JP4533701B2 - Magnetic memory - Google Patents

Description

  The present invention relates to a magnetic memory.

  Magnetoresistive random access memory (hereinafter also referred to as MRAM (Magneto Resistive Random Access Memory)) is expected and developed as an ultimate memory having non-volatility, high speed, large capacity, and low voltage drive. However, it has been found that this MRAM has difficulty in realizing large capacity, high speed, and low voltage driving due to a large write current value and a large variation in writing.

  For example, in order to construct a 32 Mbit class MRAM, it is necessary to reduce the area ratio occupied by the peripheral circuit and increase the memory array occupation ratio. For this purpose, the array block size as a unit is required to be a 1 Mbit array. However, since the write current value is as large as several mA-10 mA at present, a voltage of the order of 2V is generated at both ends of the write wiring resistance, and it is not possible to reduce the voltage of the order of 1V. It is difficult to start up at high speed, and a high-speed memory cannot be realized.

  In addition, if the width of a tunnel junction element (hereinafter also referred to as MTJ (Magnetic Tunneling Junction)), which is a memory element included in each cell of the MRAM, is made fine in order to increase the capacity (high integration), resistance to thermal disturbance. However, it is difficult to secure non-volatility.

  Further, in a method in which a write current is supplied to both the bit line and the word line as usual and only the MTJ located at the intersection is written, erroneous writing of the MTJ cell in the half-selected state other than the intersection occurs. It is difficult to ensure non-volatility. That is, since the writing margin is narrow, erroneous writing occurs or it is difficult to ensure non-volatility.

  The reversal magnetic field Hsw necessary for rewriting the magnetization information of the recording layer constituting the MTJ is given as follows.

Hsw to 4πMs × t / F (Oe) (1)
Magnetic anisotropy energy density Ku at this time is approximately Ku = Hsw · Ms / 2 (2)
It becomes. Here, Ms is the saturation magnetization of the recording layer, t is the thickness of the recording layer, and F is the width of the recording layer.

On the other hand, the thermal disturbance resistance of the recording layer is expressed by magnetic energy Ku × V, where V is the volume of the recording layer. Therefore, in the MTJ having a recording layer aspect ratio (length / width) of 2, the thermal disturbance resistance is
Ku × V = (Hsw · Ms / 2) × V
= (4πMs × t / F) × (Ms / 2) × F × 2F × t = 4πMs ² × t ² × F
= Hsw ² × F ³ / (4π)
It becomes. Therefore, when the MTJ is miniaturized, that is, when the width F of the recording layer is reduced, it is necessary to increase the reversal magnetic field Hsw in order to ensure thermal disturbance resistance.

  Since the recording layer width F is about 0.4 μm and a write current of about 8 mA is required, the write current further increases with miniaturization. In order to write at a high speed of about 10 nsec when the capacity is increased, it is necessary to reduce the write current value to about 1.5 mA or less, and to reduce the size of the peripheral circuit, the value should be about 0.5 mA or less. preferable.

As a measure to reduce the write current, a wiring with a yoke in which the write wiring (Cu) is coated with a soft magnetic material such as NiFe was proposed, and a double efficiency improvement effect (write current value 1/2) was reported. (For example, refer nonpatent literature 1). However, 1/2 (about 4 mA) is said to be the limit, and is far from the target of 1 mA or less.
Magnetoresistive RAM, Saied Tehrani, 2001 IEDM short course

  As described above, in the conventional MRAM, high-speed writing is realized by greatly reducing the write current value, non-volatility is ensured even when the capacity is increased, that is, the width of the MTJ is reduced, and writing is performed. It is necessary to enlarge the margin.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a magnetic memory capable of increasing the capacity and writing at high speed.

A magnetic memory according to one embodiment of the present invention includes a magnetic recording layer in which the magnetization direction changes according to an external magnetic field, a magnetization fixed layer in which the magnetization direction is fixed, and a gap between the magnetic recording layer and the magnetization fixed layer. a memory element having a non-magnetic intermediate layer provided, the write wiring flowing provided write current on the opposite side of the nonmagnetic intermediate layer of the magnetic recording layer, wherein on the opposite side of the magnetic recording layer of the write wiring A memory cell including a yoke having a planar shape different from the planar shape of the magnetic recording layer provided along a direction in which the write wiring extends, wherein the major axis of the magnetic recording layer extends in the direction in which the write wiring extends. up and are tilted at an angle smaller than the larger 90 degrees above 0 degrees relative to a direction perpendicular, planar shape of the magnetic recording layer, the direction of the central portion perpendicular to the direction of extension of the write wiring And the write wiring of the part where both ends in the major axis direction are cut out and the both ends are cut off in a shape in which opposite sides along the major axis direction of the magnetic recording layer are curved extending side along a direction constitute a pair of opposite side faces, each with a respective opposed pair of side surfaces of the opposed pair of side surfaces is the write wiring and the yoke of the storage elements identical It is configured to be a flat surface.

  According to the present invention, it is possible to increase the capacity and write at high speed.

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

(First embodiment)
A magnetic memory (hereinafter also referred to as MRAM (Magneto Resistive Random Access Memory)) according to a first embodiment of the present invention will be described with reference to FIG. The magnetic memory according to this embodiment includes a plurality of memory cells. FIG. 1A is a cross-sectional view showing the configuration of the memory cell of the magnetic memory of this embodiment. Each memory cell includes a tunnel junction element 2 (hereinafter also referred to as MTJ (Magnetic Tunneling Junction)) as a storage element. The MTJ 2 has a magnetic recording layer 4 whose magnetization direction is variable according to an external magnetic field, a tunnel barrier layer 6, a magnetization fixed layer 8 whose magnetization direction is fixed, and a magnetization direction of the magnetization fixed layer 8 that is fixed. The antiferromagnetic layer 10 is provided. The magnetic recording layer 4 of the MTJ 2 is provided on the write wiring 20. The write wiring 20 is provided on a yoke 25 made of a soft magnetic material that increases the magnetic flux generated by the current flowing through the write wiring 20.

  That is, in the present embodiment, the yoke 25, the write wiring 20, the magnetic recording layer 4, the tunnel barrier layer 6, the magnetization pinned layer 8, and the antiferromagnetic layer 10 are stacked. Then, the end surfaces of the write wiring 20 and the yoke 25 (the left and right end surfaces on FIG. 1A), the magnetic recording layer 4, the tunnel barrier layer 6, and the magnetization fixed in the direction orthogonal to the current flowing through the write wiring 20. The layer 8 and the end faces of the antiferromagnetic layer 10 (left and right end faces in FIG. 1A) are arranged on the same plane. That is, the yoke 25, the write wiring 20, the magnetic recording layer 4, the tunnel barrier layer 6, the magnetization pinned layer 8, and the antiferromagnetic layer 10 have the same width W. In the present embodiment, the yoke 25, the write wiring 20, the magnetic recording layer 4, the tunnel barrier layer 6, the magnetization pinned layer 8, and the antiferromagnetic layer 10 are stacked in this order, but the stacked order is reversed. It may be used.

  Further, in the present embodiment, the relative permeability of the yoke 25 is about 100, and the material of the yoke 25 is selected so that the magnetization direction of the yoke 25 is approximately parallel or antiparallel to the write current. In the present embodiment, the magnetization direction of the magnetic recording layer 4 is substantially orthogonal to the write current flowing through the write wiring 20.

  In this embodiment, when data is written in the memory cell, a write current is passed through the write wiring 25 and a write bit line (not shown) substantially orthogonal to the write wiring 25, and the magnetic recording layer of the MTJ is generated by the magnetic field generated by this current. This is done by reversing the magnetization of 4. Further, when reading data from the memory cell, is it performed by applying a voltage between a read wiring (not shown) electrically connected to the antiferromagnetic layer 10 and the write wiring 20 and measuring a current flowing through the MTJ 2? Alternatively, a constant current is passed between the read wiring and the write wiring 20 and the voltage between the read wiring and the write wiring 20 is measured.

  Usually, it is said that forming a yoke on the write wiring doubles the current / magnetic field conversion efficiency, and the write current value is halved, but this is the limit. When the yoke is formed in the write wiring and the MTJ width W is 240 nm, the write current value is expected to be about 6 mA.

Hereinafter, the magnitude of the write current of this embodiment will be described. As described above, in this embodiment, the end face of the yoke 25 and the write wiring 20 and the end face of the MTJ 2 are arranged on the same plane. The film thicknesses of the magnetic recording layer 4, the write wiring 20, and the yoke 25 are T ₁ , T ₂ , and T ₃ , respectively, and the relative magnetic permeability of the magnetic recording layer 4, the write wiring 20, and the yoke 25 are μ ₁ , Assuming that μ ₂ (= 1) and μ ₃ , the effective length Leff of the magnetic path of the magnetic closed circuit 30 indicated by the wavy line in FIG.
Leff = 2 × T2 + W / μ ₁ + W / μ ₃
It becomes. Here, when W = 240 nm, T2 = 20 nm, and μ ₁ = 5 and μ ₃ = 100, the magnetic path length (W / μ ₃ ) on the yoke side can be almost ignored. The effective magnetic path length Leff of the circuit 30 is about 88 nm.

  On the other hand, in the ordinary write wiring with yoke, unlike the present embodiment, the end face of the yoke and the write wiring and the end face of the MTJ are not arranged on the same plane, so that a 50 nm alignment error is allowed. Margins are required on both sides. Since the write wiring and the MTJ magnetic recording layer are separated by 50 nm or more by an insulating layer or the like, the effective magnetic path length is approximately 360 nm or more.

  On the other hand, in this embodiment, the alignment margin is not necessary, and the magnetic path length on the yoke side can be ignored. Therefore, the effective magnetic path length Leff of the magnetic closed circuit 30 is about 88 nm. When the same current is supplied to the memory cell of this embodiment and the memory cell having a normal write wiring with a yoke, the magnetic field generated in each memory cell by this write current is inversely proportional to the magnetic path length.

  For this reason, the magnitude of the magnetic field generated in the memory cell of this embodiment is 4.09 (= 360/88) times as large as the magnitude of the magnetic field generated in the memory cell having a normal write wiring with a yoke. Become. That is, the current / magnetic field conversion efficiency is increased by 4.09 times. This means that the write current value can be reduced to 1 / 4.09 = 0.24. As a result, the write current value of the memory cell of this embodiment can be reduced from 6 mA to 1.5 mA compared to a memory cell having a normal write wiring with a yoke.

Furthermore, when the film thickness T ₂ of the write wiring 6 is 10 nm, the effective magnetic path length Leff is W / 5 + 2 × T _{2 to} 68 nm, which can be reduced. Compared with a memory cell having a normal write wiring with a yoke, the current / magnetic field conversion efficiency is increased 360/68 times, and the write current value can be reduced to 68/360 = 0.19 times. That is, the write current value is 1.1 mA.

Further, when the relative permeability μ ₁ of the magnetic recording layer 4 of MTJ2 is 10, the effective magnetic path length can be reduced to approximately W / 10 + 2 × T _{2 to} 44 nm, and the write current value is 0.73 mA. This value is reduced to a desired write current target value of 0.5 mA in order to reduce the peripheral circuit of the magnetic memory.

When the memory cell according to this embodiment was actually prototyped and verified so that W = 240 nm, T ₂ = 10 nm, μ ₁ = 10, and μ ₃ = 100, the write current value was about 1 mA. . This value was almost close to the target value (1 mA) desirable for realizing a high writing speed of about 10 nsec when the capacity of the magnetic memory was increased.

  In addition, an experiment on the non-volatility of the prototyped memory cell revealed that the non-volatility was greater than expected. This is presumed to be due to the coupling even when the magnetizations of the magnetic recording layer 4 of the MTJ 2 and the laminated yoke 25 are orthogonal. As a result, it has been found that the resistance to thermal disturbance is much improved as compared with the conventional MRAM. This is not known at all until now and became clear for the first time in this experiment.

  Considering the improvement of the thermal disturbance resistance, it has been found that non-volatility can be ensured even if the switching magnetic field of the magnetic recording layer 4 of MTJ2 is reduced to 1/5. As a result, the write current value of the memory cell according to the present embodiment is about 1/5 of the write current value of 0.73 mA calculated when the effective magnetic path length is approximately 44 nm, that is, 0.14 mA. Accordingly, the write current of a memory cell having a normal write wiring with a yoke can be significantly reduced from 6 mA to 0.14 mA. In order to reduce the peripheral circuit of the magnetic memory, the desired target value of 0.5 mA or less could be achieved.

As a result of careful analysis, the effect that the write current can be significantly reduced is not unique to the laminated yoke, and the magnetization direction of the yoke 25 is approximately parallel or anti-parallel to the write current (the relative permeability of the yoke 25 is set to 100). It was found that this can be realized by setting the relative permeability μ ₁ of the magnetic recording layer 4 of MTJ2 to 5 or more.

In the memory cell according to the present embodiment prepares three types of memory cells relative permeability mu ₁ of the magnetic recording layer 4 of MTJ2 is 1,5,10, Toru ratio of the yoke 25 for each of the memory cells when changing the permeability mu _3, Figure 2 shows the mean magnetic field generated Heff generated in the magnetic closed circuit 30 (Oe) shown in FIG. 1 (a). Graph g ₁ has a relative magnetic permeability μ ₁ of 10 for magnetic recording layer 4, graph g ₂ has a relative magnetic permeability μ ₁ of 5 for magnetic recording layer 4, and graph g ₃ has a relative magnetic permeability μ ₁ of 1 for magnetic recording layer 4. It is a characteristic view in the case of being.

As can be seen from this characteristic diagram, when the relative permeability μ ₃ of the yoke is near 100, for example, μ ₃ is in the range of 80 to 120, the average generated magnetic field Heff is substantially constant. In this case, the ratio of the magnetic recording layer 4 is If the permeability μ ₁ is 5 or more, the average generated magnetic field Heff is 35 Oe or more.

Generally, in order to maintain the non-volatility of the magnetic recording layer 4, the average generated magnetic field Heff is preferably 30 Oe or more. As can be seen from FIG. 2, when the relative permeability μ ₁ of the magnetic recording layer 4 is 5 or more and the relative permeability μ ₃ of the yoke 25 is 30 or more, the average generated magnetic field Heff is 30 Oe or more, and the magnetic recording layer 4 can be kept non-volatile.

  As described above, according to the present embodiment, the write current can be reduced, so that high-speed writing can be realized, and the resistance to thermal disturbance is high, so that non-volatility is ensured even when miniaturized. Can do. This makes it possible to increase the capacity and write at high speed.

(Second Embodiment)
Next, a magnetic memory according to a second embodiment of the present invention is described. The magnetic memory of this embodiment has a configuration in which the electromigration resistance of the write wiring 20 is improved in the magnetic memory of the first embodiment.

In the magnetic memory, electromigration of the write wiring 20 is a matter of concern. When the write current is 1 mA, the current density is 2 × 10 ⁷ A / cm ² when the width of the write wiring 20 is 240 nm and the thickness is 20 nm. This value is as large as 4 to 10 times the allowable value when Cu is used as the material of the write wiring 20. Even if the write current value can be 0.14 mA, the current density is 0.3 × 10 ⁷ A / cm ² , and the problem cannot be overcome. As a result of an experiment, it was found that, contrary to expectations, electromigration sometimes does not occur even at 2 × 10 ⁷ A / cm ² . This is because, when the write wiring 20 made of Cu is thinned to about 30 nm or less, a yoke material (NiFe, CoFe, CoZrNb), which is a high melting point material, is used for the yoke 25 serving as the base of the write wiring 20, or FIG. As shown in (b), when a metal layer 23 such as Ta or Ti is disposed at the interface between the write wiring 20 and the yoke 25, an MTJ layer is directly disposed on the upper surface of the write wiring 20 made of Cu. It turned out to be unique.

  Therefore, in the present embodiment, the film thickness of the write wiring 20 is reduced to 30 nm or less, and the use of a high melting point material as the material of the yoke 25 can prevent electromigration from occurring. In this case, it is preferable to provide a metal layer 23 of Ta, Ti or the like at the interface between the write wiring 20 and the yoke 25 as shown in FIG.

  In addition, this embodiment can increase the capacity and perform high-speed writing as in the first embodiment.

(Third embodiment)
Next, a magnetic memory according to a third embodiment of the present invention is described. The magnetic memory of this embodiment has a configuration in which a write selection transistor is arranged for each memory cell in the magnetic memory of the first or second embodiment. In the write selection transistor, one of the source and the drain is electrically connected to the write wiring 20 shown in FIG. 1A, and the gate serves as a word line for selecting a memory cell.

  By providing a write selection transistor for each memory cell as in this embodiment, it is possible to prevent a memory cell that is not selected from being in a half-selected state. For this reason, it becomes possible to reduce a reversal magnetic field to 1/2 or less of a reversal magnetic field when the improvement of thermal disturbance tolerance is considered. As a result, the write current value can be ½ of the write current value of 0.14 mA when considering the improvement of the thermal disturbance resistance, that is, about 0.1 mA. In addition, there is no writing malfunction, and a very wide margin can be secured for the writing circuit design.

  In addition, this embodiment can increase the capacity and perform high-speed writing as in the first embodiment.

By combining all the configurations of the first to third embodiments, the margin of the write circuit can be increased, the peripheral circuit can be simplified and miniaturized, and the occupation ratio of the memory array can be 65%, which is equivalent to that of a normal memory. did it. Further, even if the MTJ width is further reduced to about 100 nm, the write current value can be reduced to 0.5 mA, and even if a write transistor is added, the cell area can be reduced to 0.5 μm ² or less. . As a result, a high-speed, large-capacity MRAM exceeding 64 Mbits can be provided.

It was found that a memory cell having a slightly larger write current value was generated in the prototyped MRAM. FIG. 3 shows the result of estimating the magnetization process of the magnetic recording layer of the memory cell by experiment. While the write current value is small good memory cells in any applied magnetic field H the magnetization increases monotonically (see graph g _1), the memory cell becomes defective does not react magnetization M of the magnetic recording layer, it has stagnated that there is a region (see graph g ₂₎ was found.

  In order to avoid stagnating the magnetization M of the magnetic recording layer with respect to the applied magnetic field H, the magnetization direction (easy axis of magnetization) 5 of the magnetic recording layer 4 of the MTJ is relative to the applied magnetic field H as shown in FIG. It turned out to be effective if it was tilted rather than at right angles. Specifically, as shown in FIG. 5, the long side direction (magnetization easy axis 5) of the magnetic recording layer 4 is set with respect to the direction of the write current flowing through the write wiring 20 (that is, the direction in which the write wiring 20 extends). It is effective to arrange it so that it is not vertical but tilted. The inclination angle θ is preferably about 45 degrees. FIG. 5 is a plan view of the magnetic recording layer 4 and the write wiring 20.

  Further, the MTJ2 has a substantially cross shape as shown in FIG. 6A, or has an asymmetric shape (for example, a convex portion with respect to the axis in the width direction of the write wiring as shown in FIG. 6B). The same effect was also obtained with the inverted S-shape and S-shape provided at both ends. Further, as shown in FIGS. 6C and 6D, the same effect was obtained even when the central portion in the longitudinal direction of the magnetic recording layer 4 had the widest shape. In addition, FIG.6 (c) is the shape which cut | disconnected both ends, such as a rugby ball and an ellipse, and FIG.6 (d) is an octagonal shape.

(First embodiment)
Next, a magnetic memory according to a first embodiment of the present invention will be described with reference to FIG. FIG. 7 is a diagram showing the configuration of the memory cell of the magnetic memory according to this embodiment. The magnetic memory of this embodiment has a plurality of memory cells, and each memory cell includes an MTJ 2, a write wiring 20, a yoke 25, and a write selection transistor 60.

  The MTJ 2 includes a magnetic recording layer 4 provided on the write wiring 20, a tunnel barrier layer 6 provided on the magnetic recording layer 4, a magnetization pinned layer 8 provided on the tunnel barrier layer 6, and a magnetization pinned layer. 8 and an antiferromagnetic layer 10 provided on the substrate 8. The yoke 25 is provided in contact with the surface of the write wiring 20 opposite to the magnetic recording layer 4. The write selection transistor 60 includes a gate 62 that also serves as a word line, a source 64, and a drain 66. The write wiring 20 is electrically connected to the source 64 of the write selection transistor 60 via the yoke 25 and the connection portion 50.

  A write bit line 40 is provided on the opposite side of the yoke 25 from the write wiring 20 via an insulating film (not shown) so as to be substantially orthogonal to the write wiring 20. The write bit line 40 is provided immediately below MTJ2. Further, the antiferromagnetic layer 10 of MTJ2 is electrically connected to the read bit line 45 through the connection portion 42.

  In this example, similarly to the first embodiment, the end surfaces of the write wiring 20 and the yoke 25, the magnetic recording layer 4, the tunnel barrier layer 6, and the magnetization fixed in the direction orthogonal to the current flowing through the write wiring 20 are used. The layer 8 and the end face of the antiferromagnetic layer 10 are configured to be disposed on the same plane. Further, the planar shape of the magnetic recording layer 4 of the MTJ 2 is such that the long side direction of the magnetic recording layer 4 is not perpendicular to the direction of the write current flowing through the write wiring 20 as described with reference to FIG. Has been placed.

  In the magnetic memory of this embodiment configured as described above, when data is written in the memory cell, first, the write selection transistor 60 is turned on, and then a write current is passed through the write wiring 20 and the write bit line 40, A writing magnetic field is generated, and the magnetic field of the magnetic recording layer 4 is reversed by the writing magnetic field.

  When reading data from the memory cell, first, the write selection transistor 60 is turned on, and then a voltage is applied between the read bit line 45 and the drain 66 of the write selection transistor 60 to measure the current flowing through the MTJ2. Or a constant current is supplied from one of the read bit line 45 and the drain 66 of the write selection transistor 60 to the MTJ2, and the voltage between the read bit line 45 and the drain 66 of the write selection transistor 60 is measured. To do.

  Needless to say, the magnetic memory according to this embodiment can also be increased in capacity and written at high speed.

(Second embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS. 8 (a), (b) and (c). This embodiment is a method of manufacturing a memory cell according to the magnetic memory of the first embodiment shown in FIG. 7, and its manufacturing steps are shown in FIGS. 8 (a), 8 (b) and 8 (c).

  First, as shown in FIG. 8A, the yoke 25, the write wiring 20, the magnetic recording layer 4, the tunnel barrier layer 6, the magnetization pinned layer 8, and the antiferromagnetic layer 10 are sequentially stacked on a substrate (not shown). The yoke 25 is made of NiFe or amorphous CoZrNb, the write wiring 20 is made of Ru, Cu, or CuNx, the magnetic recording layer 4 is made of NiFe, and the tunnel barrier layer 6 is made of AlOx. The magnetization pinned layer 8 is made of CoFe, and the antiferromagnetic layer 10 is made of PtMn.

  Next, the lithography technique is used so that the laminated film composed of the yoke 25, the write wiring 20, the magnetic recording layer 4, the tunnel barrier layer 6, the magnetization pinned layer 8, and the antiferromagnetic layer 10 becomes the shape of the write wiring. Patterning is performed (see FIG. 8B).

  Next, the magnetic recording layer 4, the tunnel barrier layer 6, the magnetization pinned layer 8, and the antiferromagnetic layer 10 are patterned using a lithography technique, thereby forming the MTJ 2 on the write wiring 20 (FIG. 8C). reference).

  As in the first embodiment, the magnetic memory manufactured by the manufacturing method of the present example, the end surfaces of the write wiring 20 and the yoke 25 in the direction orthogonal to the current flowing through the write wiring 20, the magnetic recording layer 4, the tunnel The barrier layer 6, the magnetization pinned layer 8, and the end face of the antiferromagnetic layer 10 are configured to be disposed on the same plane. Further, the planar shape of the magnetic recording layer 4 of the MTJ 2 is such that the long side direction of the magnetic recording layer 4 is not perpendicular to the direction of the write current flowing through the write wiring 20 as described with reference to FIG. Be placed.

  For this reason, the magnetic memory manufactured by the manufacturing method of this embodiment can also be increased in capacity and written at high speed.

  As described above, according to each embodiment of the present invention, it is possible to increase the capacity and write at high speed.

Sectional drawing which shows the structure of the memory cell which concerns on the magnetic memory by 1st and 2nd embodiment of this invention. In the first embodiment, in the case where the relative permeability of the magnetic recording layer as a parameter, characteristic diagram showing the average generated magnetic field which is generated in the closed magnetic circuit with respect to the ratio permeability of the yoke. The figure which shows the change of magnetization of the magnetic-recording layer with respect to an applied magnetic field. The figure which shows the relationship between the easy axis of magnetization of the magnetic-recording layer which concerns on one Embodiment of this invention, and an applied magnetic field. The top view which shows arrangement | positioning with the magnetic-recording layer which concerns on one Embodiment of this invention, and write-in wiring. The figure which shows the planar shape of the magnetic-recording layer which concerns on one Embodiment of this invention. The figure which shows the structure of the magnetic memory by 1st Example of this invention. The perspective view which shows the manufacturing process of the manufacturing method of the magnetic memory by 2nd Example of this invention.

Explanation of symbols

2 MTJ
4 Magnetic recording layer 6 Tunnel barrier layer 8 Magnetization pinned layer 10 Antiferromagnetic layer 20 Write wiring 25 Yoke 30 Magnetic closed circuit

Claims (7)

A memory having a magnetic recording layer whose magnetization direction changes according to an external magnetic field, a magnetization fixed layer whose magnetization direction is fixed, and a nonmagnetic intermediate layer provided between the magnetic recording layer and the magnetization fixed layer Elements,
A write wiring provided on a side opposite to the nonmagnetic intermediate layer of the magnetic recording layer and through which a write current flows;
A yoke provided on the opposite side of the write wiring from the magnetic recording layer along the direction in which the write wiring extends, and having a planar shape different from the planar shape of the magnetic recording layer ;
Including a memory cell with
The major axis of the magnetic recording layer is inclined at an angle greater than 0 degrees and smaller than 90 degrees with respect to a direction orthogonal to the direction in which the write wiring extends, and the planar shape of the magnetic recording layer is the extension of the write wiring. A shape having a maximum width at a central portion in a direction orthogonal to the direction to be cut and a side opposite to the long axis direction of the magnetic recording layer being a curve, both ends in the long axis direction being cut off, Constituting a set of side surfaces facing the side surfaces along the direction in which the write wiring extends, of the part where both ends are cut off;
2. A magnetic memory according to claim 1, wherein the pair of opposing side surfaces of the memory element are coplanar with the opposing pair of side surfaces of the write wiring and the yoke, respectively.   2. The magnetic memory according to claim 1, wherein a major axis of the magnetic recording layer is inclined by 45 degrees with respect to a direction orthogonal to a direction in which the write wiring extends.   3. The magnetic memory according to claim 1, wherein a planar shape of the magnetic recording layer is asymmetric with respect to a direction orthogonal to a direction in which the write wiring extends.   4. The magnetic memory according to claim 1, wherein the magnetic recording layer has a relative permeability of 5 or more, and the yoke has a relative permeability of 80 to 120. 5.   5. The magnetic memory according to claim 4, wherein the yoke is made of any one of NiFe, CoFe, and CoZrNb, and the film thickness of the write wiring is 30 nm or less.   6. The magnetic memory according to claim 5, wherein a metal layer is provided between the write wiring and the yoke.   7. The magnetic memory according to claim 1, wherein the memory cell includes a selection transistor that selects the memory cell.

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