CN113450849B - Magnetic storage unit, data writing method, memory and device - Google Patents

Abstract

The invention provides a magnetic storage unit, a data writing method, a memory and equipment, wherein the magnetic storage unit comprises a spin orbit coupling layer and a plurality of magnetic tunnel junctions arranged on the spin orbit coupling layer, the sizes of the magnetic tunnel junctions are different, and the distance length between two adjacent magnetic tunnel junctions is in a nanometer level; when currents with different current densities are respectively input to the spin orbit coupling layer along two opposite directions of the arrangement directions of the plurality of magnetic tunnel junctions, the combinations of the resistance states of the plurality of magnetic tunnel junctions are different, and the data writing of the plurality of magnetic tunnel junctions of a single layer can be realized through one-time current input.

Description

Magnetic storage unit, data writing method, memory and device

technical field

The invention relates to the technical field of semiconductors, in particular to a magnetic storage unit, a data writing method, a memory and a device.

Background technique

With the continuous shrinking of semiconductor process dimensions, Moore's Law slows down, and the increase of leakage current and interconnection delay become the bottleneck of traditional CMOS memory. Finding a new generation of storage technology solutions has become the focus of integrated circuit research, and magnetic random access memory has received extensive attention. Compared with traditional devices, Magnetic random access memory (MRAM) has the advantages of unlimited erasing times, non-volatility, fast read and write speed, and radiation resistance. and cache ideal device. A magnetic tunnel junction (Magnetic tunnel junction, MTJ) is a basic storage unit of a magnetic random access memory. The size of the magnetic tunnel junction can be reduced to below 40nm, which is expected to achieve high-density integration.

In this context, researchers have proposed a multi-level cell (Multi-level cell, MLC) composed of more than one MTJ to further increase the storage density of large-capacity storage applications. MLC needs to strictly adjust the characteristics of each MTJ to achieve a Different threshold switch current and resistance states with sufficient margin. A typical MLC is realized by connecting MTJs on two planes in series. These MTJs connected in series have different areas. The manufacturing process usually involves multi-step etching, the process is complicated, and it is difficult to achieve data one-step write.

Contents of the invention

An object of the present invention is to provide a magnetic memory cell, which can realize data writing of multiple magnetic tunnel junctions in a single layer through one current input. Another object of the present invention is to provide a data writing method for a magnetic storage unit. Another object of the present invention is to provide a magnetic random access memory. Another object of the present invention is to provide a computer device.

In order to achieve the above object, the present invention discloses a magnetic memory unit on the one hand, comprising a spin-orbit coupling layer and a plurality of magnetic tunnel junctions arranged on the spin-orbit coupling layer, and the size of the plurality of magnetic tunnel junctions is The distance between two different and adjacent magnetic tunnel junctions is nanoscale;

When currents with different current densities are respectively input into the spin-orbit coupling layer along two opposite directions of the alignment direction of the plurality of magnetic tunnel junctions, the combinations of the resistance states of the plurality of magnetic tunnel junctions are different.

Preferably, the plurality of magnetic tunnel junctions include a first magnetic tunnel junction and a second magnetic tunnel junction, and the arrangement direction of the first magnetic tunnel junction and the second magnetic tunnel junction includes both the first direction and the second direction. an opposite current input direction;

When a current of a first current density is input into the spin-orbit coupling layer along the first direction, the resistance state of the first magnetic tunnel junction is the first resistance state, and the resistance state of the second magnetic tunnel junction is is the first resistance state;

When a current of a second current density is input into the spin-orbit coupling layer along the first direction, the resistance state of the first magnetic tunnel junction is the first resistance state, and the resistance state of the second magnetic tunnel junction is is the second resistance state;

When a current with a third current density is input into the spin-orbit coupling layer along the second direction, the resistance state of the first magnetic tunnel junction is the second resistance state, and the resistance state of the second magnetic tunnel junction is is the second resistance state;

When a current with a fourth current density is input to the spin-orbit coupling layer along the second direction, the resistance state of the first magnetic tunnel junction is the second resistance state, and the resistance state of the second magnetic tunnel junction is is the first resistance state.

Preferably, the sizes of the plurality of magnetic tunnel junctions increase or decrease sequentially along the arrangement direction of the plurality of magnetic tunnel junctions.

Preferably, the first magnetic tunnel junction and the second magnetic tunnel junction have in-plane anisotropy.

Preferably, the shape of the first magnetic tunnel junction and/or the second magnetic tunnel junction is one of ellipse, triangle, rectangle and semicircle.

Preferably, at least one of the first magnetic tunnel junction and the second magnetic tunnel junction has perpendicular anisotropy;

The magnetic memory unit further includes an applied magnetic field set corresponding to the magnetic tunnel junction with vertical anisotropy or the magnetic tunnel junction with vertical anisotropy has an equivalent applied magnetic field.

Preferably, the shape of the magnetic tunnel junction with perpendicular anisotropy is circular or square.

Preferably, the storage unit includes a magnetic field generating device that provides the external magnetic field or is equivalent to the external magnetic field; or,

The first magnetic tunnel junction and/or the second magnetic tunnel junction includes a fixed layer, a barrier layer and a free layer arranged in sequence from top to bottom, at least one of the fixed layer, the barrier layer and the free layer The cross section of is trapezoidal, is used for providing described external magnetic field; Or,

The material of the spin-orbit coupling layer is an antiferromagnetic material, and the spin-orbit coupling layer and the free layer form an exchange bias field for providing the external magnetic field; or,

The magnetic tunnel junction includes a magnetic material layer for providing the external magnetic field; or,

The magnetic tunnel junction has a shape capable of forming a shape anisotropic field for providing an equivalent magnetic field of the applied magnetic field; or,

The free layer has a gradient vertical anisotropy for providing an equivalent magnetic field to the applied magnetic field.

The present invention also discloses a data writing method of the above-mentioned magnetic storage unit, comprising:

Determine the input direction and current density of the current according to the data combination to be written, the input direction is one of the two opposite directions of the arrangement direction of the plurality of magnetic tunnel junctions;

Inputting current into the spin-orbit coupling layer according to the input direction so that the combination of the plurality of magnetic tunnel junction resistance states corresponds to the combination of the data to be written.

The invention also discloses a magnetic random access memory, which comprises a plurality of the above-mentioned magnetic storage units arranged in an array.

The invention also discloses a computer device, including a memory, a processor, and a computer program stored in the memory and operable on the processor,

The processor and/or the memory comprise a magnetic storage unit as described above.

In the present invention, by setting the distance between multiple magnetic tunnel junctions on the spin-orbit coupling layer, the distance between two adjacent magnetic tunnel junctions among the multiple magnetic tunnel junctions is maintained at the nanometer level, and the multiple magnetic tunnel junctions arranged at the nanoscale distance It can be regarded as a plurality of small magnets/nanojunctions arranged, so that the magnetic memory unit can be equivalent to a magnetic quantum cellular automaton (Magnetic Quantum-dotCellular Automata, MQCA). Then, magnetic dipolar interactions (magnetic dipolar interactions) between the magnets are formed between the multiple magnetic tunnel junctions arranged on the magnetic memory unit, and the ferromagnetism of the small magnets/nanojunctions can make the magnetic properties of the free layer of the adjacent magnetic tunnel junctions The dynamic behaviors influence each other to realize data transfer or calculation. When currents of different current densities are respectively input into the spin-orbit coupling layer along two opposite directions of the direction in which the plurality of magnetic tunnel junctions are arranged, the combinations of the resistance states of the first magnetic tunnel junction and the second magnetic tunnel junction are different. , realizing the writing of any data combination of the first magnetic tunnel junction and the second magnetic tunnel junction forming a two-bit (bit) memory unit, the present invention realizes the data writing of multiple magnetic tunnel junctions of a single layer through a current input, reducing The process complexity of the memory cell.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. Those skilled in the art can also obtain other drawings based on these drawings without creative work.

Fig. 1 shows the schematic diagram of a specific embodiment of the magnetic storage unit of the present invention;

Fig. 2 shows the top view of a specific embodiment of the magnetic storage unit of the present invention;

Fig. 3 shows a schematic diagram of a specific embodiment of the magnetic memory cell of the present invention including three magnetic tunnel junctions;

Fig. 4 shows the flowchart of a specific embodiment of the data writing method of the magnetic storage unit of the present invention;

FIG. 5 shows a schematic structural diagram of a computer device suitable for implementing an embodiment of the present invention.

detailed description

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

According to an aspect of the present invention, the embodiment discloses a magnetic storage unit. As shown in FIG. 1 and FIG. 2, in this embodiment, the magnetic memory unit includes a spin-orbit coupling layer A1 and a plurality of magnetic tunnel junctions arranged on the spin-orbit coupling layer A1, and the plurality of magnetic The sizes of the tunnel junctions are different, and the distance d between two adjacent magnetic tunnel junctions is on the order of nanometers.

Wherein, when currents with different current densities are respectively input into the spin-orbit coupling layer A1 along two opposite directions of the alignment direction of the plurality of magnetic tunnel junctions, the combinations of the resistance states of the plurality of magnetic tunnel junctions are different.

In the present invention, by setting the spacing of multiple magnetic tunnel junctions on the spin-orbit coupling layer A1, the spacing between two adjacent magnetic tunnel junctions among the multiple magnetic tunnel junctions is maintained at the nanometer level, and the multiple magnetic tunnels arranged at the nanoscale spacing The junction can be regarded as a plurality of small magnets/nanojunctions arranged, so that the magnetic memory unit can be equivalent to a magnetic quantum cellular automaton (Magnetic Quantum-dot Cellular Automata, MQCA). Then, magnetic dipolar interactions (magnetic dipolar interactions) between magnets are formed between the multiple magnetic tunnel junctions arranged on the magnetic memory unit, and the ferromagnetism of the small magnets/nanojunctions can make the adjacent magnetic tunnel junction free layer B1 The magnetodynamic behavior interacts with each other to realize data transmission or calculation. When currents of different current densities are respectively input into the spin-orbit coupling layer A1 along two opposite directions of the direction in which the plurality of magnetic tunnel junctions are arranged, the first magnetic tunnel junction MTJ1 and the second magnetic tunnel junction MTJ2 are in a resistance state. The combination of the two is different, and the first magnetic tunnel junction MTJ1 and the second magnetic tunnel junction MTJ2 are realized to form the writing of any combination of data in the two-bit (bit) storage unit. The present invention realizes the multiple magnetic tunnel junctions of a single layer through a current input. Data writing reduces the process complexity of the storage unit.

It should be noted that the ferromagnetic dipolar interactions (magnetic dipolar interactions) refer to that when the distance between the small magnets/magnetic tunnel junctions is very close, the ferromagnetism of the small magnets/nanojunctions leads to mutual influence on the magnetodynamic behavior. Magnetic quantum dot cellular automata (Magnetic Quantum-dot Cellular Automata, MQCA) refers to a structure that uses specific arrangements of small magnets/nanojunctions and utilizes the iron-dipole interaction between magnets to achieve data transmission or calculation.

In a preferred embodiment, as shown in FIG. 1, the plurality of magnetic tunnel junctions include a first magnetic tunnel junction MTJ1 and a second magnetic tunnel junction MTJ2, and the first magnetic tunnel junction MTJ1 and the second magnetic tunnel junction The arrangement direction of the junction MTJ2 includes two opposite current input directions, the first direction and the second direction.

Specifically, when the current J1 of the first current density is input into the spin-orbit coupling layer A1 along the first direction, the resistance state of the first magnetic tunnel junction MTJ1 is the first resistance state, and the second The resistance state of the magnetic tunnel junction MTJ2 is the first resistance state; when the current J2 of the second current density is input to the spin-orbit coupling layer A1 along the first direction, the resistance state of the first magnetic tunnel junction MTJ1 is is the first resistance state, and the resistance state of the second magnetic tunnel junction MTJ2 is the second resistance state; when the current J3 of the third current density is input to the spin-orbit coupling layer A1 along the second direction, the The resistance state of the first magnetic tunnel junction MTJ1 is the second resistance state, and the resistance state of the second magnetic tunnel junction MTJ2 is the second resistance state; when inputting When the current J4 of the fourth current density is used, the resistance state of the first magnetic tunnel junction MTJ1 is the second resistance state, and the resistance state of the second magnetic tunnel junction MTJ2 is the first resistance state.

In a specific example, as shown in Figure 1, the spin-orbit coupling layer A1 includes a length direction along the x-axis of the rectangular coordinate system and a width direction along the y-axis of the rectangular coordinate system, and two magnetic tunnel junctions are along the spin-orbit coupling layer The length direction of A1 is arranged. Wherein, the length direction includes opposite first direction and second direction. The two ends of the spin-orbit coupling layer A1 in the length direction are respectively provided with a first electrode S3 and a second electrode S4 for inputting current +Ix and −Ix into the spin-orbit coupling layer A1 along the first direction and the second direction respectively. Wherein, Hex is the direction of the external magnetic field or the equivalent external magnetic field. The distance d between the first magnetic tunnel junction MTJ1 and the second magnetic tunnel junction MTJ2 is on the order of nanometers, that is, d is a small distance of several nanometers, and the distance between the first magnetic tunnel junction MTJ1 and the second magnetic tunnel junction MTJ2 is very close, so that the second There is an iron-dipole interaction in the first magnetic tunnel junction MTJ1 and the second magnetic tunnel junction MTJ2, and the writing of specific data combinations of multiple magnetic tunnel junctions in a single layer can be realized through one current input, reducing the process complexity of the memory cell .

It can be understood that, in a preferred embodiment, at least one of the first magnetic tunnel junction MTJ1 and the second magnetic tunnel junction MTJ2 may include a pinned layer B3 and a barrier layer B2 sequentially arranged from top to bottom and free layer B1. The bottom surface of the free layer B1 is fixedly connected to the spin-orbit coupling layer A1. The resistance of the magnetic tunnel junction depends on the magnetization directions of the pinned layer B3 and the free layer B1, and the magnetization directions of the free layer B1 and the pinned layer B3 are determined by the magnetic moment directions. Wherein, when the magnetic moment direction of the fixed layer B3 is the same as that of the free layer B1, the magnetic tunnel junction is in a low resistance state (low resistance state), and when the magnetic moment direction of the fixed layer B3 is opposite to that of the free layer B1, the magnetic tunnel junction is in a high resistance state (high impedance state). The high-resistance state and low-resistance state of the magnetic tunnel junction can be pre-corresponded to different data, for example, the high-resistance state is preset to correspond to the data "+1", and the low-resistance state is corresponding to the data "-1", then by reading Take the circuit to input current or voltage to the magnetic tunnel junction. According to the change of current or voltage, it can be determined whether the resistance state of the magnetic tunnel junction is a high resistance state or a low resistance state. According to the resistance state of the magnetic tunnel junction, the magnetic tunnel junction can be determined Whether the data stored in is "+1" or "-1". Wherein, the range of the high resistance state and the low resistance state is determined as a common technical means in this field, and those skilled in the art can determine the resistance value range of the magnetic tunnel junction high resistance state and low resistance state according to the common knowledge, and the present invention is no longer repeat.

Thus, by setting the magnetic moment direction of the pinned layer B3 and the corresponding relationship between the high-resistance state and the low-resistance state of the magnetic tunnel junction and the logic numbers "-1" and "+1", it is possible to make the spin When the orbit coupling layer A1 respectively inputs the current J1 of the first current density and the current J2 of the second current density and respectively inputs the current J4 of the third current density J3 and the fourth current density into the spin-orbit coupling layer A1 along the second direction, the first The combinations of the resistance states of the magnetic tunnel junction MTJ1 and the second magnetic tunnel junction MTJ2 are different, that is, the logical digital combinations "-1, -1", "-1, +1", "+1, +1" and " +1, -1 "four kinds of 2bit data combinations, as shown in Table 1, realize the writing of any data combination of the first magnetic tunnel junction MTJ1 and the second magnetic tunnel junction MTJ2 forming a two-bit (bit) memory cell, through One-time current input realizes data writing of multiple magnetic tunnel junctions in a single layer, reducing the process complexity of the memory cell. In practical applications, the corresponding relationship between the magnetic moment direction of the pinned layer B3 and the magnetic tunnel junction resistance state and the logic number can be adjusted so that the currents J1~ At J4, write storage of the corresponding data combination is realized.

Table 1

It can be understood that the directions of the magnetic moments of the free layer B1 of the first magnetic tunnel junction MTJ1 and the second magnetic tunnel junction MTJ2 respectively face the first magnetic easy axis and the second magnetic easy axis under the action of the spin-orbit coupling layer A1 input current. axis deflection, wherein the first easy axis includes opposite first and second magnetic moment directions, and the second easy axis includes opposite third and fourth magnetic moment directions, according to the current of the input current Depending on the direction and current density, the deflection direction of the magnetic moment direction of the free layer B1 of the first magnetic tunnel junction MTJ1 and the second magnetic tunnel junction MTJ2 is different. In a specific example, when the first current density J1 and the current J2 of the second current density are respectively input into the spin-orbit coupling layer A1 along the first direction and the third current is respectively input into the spin-orbit coupling layer A1 along the second direction Density J3 and current J4 of the fourth current density, the magnetic moment directions of the first magnetic tunnel junction MTJ1 and the second magnetic tunnel junction MTJ2 free layer B1 are respectively "the first magnetic moment direction and the third magnetic moment direction", "the second magnetic moment direction" The first magnetic moment direction and the fourth magnetic moment direction", "the second magnetic moment direction and the fourth magnetic moment direction" and "the second magnetic moment direction and the third magnetic moment direction", the first magnetic tunnel junction MTJ1 can be preset The direction of the magnetic moment of the pinned layer B3 and the second magnetic tunnel junction MTJ2 realizes writing and storage of different data combinations. For example, assume that the magnetic moment directions of the pinned layer B3 of the first magnetic tunnel junction MTJ1 and the second magnetic tunnel junction MTJ2 are respectively the first magnetic moment direction and the third magnetic moment direction. Then, after inputting the current J1 of the first current density into the spin-orbit coupling layer A1 along the first direction, the magnetic moment direction of the fixed layer B3 of the first magnetic tunnel junction MTJ1 is the same as that of the free layer B1, and the first magnetic tunnel junction MTJ1 is low-resistance state, the second magnetic tunnel junction MTJ2 pinned layer B3 has the same magnetic moment direction as the free layer B1, and the second magnetic tunnel junction MTJ2 is in a low-resistance state; input a current with a second current density to the spin-orbit coupling layer A1 along the first direction After J2, the magnetic moment direction of the first magnetic tunnel junction MTJ1 fixed layer B3 is the same as that of the free layer B1, the first magnetic tunnel junction MTJ1 is in a low resistance state, and the magnetic moment direction of the second magnetic tunnel junction MTJ2 fixed layer B3 and free layer B1 On the contrary, the second magnetic tunnel junction MTJ2 is in a high-resistance state; after the current J3 of the third current density is input to the spin-orbit coupling layer A1 along the second direction, the first magnetic tunnel junction MTJ1 fixes the magnetic moments of the layer B3 and the free layer B1 The direction is opposite, the first magnetic tunnel junction MTJ1 is in a high resistance state, the magnetic moment direction of the second magnetic tunnel junction MTJ2 fixed layer B3 is opposite to that of the free layer B1, and the second magnetic tunnel junction MTJ2 is in a high resistance state; After the spin-orbit coupling layer A1 inputs the current J4 of the fourth current density, the magnetic moment direction of the fixed layer B3 of the first magnetic tunnel junction MTJ1 is opposite to that of the free layer B1, the first magnetic tunnel junction MTJ1 is in a high resistance state, and the second magnetic tunnel junction The MTJ2 pinned layer B3 has the same magnetic moment direction as the free layer B1, and the second magnetic tunnel junction MTJ2 is in a low resistance state. Further, if the low-resistance state of the preset magnetic tunnel junction corresponds to the logic number "-1", and the high-resistance state corresponds to the logic number "+1", then input the first current density to the spin-orbit coupling layer A1 along the first direction After J1 and the current J2 of the second current density and the current J4 of the third current density J3 and the fourth current density are respectively input into the spin-orbit coupling layer A1 along the second direction, "-1, -1", " -1, +1", "+1, +1" and "+1, -1" four data combination storage.

It should be noted that, in this preferred embodiment, the magnetic memory unit includes two magnetic tunnel junctions. In other embodiments, the magnetic storage unit may also include other numbers of magnetic tunnel junctions. For example, the magnetic storage unit shown in FIG. 3 includes three magnetic tunnel junctions arranged in sequence, and the present invention does not limit the number of magnetic tunnel junctions. .

In a preferred embodiment, the sizes of the plurality of magnetic tunnel junctions increase or decrease sequentially along the arrangement direction of the plurality of magnetic tunnel junctions. It can be understood that the distance d between two adjacent magnetic tunnel junctions among the plurality of magnetic tunnel junctions may be the same or different. For example, in the magnetic storage unit as shown in FIG. 3, d ₁ and d ₂ may be the same or different, as long as they are kept at the nanometer level, which is not limited in the present invention. The size of the plurality of magnetic tunnel junctions increases or decreases sequentially along the arrangement direction of the plurality of magnetic tunnel junctions, so that the iron-dipole interaction of the plurality of magnetic tunnel junctions arranged in sequence increases or decreases sequentially, which is convenient for the magnetic storage unit The design of achievable data transfer or computation.

In a preferred embodiment, the first magnetic tunnel junction MTJ1 and the second magnetic tunnel junction MTJ2 have in-plane anisotropy. It can be understood that, for a magnetic tunnel junction with in-plane anisotropy, the magnetic moment direction of the free layer B1 of the magnetic tunnel junction can be deflected toward the easy axis under the action of a SOT (Spin-orbit torque, SOT) current.

Preferably, the shape of the first magnetic tunnel junction MTJ1 and/or the second magnetic tunnel junction MTJ2 may be one of ellipse, triangle, rectangle and semicircle, as shown in FIG. 3 . It can be understood that the shapes of the first magnetic tunnel junction MTJ1 and the second magnetic tunnel junction MTJ2 are preferably elliptical, and the long axis of the elliptical shape is the magnetic easy axis. Then, when the current is input into the spin-orbit coupling layer A1, based on the SOT principle, the final direction of the magnetic moment direction of the free layer B1 after the current input ends is the direction of the easy axis. In other embodiments, rectangles, triangles and semicircles can also achieve the same effect. In practical applications, those skilled in the art can flexibly set the shapes of the first magnetic tunnel junction MTJ1 and the second magnetic tunnel junction MTJ2 according to the requirements. The technical solution of the junction magnetic storage unit should also fall within the protection scope of the present invention.

In other embodiments, at least one of the first magnetic tunnel junction MTJ1 and the second magnetic tunnel junction MTJ2 has perpendicular anisotropy. It can be understood that, one or both of the first magnetic tunnel junction MTJ1 and the second magnetic tunnel junction MTJ2 may also adopt a magnetic tunnel junction with vertical anisotropy. For a magnetic tunnel junction with perpendicular anisotropy, the magnetic memory unit further includes an applied magnetic field set corresponding to the magnetic tunnel junction with perpendicular anisotropy or an equivalent applied magnetic field for the magnetic tunnel junction with perpendicular anisotropy magnetic field. For example, in a specific example, the shape of the first magnetic tunnel junction MTJ1 is circular, and the shape of the second magnetic tunnel junction MTJ2 is elliptical. Wherein, the first magnetic tunnel junction MTJ1 has perpendicular anisotropy, and the second magnetic tunnel junction MTJ2 has in-plane anisotropy. Therefore, the random memory cell of this specific example needs to set an external magnetic field or an equivalent external magnetic field corresponding to the first magnetic tunnel junction MTJ1, so that the first magnetic tunnel junction MTJ1 can generate a magnetic field after the spin-orbit coupling layer A1 inputs current. The corresponding change in the direction of the moment.

For the magnetic tunnel junction whose shape is oval, triangular, rectangular or semicircular, the shape of the magnetic tunnel junction is not completely symmetrical, and the shape anisotropy of the magnetic tunnel junction can replace the effect of the external magnetic field. For circular or square magnetic tunnel junctions, it is necessary to set an external magnetic field or to make the circular or square magnetic tunnel junction free layer B1 subject to the effect of an equivalent external magnetic field by setting the structure of the magnetic tunnel junction, for example, the circular A shaped or square magnetic tunnel junction includes a fixed layer B3, a barrier layer B2, and a free layer B1 arranged sequentially from top to bottom. The cross section of the free layer B1 or the barrier layer B2 can be trapezoidal. By setting the trapezoidal Section to form an equivalent external magnetic field.

In an optional embodiment, the external magnetic field or equivalent external magnetic field in the magnetic storage unit can be realized in various ways. Specifically, an external magnetic field or an equivalent external magnetic field can be formed by at least one of the following methods:

The storage unit includes a magnetic field generating device that provides the external magnetic field or is equivalent to the external magnetic field;

The magnetic tunnel junction includes a fixed layer B3, a barrier layer B2, and a free layer B1 arranged sequentially from top to bottom, and at least one of the fixed layer B3, the barrier layer B2, and the free layer B1 has a trapezoidal cross-section. To provide said equivalent external magnetic field;

The material of the spin-orbit coupling layer A1 is an antiferromagnetic material, and the spin-orbit coupling layer A1 and the free layer B1 form an exchange bias field for providing the equivalent external magnetic field;

The magnetic tunnel junction includes a magnetic material layer (such as a Co layer) for providing the equivalent external magnetic field;

The magnetic tunnel junction has a shape capable of forming a shape anisotropic field (inhomogeneous demagnetizing field) for providing the equivalent applied magnetic field. In some embodiments, the magnetic tunnel junction can be in the shape of a rectangle, an ellipse, or an isosceles right angle. Taking an ellipse as an example, the demagnetization field in the direction of the long axis is weaker than that in the direction of the short axis, and the demagnetization field can be equivalent to an external magnetic field;

The free layer B1 has a gradient vertical anisotropy for providing an equivalent magnetic field of the applied magnetic field. Specifically, when making the magnetic tunnel junction, the concentration of the target can be adjusted so that the free layer B1 has a gradient perpendicular anisotropy, which further breaks the symmetry of the magnetic moment distribution and can be used to provide an equivalent external magnetic field.

It should be noted that the magnetic field generating device or an equivalent device capable of forming an external magnetic field is a conventional technical means in the field, and those skilled in the art can flexibly set it according to requirements, so details are not repeated here. In addition, the cross-section of at least one of the fixed layer B3, the barrier layer B2 and the free layer B1 is trapezoidal, the antiferromagnetic material and the free layer B1 are used to form an exchange bias field, and the magnetic material layer is arranged to provide an external magnetic field. . In practical applications, the external magnetic field can also be formed in other feasible ways, which is not limited in the present invention.

In a preferred embodiment, in order to adjust the vertical anisotropy of the magnetic tunnel junction and the smoothness of each layer, the magnetic tunnel junction can also include layer structures such as an insertion layer, a pinning layer, a seed layer, and a capping layer. at least one. Wherein, the arrangement of each layer structure can be arranged in one or more layers according to actual needs, and those skilled in the art can set the arrangement order of each layer structure of the magnetic tunnel junction from top to bottom according to requirements, which is not limited in the present invention.

In a preferred embodiment, the magnetic storage unit further includes a control module, which is used to determine the input direction and current density of the current according to the combination of data to be written, the input direction is the arrangement of the plurality of magnetic tunnel junctions One of two opposite directions of the direction. Input current to the spin-orbit coupling layer A1 according to the input direction so that the combination of the resistance states of the first magnetic tunnel junction MTJ1 and the second magnetic tunnel junction MTJ2 corresponds to the combination of data to be written. It can be understood that the current input direction and the current input direction can be determined according to the current input direction, current density and data combination corresponding to the different data combinations stored in the predetermined first magnetic tunnel junction MTJ1 and the second magnetic tunnel junction MTJ2. According to the input direction, a current corresponding to the current density is input to the spin-orbit coupling layer A1 so that the combinations of the resistance states of the first magnetic tunnel junction MTJ1 and the second magnetic tunnel junction MTJ2 are different, so as to realize the to-be-written Deterministic writing of data combinations.

In a preferred embodiment, the magnetic storage unit further includes a reading module, which can apply a detection current to the first magnetic tunnel junction MTJ1 and the second magnetic tunnel junction MTJ2, and determine the first Logical numbers stored in the magnetic tunnel junction MTJ1 and the second magnetic tunnel junction MTJ2. Specifically, as shown in FIG. 1, the reading module can input detection currents to the first magnetic tunnel junction MTJ1 and the second magnetic tunnel junction MTJ2 through the interface S1 and the interface S2 respectively, and the resistance state of the magnetic tunnel junction is a high resistance state or a low resistance state. Resistance state, the detection current flows through the high-resistance state and the low-resistance state of the magnetic tunnel junction. Data reading. It should be noted that the interface S1 and the interface S2 can be different interfaces, and input independent detection currents to the first magnetic tunnel junction MTJ1 and the second magnetic tunnel junction MTJ2 respectively to read data; the interface S1 and the interface S2 can also be the same At the same time, input the detection current to the first magnetic tunnel junction MTJ1 and the second magnetic tunnel junction MTJ2 to read data respectively, or input the detection current to the first magnetic tunnel junction MTJ1 and the second magnetic tunnel junction MTJ2 to read data respectively , those skilled in the art can set the interface S1 and interface S2 according to actual needs, and those skilled in the art can also set the specific circuit structure of the control module and the reading module according to actual needs, which are conventional technical means in the field, and will not be repeated here. .

Preferably, the spin-orbit coupling layer A1 can be rectangular, so that the top surface area of the spin-orbit coupling layer A1 is larger than the area occupied by the multiple magnetic tunnel junctions arranged on the spin-orbit coupling layer A1, even if multiple magnetic tunnel junctions Junctions may be provided on the spin-orbit coupling layer A1 such that the outer edges of the plurality of magnetic tunnel junctions are located inside the outer edges of the spin-orbit coupling layer A1 . Among them, the spin-orbit coupling layer A1 is preferably a heavy metal strip film or an antiferromagnetic strip film.

It should be noted that the number of magnetic tunnel junctions on the spin-orbit coupling layer A1 can be two or more than two. Preferably, multiple magnetic tunnel junctions can be arranged on the same spin-orbit coupling layer A1, which can realize The one-time data writing operation to multiple magnetic tunnel junctions can reduce the number of control transistors that input the spin-orbit moment current, thereby improving integration and reducing circuit power consumption.

In a preferred embodiment, a top electrode may be provided on the top of the magnetic tunnel junction, and a current input electrode and an output electrode may be respectively provided on opposite sides of the spin-orbit coupling layer A1 for detecting the input of current and spin-orbit moment current. Wherein, preferably, the material of the electrode may be any one of tantalum Ta, aluminum Al, gold Au or copper Cu.

Preferably, the material of the free layer B1 and the pinned layer B3 can be a ferromagnetic metal, and the material of the barrier layer B2 can be an oxide. Wherein, the ferromagnetic metal may be a mixed metal material formed of at least one of materials such as cobalt-iron-CoFe, cobalt-iron-boron CoFeB, or nickel-iron NiFe, and the ratio of the mixed metal materials may be the same or different. The oxide can be one of oxides such as magnesium oxide MgO or aluminum oxide Al2O3, which is used to generate tunneling magnetoresistance effect. In practical applications, ferromagnetic metals and oxides can also use other feasible materials, which are not limited in the present invention.

The free layer B1 of the magnetic tunnel junction is fixed in contact with the spin-orbit coupling layer A1, and the layers of the magnetic tunnel junction and the spin-orbit coupling layer A1 can be formed by conventional methods such as ion beam epitaxy, atomic layer deposition, or magnetron sputtering. It is plated on the substrate sequentially from bottom to top, and then two or more magnetic tunnel junctions are formed by traditional nano-device processing techniques such as photolithography and etching.

In a preferred embodiment, the spin-orbit coupling layer A1 is a spin-orbit coupling layer A1 made of a heavy metal film, an antiferromagnetic film or other materials. The heavy metal thin film or antiferromagnetic thin film can be made into a rectangle, and its top area is preferably larger than the bottom area of the outline formed by all magnetic tunnel junctions, so that two or more magnetic tunnel junctions can be set, and the shape of the bottom surface of the magnetic tunnel junction is completely embedded The shape of the top surface of the heavy metal thin film or antiferromagnetic thin film. Preferably, the material of the spin-orbit coupling layer A1 may be one of platinum Pt, tantalum Ta or tungsten W and the like. In practical applications, the spin-orbit coupling layer A1 may also be formed using other feasible materials, which is not limited in the present invention.

In this embodiment, the first magnetic tunnel junction MTJ1 and/or the second magnetic tunnel junction MTJ2 include a pinned layer B3 on the top, a free layer B1 in contact with the spin-orbit coupling layer A1, and a layer located on the pinned layer B3 and the Referring to the barrier layer B2 between the free layers B1, the magnetic tunnel junction has a three-layer structure, including only one free layer B1. In other embodiments, there may be multiple free layers B1, ie more than two free layers B1. The magnetic tunnel junction includes a fixed layer B3 at the top, a plurality of free layers B1 and a barrier layer B2 disposed between two adjacent layers, and the bottom free layer B1 is disposed in contact with the spin-orbit coupling layer A1. For example, in a specific example, when two free layers B1 are included, the magnetic memory cell structure may include a spin-orbit coupling layer A1, a second free layer B1 sequentially disposed on the spin-orbit coupling layer A1, a potential The barrier layer B2, the first free layer B1, the potential barrier layer B2 and the pinned layer B3.

To sum up, the magnetic memory cell of the present invention can realize the writing of a specific 2-bit data combination through one current writing, without considering the initial resistance state in the magnetic tunnel junction, the first magnetic tunnel junction MTJ1 and the second magnetic tunnel junction MTJ2 The final resistance state of is determined only by the direction of the input current. Among them, the present invention uses the spin-orbit moment current to write data, and the writing speed is fast and the power consumption is low. The magnetic tunnel junction of the present invention can adopt a completely symmetrical and regular shape, which is beneficial to the continuous miniaturization of the size of the magnetic random memory device and improves the storage density. In addition, the spin-orbit coupling layer A1 of the present invention can adopt a rectangular regular shape, without processing the spin-orbit coupling layer A1 , and can be manufactured without complex processes, thereby reducing process requirements.

Based on the same principle, this embodiment also discloses a data writing method for a magnetic storage unit. As shown in Figure 4, the method includes:

S100: Determine a current input direction and a current density according to the combination of data to be written, the input direction being one of two opposite directions of the arrangement directions of the plurality of magnetic tunnel junctions.

S200: Input a current into the spin-orbit coupling layer according to the input direction so that a combination of the plurality of magnetic tunnel junction resistance states corresponds to the combination of data to be written.

Specifically, when the magnetic storage unit further includes a control module, the input direction and current density of the current can be determined by the control module according to the combination of data to be written, and the input direction is two directions of the arrangement directions of the plurality of magnetic tunnel junctions. one of the opposite directions. Input current to the spin-orbit coupling layer A1 according to the input direction so that the combination of the resistance states of the first magnetic tunnel junction MTJ1 and the second magnetic tunnel junction MTJ2 corresponds to the combination of data to be written. It can be understood that the current input direction and the current input direction can be determined according to the current input direction, current density and data combination corresponding to the different data combinations stored in the predetermined first magnetic tunnel junction MTJ1 and the second magnetic tunnel junction MTJ2. According to the input direction, a current corresponding to the current density is input to the spin-orbit coupling layer A1 so that the combinations of the resistance states of the first magnetic tunnel junction MTJ1 and the second magnetic tunnel junction MTJ2 are different, so as to realize the to-be-written Deterministic writing of data combinations.

In a preferred embodiment, when the magnetic storage unit further includes a readout module, a detection current can be applied to the first magnetic tunnel junction MTJ1 and the second magnetic tunnel junction MTJ2 through the readout module, and according to the variation of the detection current The logic numbers stored in the first magnetic tunnel junction MTJ1 and the second magnetic tunnel junction MTJ2 are determined. Specifically, as shown in FIG. 1, the reading module can input detection currents to the first magnetic tunnel junction MTJ1 and the second magnetic tunnel junction MTJ2 through the interface S1 and the interface S2 respectively, and the resistance state of the magnetic tunnel junction is a high resistance state or a low resistance state. Resistance state, the detection current flows through the high-resistance state and the low-resistance state of the magnetic tunnel junction. Data reading. It should be noted that the interface S1 and the interface S2 can be different interfaces, and input independent detection currents to the first magnetic tunnel junction MTJ1 and the second magnetic tunnel junction MTJ2 respectively to read data; the interface S1 and the interface S2 can also be the same At the same time, input the detection current to the first magnetic tunnel junction MTJ1 and the second magnetic tunnel junction MTJ2 to read data respectively, or input the detection current to the first magnetic tunnel junction MTJ1 and the second magnetic tunnel junction MTJ2 to read data respectively , those skilled in the art can set the interface S1 and interface S2 according to actual needs, and those skilled in the art can also set the specific circuit structure of the control module and the reading module according to actual needs, which are conventional technical means in the field, and will not be repeated here. .

Since the problem-solving principle of this method is similar to that of the magnetic storage unit above, the implementation of this method can refer to the implementation of the magnetic storage unit above, and will not be repeated here.

Based on the same principle, this embodiment also discloses a magnetic random access memory. The magnetic random access memory includes a plurality of magnetic storage units as described in this embodiment arranged in an array.

Magnetic random access memory includes permanent and non-permanent, removable and non-removable media, and information storage can be realized by any method or technology. Information may be computer readable instructions, data structures, modules of a program, or other data. Examples of MRAM applications include, but are not limited to, Random Access Memory (RAM), Read Only Memory (ROM), Electrically Erasable Programmable Read Only Memory (EEPROM), Flash or other memory technologies, Read Only Compact disc read-only memory (CD-ROM), digital versatile disc (DVD) or other optical storage, magnetic tape cartridge, magnetic magnetic disk storage or other magnetic storage device or any other non-transmission medium that can be used to store information that can be read by a computing device access information.

Since the problem-solving principle of the MRAM is similar to that of the magnetic storage unit above, the implementation of the MRAM can refer to the implementation of the above-mentioned magnetic storage unit, and will not be repeated here.

Based on the same principle, this embodiment also discloses a computer device, including a memory, a processor, and a computer program stored in the memory and operable on the processor.

The processor and/or the memory include the magnetic storage unit as described in this embodiment.

The magnetic storage unit described in the above embodiments can be specifically arranged in a product device with a certain function. A typical implementing device is a computer device. Specifically, the computer device can be, for example, a personal computer, a laptop computer, a cellular phone, a camera phone, a smart phone, a personal digital assistant, a media player, a navigation device, an email device, Game consoles, tablets, wearables, or a combination of any of these devices.

In a typical example, the computer device specifically includes a memory, a processor, and a computer program stored on the memory and operable on the processor. The processor and/or the memory include the magnetic storage as described in this embodiment. unit.

Referring now to FIG. 5 , it shows a schematic structural diagram of a computer device suitable for implementing the embodiments of the present application.

As shown in FIG. 5 , the computer device includes a central processing unit (CPU) 601, which can operate according to a program stored in a read-only memory (ROM) 602 or a program loaded from a storage section 608 into a random-access memory (RAM) 603 And perform various appropriate work and processing. Various programs and data necessary for system operation are also stored in RAM 603 . The CPU 601 , ROM 602 , and RAM 603 are connected to each other via a bus 604 . An input/output (I/O) interface 605 is also connected to the bus 604 .

The following components are connected to the I/O interface 605: an input section 606 including a keyboard, a mouse, etc.; an output section 607 including a cathode ray tube (CRT), a liquid crystal feedback device (LCD), etc., and a speaker; a storage section including a hard disk, etc. 608; and a communication section 609 including a network interface card such as a LAN card, a modem, or the like. The communication section 609 performs communication processing via a network such as the Internet. A drive 610 is also connected to the I/O interface 605 as needed. A removable medium 611 such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, etc. is mounted on the drive 610 as necessary so that a computer program read therefrom is installed as the storage section 608 as necessary.

The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It should be understood that each procedure and/or block in the flowchart and/or block diagram, and a combination of procedures and/or blocks in the flowchart and/or block diagram can be realized by computer program instructions. These computer program instructions may be provided to a general purpose computer, special purpose computer, embedded processor, or processor of other programmable data processing equipment to produce a machine such that the instructions executed by the processor of the computer or other programmable data processing equipment produce a An apparatus for realizing the functions specified in one or more procedures of the flowchart and/or one or more blocks of the block diagram.

These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing apparatus to operate in a specific manner, such that the instructions stored in the computer-readable memory produce an article of manufacture comprising instruction means, the instructions The device realizes the function specified in one or more procedures of the flowchart and/or one or more blocks of the block diagram.

These computer program instructions can also be loaded onto a computer or other programmable data processing device, causing a series of operational steps to be performed on the computer or other programmable device to produce a computer-implemented process, thereby The instructions provide steps for implementing the functions specified in the flow chart or blocks of the flowchart and/or the block or blocks of the block diagrams.

It should also be noted that the term "comprises", "comprises" or any other variation thereof is intended to cover a non-exclusive inclusion such that a process, method, article, or apparatus comprising a set of elements includes not only those elements, but also includes Other elements not expressly listed, or elements inherent in the process, method, commodity, or apparatus are also included. Without further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article or apparatus comprising said element.

Those skilled in the art should understand that the embodiments of the present application may be provided as methods, systems or computer program products. Accordingly, the present application can take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application finds application in the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) having computer-usable program code embodied therein.

This application may be described in the general context of computer-executable instructions, such as program modules, being executed by a computer. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types. The application may also be practiced in distributed computing environments where tasks are performed by remote processing devices that are linked through a communications network. In a distributed computing environment, program modules may be located in both local and remote computer storage media including storage devices.

Each embodiment in this specification is described in a progressive manner, the same and similar parts of each embodiment can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, as for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and for the related parts, please refer to the part of the description of the method embodiment.

The above descriptions are only examples of the present application, and are not intended to limit the present application. For those skilled in the art, various modifications and changes may occur in this application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the scope of the claims of the present application.

Claims (10)

1. A magnetic memory unit, characterized in that, comprising a spin-orbit coupling layer and a plurality of magnetic tunnel junctions arranged on the spin-orbit coupling layer, the plurality of magnetic tunnel junctions have different sizes and are adjacent to each other The pitch length of each magnetic tunnel junction is nanoscale; When currents of different current densities are respectively input into the spin-orbit coupling layer along two opposite directions of the alignment direction of the plurality of magnetic tunnel junctions, the combinations of resistance states of the plurality of magnetic tunnel junctions are different; The multiple magnetic tunnel junctions include a first magnetic tunnel junction and a second magnetic tunnel junction, and the arrangement directions of the first magnetic tunnel junction and the second magnetic tunnel junction include two opposite directions of the first direction and the second direction. Current input direction; When a current of a first current density is input into the spin-orbit coupling layer along the first direction, the resistance state of the first magnetic tunnel junction is the first resistance state, and the resistance state of the second magnetic tunnel junction is is the first resistance state; When a current of a second current density is input into the spin-orbit coupling layer along the first direction, the resistance state of the first magnetic tunnel junction is the first resistance state, and the resistance state of the second magnetic tunnel junction is is the second resistance state; When a current with a third current density is input into the spin-orbit coupling layer along the second direction, the resistance state of the first magnetic tunnel junction is the second resistance state, and the resistance state of the second magnetic tunnel junction is is the second resistance state; When a current with a fourth current density is input to the spin-orbit coupling layer along the second direction, the resistance state of the first magnetic tunnel junction is the second resistance state, and the resistance state of the second magnetic tunnel junction is is the first resistance state. 2 . The magnetic memory unit according to claim 1 , wherein the sizes of the plurality of magnetic tunnel junctions increase or decrease sequentially along the arrangement direction of the plurality of magnetic tunnel junctions. 3. The magnetic memory cell according to claim 1, wherein the first magnetic tunnel junction and the second magnetic tunnel junction have in-plane anisotropy. 4. The magnetic memory unit according to claim 3, wherein the shape of the first magnetic tunnel junction and/or the second magnetic tunnel junction is one of ellipse, triangle, rectangle and semicircle kind. 5. The magnetic memory unit according to claim 1, wherein at least one of the first magnetic tunnel junction and the second magnetic tunnel junction has perpendicular anisotropy; The magnetic memory unit further includes an applied magnetic field set corresponding to the magnetic tunnel junction with vertical anisotropy or the magnetic tunnel junction with vertical anisotropy has an equivalent applied magnetic field. 6 . The magnetic memory unit according to claim 5 , wherein the shape of the magnetic tunnel junction with perpendicular anisotropy is a circle or a square. 7. The magnetic storage unit according to claim 5, wherein the storage unit comprises a magnetic field generating device that provides the applied magnetic field or is equivalent to the applied magnetic field; or, The first magnetic tunnel junction and/or the second magnetic tunnel junction includes a fixed layer, a barrier layer and a free layer arranged in sequence from top to bottom, at least one of the fixed layer, the barrier layer and the free layer The cross section of is trapezoidal, is used for providing described external magnetic field; Or, The material of the spin-orbit coupling layer is an antiferromagnetic material, and the spin-orbit coupling layer and the free layer form an exchange bias field for providing the external magnetic field; or, The magnetic tunnel junction includes a magnetic material layer for providing the external magnetic field; or, The magnetic tunnel junction has a shape capable of forming a shape anisotropic field for providing an equivalent magnetic field of the applied magnetic field; or, The free layer has a gradient vertical anisotropy for providing an equivalent magnetic field to the applied magnetic field. 8. A method for writing data into the magnetic storage unit according to any one of claims 1-7, comprising: Determine the input direction and current density of the current according to the data combination to be written, the input direction is one of the two opposite directions of the arrangement direction of the plurality of magnetic tunnel junctions; Inputting current into the spin-orbit coupling layer according to the input direction so that the combination of the plurality of magnetic tunnel junction resistance states corresponds to the combination of the data to be written. 9. A magnetic random access memory, characterized in that it comprises a plurality of magnetic storage units according to any one of claims 1-7 arranged in an array. 10. A computer device comprising a memory, a processor and a computer program stored on the memory and operable on the processor, The processor and/or the memory comprises the magnetic storage unit according to any one of claims 1-7.

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