Magnetic multilayer film and magnetic memory

Abstract

The application discloses a magnetic multilayer film and a magnetic memory. The magnetic multilayer film comprises a first magnetic layer and a magnetic memory device. The magnetic memory device comprises a second magnetic layer and a magnetic memory unit. The second magnetic layer is stacked with the first magnetic layer. The magnetic memory unit is stacked with the interface of the second magnetic layer which is away from the first magnetic layer. The size of the first magnetic layer is greater than the size of the second magnetic layer and the size of the magnetic memory unit. The shape of the first magnetic layer is long strip. Due to the shape anisotropy, the magnetic moment of the first magnetic layer is arranged along the long side direction. The magnetic moment of the first magnetic layer and the magnetic moment of the second magnetic layer are coupled with each other. Due to the coupling effect, the magnetic moment of the second magnetic layer is also arranged along the long side direction of the first magnetic layer. Therefore, the second magnetic layer can introduce a stable in-plane magnetic field, and the magnetic memory device is arranged in multiple, thereby increasing the storage density of the magnetic memory.

Description

Technical Field

[0001] This invention relates to the field of magnetic storage technology, and in particular to a magnetic multilayer film and a magnetic memory. Background Technology

[0002] Magnetic multilayer films, especially magnetic tunnel junction (MTJ) structures, have been widely used in magnetic sensors and magnetic random access memories (MRAMs). For spin-orbit moment magnetic random access memories (SOT-MRAMs), an additional in-plane magnetic field must be applied to break their symmetry in order to achieve deterministic flipping of the free layer. For voltage-controlled magnetic random access memories (VC-MRAMs), an additional in-plane magnetic field is also required as an effective field for the precession of the free layer, inducing ultrafast precession of the free layer, thereby achieving the flipping of the free layer.

[0003] Setting up a magnetic hard mask layer is one of the main methods for embedding an in-plane magnetic field. The magnetic hard mask layer consists of a relatively thick layer of magnetic material, and the magnetic material disperses a magnetic field to provide an in-plane magnetic field in a specific direction. However, the fabrication of magnetic hard masks in existing technologies can only be used for a single magnetic storage device, and the area of ​​the magnetic hard mask layer is relatively large, greatly reducing the storage density of the magnetic storage device. Summary of the Invention

[0004] Therefore, it is necessary to provide a magnetic multilayer film and a magnetic memory to solve the technical problem of low storage density in existing magnetic memory devices.

[0005] The present invention provides a magnetic multilayer film comprising:

[0006] A first magnetic layer, wherein the shape of the first magnetic layer is elongated; and

[0007] A magnetic storage device is provided, wherein multiple magnetic storage devices are configured, each magnetic storage device includes a second magnetic layer and a magnetic storage unit, the second magnetic layer is stacked with a first magnetic layer, the magnetic storage unit is stacked with the second magnetic layer at the interface opposite to the first magnetic layer, the magnetic moment of the first magnetic layer is coupled to the magnetic moment of the second magnetic layer, and the size of the first magnetic layer is larger than the size of the second magnetic layer and the size of the magnetic storage unit.

[0008] Furthermore, the shape and size of the second magnetic layer are the same as those of the magnetic storage cell.

[0009] Furthermore, the second magnetic layer and the magnetic storage cell are cylindrical or elliptical in shape.

[0010] Furthermore, the material of the first magnetic layer includes one or more combinations of CoFeB, CoFe, Co, Ni, FeB, and CoFeSi.

[0011] Furthermore, the magnetic storage device further includes a first non-magnetic layer, which is stacked between the second magnetic layer and the magnetic storage cell.

[0012] Furthermore, the material of the first non-magnetic layer includes one or more combinations of Ta, TiN, Cu, and W.

[0013] Furthermore, the magnetic storage device further includes a second non-magnetic layer, which is stacked on the interface of the magnetic storage cell on the side opposite to the first magnetic layer.

[0014] Furthermore, the magnetic storage device further includes a third non-magnetic layer, which is stacked between the first magnetic layer and the second magnetic layer.

[0015] Furthermore, the first magnetic layer serves as, or in part serves as, an interconnect layer in the CMOS back-end process.

[0016] The present invention also provides another magnetic multilayer film, comprising:

[0017] The third magnetic layer is elongated in shape.

[0018] A fourth non-magnetic layer, wherein the fourth non-magnetic layer is stacked with the third magnetic layer; and

[0019] A magnetic storage unit is stacked with the fourth non-magnetic layer on the interface opposite to the third magnetic layer, and the size of both the third magnetic layer and the fourth non-magnetic layer is larger than the size of the magnetic storage unit.

[0020] The present invention also provides a magnetic memory comprising the above-described magnetic multilayer film.

[0021] The present invention provides a magnetic multilayer film, comprising a first magnetic layer and a magnetic storage device. The first magnetic layer is elongated in shape so that the magnetic moment of the first magnetic layer tends to be oriented along the long side. The magnetic moments of the first magnetic layer are coupled with the magnetic moments of a second magnetic layer. The magnetic moments of the second magnetic layer also tend to be aligned along the long side of the first magnetic layer to introduce an in-plane magnetic field. The second magnetic layer and the magnetic storage cells constitute a magnetic storage device, and multiple magnetic storage devices are configured to increase the storage density of the magnetic storage device. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention 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 the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of a magnetic multilayer film in an embodiment of the present invention.

[0024] Figure 2 This is a perspective view of a magnetic multilayer film according to an embodiment of the present invention.

[0025] Figure 3 This is a schematic diagram of a magnetic multilayer film with a third non-magnetic layer in an embodiment of the present invention.

[0026] Figure 4 This is a schematic diagram of a magnetic multilayer film that introduces an in-plane magnetic field from the bottom in an embodiment of the present invention.

[0027] Figure 5 This is a schematic diagram of a magnetic multilayer film with a third non-magnetic layer that introduces an in-plane magnetic field from the bottom, according to an embodiment of the present invention.

[0028] Figure 6 This is a schematic diagram of a magnetic multilayer film in another embodiment of the present invention.

[0029] Figure 7 This is a schematic diagram of a magnetic multilayer film in another embodiment of the present invention.

[0030] in:

[0031] 100, First magnetic layer; 210, Second magnetic layer; 220, Magnetic storage unit; 300, First non-magnetic layer; 400, Second non-magnetic layer; 500, Third non-magnetic layer; 600, Third magnetic layer; 700, Fourth non-magnetic layer; 800, Fifth non-magnetic layer.

[0032] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0033] 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 a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0034] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0035] Furthermore, the use of terms such as "first" and "second" in this invention is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the term "and / or" throughout the text includes three solutions; taking A and / or B as an example, it includes technical solution A, technical solution B, and a technical solution that simultaneously satisfies A and B. Furthermore, the technical solutions of various embodiments can be combined with each other, but this must be based on the ability of a person skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0036] like Figure 1 and Figure 2 As shown, in some embodiments, a magnetic multilayer film includes a first magnetic layer 100 and magnetic storage devices. The first magnetic layer 100 is elongated in shape, and multiple magnetic storage devices are provided. Each magnetic storage device includes a second magnetic layer 210 and magnetic storage cells 220 (magnetic storage cells 220 refer to magnetic storage device cells including SOT-MRAM or VC-MRAM, i.e., a multilayer film system composed of tunnel junctions, buffer layers, and capping layers). The second magnetic layer 210 is stacked with the first magnetic layer 100. The interface between the magnetic storage cells 220 and the second magnetic layer 210 on the side away from the first magnetic layer 100 (i.e., the interface where the surfaces of the first magnetic layer 100 and the second magnetic layer 210 are in contact) is stacked. The magnetic moment of the first magnetic layer 100 is coupled to the magnetic moment of the second magnetic layer 210. The size of the first magnetic layer 100 is larger than the size of the second magnetic layer 210 and the size of the magnetic storage cells 220, respectively.

[0037] The second magnetic layer 210 provides an in-plane magnetic field. The first magnetic layer 100 is elongated in shape so that the magnetic moment direction of the first magnetic layer 100 tends to be along its longer side. The magnetic moments of the first magnetic layer 100 and the second magnetic layer 210 are coupled to each other. The magnetic moments of the second magnetic layer 210 also tend to align along the longer side of the first magnetic layer 100 to introduce an in-plane magnetic field. Figure 1The direction of the magnetic field lines of the second magnetic layer 210 is shown in the figure (the magnetic field dissipating the magnetic storage cell 220 is along the in-plane direction). The second magnetic layer 210 and the magnetic storage cell 220 constitute a magnetic storage device, and multiple magnetic storage devices are provided to increase the storage density of the magnetic storage device.

[0038] Currently, another method for embedding in-plane magnetic fields is the antiferromagnetic pinning in-plane magnetic layer. This layer mainly consists of a layer of antiferromagnetic material (such as IrMn, PtMn, etc.) and a layer of in-plane magnetized ferromagnetic material (such as CoFe, NiFe, etc.). The antiferromagnetic material provides an interface pinning effect and generates an exchange bias, causing the magnetic moment of the ferromagnetic material to tend towards a predetermined in-plane direction, and providing an in-plane diffuse magnetic field. However, due to the limited distribution range of antiferromagnetic material grain size, etching the thin film material into small devices, especially when the size is less than 100 nm, significantly reduces the antiferromagnetic exchange bias field, thus affecting the stability of the in-plane magnetic field. Furthermore, increased temperature can also weaken the strength of the in-plane pinning field, further affecting the stability of the magnetic field. In this invention, the first magnetic layer 100 is elongated and integrated with multiple magnetic storage devices. The first magnetic layer 100 is coupled to the second magnetic layer 210, thereby enhancing the stability of the magnetic field of the second magnetic layer 210.

[0039] Specifically, such as Figure 2 As shown, a is the length of the first magnetic layer 100, b is the width of the first magnetic layer 100, and c is the thickness of the first magnetic layer 100, where a > b. b is greater than the dimensions of the second magnetic layer 210 and the magnetic storage cell 220. The specific dimensions of the first magnetic layer 100, the second magnetic layer 210, and the magnetic storage cell 220 need to be determined based on the magnitude of the introduced magnetic field and the CMOS back-end process parameters. CMOS (Complementary Metal Oxide Semiconductor) refers to a technology used to manufacture large-scale integrated circuit chips or chips manufactured using this technology.

[0040] More specifically, the second magnetic layer 210 has the same shape and size as the magnetic storage cell 220, so that space can be saved when the second magnetic layer 210 and the magnetic storage cell 220 are stacked. The second magnetic layer 210 can be a cylinder or an elliptical cylinder. The second magnetic layer 210 alone cannot provide a stable, fixed-direction in-plane magnetic field. The first magnetic layer 100 is elongated. Due to its anisotropic shape, the magnetic moment of the first magnetic layer 100 is directed along its long side. At the same time, by adjusting the distance between the first magnetic layer 100 and the second magnetic layer 210, a strong coupling effect is formed between the two, so that the magnetic moment of the second magnetic layer 210 also has anisotropy, thereby enhancing the stability of the second magnetic layer 210.

[0041] Furthermore, the material of the first magnetic layer 100 includes one or more combinations of CoFeB, CoFe, Co, Ni, FeB, and CoFeSi. Even further, the material of the second magnetic layer 210 includes one or more combinations of CoFeB, CoFe, Co, Ni, FeB, and CoFeSi.

[0042] In this embodiment, the magnetic storage device further includes a first non-magnetic layer 300, which is stacked between the second magnetic layer 210 and the magnetic storage cell 220. The strength of the dispersive magnetic field is adjusted by regulating the thickness of the first non-magnetic layer 300. The first non-magnetic layer 300 can be constructed using CMOS process-compatible metal materials, or it can be a metal mask material for magnetic tunnel junctions (such as Ta, TiN, etc.), or it can be a conductive material for semiconductor back-end processes (such as a combination of Cu, W, TiN, etc.). It should be noted that multiple second magnetic layers 210 and multiple magnetic storage cells 220 are disposed below the first magnetic layer 100. The first magnetic layer 100 can serve as or partially serve as an interconnect layer in the CMOS back-end process (such as 90nm aluminum interconnect process, 28nm Cu interconnect process, etc.). In actual operation, the first non-magnetic layer 300 may not be provided, that is, the second magnetic layer 210 can be directly deposited on the magnetic storage cell 220.

[0043] Furthermore, the magnetic storage device also includes a second non-magnetic layer 400, which is stacked on the interface of the magnetic storage cell 220 on the side opposite to the first magnetic layer 100. Specifically, the second non-magnetic layer 400 is a non-magnetic metal layer. The second non-magnetic layer 400 can be a conductive material used in semiconductor back-end processes (such as a combination of Cu, W, TiN, etc.), or a heavy metal material (including but not limited to metals such as Ta, W, Pt, Cr, or their alloys) that generates spin current in SOT-MRAM.

[0044] Furthermore, such as Figure 3 As shown, the magnetic storage device also includes a third non-magnetic layer 500, which is stacked between the first magnetic layer 100 and the second magnetic layer 210. The thickness of the third non-magnetic layer 500 can be adjusted to regulate the coupling strength between the first magnetic layer 100 and the second magnetic layer 210, and to meet the requirements of CMOS back-end process integration parameters. The third non-magnetic layer 500 can be constructed using CMOS process-compatible metal materials, such as metal mask materials for magnetic tunnel junctions (e.g., Ta, TiN), or conductive materials for semiconductor back-end processes (e.g., a combination of Cu, W, TiN, etc.).

[0045] Figure 4This diagram illustrates a magnetic multilayer film that introduces an in-plane magnetic field from the bottom in an embodiment of the present invention (without a third non-magnetic layer 500).

[0046] Figure 5 This is a schematic diagram of a magnetic multilayer film having a third non-magnetic layer 500 that introduces an in-plane magnetic field from the bottom, as described in an embodiment of the present invention.

[0047] Figure 6 Another embodiment of the magnetic multilayer film includes a third magnetic layer 600, a fourth non-magnetic layer 700, and a magnetic storage cell 220. The third magnetic layer 600 is elongated. The fourth non-magnetic layer 700 is stacked on top of the third magnetic layer 600. The magnetic storage cell 220 is stacked on the interface of the fourth non-magnetic layer 700 away from the third magnetic layer. The dimensions of both the third magnetic layer 600 and the fourth non-magnetic layer 700 are larger than the size of the magnetic storage cell 220. Because the fourth magnetic layer is elongated (its cross-section can be rectangular), it has an irregular shape to align the magnetic moments along its long side. Specifically, the thickness of the fourth magnetic layer is 2 nm to 100 nm. By adjusting the thickness of the fourth non-magnetic layer 700, the distance between the third magnetic layer 600 and the magnetic storage cell 220 can be adjusted, thereby adjusting the magnitude of the in-plane magnetic field. Specifically, the fourth non-magnetic layer 700 serves as an isolation layer, and its shape and size can be identical to those of the magnetic storage cell 220. It should be noted that for SOT-MRAM devices, the SOT source can be provided by at least one fourth non-magnetic layer 700 (generally composed of heavy metals Pt, W, Ta, and their alloys). In this case, the size of the fourth non-magnetic layer 700 can be larger than the size of the magnetic memory cell 220, and even larger than the size of the third magnetic layer 600. It serves as the SOT current channel, and multiple magnetic memory cells 220 can be integrated on top of it simultaneously.

[0048] like Figure 7 As shown, to obtain a larger static magnetic field, the fourth non-magnetic layer 700 can be omitted, meaning the third magnetic layer 600 and the magnetic storage cell 220 are stacked together. The magnetic multilayer film also includes a fifth non-magnetic layer 800, which is disposed at the interface of the magnetic storage cell 220 on the side opposite to the third magnetic layer 600.

[0049] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A magnetic multilayer film, characterized in that, include: The first magnetic layer is elongated in shape. and A magnetic storage device is provided, comprising multiple magnetic storage devices, each including a second magnetic layer and a magnetic storage unit. The second magnetic layer is stacked with a first magnetic layer, and the magnetic storage unit is stacked with the interface of the second magnetic layer on the side opposite to the first magnetic layer. The magnetic moments of the first magnetic layer and the second magnetic layer are coupled to each other. The size of the first magnetic layer is larger than the size of the second magnetic layer and the size of the magnetic storage unit, respectively. The magnetic storage device also includes a first non-magnetic layer and a third non-magnetic layer. The first non-magnetic layer is stacked between the second magnetic layer and the magnetic storage unit, and the third non-magnetic layer is stacked between the first magnetic layer and the second magnetic layer, introducing an in-plane magnetic field from the bottom. The magnetic moments of the first magnetic layer are oriented towards the long side, and the magnetic moments of the second magnetic layer are also oriented towards the long side of the first magnetic layer to introduce an in-plane magnetic field; the thickness of the first non-magnetic layer is adjusted to adjust the strength of the in-plane magnetic field.

2. The magnetic multilayer film according to claim 1, characterized in that, The shape and size of the second magnetic layer are the same as those of the magnetic storage cell.

3. The magnetic multilayer film according to claim 1, characterized in that, The second magnetic layer and the magnetic storage unit are cylindrical or elliptical in shape.

4. The magnetic multilayer film according to claim 1, characterized in that, The material of the first magnetic layer includes one or more combinations of CoFeB, CoFe, Co, Ni, FeB, and CoFeSi.

5. The magnetic multilayer film according to claim 1, characterized in that, The material of the first non-magnetic layer includes one or more combinations of Ta, TiN, Cu, and W.

6. The magnetic multilayer film according to claim 1, characterized in that, The magnetic storage device further includes a second non-magnetic layer, which is stacked on the interface of the magnetic storage cell on the side opposite to the first magnetic layer.

7. The magnetic multilayer film according to claim 1, characterized in that, The first magnetic layer serves as, or partially serves as, an interconnect layer in the CMOS back-end process.

8. A magnetic storage device, characterized in that, The magnetic memory includes the magnetic multilayer film according to any one of claims 1 to 7.

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