WO2021103852A1 - Spin orbit torque-based differential memory cell and manufacturing method therefor - Google Patents

Abstract

The present invention provides a spin orbit torque-based differential memory cell and a manufacturing method therefor. The memory cell comprises a spin orbit torque providing line, two magnetic layers, and two magnetic tunnel junctions having the same structure; the two magnetic layers are located on one side surface of the spin orbit torque providing line, and separately form a combination structure together with the spin orbit torque providing line; the two magnetic layers have anomalous Hall conductivity with opposite positive and negative signs; the two magnetic tunnel junctions are located on the other side surface of the spin orbit torque providing line opposite to the two magnetic layers, and the positions of the two magnetic tunnel junctions have one-to-one correspondence to the two magnetic layers. In the present invention, by using the two magnetic layers having the anomalous Hall conductivity with opposite positive and negative signs to separately form the combination structure together with the spin orbit torque providing line, the spin Hall angles of the two combination structures have opposite positive and negative signs, and the two magnetic tunnel junctions achieve the storage of differential data, and thus, the data storage density of a memory cell can be enhanced.

Description

Differential storage unit based on spin orbit moment and preparation method thereof Technical field

The invention relates to the technical field of magnetic memory, in particular to a spin-orbit moment-based differential storage unit and a preparation method thereof.

Background technique

Studies have found that when a current is applied to a material with a spin-orbit moment effect (Spin Orbit Torque, SOT), a spin-polarized spin current will be generated at the interface of the material, and this spin current can be used to flip the nanometer Magnets, such as the free layer in a magnetic tunnel junction MTJ. A new type of magnetic storage device based on spin-orbit moment and MTJ (which can be called SOT-MRAM memory) has the advantages of separation of reading and writing, fast writing speed, and low writing current density, and is considered to be the future development trend.

However, the SOT-MRAM storage unit is a three-terminal device, which occupies a larger area compared to the traditional STT-MRAM storage unit, resulting in lower data storage density. Therefore, how to improve the storage density of SOT-MRAM memory cells is an urgent technical problem to be solved.

Summary of the invention

In view of this, the present invention provides a spin-orbit moment-based differential storage unit and a preparation method thereof, which can improve the data storage density of the storage unit.

In the first aspect, the present invention provides a spin-orbit moment-based differential storage unit, including:

Spin orbit moment providing line;

Two magnetic layers, the two magnetic layers are located on one side surface of the spin orbital moment providing line, and respectively form a combined structure with the spin orbital moment providing line, and the two magnetic layers have opposite signs The abnormal Hall conductivity;

Two magnetic tunnel junctions with the same structure, the two magnetic tunnel junctions are located on the other side surface of the spin-orbit moment providing line opposite to the two magnetic layers, and are located at the same positions as the two magnetic layers. One-to-one correspondence.

Optionally, the magnetization directions of the two magnetic layers are in-plane magnetization.

Optionally, the material of the spin-orbit moment providing line includes one of Ti, Au, and Zr.

Optionally, the material of one of the magnetic layers includes one of Co, Fe, CoFe, and CoFeB, and the material of the other magnetic layer includes one of NiFe and NiCo.

Optionally, it further includes: two anti-oxidation layers, and the two anti-oxidation layers are respectively located between the two magnetic layers and the spin-orbit moment supply line.

Optionally, the anti-oxidation layer is made of the same material as the spin-orbit moment providing line.

In a second aspect, the present invention provides a method for manufacturing a spin-orbit moment-based differential memory cell, including:

Providing a substrate, and depositing a barrier layer on the substrate;

Forming two magnetic layers spaced apart on the barrier layer, the two magnetic layers having anomalous Hall conductivity with opposite signs;

Filling an insulating medium and performing a planarization treatment to form a smooth surface exposing the two magnetic layers;

Forming a spin orbit moment supply line on the smooth surface;

Two magnetic tunnel junctions are formed on the spin-orbit moment supply line, and the positions of the two magnetic tunnel junctions are in one-to-one correspondence with the two magnetic layers, respectively.

Optionally, the material of the spin-orbit moment providing line includes one of Ti, Au, and Zr.

Optionally, the material of one of the magnetic layers includes one of Co, Fe, CoFe, and CoFeB, and the material of the other magnetic layer includes one of NiFe and NiCo.

Optionally, the forming two magnetic layers on the barrier layer includes:

Depositing a first magnetic material layer and a first anti-oxidation material layer in sequence, spin-coating photoresist and performing a photolithography process to obtain a first photolithography pattern;

The first magnetic material layer and the first anti-oxidation material layer are etched according to the first photolithography pattern to form a first magnetic layer and a corresponding first anti-oxidation layer, and the first anti-oxidation layer remains after etching The photoresist on the top;

Sequentially depositing a second magnetic material layer and a second anti-oxidation material layer, spin-coating photoresist and performing a photolithography process to obtain a second photolithography pattern;

The second magnetic material layer and the second anti-oxidation material layer are etched according to the second photolithography pattern to form a second magnetic layer and a corresponding second anti-oxidation layer, and the first anti-oxidation layer is removed after etching The photoresist above and the photoresist above the second anti-oxidation layer.

Optionally, the forming two magnetic layers on the barrier layer includes:

Sequentially depositing a first magnetic material layer, a first anti-oxidation material layer and a first protective medium material layer, spin-coating photoresist and performing a photolithography process to obtain a first photolithography pattern;

The first magnetic material layer, the first anti-oxidation material layer, and the first protective medium material layer are etched according to the first photolithography pattern to form the first magnetic layer and the corresponding first anti-oxidation layer, first Protect the dielectric layer, remove the photoresist after etching;

Sequentially depositing a second magnetic material layer, a second anti-oxidation material layer and a second protective medium material layer, spin-coating photoresist and performing a photolithography process to obtain a second photolithography pattern;

The second magnetic material layer, the second anti-oxidation material layer, and the second protective dielectric material layer are etched according to the second photolithography pattern to form a second magnetic layer and the corresponding second anti-oxidation layer, second Protect the dielectric layer, and remove the photoresist after etching.

In the differential storage unit based on the spin orbit moment provided by the present invention, two magnetic layers form a combined structure with the spin orbit moment supply line respectively. When current is passed through the spin orbit moment supply line, the two magnetic layers have positive and negative effects. Anomalous Hall conductivity with opposite signs, the interface characteristics between the two magnetic layers and the spin-orbital moment supply line are opposite, and the spin Hall angles of the two combined structures have opposite signs, which makes the two magnetic tunnels The resistance value of the junction is opposite under different direction currents, which can realize differential storage and improve storage density. At the same time, the memory cell directly stacks two parallel MTJs on a metal layer to achieve a differential structure. Compared with the differential memory cell of the 2T2R structure, it reduces the use of gate transistors, source lines, word lines, bit lines, etc., and simplifies The array structure is improved, and the degree of integration is improved.

Description of the drawings

FIG. 1 is a schematic structural diagram of a spin-orbit moment-based differential memory cell according to an embodiment of the present invention;

FIG. 2 is a simplified schematic diagram of the structure of the storage unit shown in FIG. 1;

3 is a schematic structural diagram of a complete differential SOT-MRAM memory cell including the memory cell shown in FIG. 2;

4 is a schematic diagram of a writing process of a differential memory cell based on spin-orbit moments according to an embodiment of the present invention;

5 is a schematic structural diagram of a spin-orbit moment-based differential memory cell according to another embodiment of the present invention;

6A to 6H are schematic diagrams of the cross-sectional structure of each step of a method for fabricating a spin-orbit moment-based differential memory cell according to an embodiment of the present invention;

7A to 7H are schematic diagrams of the cross-sectional structure of each step of a method for fabricating a spin-orbit moment-based differential memory cell according to an embodiment of the present invention.

Detailed ways

In order to make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be described clearly and completely in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments It is only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

An embodiment of the present invention provides a spin-orbit moment-based differential storage unit, as shown in FIG. 1, including:

The spin orbit moment providing line 101 and the two magnetic layers 104 and 105 on one side surface of the spin orbit moment providing line 101, the two magnetic layers respectively form a combined structure with the spin orbit moment providing line 101, two The magnetic layer has an abnormal Hall conductivity with opposite signs;

It also includes: two magnetic tunnel junctions 102 and 103 with the same structure, and the two magnetic tunnel junctions 102 and 103 are located on the other side of the spin-orbit moment supply line 101 opposite to the two magnetic layers 104 and 105. The side surfaces and positions correspond to the two magnetic layers respectively.

Specifically, in FIG. 1, the magnetic tunnel junction 102 includes a free layer 1021, a barrier layer 1022, and a reference layer 1023 that are stacked, and the magnetic tunnel junction 103 includes a free layer 1031, a barrier layer 1032, and a reference layer 1033 that are stacked. The two magnetic tunnel junctions 104 and 105 are perpendicular magnetization structures or in-plane magnetization structures. The spin-orbit moment providing line 101 is close to the free layers 1021 and 1031 of the magnetic tunnel junctions 102 and 103, which are used to flip the free layers of the magnetic tunnel junctions 102 and 103. Provide the required spin-orbit moment. The in-plane magnetization of the two magnetic layers 104, 105, considering that the same magnetization direction is easier to achieve during preparation, in this embodiment, the two magnetic layers 104, 105 have the same in-plane magnetization direction, and the two magnetic layers 104, 105 have the same in-plane magnetization direction. It has an abnormal Hall conductivity with opposite signs, so that the combined structure of the first magnetic layer 104 and the spin-orbital moment providing line 101 is compared with the combined structure of the second magnetic layer 105 and the spin-orbital moment providing line 101. They have different interface characteristics, and the formed spin Hall angle has opposite signs, which in turn makes the free layer flipping of the two magnetic tunnel junctions opposite.

In this embodiment, the material of the spin-orbit moment providing line 101 includes one of Ti, Au, and Zr. The first magnetic layer 104 uses a magnetic material with an abnormal Hall conductivity of a positive value, such as Co, Fe, CoFe, CoFeB, and the second magnetic layer 105 uses a magnetic material with an abnormal Hall conductivity of a negative value, such as NiFe, NiCo.

For example, if the spin-orbit moment providing line 101 is made of Ti, the first magnetic layer 104 is made of CoFeB, the second magnetic layer 105 is made of NiFe, the free layer and the reference layer are made of CoFeB, and the barrier layer is made of MgO. For CoFeB /Ti/CoFeB/MgO structure, the resistance value changes from negative to positive, a positive current needs to be passed; the resistance value changes from positive to negative, and a negative current needs to be passed; for the NiFe/Ti/CoFeB/MgO structure, the resistance value changes from negative to negative Positive, negative current is required; resistance value changes from positive to negative, and positive current is required. It is precisely because the abnormal Hall conductivity of CoFeB is positive and the abnormal Hall conductivity of NiFe is negative, so that the spin Hall angle of CoFeB/Ti is positive, and the spin Hall angle of NiFe/Ti is negative. Furthermore, the resistance values of the two magnetic tunnel junctions are reversed.

To facilitate the analysis of the characteristics of the memory cell, the spin-orbital moment-based differential memory cell shown in Figure 1 is simplified to the form shown in Figure 2, where FM1 represents the first magnetic layer, FM2 represents the second magnetic layer, and FL represents Magnetic tunnel junction free layer, TBL stands for magnetic tunnel junction barrier layer, RL stands for magnetic tunnel junction reference layer, two magnetic tunnel junctions adopt perpendicular magnetization structure, free layer and reference layer are perpendicular magnetization, have the same perpendicular magnetization direction.

Figure 3 is a structural schematic diagram of a complete differential SOT-MRAM memory cell containing a memory cell read-write circuit. SA is a sense amplifier, BLW is a write bit line, BL/BLB is a pair of complementary bit lines, WL is a word line, SL It is the source line, and the write operation is: WL energizes the strobe transistor, BLW is energized, and SL is grounded. When the current flows through the spin orbit moment supply line, the resistance of the magnetic tunnel junction corresponding to FM1 and FM2 is opposite; the read operation is: WL Power on the strobe transistor, SL is energized, current flows through the two magnetic tunnel junctions, and the sensitive amplifier SA reads the data.

The specific writing process is as follows:

As mentioned earlier, the magnetic tunnel junction is magnetized perpendicularly, the anomalous Hall conductivity of FM1 is positive, and the anomalous Hall conductivity of FM2 is negative. As shown in Figure 4(a), in the initial state, the free layer and the reference layer are parallel, and the two magnetic tunnel junctions are both in a low resistance state (0); as shown in Figure 4(b), a positive current (+ I), the corresponding unit of FM1 becomes high-impedance state (1), and the resistance of the corresponding unit of FM2 remains unchanged (0); as shown in Figure 4(c), a negative current (-I) is applied, and the corresponding unit of FM1 becomes low Resistance state (0), the corresponding unit of FM2 becomes high resistance state (1). It can be seen that, in the case of currents in different directions, the resistance values of the corresponding units of FM1 and FM2 are opposite, and differential storage can be realized.

In the differential memory cell based on the spin-orbit moment provided by the embodiment of the present invention, two magnetic layers form a combined structure with the spin-orbit moment supply line respectively. When the current is passed through the spin-orbit moment supply line, the two magnetic layers have For abnormal Hall conductivity with opposite signs, the interface characteristics between the two magnetic layers and the spin-orbital moment supply line are opposite. The spin Hall angles of the two combined structures have opposite signs, which makes the two The resistance value of the magnetic tunnel junction is opposite under different direction currents, which can realize differential storage and improve storage density. At the same time, the memory cell directly stacks two parallel MTJs on a metal layer to achieve a differential structure. Compared with the differential memory cell of the 2T2R structure, it reduces the use of gate transistors, source lines, word lines, bit lines, etc., and simplifies The array structure is improved, and the degree of integration is improved.

In addition, it should be noted that, regarding the two magnetic tunnel junctions used in the embodiment of the present invention, the shape may be one of a circle, an ellipse, a square, a diamond, and a rectangle. The specific laminated structure can be realized in various forms, for example, the following structures can be adopted, including:

A free layer, where the free layer is located on a side surface of the spin-orbit moment providing line;

A barrier layer, the barrier layer is located on a side surface of the free layer away from the spin-orbit moment providing line;

A reference layer, where the reference layer is located on a side surface of the barrier layer away from the free layer;

A coupling layer, where the coupling layer is located on a side surface of the reference layer away from the barrier layer;

A pinning layer, the pinning layer is located on a side surface of the coupling layer away from the reference layer;

The protective layer is located on the side surface of the pinning layer away from the coupling layer.

That is, the free layer, the barrier layer, the reference layer, the coupling layer, the pinned layer, and the protective layer are stacked. The materials of the free layer and the reference layer include but are not limited to magnetic materials such as Co, CoFe, CoFeB, or Co/ Mo/CoFeB, CoFe/Mo/CoFeB and other synthetic magnetic materials formed by ferromagnetic or anti-ferromagnetic coupling, the material of the barrier layer includes but not limited to MgO, MgAl ₂ O ₄ and other materials. The material of the coupling layer includes but is not limited to materials such as Ru and Mo. The material of the pinning layer includes, but is not limited to, [Co/Pt]n, [Co/Pd]n, [CoFe/Pt]n and other materials. The material of the protective layer includes, but is not limited to, Ta, Pt and other materials.

When the above structure is adopted, the free layer, the reference layer, and the pinned layer are perpendicularly magnetized, and the two magnetic layers are in-plane magnetized to generate a bias magnetic field. This structure can achieve magnetic moment flipping without an external magnetic field, and the two memory cells are in The resistance value under different direction currents is opposite, which can realize differential storage.

In particular, if the memory cell structure shown in FIG. 1 is turned upside down, the same effect can still be obtained, and it is also within the protection scope of the present invention.

Further, on the basis of the memory cell structure shown in FIG. 1, in order to prevent oxidation of the first magnetic layer and the second magnetic layer during the manufacturing process, as shown in FIG. 5, the memory cell further includes a first anti-oxidation layer 106 and a second anti-oxidation layer 106. The second anti-oxidation layer 107, the first anti-oxidation layer 106 is located between the first magnetic layer 104 and the spin-orbit moment supply line 101, and is used to prevent the first magnetic layer 104 from being oxidized during the preparation process; The oxide layer 107 is located between the second magnetic layer 105 and the spin-orbit moment supply line 101 to prevent the second magnetic layer 105 from being oxidized during the manufacturing process. The first anti-oxidation layer 106 and the second anti-oxidation layer 107 use the same material as the spin-orbit moment providing line 101.

Another embodiment of the present invention provides a method for manufacturing a spin-orbit moment-based differential memory cell, including:

S1, providing a substrate, and depositing a barrier layer on the substrate;

S2, forming two magnetic layers spaced apart on the barrier layer, and the two magnetic layers have anomalous Hall conductivity with opposite positive and negative signs;

S3, filling an insulating medium and performing a planarization treatment to form a smooth surface exposing the two magnetic layers;

S4, forming a spin orbit moment supply line on the smooth surface;

S5. Two magnetic tunnel junctions are formed on the spin-orbit moment supply line, and the positions of the two magnetic tunnel junctions are in one-to-one correspondence with the two magnetic layers, respectively.

In step S1, as shown in FIG. 6A, the material of the substrate 601 is generally Si, and the barrier layer 602 is first provided on the substrate 601, which is beneficial to reduce the etching of the first magnetic layer and the second magnetic layer of the magnetization in the bottom surface. Roughness, and non-conductive, improve the feasibility of the process. The material of the barrier layer 602 includes, but is not limited to, SiO ₂ , Si ₃ N ₄ and other materials.

Specifically, step S2 includes:

S21, as shown in FIG. 6B, sequentially deposit a first magnetic material layer 603 and a first anti-oxidation material layer 604, spin-coating photoresist and perform a photolithography process to obtain a first photolithography pattern;

Generally, in order to prevent oxidation of the magnetic material during preparation, a layer of anti-oxidation material is deposited on the magnetic material, and heavy metals have good oxidation resistance, so a further layer is deposited when the first magnetic material layer is deposited. For thin heavy metals, considering that the spin-orbital moment supply line is also a heavy metal material, the deposited anti-oxidation material and the spin-orbital moment supply line use the same heavy metal material.

S22. As shown in FIG. 6C, the first magnetic material layer 603 and the first anti-oxidation material layer 604 are etched according to the first photolithography pattern, and the first magnetic layer 6031 and the corresponding first anti-oxidation layer 6041 are formed by etching. After etching, the photoresist above the first anti-oxidation layer 6041 is retained;

S23, as shown in FIG. 6D, sequentially deposit a second magnetic material layer 605 and a second anti-oxidation material layer 606, spin-coating photoresist and perform a photolithography process to obtain a second photolithography pattern;

S24. As shown in FIG. 6E, the second magnetic material layer 605 and the second anti-oxidation material layer 606 are etched according to the second photolithography pattern, and the second magnetic layer 6051 and the corresponding second anti-oxidation layer 6061 are formed by etching. After etching, the photoresist above the first anti-oxidation layer 6041 and the photoresist above the second anti-oxidation layer 6061 are removed.

In this embodiment, the material of the first magnetic layer 6031 formed includes but is not limited to magnetic materials with abnormal Hall conductivity such as Co, Fe, CoFe, CoFeB, etc., and the material of the second magnetic layer 6051 formed includes but not Limited to NiFe, NiCo and other magnetic materials with negative Hall conductivity. In principle, there is no fixed preparation sequence for the first magnetic layer and the second magnetic layer, and materials with low surface roughness requirements are preferentially prepared. The thickness of the first magnetic layer and the second magnetic layer ranges from 3 to 10 nm. The two magnetic planes are magnetized in-plane and have the same in-plane magnetization direction.

The first anti-oxidation material layer and the second anti-oxidation material layer have the same material, which can be Ti, Au or Zr. The first anti-oxidation layer 6041 and the second anti-oxidation layer 6061 formed are relatively thin, with a thickness ranging from 0.5 to 2 nm.

Step S3, as shown in FIG. 6F, fill the insulating medium 607 to isolate the two magnetic layers. The insulating medium can be SiO ₂ , Si ₃ N ₄ and other materials. The magnetization directions of the two magnetic layers are set through high-temperature magnetic field annealing treatment. The flattening process is performed. Since the anti-oxidation layer is deposited on the surfaces of the two magnetic layers, after flattening, a smooth surface is formed with the anti-oxidation layer exposed.

Step S4, as shown in FIG. 6G, a spin orbit moment providing line 608 is formed on the formed smooth surface, and the material of the spin orbit moment providing line 608 is the same as that of the anti-oxidation layers 6041 and 6061. The spin-orbital moment supply line is thicker, with a thickness ranging from 2 to 5 nm.

In the analysis, the spin-orbital moment supply line 608 and the anti-oxidation layers 6041 and 6061 can be regarded as the spin-orbital moment supply line as a whole. The combined structure of the first magnetic layer and the spin-orbital moment supply line is compared to The combined structure of the second magnetic layer and the spin-orbital moment providing line, and the signs of the spin Hall angles of the two are opposite.

Step S5, as shown in FIG. 6H, two magnetic tunnel junctions 6091 and 6092 are formed above the spin-orbit moment providing line 608, wherein the position of the magnetic tunnel junction 6091 corresponds to the position of the first magnetic layer 6031, and the magnetic tunnel junction The position of 6092 corresponds to the position of the second magnetic layer 6051. Specifically, step S5 includes: depositing various layers of films of the magnetic tunnel junction, and obtaining the magnetic tunnel junction through photolithography and etching. The embodiment of the present invention does not specifically limit the structure of the magnetic tunnel junction, which may include a basic free layer, a barrier layer, and a reference layer, and a coupling layer, a pinning layer, and a protective layer may also be provided above the reference layer. The free layer, the reference layer, and the pinned layer are magnetized perpendicularly, and the first magnetic layer and the second magnetic layer are magnetized to generate a bias magnetic field. Alternatively, the free layer, the reference layer, the pinned layer, the first magnetic layer, and the second magnetic layer are all set to in-plane magnetization. After the protective layer is deposited, the high-temperature magnetic field annealing sets the bias magnetization direction, or the high-temperature magnetic field annealing and the magnetic tunnel junction annealing are performed simultaneously.

Referring to FIGS. 7A to 7H, another embodiment of the present invention provides a method for manufacturing a spin-orbit moment-based differential memory cell, including:

As shown in FIG. 7A, a substrate 701 is provided, and a barrier layer 702 is deposited on the substrate 701;

As shown in FIG. 7B, a first magnetic material layer 703, a first anti-oxidation material layer 704, and a first protective medium layer 705 are sequentially deposited on the barrier layer 702, and photoresist is spin-coated and a photolithography process is performed to obtain the first photoresist. Carved pattern

As shown in FIG. 7C, the first magnetic material layer 703, the first anti-oxidation material layer 704, and the first protective dielectric material layer 705 are etched according to the first photolithography pattern to form a first magnetic layer 7031. The layer 7041 and the first protective dielectric layer 7051 are etched to remove the photoresist. The first protective medium layer 7051 effectively protects the first magnetic layer 7031 and the first anti-oxidation layer 7041.

As shown in FIG. 7D, a second magnetic material layer 706, a second anti-oxidation material layer 707, and a second protective medium material layer 708 are further deposited in sequence, photoresist is spin-coated and a photolithography process is performed to obtain a second photolithography pattern;

As shown in FIG. 7E, the second magnetic material layer 706, the second oxidation resistant material layer 707, and the second protective dielectric material layer 708 are etched according to the second photolithography pattern to form a second magnetic layer 7061, a second oxidation resistant material layer 708 After etching the layer 7071 and the second protective dielectric layer 7081, the photoresist is removed. The second protective medium layer 7081 effectively protects the second magnetic layer 7061 and the second anti-oxidation layer 7071.

As shown in FIG. 7F, the insulating medium 709 is filled to fill the gap between the two magnetic layers and the anti-oxidation layer and the protective medium layer above. The material of the dielectric 7081 is the same, which can be SiO ₂ , Si ₃ N ₄ and other materials. The magnetization direction of the two magnetic layers is set by high-temperature magnetic field annealing treatment, and the planarization process is performed. During the planarization process, the first protective dielectric layer 7051 The second protective medium 7081 is removed, forming a smooth surface exposing the anti-oxidation layer 7041 and 7071.

As shown in FIG. 7G, a spin orbit moment providing line 710 is formed on the formed smooth surface, and the material of the spin orbit moment providing line 710 is the same as that of the anti-oxidation layer 7041 and 7071.

As shown in FIG. 7H, two magnetic tunnel junctions 7111, 7112 are formed above the spin-orbit moment supply line 710, wherein the position of the magnetic tunnel junction 7111 corresponds to the position of the first magnetic layer 7031, and the position of the magnetic tunnel junction 7112 It corresponds to the position of the second magnetic layer 7061.

In this embodiment, the materials and thicknesses of the various layers involved can refer to the previous embodiment, and will not be repeated here.

The spin-orbital moment-based differential memory cell prepared by the above process, the free layer and the reference layer are perpendicular magnetization, and the two magnetic layers are in-plane magnetization to generate a bias magnetic field. , Can realize the magnetic moment reversal without external magnetic field, and the resistance value of the two magnetic tunnel junctions under different direction currents is opposite, which can realize differential storage and improve storage density. At the same time, the memory cell directly stacks two parallel MTJs on a metal layer to achieve a differential structure. Compared with the differential memory cell of the 2T2R structure, the use of strobe transistors, source lines, word lines, bit lines, etc. is reduced, simplifying The array structure is improved, and the degree of integration is improved.

The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited to this. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention. All should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims (11)

1. A differential storage unit based on spin-orbit moment, which is characterized in that it comprises:

   Spin orbit moment providing line;

   Two magnetic layers, the two magnetic layers are located on one side surface of the spin-orbital moment providing line, and respectively form a combined structure with the spin-orbital moment providing line, and the two magnetic layers have opposite signs The abnormal Hall conductivity;

   Two magnetic tunnel junctions with the same structure, the two magnetic tunnel junctions are located on the other side surface of the spin-orbit moment providing line opposite to the two magnetic layers, and are located at the same positions as the two magnetic layers. One-to-one correspondence.
2. The differential memory cell based on the spin-orbit moment of claim 1, wherein the magnetization directions of the two magnetic layers are in-plane magnetization.
3. The differential memory cell based on the spin orbit moment of claim 1, wherein the material of the spin orbit moment providing line includes one of Ti, Au, and Zr.
4. The differential memory cell based on the spin-orbit moment of claim 1, wherein the material of one of the magnetic layers includes one of Co, Fe, CoFe, and CoFeB, and the material of the other magnetic layer The material includes one of NiFe and NiCo.
5. The differential memory cell based on the spin-orbit moment of claim 1, further comprising: two anti-oxidation layers, the two anti-oxidation layers are respectively located on the two magnetic layers and the spin-orbital moment. Orbital moments are provided between the lines.
6. The differential memory cell based on the spin orbit moment of claim 5, wherein the anti-oxidation layer is made of the same material as the spin orbit moment supply line.
7. A method for preparing a spin-orbit moment-based differential storage unit, which is characterized in that it comprises:

   Providing a substrate, and depositing a barrier layer on the substrate;

   Forming two magnetic layers spaced apart on the barrier layer, the two magnetic layers having anomalous Hall conductivity with opposite signs;

   Filling an insulating medium and performing a planarization treatment to form a smooth surface exposing the two magnetic layers;

   Forming a spin-orbit moment supply line on the smooth surface;

   Two magnetic tunnel junctions are formed on the spin-orbit moment supply line, and the positions of the two magnetic tunnel junctions are in one-to-one correspondence with the two magnetic layers, respectively.
8. The method according to claim 7, wherein the material of the spin-orbit moment providing line includes one of Ti, Au, and Zr.
9. The method according to claim 7, wherein the material of one of the magnetic layers includes one of Co, Fe, CoFe, and CoFeB, and the material of the other magnetic layer includes one of NiFe and NiCo. Kind.
10. 8. The method of claim 7, wherein the forming two magnetic layers on the barrier layer comprises:

    Depositing a first magnetic material layer and a first anti-oxidation material layer in sequence, spin-coating photoresist and performing a photolithography process to obtain a first photolithography pattern;

    The first magnetic material layer and the first anti-oxidation material layer are etched according to the first photolithography pattern to form a first magnetic layer and a corresponding first anti-oxidation layer, and the first anti-oxidation layer remains after etching The photoresist on the top;

    Sequentially depositing a second magnetic material layer and a second anti-oxidation material layer, spin-coating photoresist and performing a photolithography process to obtain a second photolithography pattern;

    The second magnetic material layer and the second anti-oxidation material layer are etched according to the second photolithography pattern to form a second magnetic layer and a corresponding second anti-oxidation layer, and the first anti-oxidation layer is removed after etching The photoresist above and the photoresist above the second anti-oxidation layer.
11. 8. The method of claim 7, wherein the forming two magnetic layers on the barrier layer comprises:

    Sequentially depositing a first magnetic material layer, a first anti-oxidation material layer and a first protective medium material layer, spin-coating photoresist and performing a photolithography process to obtain a first photolithography pattern;

    The first magnetic material layer, the first anti-oxidation material layer, and the first protective dielectric material layer are etched according to the first photolithography pattern to form a first magnetic layer and corresponding first anti-oxidation layer, first Protect the dielectric layer, remove the photoresist after etching;

    Sequentially depositing a second magnetic material layer, a second anti-oxidation material layer and a second protective medium material layer, spin-coating photoresist and performing a photolithography process to obtain a second photolithography pattern;

    The second magnetic material layer, the second anti-oxidation material layer, and the second protective medium material layer are etched according to the second photolithography pattern to form a second magnetic layer and the corresponding second anti-oxidation layer, second Protect the dielectric layer, and remove the photoresist after etching.

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