Magnetic memory cell and computer device

Abstract

The application provides a magnetic storage unit and a computer device, 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 spin orbit coupling layer comprises at least three branches arranged towards different directions for inputting spin orbit moment current respectively; at least one magnetic tunnel junction is arranged on each branch of at least two branches, and the plurality of magnetic tunnel junctions have the same easy magnetic direction. The application can realize one-time data writing of the plurality of magnetic tunnel junctions, reduce the process complexity of the magnetic storage unit with the plurality of magnetic tunnel junctions, and optimize the data writing mode.

Description

Technical Field

[0001] This application relates to the field of semiconductor technology, and more particularly to a magnetic storage cell and a computer device. Background Technology

[0002] As semiconductor process dimensions continue to shrink and Moore's Law slows down, increased leakage current and interconnect delays have become bottlenecks for traditional CMOS memories. Finding solutions for next-generation memory technologies has become a key focus of integrated circuit research, with magnetic random access memory (MRAM) attracting widespread attention. Compared to traditional devices, MRAM offers advantages such as unlimited erase / write cycles, non-volatility, fast read / write speeds, and radiation resistance, making it a promising candidate for general-purpose memory and an ideal device for building next-generation non-volatile main memory and caches. Magnetic tunnel junctions (MTJs) are the basic memory cells of MRAMs. The size of MRAMs can be reduced to below 40nm, potentially enabling high-density integration.

[0003] Against this backdrop, researchers have proposed multi-level cells (MLCs) composed of one or more medium-level switching units (MTJs) to further improve the storage density of high-capacity storage applications. MLCs require precise tuning of the characteristics of each MTJ to achieve different threshold switching currents and resistance states with sufficient margin. A typical MLC is implemented by connecting MTJs on two planes in series or parallel, such as... Figure 1 As shown. These MTJs, connected in series or parallel, have different magnetization directions or areas, and their manufacturing process is relatively complex. Summary of the Invention

[0004] One objective of this application is to provide a magnetic storage cell that enables simultaneous data writing of multiple magnetic tunnel junctions, reduces the fabrication complexity of the multi-magnetic tunnel junction magnetic storage cell, and optimizes the data writing method. Another objective of this application is to provide a computer device.

[0005] To achieve the above objectives, this application discloses a magnetic storage cell, including a spin-orbit coupling layer and a plurality of magnetic tunnel junctions disposed on the spin-orbit coupling layer;

[0006] The spin-orbit coupling layer includes at least three branches oriented in different directions for inputting spin-orbit moment currents respectively;

[0007] At least one magnetic tunnel junction is provided on each of the at least two branches, and the magnetic orientation of the plurality of magnetic tunnel junctions is the same.

[0008] Preferably, the spin-orbit coupling layer includes three branches—a first branch, a second branch, and a third branch—arranged in different directions;

[0009] A first magnetic tunnel junction and a second magnetic tunnel junction are respectively provided on the first branch and the second branch.

[0010] Preferably, when at least two of the first signal, the second signal, and the third signal are input along the ends of the first branch, the second branch, and the third branch respectively, a first spin-orbit moment current, a second spin-orbit moment current, and a third spin-orbit moment current are formed on the first branch, the second branch, and the third branch respectively.

[0011] The first branch, the second branch, and the third branch include a first direction toward the center of the spin-orbit coupling layer and a second direction opposite to the first direction;

[0012] If the first spin orbital moment current is oriented in the first direction and is greater than the critical flip current of the first magnetic tunnel junction, the first magnetic tunnel junction is in the first resistive state.

[0013] If the second spin orbital moment current is oriented in the first direction and is greater than the critical flip current of the second magnetic tunnel junction, the resistive state of the second magnetic tunnel junction is the second resistive state.

[0014] If the second spin orbital moment current is oriented in the second direction and is greater than the critical flip current of the second magnetic tunnel junction, the resistance state of the second magnetic tunnel junction is the third resistance state.

[0015] If the first spin orbital moment current is oriented in the second direction and is greater than the critical flip current of the first magnetic tunnel junction, the first magnetic tunnel junction is in the fourth resistive state.

[0016] Preferably, a third magnetic tunnel junction is provided on the third branch;

[0017] If the third spin orbital moment current is oriented in the first direction and is greater than the critical flip current of the third magnetic tunnel junction, the resistance state of the third magnetic tunnel junction is the fifth resistance state.

[0018] If the third spin orbital moment current is oriented in the second direction and is greater than the critical flip current of the third magnetic tunnel junction, the resistance state of the third magnetic tunnel junction is the sixth resistance state.

[0019] Preferably, the direction of the easy magnetic axis of the plurality of magnetic tunnel junctions forms an angle with the direction of the corresponding branch.

[0020] Preferably, the spin-orbit coupling layer is Y-shaped, T-shaped, or star-shaped radial.

[0021] Preferably, the magnetic tunnel junction has a non-perfectly symmetrical shape.

[0022] Preferably, the magnetic tunnel junction is shaped as an ellipse, triangle, rectangle, or semicircle.

[0023] Preferably, at least one of the magnetic tunnel junctions has vertical anisotropy, and the magnetic storage cell further includes an applied magnetic field or an equivalent applied magnetic field; or, at least one of the magnetic tunnel junctions has in-plane anisotropy.

[0024] This application also discloses a computer device including a memory and / or a processor, wherein the memory and / or the processor includes magnetic storage units as described above.

[0025] The magnetic storage cell of this application includes a spin-orbit coupling layer and a plurality of magnetic tunnel junctions disposed on the spin-orbit coupling layer. The spin-orbit coupling layer includes at least three branches oriented in different directions for respectively inputting spin-orbit moment currents; at least two of the branches each have at least one magnetic tunnel junction, and the easy magnetic directions of the plurality of magnetic tunnel junctions are the same. Thus, the plurality of magnetic tunnel junctions of this application are disposed on branches in different directions of the spin-orbit coupling layer, and the easy magnetic axes of the plurality of magnetic tunnel junctions are in the same direction. Therefore, the angle between the easy magnetic direction of different magnetic tunnel junctions and the spin-orbit moment current input on the corresponding branch is different. When spin-orbit moment currents in different directions are input along the multiple branches of the spin-orbit coupling layer, the combination of resistance states of the plurality of magnetic tunnel junctions is different, realizing the one-time writing of data to the plurality of magnetic tunnel junctions. The easy magnetic axes of the plurality of magnetic tunnel junctions of this application are in the same direction, meaning that the shape and / or relative position of the plurality of magnetic tunnel junctions relative to the center can be completely identical. The plurality of magnetic tunnel junctions can be obtained synchronously in the same series of fabrication processes, simplifying the fabrication process of MLC devices. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 A schematic diagram of an MLC device in the prior art is shown;

[0028] Figure 2 This diagram illustrates a structural diagram of a specific embodiment of the magnetic storage cell of this application;

[0029] Figure 3This diagram illustrates the arrangement of a first magnetic tunnel junction and a second magnetic tunnel junction in a specific example of the magnetic storage cell of this application.

[0030] Figure 4 This diagram illustrates the arrangement of a first magnetic tunnel junction, a second magnetic tunnel junction, and a third magnetic tunnel junction in a specific embodiment of the magnetic storage cell of this application.

[0031] Figure 5 This diagram illustrates the arrangement of a first magnetic tunnel junction, a second magnetic tunnel junction, and a third magnetic tunnel junction in another specific example of the magnetic storage cell of this application.

[0032] Figure 6 A schematic diagram of the structure of a computer device suitable for implementing embodiments of this application is shown. Detailed Implementation

[0033] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0034] Figure 1 An MLC device in the prior art is shown. Figure 1 In this MLC device, two magnetic tunnel junctions are positioned on the spin-orbit coupling layer. These two magnetic tunnel junctions can achieve four different combinations of resistive states under the influence of spin-orbit torque current inputs in four directions of the spin-orbit coupling layer, enabling the writing of 2 bits of data. This MLC device requires external circuitry to implement data writing in all four directions of the spin-orbit coupling layer, making the data writing process quite complex. Furthermore, the two magnetic tunnel junctions on the spin-orbit coupling layer have different orientations and different easy magnetic axes, requiring separate etching and annealing processes to fabricate them, further complicating the MLC device fabrication process.

[0035] To address the problems existing in the prior art, this application provides a magnetic storage cell. The spin-orbit coupling layer of the magnetic storage cell includes at least three branches oriented in different directions for respectively inputting spin-orbit moment currents; each of at least two of these branches has at least one magnetic tunnel junction, and the easy magnetic axes of the multiple magnetic tunnel junctions share the same easy magnetic direction. When spin-orbit moment currents in different directions are input along the multiple branches of the spin-orbit coupling layer, the combination of resistance states of the multiple magnetic tunnel junctions differs, enabling the simultaneous writing of data to the multiple magnetic tunnel junctions. The spin-orbit coupling layer requires at least three branches, meaning at least three branches need to be configured with circuit structures for inputting spin-orbit moment currents. Compared to the prior art circuit structures requiring four directions of spin-orbit moment current, the magnetic storage cell of this application has a simpler structure and optimizes the data writing process. Furthermore, the easy magnetic axes of the multiple magnetic tunnel junctions share the same easy magnetic direction, meaning the shapes and / or relative positions of the multiple magnetic tunnel junctions with respect to the center can be identical. The multiple magnetic tunnel junctions can be simultaneously obtained in the same series of fabrication processes, simplifying the fabrication process of MLC devices.

[0036] According to one aspect of this application, this embodiment discloses a magnetic storage cell. For example... Figure 2 As shown, the magnetic storage cell includes a spin-orbit coupling layer D1 and multiple magnetic tunnel junctions disposed on the spin-orbit coupling layer D1.

[0037] The spin-orbit coupling layer D1 includes at least three branches oriented in different directions for inputting spin-orbit torque currents respectively. Each of at least two of these branches has at least one magnetic tunnel junction, and the easy magnetization directions of the plurality of magnetic tunnel junctions are the same.

[0038] The magnetic storage cell of this application includes a spin-orbit coupling layer D1 and a plurality of magnetic tunnel junctions disposed on the spin-orbit coupling layer D1. The spin-orbit coupling layer D1 includes at least three branches arranged in different directions for respectively inputting spin-orbit moment currents; at least two of the branches each have at least one magnetic tunnel junction disposed on them, and the easy magnetic axes of the plurality of magnetic tunnel junctions have the same easy magnetic direction. Thus, the plurality of magnetic tunnel junctions of this application are disposed on branches in different directions of the spin-orbit coupling layer D1, and the easy magnetic axes of the plurality of magnetic tunnel junctions have the same easy magnetic direction. Therefore, the angle between the easy magnetic direction of the different magnetic tunnel junctions and the spin-orbit moment current input on the corresponding branch is different. When spin-orbit moment currents in different directions are input along the multiple branches of the spin-orbit coupling layer D1, the combination of the resistance states of the plurality of magnetic tunnel junctions is different, realizing the one-time writing of data of the plurality of magnetic tunnel junctions. The multiple magnetic tunnel junctions of this application have the same easy magnetic axis and easy magnetic direction, that is, the shape and / or relative position of the multiple magnetic tunnel junctions with respect to the center can be exactly the same. The multiple magnetic tunnel junctions can be obtained synchronously in the same series of fabrication processes, which simplifies the fabrication process of MLC devices.

[0039] In a preferred embodiment, such as Figure 2 As shown, the spin-orbit coupling layer D1 includes three branches, a first branch A1, a second branch A2, and a third branch A3, arranged in different directions. A first magnetic tunnel junction MTJ1 and a second magnetic tunnel junction MTJ2 are respectively arranged on the first branch A1 and the second branch A2.

[0040] Specifically, in this preferred embodiment, the spin-orbit coupling layer D1 includes three branches—a first branch A1, a second branch A2, and a third branch A3—oriented in different directions. A first magnetic tunnel junction (MTJ1) and a second magnetic tunnel junction (MTJ2) with the same easy magnetic direction are disposed on the first branch A1 and the second branch A2. Since the easy magnetic directions of the first magnetic tunnel junction (MTJ1) and the second magnetic tunnel junction (MTJ2) form different angles with their respective branches, the spin-orbit torque currents on the three branches of the spin-orbit coupling layer D1 can be set respectively, allowing for different combinations of resistance states of the first magnetic tunnel junction (MTJ1) and the second magnetic tunnel junction (MTJ2), thus enabling the writing of 2 bits of data.

[0041] In an optional implementation, when at least two of the first signal S1, the second signal S2, and the third signal S3 are input along the ends of the first branch A1, the second branch A2, and the third branch A3, a first spin-orbit moment current, a second spin-orbit moment current, and a third spin-orbit moment current are formed on the first branch A1, the second branch A2, and the third branch A3, respectively.

[0042] The first branch A1, the second branch A2, and the third branch A3 include a first direction toward the center of the spin-orbit coupling layer D1 and a second direction opposite to the first direction. If the first spin-orbit moment current is toward the first direction and is greater than the critical flip current of the first magnetic tunnel junction MTJ1, the first magnetic tunnel junction MTJ1 is in a first resistive state. If the second spin-orbit moment current is toward the first direction and is greater than the critical flip current of the second magnetic tunnel junction MTJ2, the second magnetic tunnel junction MTJ2 is in a second resistive state. If the second spin-orbit moment current is toward the second direction and is greater than the critical flip current of the second magnetic tunnel junction MTJ2, the second magnetic tunnel junction MTJ2 is in a third resistive state. If the first spin-orbit moment current is toward the second direction and is greater than the critical flip current of the first magnetic tunnel junction MTJ1, the first magnetic tunnel junction MTJ1 is in a fourth resistive state.

[0043] The easy magnetization direction of a magnetic tunnel junction can be defined as the direction in which the easy magnetization axis of the magnetic tunnel junction approaches the +x or +y direction of the set rectangular coordinate system. Figure 3 In a specific example, the easy magnetization direction of the first magnetic tunnel junction MTJ1 and the second magnetic tunnel junction MTJ2 is the +y direction. Under the action of the first signal S1, the second signal S2, and the third signal S3, a first spin-orbit moment current, a second spin-orbit moment current, and a third spin-orbit moment current can be formed on the first branch A1, the second branch A2, and the third branch A3. Depending on the angle between the first magnetic tunnel junction MTJ1 and the first spin-orbit moment current, and the angle between the second magnetic tunnel junction MTJ2 and the second spin-orbit moment current, the first magnetic tunnel junction MTJ1 can have a first resistive state and a second resistive state, and the second magnetic tunnel junction MTJ2 can have a third resistive state and a fourth resistive state. The first resistive state can be a high-resistance state or a low-resistance state; correspondingly, when the first resistive state is high-resistance, the second resistive state is low-resistance; and when the first resistive state is low-resistance, the second resistive state is high-resistance. Similarly, the third resistance state can be either a high resistance state or a low resistance state. Correspondingly, when the third resistance state is a high resistance state, the fourth resistance state is a low resistance state; when the third resistance state is a low resistance state, the fourth resistance state is a high resistance state.

[0044] In a specific example, when the spin-orbit moment current input to the first branch A1 is greater than the critical flip current of the first magnetic tunnel junction MTJ1, if the angle between the direction of the spin-orbit moment current and the easy magnetic direction of the first magnetic tunnel junction MTJ1 in a clockwise direction is less than a flat angle (0-180 degrees), the first magnetic tunnel junction MTJ1 is in a low-resistance state. Conversely, if the angle between the direction of the spin-orbit moment current and the easy magnetic direction of the first magnetic tunnel junction MTJ1 in a clockwise direction is greater than a flat angle (180-360 degrees), the first magnetic tunnel junction MTJ1 is in a high-resistance state. If the easy magnetization direction of the second magnetic tunnel junction MTJ2 is the same as that of the first magnetic tunnel junction MTJ1, then when the spin-orbit moment current input to the second branch A2 is greater than the critical flip current of the second magnetic tunnel junction MTJ2, if the angle between the direction of the spin-orbit moment current and the easy magnetization direction of the second magnetic tunnel junction MTJ2 in a clockwise direction is less than a flat angle (0-180 degrees), the resistance state of the second magnetic tunnel junction MTJ2 is a low resistance state. Conversely, if the angle between the direction of the spin-orbit moment current and the easy magnetization direction of the second magnetic tunnel junction MTJ2 in a clockwise direction is greater than a flat angle (180-360 degrees), the resistance state of the second magnetic tunnel junction MTJ2 is a high resistance state.

[0045] It should be noted that, in this embodiment, the angle between the spin-orbit moment current and the easy magnetic direction of the magnetic tunnel junction refers to the angle formed by the easy magnetic direction of the magnetic tunnel junction and the spin-orbit moment current in the clockwise direction of the spin-orbit moment current, based on the spin-orbit moment current.

[0046] In practical applications, those skilled in the art can set the reference layer direction, the easy magnetic direction of the easy magnetic axis of the magnetic tunnel junction, and the correspondence between the angle between the easy magnetic direction of the magnetic tunnel junction and the direction of the spin-orbit torque current and the resistance state of the magnetic tunnel junction according to actual needs. This embodiment is only used as a specific example for explanation and illustration, and this application does not limit it.

[0047] It should be noted that in practical applications, when the sign of the spin Hall angle changes, the correspondence between the current direction and the final resistance state should be reversed.

[0048] It is 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 fixed layer B3, a barrier layer B2, and a free layer B1 arranged sequentially from top to bottom. The bottom surface of the free layer B1 is fixedly connected to the spin-orbit coupling layer D1. The resistance of the magnetic tunnel junction depends on the magnetization directions of the fixed layer B3 and the free layer B1, which are determined by the magnetic moment directions. Specifically, when the magnetic moment directions of the fixed layer B3 and the free layer B1 are the same, the magnetic tunnel junction is in a low-resistance state; when the magnetic moment directions of the fixed layer B3 and the free layer B1 are opposite, the magnetic tunnel junction is in a high-resistance state. The high-resistance and low-resistance states of a magnetic tunnel junction can be pre-assigned to different data. For example, a high-resistance state can be pre-set to correspond to data "1", and a low-resistance state to data "0". Then, by inputting current or voltage into the magnetic tunnel junction through a reading circuit, the resistance state of the magnetic tunnel junction (whether it is a high-resistance or low-resistance state) can be determined based on the change in current or voltage. Based on the resistance state of the magnetic tunnel junction, the data stored in the magnetic tunnel junction (whether it is "1" or "0") can be determined. Determining the range of high-resistance and low-resistance states is a common technique in this field. Those skilled in the art can determine the resistance range of the high-resistance and low-resistance states of the magnetic tunnel junction based on common knowledge, and this application will not elaborate further.

[0049] In a specific example, for Figure 3 The magnetic storage unit shown allows the end of the third branch A3 to be suspended. Even if the third signal S3 is empty, the first signal S1 and the second signal S2 are only input at the ends of the first branch A1 and the second branch A2. There is a voltage difference between the ends of the first branch A1 and the second branch A2, thereby forming a first spin-orbit moment current and a second spin-orbit moment current on the first branch A1 and the second branch A2. The magnitudes of the first spin-orbit moment current and the second spin-orbit moment current are equal, and their directions are respectively along the direction of the corresponding branch. At this time, the third spin-orbit moment current is approximately 0.

[0050] If the first signal S1 is greater than the second signal S2, the current direction on the first branch A1 and the second branch A2 is from the end of the first branch A1 to the end of the second branch A2. The angle between the first spin-orbit current and the easy magnetic direction (+y) of the first magnetic tunnel junction MTJ1 in a clockwise direction is greater than a horizontal angle, and the resistance state of the first magnetic tunnel junction MTJ1 is a high-resistance state. The angle between the second spin-orbit current and the easy magnetic direction (+y) of the first magnetic tunnel junction MTJ1 in a clockwise direction is also greater than a horizontal angle, and the resistance state of the second magnetic tunnel junction MTJ2 is a high-resistance state. If the low-resistance state corresponds to data "0" and the high-resistance state corresponds to data "1", then the writing of data "11" is completed. Conversely, similarly, if the first signal S1 is less than the second signal S2, the current direction on the first branch A1 and the second branch A2 flows from the end of the second branch A2 to the end of the first branch A1. The angle between the first spin-orbit current and the easy magnetic direction (+y) of the first magnetic tunnel junction MTJ1 in a clockwise direction is less than a straight angle, and the resistance state of the first magnetic tunnel junction MTJ1 is a low-resistance state. The angle between the second spin-orbit current and the easy magnetic direction (+y) of the second magnetic tunnel junction MTJ2 in a clockwise direction is also less than a straight angle, and the resistance state of the second magnetic tunnel junction MTJ2 is a low-resistance state. If the low-resistance state corresponds to data "0" and the high-resistance state corresponds to data "1", then the writing of data "00" is completed.

[0051] Optionally, the first signal S1 can be set to a low level, the second signal S2 to a high level, and the third signal S3 to a low level. The voltage difference between these three signals will form a first spin-orbit moment current, a second spin-orbit moment current, and a third spin-orbit moment current in the first branch A1, the second branch A2, and the third branch A3, respectively. According to Kirchhoff's laws, the second spin-orbit moment current is the sum of the first and third spin-orbit moment currents. Therefore, by properly configuring these signals, only the second spin-orbit moment current can be greater than the critical flip current of the magnetic tunnel junction on its branch. The direction of the second spin-orbit moment current is from the end of the second branch A2 to the end of the third branch A3. The angle between the second spin-orbit moment current and the clockwise direction (+y) of the second magnetic tunnel junction MTJ2 is less than a flat angle, and the resistance state of the second magnetic tunnel junction MTJ2 is a low-resistance state. If the low-resistance state corresponds to data "0" and the high-resistance state corresponds to data "1", then the writing of data "0" to the second magnetic tunnel junction MTJ2 is complete.

[0052] Similarly, by setting the first signal S1 to a high level, the second signal S2 to a low level, and the third signal S3 to a high level, the data "1" can be written to the second magnetic tunnel junction MTJ2; by setting the first signal S1 to a low level, the second signal S2 to a high level, and the third signal S3 to a high level, the data "0" can be written to the first magnetic tunnel junction MTJ1; and by setting the first signal S1 to a high level, the second signal S2 to a low level, and the third signal S3 to a low level, the data "1" can be written to the first magnetic tunnel junction MTJ1. In summary, by setting the first signal S1, the second signal S2, and the third signal S3, the data writing process for one magnetic tunnel junction can be made to have no effect on the resistance state of other magnetic tunnel junctions. Therefore, the magnetic storage unit of this application can also realize the writing of data to a single magnetic tunnel junction.

[0053] Optionally, the third signal S3 can be set to a high level, while the first signal S1 and the second signal S2 are set to a low level. The voltage difference between the third signal S3, the second signal S2, and the first signal S1 forms a first spin-orbit moment current and a second spin-orbit moment current on the first branch A1 and the second branch A2, respectively. The direction of the first spin-orbit moment current is from the end of the third branch A3 to the end of the first branch A1, and the direction of the second spin-orbit moment current is from the end of the third branch A3 to the end of the second branch A2. The angle between the first spin-orbit moment current and the clockwise direction (+y) of the first magnetic tunnel junction MTJ1 is less than a horizontal angle, and the resistance state of the first magnetic tunnel junction MTJ1 is low-resistance. The angle between the second spin-orbit moment current and the clockwise direction (+y) of the second magnetic tunnel junction MTJ2 is greater than a horizontal angle, and the resistance state of the second magnetic tunnel junction MTJ2 is high-resistance. If the low-resistance state corresponds to data "0" and the high-resistance state corresponds to data "1", then the data "01" is written. Similarly, by setting the first signal S1 to a high level, the second signal S2 to a high level, and the third signal S3 to a low level, the data "10" can be written.

[0054] It should be noted that when writing data to the first magnetic tunnel junction MTJ1 and the second magnetic tunnel junction MTJ2, the levels of the first signal S1, the second signal S2 and the third signal S3 can be controlled to generate a voltage difference between the first signal S1, the second signal S2 and the third signal S3, thereby obtaining the corresponding spin-orbit moment current, so that the final resistance state of at least one of the multiple magnetic tunnel junctions reaches the expected state, and the corresponding data is written. Those skilled in the art can determine the first signal S1, the second signal S2 and the third signal S3 according to the actual situation. This embodiment is only an example and this application does not limit it.

[0055] In another specific example, for Figure 4The magnetic storage unit shown allows the end of the third branch A3 to be left floating. Even if the third signal S3 is empty, the first signal S1 and the second signal S2 are only input at the ends of the first branch A1 and the second branch A2. If the first signal S1 is greater than the second signal S2, the direction of the current in the first branch A1 and the second branch A2 is from the end of the first branch A1 to the end of the second branch A2. The angle between the first spin-orbit moment current and the easy magnetic direction (+x) of the first magnetic tunnel junction MTJ1 in a clockwise direction is less than a flat angle, and the resistance state of the first magnetic tunnel junction MTJ1 is a low-resistance state. The angle between the second spin-orbit moment current and the easy magnetic direction (+x) of the second magnetic tunnel junction MTJ2 in a clockwise direction is greater than a flat angle, and the resistance state of the second magnetic tunnel junction MTJ2 is a high-resistance state. If the low-resistance state corresponds to data "0" and the high-resistance state corresponds to data "1", then the writing of data "01" is completed. Therefore, by changing the orientation of the magnetic tunnel junction on the branch, the correspondence between the spin-orbit torque current and the resistance state of the magnetic tunnel junction can be changed. In practical applications, those skilled in the art can set the orientation of multiple magnetic tunnel junctions on the spin-orbit coupling layer D1 according to the actual situation, that is, set the angle between the easy magnetic direction of the magnetic tunnel junction and the corresponding branch to realize the correspondence between the spin-orbit torque current on the branch and the written data. This application does not limit this.

[0056] Optionally, when setting the levels of the first signal S1, the second signal S2, and the third signal S3, the effect of inter-branch current shunting can be considered. This ensures that the spin-orbit moment current in a certain branch, after shunting, is less than the critical flip current of the magnetic tunnel junction in that branch, preventing a change in the resistance state of the magnetic tunnel junction. Consequently, this does not affect the resistance state of the magnetic tunnel junction during data writing to other magnetic tunnel junctions, increasing the current margin of the spin-orbit moment current. For example, for Figure 2 The magnetic storage cell shown is defined with a preset level of "1" and a low level of "0". The initial stored data of the first magnetic tunnel junction MTJ1 and the second magnetic tunnel junction MTJ2 are both "0". The truth table shown in Table 1 can be obtained. As can be seen from Table 1, the magnetic storage cell of this application can also be used for logic operations to form a logic device.

[0057] Table 1

[0058] 0 0 0 0 0 0 0 1 0 0 0 1 0 0 0 1 0 0 1 0 1 1 0 0 0 1 0 1 0 1 0 1 1 0 0 1 1 1 0 0

[0059] As shown in Table 1, for example, when the second signal S2 and the third signal S3 are at low levels, and the first signal S1 is at a preset level, the current shunted by the second magnetic tunnel junction MTJ2 does not reach the critical switching current, and the resistance of the second magnetic tunnel junction MTJ2 is related to the initial resistance, so it is "0". The current shunted by the first magnetic tunnel junction MTJ1 is not shunted, and the resistance of the first magnetic tunnel junction MTJ1 is determined by the current direction, so the data stored in the first magnetic tunnel junction MTJ1 is "1".

[0060] In alternative implementations, such as Figure 5 As shown, a third magnetic tunnel junction (MTJ3) is provided on the third branch A3. If the third spin-orbit current is oriented in the first direction and is greater than the critical flip current of the third magnetic tunnel junction (MTJ3), the resistance state of the third magnetic tunnel junction (MTJ3) is the fifth resistance state; if the third spin-orbit current is oriented in the second direction and is greater than the critical flip current of the third magnetic tunnel junction (MTJ3), the resistance state of the third magnetic tunnel junction (MTJ3) is the sixth resistance state.

[0061] Understandably, at least one magnetic tunnel junction (MTJ) can be set on each branch of the spin-orbit coupling layer D1. Data from multiple MTJs can be written simultaneously by controlling the spin-orbit moment current on each branch. Specifically, when a third MTJ3 is set on the third branch A3, the final resistance state of the third MTJ3 is determined based on the angle between the easy magnetic axis direction of the third MTJ3 and the direction of the third spin-orbit moment current. Where the fifth resistance state can be a high resistance state, then the sixth resistance state is a low resistance state; conversely, if the fifth resistance state is a low resistance state, then the sixth resistance state is a high resistance state.

[0062] In an optional implementation, the spin-orbit coupling layer D1 is Y-shaped, T-shaped, or star-shaped radial.

[0063] It can be understood that the spin-orbit coupling layer D1 may include three branches or more than three branches. The shape of the spin-orbit coupling layer D1 with three branches can be Y-shaped or T-shaped as needed, while the spin-orbit coupling layer with three or more branches can be star-shaped or radial.

[0064] Optionally, when the spin-orbit coupling layer D1 is in the shape of a Y-shape or a star-shaped radial shape, the acute angles in the Y-shape or star shape can be made as small as possible, provided that the process conditions allow, in order to reduce the volume occupied by the spin-orbit coupling layer D1, reduce the volume of the magnetic storage cell, and increase the storage density.

[0065] In an optional embodiment, the magnetic tunnel junction has a non-perfectly symmetrical shape. Preferably, the magnetic tunnel junction is elliptical, triangular, rectangular, or semi-circular in shape.

[0066] It is understood that the preferred shapes of the first magnetic tunnel junction MTJ1 and the second magnetic tunnel junction MTJ2 are elliptical, with the major axis of the ellipse being the easy magnetic axis. Therefore, when current is input to the spin-orbit coupling layer D1, based on the spin-orbit moment principle, the final direction of the magnetic moment of the free layer B1 after the current input ends is the easy magnetic axis direction. 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 requirements. This application does not limit this; technical solutions for magnetic storage cells using magnetic tunnel junctions of other feasible shapes based on the same inventive concept should also be within the protection scope of this application.

[0067] In an optional embodiment, at least one of the magnetic tunnel junctions has vertical anisotropy, and the magnetic storage cell further includes an applied magnetic field or an equivalent applied magnetic field; or, at least one of the magnetic tunnel junctions has in-plane anisotropy.

[0068] Understandably, 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 towards the easy magnetic axis under the influence of the spin-orbit moment current. Understandably, one or both of the first magnetic tunnel junction MTJ1 and the second magnetic tunnel junction MTJ2 can also be magnetic tunnel junctions with vertical anisotropy. For magnetic tunnel junctions with vertical anisotropy, the magnetic storage cell further includes an external magnetic field corresponding to the magnetic tunnel junction with vertical anisotropy, or the magnetic tunnel junction with vertical anisotropy has an equivalent external magnetic field.

[0069] In optional implementations, the external magnetic field or equivalent external magnetic field in the magnetic storage cell can be implemented in various ways. Specifically, the external magnetic field or equivalent external magnetic field can be formed by at least one of the following methods:

[0070] The storage unit includes a magnetic field generating device that provides the external magnetic field or is equivalent to the external magnetic field;

[0071] The magnetic tunnel junction includes a fixed layer B3, a barrier layer B2, and a free layer B1 arranged sequentially from top to bottom. At least one of the fixed layer B3, the barrier layer B2, and the free layer B1 has a trapezoidal cross-section to provide the equivalent external magnetic field.

[0072] The spin-orbit coupling layer D1 is made of an antiferromagnetic material. The spin-orbit coupling layer D1 and the free layer B1 form an exchange bias field to provide the equivalent external magnetic field.

[0073] The magnetic tunnel junction includes a magnetic material layer (e.g., a Co layer) for providing the equivalent applied magnetic field;

[0074] The free layer B1 has a gradient of vertical anisotropy, which is used to provide an equivalent magnetic field for the applied magnetic field. Specifically, when fabricating a magnetic tunnel junction, the concentration of the target material can be adjusted to make the free layer B1 have a gradient of vertical anisotropy, further disrupting the symmetry of the magnetic moment distribution, which can be used to provide an equivalent applied magnetic field.

[0075] It should be noted that magnetic field generating devices or equivalent devices capable of forming an external magnetic field are conventional techniques in this field, and those skilled in the art can flexibly configure them according to their needs, which will not be elaborated here. In addition, external magnetic fields can also be provided by making at least one of the fixed layer B3, barrier layer B2, and free layer B1 trapezoidal in cross-section, using an antiferromagnetic material to form an exchange bias field with the free layer B1, and providing a magnetic material layer. In practical applications, external magnetic fields can also be formed through other feasible methods, which are not limited in this application.

[0076] In a preferred embodiment, to adjust the vertical anisotropy of the magnetic tunnel junction and the smoothness of each layer, the magnetic tunnel junction may further include at least one of the following layer structures: an insertion layer, a pinning layer, a seed layer, and a capping layer. The arrangement of each layer structure can be one or more layers according to actual needs, and those skilled in the art can determine the top-to-bottom arrangement order of the magnetic tunnel junction layers as required; this application does not limit this.

[0077] In a preferred embodiment, the magnetic storage unit further includes a control module, which is used to determine the input direction of the current in each branch according to the combination of data to be written; and to input and set a first signal S1, a second signal S2 and a third signal S3 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 is different.

[0078] In a preferred embodiment, the magnetic storage unit further includes a read module, which can apply a detection current to the first magnetic tunnel junction MTJ1 and the second magnetic tunnel junction MTJ2, and determine the logic numbers stored in the first magnetic tunnel junction MTJ1 and the second magnetic tunnel junction MTJ2 based on the change of the detection current.

[0079] In an optional embodiment, a top electrode can be provided at the top of the magnetic tunnel junction, and current input electrodes and output electrodes can be provided on opposite sides of the spin-orbit coupling layer D1, respectively, for detecting the input current and spin-orbit torque current. Preferably, the electrode material can be any one of tantalum (Ta), aluminum (Al), gold (Au), or copper (Cu).

[0080] Preferably, the materials of the free layer B1 and the fixed layer B3 can be ferromagnetic metals, and the material of the barrier layer B2 can be an oxide. The ferromagnetic metal can be a mixed metal material formed from at least one of cobalt-iron (CoFe), cobalt-iron-boron (CoFeB), or nickel-iron (NiFe), and the proportions of the mixed metal materials can be the same or different. The oxide can be one of magnesium oxide (MgO) or aluminum oxide (Al2O3), used to generate the tunneling magnetoresistance effect. In practical applications, other feasible materials can also be used for the ferromagnetic metal and oxide, and this application does not limit this.

[0081] The free layer B1 of the magnetic tunnel junction is fixed in contact with the spin-orbit coupling layer D1. The layers of the magnetic tunnel junction and the spin-orbit coupling layer D1 can be deposited on the substrate in a bottom-to-top order by traditional methods such as ion beam epitaxy, atomic layer deposition or magnetron sputtering. Then, two or more magnetic tunnel junctions can be formed by traditional nano-device processing technology such as photolithography and etching.

[0082] In a preferred embodiment, the spin-orbit coupling layer D1 is a spin-orbit coupling layer D1 made of a heavy metal thin film, an antiferromagnetic thin film, or other materials. Preferably, the top area of ​​the heavy metal thin film or antiferromagnetic thin film in each branch is larger than the bottom area of ​​the contour formed by all magnetic tunnel junctions, so that two or more magnetic tunnel junctions can be formed, with the bottom shape of the magnetic tunnel junction completely embedded within the top shape of the heavy metal thin film or antiferromagnetic thin film. Preferably, the material of the spin-orbit coupling layer D1 can be one of platinum (Pt), tantalum (Ta), or tungsten (W). In practical applications, the spin-orbit coupling layer D1 can also be formed using other feasible materials, and this application does not limit this.

[0083] In this embodiment, the first magnetic tunnel junction MTJ1 and / or the second magnetic tunnel junction MTJ2 include a top fixed layer B3, a free layer B1 in contact with the spin-orbit coupling layer D1, and a barrier layer B2 disposed between the fixed layer B3 and the free layer B1. The magnetic tunnel junction is a three-layer structure, including only one free layer B1. In other embodiments, there may be multiple free layers B1, i.e., two or more free layers B1. Then the magnetic tunnel junction includes a top fixed layer B3, multiple free layers B1, and a barrier layer B2 disposed between each adjacent pair of layers, with the bottom free layer B1 in contact with the spin-orbit coupling layer D1. For example, in a specific example, when two free layers B1 are included, the magnetic storage cell structure may include a spin-orbit coupling layer D1, a second free layer, a barrier layer, a first free layer, a barrier layer, and a fixed layer B3 sequentially disposed on the spin-orbit coupling layer D1.

[0084] In summary, the magnetic storage cell of this application achieves 2-bit data writing operations compared to existing MLC devices, reducing the number of signal ports and enabling one-time deterministic writing of 2 bits of data without considering the initial state in the magnetic tunnel junction. Furthermore, writing is entirely achieved through spin-orbit moments, mitigating the risk of barrier breakdown. The spin-orbit moment current direction of the branch in the magnetic tunnel junction of this application is tilted, theoretically resulting in a lower critical switching current density, faster switching speed, and lower write power consumption. Moreover, the magnetic tunnel junction reference layer of the magnetic storage cell of this application has a consistent magnetization direction, allowing for uniform annealing. The design of the Y-type spin-orbit coupling layer optimizes layout complexity, reduces fabrication and process difficulty, and allows for 1-bit data writing even with signal input from multiple branches, improving operational flexibility.

[0085] 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 cells arranged in an array as described in this embodiment.

[0086] Magnetic random access memory (RAM) encompasses both permanent and non-permanent, removable and non-removable media, and information storage can be achieved by any method or technology. Information can be computer-readable instructions, data structures, program modules, or other data. Examples of applications of magnetic RAM include, but are not limited to, random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic magnetic disk storage or other magnetic storage devices, or any other non-transfer medium that can be used to store information accessible by computing devices.

[0087] Since the principle of this magnetic random access memory in solving the problem is similar to that of the magnetic storage unit described above, the implementation of this magnetic random access memory can be referred to the implementation of the magnetic storage unit described above, and will not be repeated here.

[0088] Based on the same principle, this embodiment also discloses a computer device, including a memory and / or a processor.

[0089] The processor and / or the memory include magnetic storage units as described in this embodiment.

[0090] The magnetic storage unit described in the above embodiments can be specifically installed in a product device with a certain function. A typical implementation device is a computer device, specifically, such as a personal computer, laptop computer, cellular phone, camera phone, smartphone, personal digital assistant, media player, navigation device, email device, game console, tablet computer, wearable device, or any combination of these devices.

[0091] In a typical example, a computer device specifically includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor and / or the memory includes magnetic storage units as described in this embodiment.

[0092] The following is for reference. Figure 6 It shows a schematic diagram of the structure of a computer device suitable for implementing the embodiments of this application.

[0093] like Figure 6 As shown, the computer device includes a central processing unit (CPU) 601, which can perform various appropriate tasks and processes based on programs stored in read-only memory (ROM) 602 or programs loaded from storage section 608 into random access memory (RAM) 603. RAM 603 also stores various programs and data required for system operation. CPU 601, ROM 602, and RAM 603 are interconnected via bus 604. Input / output (I / O) interface 605 is also connected to bus 604.

[0094] The following components are connected to I / O interface 605: an input section 606 including a keyboard, mouse, etc.; an output section 607 including a cathode ray tube (CRT), liquid crystal feedback (LCD), etc., and speakers, etc.; a storage section 608 including a hard disk, etc.; and a communication section 609 including a network interface card such as a LAN card, modem, etc. The communication section 609 performs communication processing via a network such as the Internet. A drive 610 is also connected to I / O interface 605 as needed. A removable medium 611, such as a disk, optical disk, magneto-optical disk, semiconductor memory, etc., is installed on drive 610 as needed so that computer programs read from it can be installed in storage section 608 as needed.

[0095] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0096] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0097] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0098] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0099] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can be applied as a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0100] This application can be described in the general context of computer-executable instructions, such as program modules, that are executed by a computer. Generally, program modules include routines, programs, objects, components, data structures, etc., that perform a specific task or implement a specific abstract data type. This application can also be practiced in distributed computing environments where tasks are performed by remote processing devices connected via a communication network. In distributed computing environments, program modules can reside in local and remote computer storage media, including storage devices.

[0101] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

[0102] The above description is merely an embodiment of this application and is not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A magnetic storage unit, characterized in that, It includes a spin-orbit coupling layer and multiple magnetic tunnel junctions disposed on the spin-orbit coupling layer; The spin-orbit coupling layer includes at least three branches oriented in different directions for inputting spin-orbit torque currents respectively; At least two of the aforementioned branches each have at least one magnetic tunnel junction, and the easy magnetization directions of the plurality of magnetic tunnel junctions are the same; wherein, The spin-orbit coupling layer includes three branches—a first branch, a second branch, and a third branch—arranged in different directions. A first magnetic tunnel junction and a second magnetic tunnel junction are respectively provided on the first branch and the second branch; When at least two of the first, second, and third signals are input along the ends of the first, second, and third branches respectively, a first spin-orbit moment current, a second spin-orbit moment current, and a third spin-orbit moment current are formed on the first, second, and third branches respectively, so that the combination of the resistance states of the plurality of magnetic tunnel junctions is different, thereby realizing the one-time writing of data of the plurality of magnetic tunnel junctions.

2. The magnetic storage unit according to claim 1, characterized in that, The first branch, the second branch, and the third branch include a first direction toward the center of the spin-orbit coupling layer and a second direction opposite to the first direction; If the first spin orbital moment current is oriented in the first direction and is greater than the critical flip current of the first magnetic tunnel junction, the first magnetic tunnel junction is in the first resistive state. If the second spin orbital moment current is oriented in the first direction and is greater than the critical flip current of the second magnetic tunnel junction, the resistive state of the second magnetic tunnel junction is the second resistive state. If the second spin orbital moment current is oriented in the second direction and is greater than the critical flip current of the second magnetic tunnel junction, the resistance state of the second magnetic tunnel junction is the third resistance state. If the first spin orbital moment current is oriented in the second direction and is greater than the critical flip current of the first magnetic tunnel junction, the first magnetic tunnel junction is in the fourth resistive state.

3. The magnetic storage unit according to claim 2, characterized in that, A third magnetic tunnel junction is provided on the third branch road; If the third spin orbital moment current is oriented in the first direction and is greater than the critical flip current of the third magnetic tunnel junction, the resistance state of the third magnetic tunnel junction is the fifth resistance state. If the third spin orbital moment current is oriented in the second direction and is greater than the critical flip current of the third magnetic tunnel junction, the resistance state of the third magnetic tunnel junction is the sixth resistance state.

4. The magnetic storage unit according to claim 1, characterized in that, The direction of the easy magnetic axis of the plurality of magnetic tunnel junctions forms an angle with the direction of the corresponding branch.

5. The magnetic storage unit according to claim 1, characterized in that, The spin-orbit coupling layer is Y-shaped, T-shaped, or star-shaped radial.

6. The magnetic storage unit according to claim 1, characterized in that, The magnetic tunnel junction has a non-perfectly symmetrical shape.

7. The magnetic storage unit according to claim 6, characterized in that, The magnetic tunnel junction is shaped as an ellipse, triangle, rectangle, or semicircle.

8. The magnetic storage unit according to claim 1, characterized in that, At least one of the magnetic tunnel junctions has vertical anisotropy, and the magnetic storage cell further includes an applied magnetic field or an equivalent applied magnetic field; or, at least one of the magnetic tunnel junctions has in-plane anisotropy.

9. A computer device, characterized in that, It includes a memory and / or a processor, wherein the memory and / or the processor includes a magnetic storage unit as described in any one of claims 1-8.

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