the wiring 22, and the vertical axis of the drawing represents the magnetic field strength.

Here, assuming that the wiring 22 has a width of 200 nm and a height of 100 nm, the wiring 22 has a length of 2 m.
The magnetic field generated when an electric current of A was passed was plotted.

Further, the coating layer S formed around the wiring 22
M is formed of nickel iron (NiFe) having a relative magnetic permeability of 1000 and a saturation magnetization of 10000, and its thickness is about 10 nm.
And Further, as shown in FIGS. 1 and 2, a tapered portion T is provided at the tip thereof. The taper portion T is formed so that the thickness of the coating layer SM gradually decreases from the half in the height direction of the wiring 22, that is, from around 50 nm toward the tip thereof, and the thickness at the tip is almost half.

FIG. 12 shows the case where such a tapered portion T is provided (diamond-shaped plot) and the case where such a tapered portion T is not provided (triangular plot).

As can be seen from the figure, about 1 from the wiring 22.
In the range up to the distance of 00 nm, the generated magnetic field is higher when the taper portion T is provided than when it is not provided.

As described above, the effect of the present invention becomes particularly remarkable when the degree of integration of the magnetic memory is increased.

(Second Embodiment) Next, as a second embodiment of the present invention, a specific example of a magnetic memory provided with a protrusion P as shown in FIG. 3 will be described.

Also in this embodiment, a magnetic memory was formed by a procedure substantially similar to the procedure described above with respect to the first embodiment.

Here, the width of the wiring 22 was 200 nm and the height was 100 nm, and the magnetic field generated when a current of 2 mA was passed in the longitudinal direction of this wiring was determined.

FIG. 13 is a graph showing the distribution of the magnetic field generated from the write wiring 22 in this embodiment. That is, FIG. 3A shows the magnetoresistive effect element 2 from the wiring 22.
When the vertical direction toward the center of 1 is the z axis, the magnetic field distribution in the z axis direction is represented. Further, FIG. 6B shows that at a position separated by 110 nm in the z-axis direction of the wiring 22,
The magnetic field distribution in the direction perpendicular to the longitudinal direction of the wiring 22 is shown. Moreover, in any of these graphs, the protrusion P
When not provided (diamond-shaped plot), the protrusion amount is 100
The case where the protrusion P of nm is provided (cross plot) is shown.

From FIG. 13A, it can be seen that the magnetic field generated on the z axis is increased by providing the protrusion P. From FIG. 13B, the magnetic field is converged between the pair of protrusions P to obtain a high generated magnetic field, while the magnetic field leakage is significantly suppressed outside the pair of protrusions P. It can be seen that the generated magnetic field has dropped significantly. That is, it is understood that by providing such a protruding portion P, the generated magnetic field can be converged toward the magnetoresistive effect element 21 very efficiently, and the divergence to the surroundings can be significantly reduced.

(Third Embodiment) Next, as a third embodiment of the present invention, a specific example of the magnetic memory shown in FIGS. 8 to 9 will be described.

Also in this embodiment, a magnetic memory was formed by a procedure substantially similar to the procedure described above with respect to the first and second embodiments.

Here, the width of the wiring 22 was 200 nm and the height was 100 nm, and the magnetic field generated when a current of 2 mA was passed in the longitudinal direction of this wiring was determined. Also, the protrusion P
Was formed by bending from the root so as to be inwardly about 10 nm from the side surface of the wiring 22.

As a result, the wiring 110 is 110 in the z-axis direction.
At a position separated by nm, the linear protrusion P (second embodiment)
In this case, a magnetic field of about 90 Oersted is generated, whereas in the present embodiment, when the protrusion P is angled and bent inward, a generated magnetic field of about 98 Oersted is obtained, The effect of increasing the magnetic field was confirmed.

The embodiments of the present invention have been described above with reference to specific examples. However, the present invention is not limited to these specific examples. For example, the present invention can be similarly implemented by those skilled in the art by appropriately selecting the structure and arrangement relationship of the magnetoresistive element and the switching element forming the magnetic memory, or the wiring relationship and material of each wiring, and the like effect. What can obtain is also included in the scope of the present invention.

Further, the taper portions T, TW, and TT in the thickness direction or the width direction of the coating layer as described above are not limited to the configuration provided symmetrically on both sides of the wiring 22 or 23. That is, the hysteresis of the magnetic recording layer of the magnetoresistive effect element is usually made to correspond to the zero magnetic field in the center of the hysteresis characteristic curve in many cases, which makes it easy to use as a device.

However, it is often the case that the hysteresis of the magnetic recording layer shifts to either the left or the right on the characteristic graph due to the influence of the magnetic laminated film and its fine processing. To cope with such a case, a tapered portion may be provided on only one side of the wiring, or the thickness distribution and the taper angle of the left and right tapered portions of the wiring may be different.

In addition, all magnetic memories that can be appropriately designed and implemented by those skilled in the art based on the magnetic memories described above as the embodiments of the present invention also belong to the scope of the present invention.

[0106]

As described in detail above, according to the present invention,
By providing a coating layer around the write wiring of the magnetic memory, and by giving a unique feature to the form, the leakage of the write magnetic field is blocked and the write crosstalk to the adjacent magnetoresistive effect element is suppressed. it can.

Furthermore, by making the coating layer act as a magnetic yoke, the write magnetic field can be concentrated on the magnetic recording layer of the magnetoresistive effect element, and writing can be performed with high efficiency.

As a result, the write current required for recording bit information can be greatly reduced,
A magnetic memory with low power consumption can be provided.

Furthermore, even if the magnetoresistive effect element is miniaturized in order to increase the integration degree of the magnetic memory and the coercive force of the recording layer is increased, stable writing is possible.

Further, by reducing the write current flowing in the write wiring, the occurrence of electromigration of the wiring can be suppressed, the reliability of the magnetic memory can be improved, and the life can be extended.

That is, according to the present invention, it is possible to realize a magnetic memory with low power consumption and a high degree of integration, which is a great industrial advantage.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing a sectional structure of a main part of a magnetic memory according to a first embodiment of the present invention, and FIG. 1B is a sectional view taken along the line AA ′ of FIG. is there.

FIG. 2 is a perspective view of a main part of the magnetic memory according to the first embodiment of the present invention.

FIG. 3 is a conceptual diagram showing a sectional structure of a main part of a magnetic memory according to a second embodiment of the present invention, and FIG. 3B is a sectional view taken along the line AA ′ of FIG. is there.

FIG. 4 is a perspective view of essential parts of a magnetic memory according to a second embodiment of the present invention.

FIG. 5 is a perspective view showing a main part of a magnetic memory in which a tapered portion TW is provided in a portion of a coating layer adjacent to a wiring.

FIG. 6 is a conceptual diagram showing a sectional structure of a main part of a magnetic memory according to a third embodiment of the present invention, and FIG. 6B is a sectional view taken along the line AA ′ of FIG. is there.

FIG. 7 is a perspective view of essential parts of a magnetic memory according to a third embodiment of the present invention.

FIG. 8 is a conceptual diagram showing a cross-sectional structure of a main part of a magnetic memory according to a fourth embodiment of the present invention, and FIG.
It is the sectional view on the AA 'line of the figure (a).

FIG. 9 is a perspective view of essential parts of a magnetic memory according to a fourth embodiment of the present invention.

FIG. 10 is a conceptual diagram illustrating the matrix configuration of the magnetic memory of the present invention.

FIG. 11 is a conceptual diagram showing another specific example of the matrix configuration of the magnetic memory of the present invention.

FIG. 12 is a graph showing the distribution of the magnetic field generated from the write wiring 22 in the example of the present invention.

FIG. 13 is a graph showing the distribution of the magnetic field generated from the write wiring 22 in the example of the present invention.

[Explanation of symbols]

11 Memory element part 12 Transistor part for selection 21 Magnetoresistive element 22 bit line 23 word lines 24 Lower electrode 26 beer 30 transistors 32 gates (word line) 34 bit line 34 word lines 50 column decoder 51 row decoder 52 sense amplifier 60 decoder D diode M magnetic field P protrusion SM coating layer T, TW, TT taper part

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[Procedure amendment]

[Submission date] January 28, 2002 (2002.1.2
8)

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Correction target item name] All drawings

[Correction method] Change

[Correction content]

[Figure 1]

[Fig. 2]

[Figure 3]

[Figure 4]

[Figure 5]

[Figure 6]

[Figure 7]

[Figure 8]

[Figure 9]

[Figure 10]

FIG. 11

[Fig. 12]

[Fig. 13]

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Minoru Amano             1st Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa             Inside the Toshiba Research and Development Center (72) Inventor Shigeki Takahashi             1st Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa             Inside the Toshiba Research and Development Center (72) Inventor Katsuya Nishiyama             1st Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa             Inside the Toshiba Research and Development Center (72) Inventor Tomomasa Ueda             1st Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa             Inside the Toshiba Research and Development Center (72) Inventor Hiroaki Yasuda             1st Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa             Inside the Toshiba Research and Development Center (72) Inventor Yoshiaki Asao             8th Shinsugita Town, Isogo Ward, Yokohama City, Kanagawa Prefecture             Ceremony company Toshiba Yokohama office (72) Inventor Yoshihisa Iwata             1st Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa             Ceremony Company Toshiba Microelectronics Sen             Inside F term (reference) 5F083 FZ10 GA15 LA12 LA16 PR40

Claims (11)

[Claims] 1. A first write wiring comprising: a magnetoresistive effect element having a magnetic recording layer; and a first write wiring extending in a first direction above or below the magnetoresistive effect element. The direction of magnetization of the magnetic recording layer is made variable by a magnetic field formed by applying a current to the first write wiring, and the first write wiring has a coating layer made of a magnetic material on at least one of both side surfaces thereof. In the cross section perpendicular to the first direction, the coating layer has a thickness at a tip portion closest to the magnetoresistive effect element smaller than a thickness at other portions. 2. A magnetoresistive effect element having a magnetic recording layer, and a first write wiring extending in a first direction above or below the magnetoresistive effect element. The direction of magnetization of the magnetic recording layer is made variable by a magnetic field formed by applying a current to the first write wiring, and the first write wiring has a coating layer made of a magnetic material on at least one of both side surfaces thereof. In the magnetic memory, the width of the coating layer in the first direction is narrower at a tip portion closest to the magnetoresistive effect element than at a portion other than the tip portion. 3. A magnetoresistive effect element having a magnetic recording layer, and a first write wiring extending in a first direction above or below the magnetoresistive effect element, wherein the first write wiring is provided. The direction of magnetization of the magnetic recording layer is made variable by a magnetic field formed by applying a current to the first write wiring, and the first write wiring has a coating layer made of a magnetic material on at least one of both side surfaces thereof. In the cross section perpendicular to the first direction, the coating layer has a thickness at a tip portion closest to the magnetoresistive effect element smaller than a thickness at other portions, and the coating layer is the first layer. The magnetic memory is characterized in that the width viewed in the direction is narrower at the tip portion closest to the magnetoresistive effect element than at the other portions. 4. The coating layer has a taper portion whose thickness is gradually reduced toward the magnetoresistive element in a cross section perpendicular to the first direction. 1. The magnetic memory according to 1 or 3. 5. The magnetic layer according to claim 1, wherein the coating layer has a taper portion in which the width is gradually narrowed toward the magnetoresistive effect element. memory. 6. The coating layer according to claim 1, wherein the coating layer has a protrusion that protrudes from the first write wiring toward the magnetoresistive effect element. Magnetic memory. 7. The magnetic memory according to claim 6, wherein the protrusion is provided so as to be inclined from the side surface of the first write wiring toward the magnetoresistive effect element. 8. The magnetic memory according to claim 6, wherein at least a part of the projecting portion has a taper portion whose thickness is gradually reduced toward the magnetoresistive element. 9. At least a part of the protruding portion has a taper portion whose width is gradually narrowed toward the magnetoresistive effect element.
2. The magnetic memory according to any one of 1. 10. A second line intersecting the first write line.
Further comprising a second write wiring extending in the direction of, wherein the magnetoresistive effect element is disposed at an intersection of the first write wiring and the second write wiring sandwiched by these wirings, 10. The magnetization direction of the magnetic recording layer is made variable by a magnetic field formed by applying a current to each of the first and second write wirings.
2. The magnetic memory according to any one of 1. 11. The second write wiring has a coating layer made of a magnetic material on at least one of both side surfaces thereof and a surface opposite to the magnetoresistive effect element. Magnetic memory.