Magnetic memory

Abstract

The application provides a magnetic memory, comprising: a first electrode; at least two magnetic tunnel junctions, the at least two magnetic tunnel junctions being arranged in the coverage of the first electrode; a first surface of the magnetic tunnel junction being electrically connected with a first surface of the first electrode; and at least one first metal plug, the first metal plug being electrically connected with a second surface of the first electrode. The magnetic memory provided by the application can share one first electrode by changing the array structure, so that the magnetic tunnel junctions can have higher temperature in the writing process and the writing voltage can be reduced.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and more particularly to a magnetic memory. Background Technology

[0002] Magnetic random access memory (MRAM) is a promising new type of memory due to its fast read / write speeds, low power consumption, high density, and integration with CMOS technology. The magnetic tunnel junction (MTJ) is the core unit of an MRAM chip, primarily composed of a magnetic free layer, an insulating layer, and a magnetic reference layer. One MRAM is called one bit. The magnetic free layer can change its state through a magnetic field or spin-polarized current. The relative relationship between the magnetic free layer and the reference layer (parallel / antiparallel state) determines the resistance of the bit, thus storing "0" or "1" information.

[0003] In existing technologies, to reduce the switching voltage and improve the lifespan of magnetic tunnel junctions (MTJs), the following methods are commonly used: First, a thermotropic phase change material with antiferromagnetic to ferromagnetic properties is added to the original film layer of the MT. The magnetic properties of the phase change material are induced by the thermal effect of current, which assists in the switching of the MT and reduces the switching voltage. Second, a piezoelectric material is added to the original film layer. The deformation of the piezoelectric material when current passes through it generates stress, reducing the magnetic anisotropy of the free layer and thus decreasing the critical switching voltage of the MT. However, these existing technologies all involve altering the film structure of the MT, requiring significant changes to the manufacturing process and increasing costs. Summary of the Invention

[0004] The magnetic memory provided by this invention can reduce heat loss of the magnetic tunnel junctions during the writing process by changing the array structure so that multiple magnetic tunnel junctions share a first electrode, thereby enabling the magnetic tunnel junctions to have a higher temperature during the writing process and reducing the writing voltage.

[0005] This invention provides a magnetic memory, comprising:

[0006] First electrode;

[0007] At least two magnetic tunnel junctions are provided, with the coverage area of ​​the at least two magnetic tunnel junctions being disposed within the coverage area of ​​the first electrode; the first surface of the magnetic tunnel junction is electrically connected to the first surface of the first electrode.

[0008] At least one first metal plug, the first metal plug being electrically connected to the second surface of the first electrode.

[0009] Optionally, the first metal plug is positioned at the axis of symmetry of two adjacent magnetic tunnel junctions; and / or,

[0010] The magnetic tunnel junction is positioned at the axis of symmetry between two adjacent first metal plugs.

[0011] Optionally, it also includes:

[0012] The second electrode has its first surface electrically connected to the second surface of the magnetic tunnel junction.

[0013] A second metal plug, wherein the first surface of the second metal plug is electrically connected to the second surface of the second electrode; wherein...

[0014] The axis of the second metal plug and the axis of the corresponding magnetic tunnel junction are spaced apart.

[0015] Optionally, the second metal plug and the second electrode are electrically connected via a first contact structure; wherein,

[0016] The first contact structure is a contact post structure or a contact film structure.

[0017] Optionally, the first contact structure is prepared using one or more of tantalum, tantalum nitride, titanium, and titanium nitride.

[0018] Optionally, the first metal plug and the second metal plug are made of one or both of copper and tungsten.

[0019] Optionally, it further includes a first metal layer electrically connected to the first metal plug and a second metal layer electrically connected to the second metal plug;

[0020] The first metal layer and the second metal layer are prepared using one or both of copper and aluminum.

[0021] Optionally, the first electrode and the second electrode are prepared using one or both of tantalum nitride and titanium nitride.

[0022] Optionally, the number of magnetic tunnel junctions is one more than the number of first metal plugs, and the first metal plugs are located at the axis of symmetry between two adjacent magnetic tunnel junctions.

[0023] Optionally, the number of the first metal plugs is one more than the number of magnetic tunnel junctions, and the magnetic tunnel junctions are arranged at symmetrical positions between two adjacent first metal plugs.

[0024] The technical solution provided by this invention modifies the entire array structure, allowing multiple magnetic tunnel junctions to share a single first electrode. This extends the heat dissipation path of the magnetic tunnel junction, increases thermal resistance, and reduces heat loss during the writing process. Consequently, the magnetic tunnel junction maintains a higher temperature during writing, reducing the writing voltage. Furthermore, since this invention does not alter the film structure of the magnetic tunnel junction, the fabrication process remains unchanged, utilizing existing techniques, which helps reduce process development costs. Attached Figure Description

[0025] Figure 1a This is a schematic diagram of the structure of a magnetic memory according to an embodiment of the present invention;

[0026] Figure 1b for Figure 1a Simulation results of magnetic storage;

[0027] Figure 2 This is a schematic diagram of the structure of a magnetic memory according to an embodiment of the present invention;

[0028] Figure 3 This is a schematic diagram of the structure of a magnetic memory according to an embodiment of the present invention;

[0029] Figure 4 This is a schematic diagram of the structure of a magnetic memory according to an embodiment of the present invention;

[0030] Figure 5 This is a schematic diagram of the structure of a magnetic memory according to an embodiment of the present invention;

[0031] Figure 6 This is a schematic diagram of the structure of a magnetic memory according to an embodiment of the present invention;

[0032] Figure 7a This is a schematic diagram of the structure of a conventional magnetic memory.

[0033] Figure 7b for Figure 7a Simulation results of magnetic memory. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] This invention provides a magnetic memory, comprising:

[0036] First electrode; in some embodiments, the first electrode is an electrode used to electrically connect the magnetic tunnel junction to an external signal source;

[0037] At least two magnetic tunnel junctions are provided, with the coverage area of ​​the at least two magnetic tunnel junctions being disposed within the coverage area of ​​the first electrode; the first surface of the magnetic tunnel junction is electrically connected to the first surface of the first electrode; in some embodiments, in a top view, at least two magnetic tunnels are located within the coverage area of ​​the first electrode, thereby enabling at least two magnetic tunnel junctions to share the same first electrode.

[0038] At least one first metal plug is provided, the first metal plug being electrically connected to the second surface of the first electrode, and the axis of the first metal plug being spaced apart from the axis of the magnetic tunnel junction. In some embodiments, the axis of the first metal plug is spaced apart from the axis of the magnetic tunnel junction, so that heat dissipation from the magnetic tunnel junction requires a longer first electrode length to reach the first metal plug before dissipating outward.

[0039] The technical solution provided by this invention modifies the entire array structure, allowing multiple magnetic tunnel junctions to share a single first electrode. This extends the heat dissipation path of the magnetic tunnel junction, increases thermal resistance, and reduces heat loss during the writing process. Consequently, the magnetic tunnel junction maintains a higher temperature during writing, reducing the writing voltage. Furthermore, since this invention does not alter the film structure of the magnetic tunnel junction, the fabrication process remains unchanged, utilizing existing techniques, which helps reduce process development costs.

[0040] As an optional implementation, the first metal plug is positioned at the axis of symmetry of two adjacent magnetic tunnel junctions; and / or, the magnetic tunnel junction is positioned at the axis of symmetry of two adjacent first metal plugs. In this embodiment, by symmetrically positioning the first metal plugs about the magnetic tunnel junctions, or symmetrically positioning the magnetic tunnel junctions about the first metal plugs, the heat dissipation path of each magnetic tunnel junction is the same, ensuring that the heat dissipation rate of each magnetic tunnel junction is the same. Therefore, the thermal parameters of each magnetic tunnel junction are the same during the writing process.

[0041] As an optional implementation, it also includes:

[0042] The second electrode has its first surface electrically connected to the second surface of the magnetic tunnel junction.

[0043] The second metal plug has a first surface electrically connected to the second surface of the second electrode; wherein the axis of the second metal plug and the corresponding magnetic tunnel junction axis are spaced apart.

[0044] In this embodiment, the second electrode, the second metal plug, and the magnetic tunnel junction have a one-to-one correspondence. The axis of the second metal plug is spaced apart from the axis of the corresponding magnetic tunnel junction. Therefore, the second electrode needs to be longer to electrically connect the magnetic tunnel junction to the second metal plug. Consequently, the magnetic tunnel junction in this embodiment has a longer heat dissipation path through the second metal plug, which reduces the heat dissipation rate. This results in a higher temperature of the magnetic tunnel junction during writing, further reducing the switching voltage.

[0045] As an optional implementation, the second metal plug and the second electrode are electrically connected through a first contact structure; wherein the first contact structure is a contact post structure or a contact film structure.

[0046] In this embodiment, the second metal plug and the second electrode are electrically connected through a first contact structure. The first contact structure can be a contact post structure or a contact film structure. In some preferred embodiments, the contact post structure has a longer heat dissipation path, which is more conducive to increasing the temperature of the magnetic tunnel junction and reducing the switching voltage of the magnetic tunnel junction.

[0047] As an optional implementation, the first contact structure is prepared using one or more of tantalum, tantalum nitride, titanium, and titanium nitride. In some embodiments, the material of the first contact structure includes, but is not limited to, tantalum, tantalum nitride, titanium, and titanium nitride, and can be a single metal material, a combination of multiple metal materials, or a metal compound, with materials having low thermal conductivity being preferred.

[0048] As an optional implementation, the first and second metal plugs are made of one or both of copper and tungsten. In some embodiments, the materials used for the first and second metal plugs include, but are not limited to, low-resistivity and easily filled materials such as copper and tungsten. Since the fabrication process of the first and second metal plugs typically involves filling the via with conductive material, easily filled materials are required to ensure the formation of the metal plugs. Furthermore, since the metal plugs are used to electrically connect the magnetic tunnel junction to an external signal source, they need to have good conductivity.

[0049] As an optional implementation, the system further includes a first metal layer electrically connected to the first metal plug and a second metal layer electrically connected to the second metal plug; the first metal layer and the second metal layer are made of one or both of copper and aluminum. In some embodiments, since the first metal layer and the second metal layer are used to electrically connect the metal plug to an external signal source and have a relatively long distance between them, a low-resistance material is required.

[0050] As an optional implementation, the first and second electrodes are fabricated using one or both of tantalum nitride and titanium nitride. In some embodiments, the first and second electrodes use materials including, but not limited to, low thermal conductivity materials such as tantalum nitride and titanium nitride. Using low thermal conductivity materials for the first and second electrodes can reduce the heat dissipation rate of the magnetic tunnel junction, increase the temperature of the magnetic tunnel junction during the writing process, and further reduce the switching voltage.

[0051] As an optional implementation, the number of magnetic tunnel junctions is one more than the number of first metal plugs, and the first metal plugs are located at the axis of symmetry of two adjacent magnetic tunnel junctions.

[0052] As an optional implementation, the number of first metal plugs is one more than the number of magnetic tunnel junctions, and the magnetic tunnel junctions are arranged symmetrically on two adjacent first metal plugs.

[0053] In the above embodiments, the first metal plug can be set as the top metal plug, the first electrode as the top electrode, and the second metal plug as the bottom metal plug, with the second electrode also set as the bottom electrode. Alternatively, the first metal plug can be set as the bottom metal plug, the second electrode as the bottom electrode, and the second metal plug as the top metal plug, with the second electrode also set as the top electrode.

[0054] The following simulation compares the array structure of the prior art with the technical solution provided by the specific embodiments of the present invention:

[0055] like Figure 1a The figure shows a technical solution provided by a specific embodiment of the present invention, which uses two magnetic tunnel junctions and a first metal plug as a group, and sets the first metal plug at the position of the axis of symmetry of the two magnetic tunnel junctions. Figure 7a This is a technical solution in the prior art. Based on the structural characteristics of a magnetic memory array, all magnetic tunnel junction bits under the same metal line are connected to the same top metal line through their respective top electrodes and top vias. This means that the top electrodes of different magnetic tunnel junctions are at the same potential without considering the voltage distribution of the line components. By connecting the top electrodes of every two magnetic tunnel junctions and sharing a top via connecting to the top metal line at the midpoint between the two magnetic tunnel junctions (i.e., two magnetic tunnel junctions sharing one top via), the length of the top electrode in the heat conduction path can be increased, thus increasing the thermal resistance of the top electrode. In this embodiment, the top electrode is the first electrode, the top via is the first metal plug, and the top metal line is the metal line in the first metal layer. Figure 1b and Figure 7b As can be seen from the comparison, by using the array structure in this embodiment, the temperature of the MgO tunneling layer is increased by about 35°C, that is, a temperature increase of more than 30% can be achieved.

[0056] like Figure 2The figure shows a technical solution provided by a specific embodiment of the present invention. Based on the characteristics of equipotentiality, it is possible to connect the top electrodes on all magnetic tunnel junctions into a whole line like a top metal wire. Top through holes are placed at the positions between every two magnetic tunnel junctions and at the outermost half-space from both ends, forming the effect of n magnetic tunnel junctions sharing n+1 top through holes. Figure 7a This is a technical solution in the prior art. In this embodiment, the top electrode is the first electrode, the top through-hole is the first metal plug, and the top metal wire is the metal wire in the first metal layer. Using the array structure in this embodiment, the temperature of the tunneling layer MgO can be increased by 25%.

[0057] like Figure 3 The diagram illustrates a technical solution provided by a specific embodiment of the present invention, showing the arrangement of the top metal and the top electrode as described above. Figure 1a The setup is the same as in the previous one. The difference is that the axes of the bottom electrode and the bottom via are spaced apart, thereby further increasing the equivalent thermal resistance length of the bottom electrode and increasing the temperature of the subtunnel junction when energized. Figure 7a This is a technical solution in the prior art. Using the array structure in this embodiment, the temperature of the MgO tunneling layer can be increased by 50%.

[0058] like Figure 4 The diagram illustrates a technical solution provided by a specific embodiment of the present invention, showing the arrangement of the top metal and the top electrode as described above. Figure 2 The setup is the same as in the previous one. The difference is that the axes of the bottom electrode and the bottom via are spaced apart, thereby further increasing the equivalent thermal resistance length of the bottom electrode and increasing the temperature of the subtunnel junction when energized. Figure 7a This is a technical solution in the prior art. Using the array structure in this embodiment, the temperature of the MgO tunneling layer can be increased by 40%.

[0059] like Figure 5 The diagram illustrates a technical solution provided by a specific embodiment of the present invention, showing the arrangement of the top metal and the top electrode as described above. Figure 1a The setup is the same as in the previous example. The difference lies in that the bottom electrode and the bottom via are electrically connected through a first contact structure, while the bottom of the magnetic tunnel junction uses a contact pillar structure to electrically connect the bottom electrode and the bottom via. Furthermore, a material with low thermal conductivity, such as TaN, is used to fabricate the contact pillars, which allows the magnetic tunnel junction to have a larger equivalent thermal resistance length at the bottom. Figure 1a This can further increase the temperature of the magnetic tunnel junction itself. Figure 7a This is a technical solution in the prior art. Using the array structure in this embodiment, the temperature of the MgO tunneling layer can be increased by 70%.

[0060] like Figure 6The diagram illustrates a technical solution provided by a specific embodiment of the present invention, showing the arrangement of the top metal and the top electrode as described above. Figure 2 The setup is the same as in the previous example. The difference lies in that the bottom electrode and the bottom via are electrically connected through a first contact structure, while the bottom of the magnetic tunnel junction uses a contact pillar structure to electrically connect the bottom electrode and the bottom via. Furthermore, a material with low thermal conductivity, such as TaN, is used to fabricate the contact pillars, which allows the magnetic tunnel junction to have a larger equivalent thermal resistance length at the bottom. Figure 2 This can further increase the temperature of the magnetic tunnel junction itself. Figure 7a This is a technical solution in the prior art. Using the array structure in this embodiment, the temperature of the MgO tunneling layer can be increased by 60%.

[0061] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A magnetic storage device, characterized in that, include: First electrode; At least two magnetic tunnel junctions are provided, with the coverage area of ​​the at least two magnetic tunnel junctions being disposed within the coverage area of ​​the first electrode; the first surface of the magnetic tunnel junction is electrically connected to the first surface of the first electrode. At least one first metal plug is electrically connected to the second surface of the first electrode; the axis of the first metal plug is spaced apart from the axis of the magnetic tunnel junction; so that heat dissipation from the magnetic tunnel junction requires a longer transfer distance from the first electrode to the first metal plug.

2. The magnetic memory according to claim 1, characterized in that, The first metal plug is positioned at the axis of symmetry of two adjacent magnetic tunnel junctions; and / or, The magnetic tunnel junction is positioned at the axis of symmetry between two adjacent first metal plugs.

3. The magnetic storage device according to claim 1, characterized in that, Also includes: The second electrode has its first surface electrically connected to the second surface of the magnetic tunnel junction. A second metal plug, wherein the first surface of the second metal plug is electrically connected to the second surface of the second electrode; wherein... The axis of the second metal plug and the axis of the corresponding magnetic tunnel junction are spaced apart.

4. The magnetic memory according to claim 3, characterized in that, The second metal plug and the second electrode are electrically connected through a first contact structure; wherein, The first contact structure is a contact post structure or a contact film structure.

5. The magnetic memory according to claim 4, characterized in that, The first contact structure is prepared using one or more of tantalum, tantalum nitride, titanium, and titanium nitride.

6. The magnetic memory according to claim 3, characterized in that, The first metal plug and the second metal plug are made of one or both of copper and tungsten.

7. The magnetic memory according to claim 3, characterized in that, It also includes a first metal layer electrically connected to the first metal plug and a second metal layer electrically connected to the second metal plug; The first metal layer and the second metal layer are prepared using one or both of copper and aluminum.

8. The magnetic memory according to claim 3, characterized in that, The first electrode and the second electrode are prepared using one or both of tantalum nitride and titanium nitride.

9. The magnetic storage device according to claim 1, characterized in that, The number of magnetic tunnel junctions is one more than the number of first metal plugs, and the first metal plugs are located at the axis of symmetry between two adjacent magnetic tunnel junctions.

10. The magnetic memory according to claim 1, characterized in that, The number of the first metal plugs is one more than the number of magnetic tunnel junctions, and the magnetic tunnel junctions are arranged symmetrically between two adjacent first metal plugs.

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