A pinned ferromagnetic layer structure and method of manufacturing the same, electromagnetic device

Abstract

The application provides a pinned ferromagnetic layer structure, a manufacturing method thereof and an electromagnetic device. The pinned ferromagnetic layer structure comprises a substrate, a ferromagnetic layer to be pinned, and an antiferromagnetic layer which is wrapped around the ferromagnetic layer to be pinned. The direction of the magnetic moment of the antiferromagnetic layer is parallel to the direction of the pinning magnetic field required by the ferromagnetic layer to be pinned. The pinning of the ferromagnetic layer to be pinned is achieved by forming the antiferromagnetic layer on the side of the ferromagnetic layer to be pinned and making the direction of the magnetic moment of the antiferromagnetic layer parallel to the direction of the pinning magnetic field required by the ferromagnetic layer to be pinned. Since the antiferromagnetic layer is located on the side of the ferromagnetic layer to be pinned, no antiferromagnetic layer is required above and below the ferromagnetic layer to be pinned. Therefore, other additional layers such as buffer layers can be arranged above and below the ferromagnetic layer to be pinned without being affected by the antiferromagnetic layer, so that the pinning effect of the antiferromagnetic layer is not weakened due to lattice mismatch and material mixing at the interface, and the pinning effect is improved.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and in particular to a pinned ferromagnetic layer structure, its manufacturing method, and an electromagnetic device. Background Technology

[0002] Magnetic random access memory (MRAM) is one of the most promising new memory technologies, with the potential to replace dynamic random access memory (DRAM) and static random access memory (SRAM). The core structure of MRAM is the magnetic tunnel junction (MTJ), a sandwich structure consisting of two ferromagnetic layers and one tunneling layer. Of the two ferromagnetic layers, one layer's magnetization can be flipped by an electric current or magnetic field; this is called the free layer. The other layer's magnetization remains constant; this is called the reference layer (fixed layer). When the free and reference layers are parallel to each other, the MTJ is in a low-resistance state; when they are antiparallel, the MTJ is in a high-resistance state. These high and low resistance states can be used to store data "0" and "1". To improve data retention and stability, the magnetization of the reference layer needs to be able to resist interference from external magnetic fields, electromagnetic waves, and thermal effects.

[0003] To improve the stability of the reference layer magnetization, a pinning field is typically provided by an antiferromagnetic layer adjacent to the reference layer, or a synthetic antiferromagnetic structure is used to enhance its stability. This is achieved through a multilayer film structure consisting of an antiferromagnetic layer and a reference layer. This multilayer film structure requires bottom pinning to achieve better results; the antiferromagnetic layer / reference layer must be directly grown on the substrate as the bottom electrode of the MTJ, followed by the growth of the insulating layer and free layer of the MTJ. In SOT-MRAM, only top pinning is possible to achieve magnetic reversal of the SOT-driven free layer. However, top pinning results in weaker pinning due to the inability to grow a buffer layer, lattice mismatch, and intermixing at the interface. Nevertheless, in spin-based logic and memristor devices such as SOT-MRAM, pinning layers are necessary to improve the reliability of data processing and storage; the pinning effect directly impacts the reliability of data processing and storage. Summary of the Invention

[0004] This invention provides a pinned ferromagnetic layer structure, its manufacturing method, and an electromagnetic device to improve the pinning effect and solve the problems of complex pinning structures and insignificant pinning effects in existing technologies.

[0005] In a first aspect, the present invention provides a pinned ferromagnetic layer structure, the pinned ferromagnetic layer structure comprising a substrate, on which a ferromagnetic layer to be pinned is formed and an antiferromagnetic layer surrounding the ferromagnetic layer to be pinned, wherein the magnetic moment direction of the antiferromagnetic layer is parallel to the direction of the pinning magnetic field required by the ferromagnetic layer to be pinned.

[0006] In the above-described scheme, an antiferromagnetic layer is formed on the side of the ferromagnetic layer to be pinned, and the magnetic moment direction of the antiferromagnetic layer is parallel to the direction of the pinning magnetic field required by the ferromagnetic layer to be pinned, thereby achieving pinning of the ferromagnetic layer to be pinned. Compared with the multilayer film pinning method in the prior art, which uses a stacked arrangement of the ferromagnetic layer to be pinned and the antiferromagnetic layer, in this application, since the antiferromagnetic layer is located on the side of the ferromagnetic layer to be pinned, there is no need to set antiferromagnetic layers above or below the ferromagnetic layer to be pinned. This allows for the setting of other additional layers, such as buffer layers, above and below the ferromagnetic layer to be pinned, without being affected by the antiferromagnetic layer. This prevents the pinning effect of the antiferromagnetic layer from being weakened due to lattice mismatch and material mixing at the interface, thereby improving the pinning effect and solving the problems of complex pinning structures and insignificant pinning effects in the prior art. Furthermore, since the antiferromagnetic layer surrounds and wraps the side of the ferromagnetic layer to be pinned, it can protect the ferromagnetic layer from the influence of the surrounding environment.

[0007] In one specific implementation, the ferromagnetic layer to be pinned includes at least one ferromagnetic layer, and the antiferromagnetic layer at least surrounds and wraps around the side of one of the at least one ferromagnetic layers to improve the pinning effect of magnetic field pinning of the target ferromagnetic layer.

[0008] In one specific embodiment, the ferromagnetic layer to be pinned is a magnetic tunnel junction formed by sequentially stacking a free layer, an insulating layer, and a reference layer, wherein the free layer and the reference layer are separated by the insulating layer. Both the free layer and the reference layer are ferromagnetic layers, and an antiferromagnetic layer at least surrounds and encloses the sides of the free layer and / or the reference layer. This not only improves the pinning effect of magnetic field pinning of the free layer or the reference layer, but also does not affect the provision of other additional layers, such as buffer layers, on the surface of the free layer or the reference layer.

[0009] In one specific embodiment, the material of the ferromagnetic layer is CoFeB, Co, Ni, Fe, CoFe, NiFe, CoGd, CoTb, or La1. x Sr x MnO3, MnSb, MnAs, MnGa, Gd, Tb, Dy, EuO, Y3Fe5O 12 Any one of the materials or an alloy of any combination thereof; the antiferromagnetic layer is made of CoO. x FeO x NiO x CrOx MnO x Cr, IrMn, CoFeO x Any one of the following materials: PtMn, MnSe, MnS, MnTe, Mn2Au, CuMnAs.

[0010] In one specific embodiment, the ferromagnetic layer to be pinned is disc-shaped, the antiferromagnetic layer is annular-shaped, and the antiferromagnetic layer surrounds the side of the disc-shaped ferromagnetic layer to be pinned. Alternatively, the ferromagnetic layer to be pinned is cubic-shaped, the antiferromagnetic layer is rectangular annular-shaped, and the antiferromagnetic layer surrounds the side of the cubic-shaped ferromagnetic layer to be pinned.

[0011] In one specific implementation, the thickness of the antiferromagnetic layer surrounding the ferromagnetic layer to be pinned is from 0.5 nanometers to 500 micrometers to further improve the pinning effect while better protecting the ferromagnetic layer to be pinned from the influence of the surrounding environment.

[0012] Secondly, the present invention also provides a method for manufacturing a pinned ferromagnetic layer structure, the method comprising: providing a substrate; forming a ferromagnetic layer to be pinned on the substrate; forming an antiferromagnetic layer surrounding the ferromagnetic layer to be pinned; and adjusting the magnetic moment direction of the antiferromagnetic layer so that the magnetic moment direction of the antiferromagnetic layer is parallel to the direction of the pinning magnetic field required for the ferromagnetic layer to be pinned.

[0013] In the above-described scheme, an antiferromagnetic layer is formed on the side of the ferromagnetic layer to be pinned, and the magnetic moment direction of the antiferromagnetic layer is parallel to the direction of the pinning magnetic field required by the ferromagnetic layer to be pinned, thereby achieving pinning of the ferromagnetic layer to be pinned. Compared with the multilayer film pinning method in the prior art, which uses a stacked arrangement of the ferromagnetic layer to be pinned and the antiferromagnetic layer, in this application, since the antiferromagnetic layer is located on the side of the ferromagnetic layer to be pinned, there is no need to set antiferromagnetic layers above or below the ferromagnetic layer to be pinned. This allows for the setting of other additional layers, such as buffer layers, above and below the ferromagnetic layer to be pinned, without being affected by the antiferromagnetic layer. This prevents the pinning effect of the antiferromagnetic layer from being weakened due to lattice mismatch and material mixing at the interface, thereby improving the pinning effect and solving the problems of complex pinning structures and insignificant pinning effects in the prior art. Furthermore, since the antiferromagnetic layer surrounds and wraps the side of the ferromagnetic layer to be pinned, it can protect the ferromagnetic layer from the influence of the surrounding environment.

[0014] In one specific embodiment, forming the ferromagnetic layer to be pinned on the substrate includes: growing at least one ferromagnetic material layer on the substrate; and patterning the at least one ferromagnetic material layer into a ferromagnetic layer to be pinned containing at least one ferromagnetic layer by electron beam exposure and ion etching. Forming an antiferromagnetic layer surrounding the ferromagnetic layer to be pinned includes: growing an antiferromagnetic material around the ferromagnetic layer to be pinned, forming a ferromagnetic layer to be pinned that at least surrounds the side of one of the at least one ferromagnetic layers, thereby improving the pinning effect of magnetic field pinning of the target ferromagnetic layer.

[0015] In one specific embodiment, forming an antiferromagnetic layer surrounding the ferromagnetic layer to be pinned includes: growing an antiferromagnetic material around the ferromagnetic layer to be pinned using a sputtering process, wherein the incident angle between the sputtered ions and the substrate surface is greater than 0 degrees and less than 90 degrees. This facilitates the generation of antiferromagnetic material around the ferromagnetic layer to be pinned, improves the adhesion between the antiferromagnetic layer and the sides of the ferromagnetic layer to be pinned, and prevents the antiferromagnetic layer from detaching.

[0016] In one specific embodiment, adjusting the magnetic moment direction of the antiferromagnetic layer to be parallel to the direction of the pinning magnetic field required for the pinning ferromagnetic layer includes: vacuum annealing the substrate and the antiferromagnetic layer under the application of an external magnetic field; wherein the annealing temperature of the vacuum annealing is higher than the Nieer temperature of the antiferromagnetic layer, and the direction of the external magnetic field is parallel to the direction of the pinning magnetic field required for the pinning ferromagnetic layer. This facilitates adjusting the magnetic moment direction of the antiferromagnetic layer so that the magnetic moment direction within it is parallel to the direction of the pinning magnetic field required for the pinning ferromagnetic layer.

[0017] Thirdly, the present invention also provides an electromagnetic device comprising any of the aforementioned pinned ferromagnetic layer structures. Pinning of the ferromagnetic layer is achieved by forming an antiferromagnetic layer on the side of the ferromagnetic layer to be pinned, and by ensuring that the magnetic moment direction of the antiferromagnetic layer is parallel to the direction of the pinning magnetic field required for the ferromagnetic layer to be pinned. Compared with the multilayer film pinning method in the prior art, which uses a stacked arrangement of the ferromagnetic layer to be pinned and an antiferromagnetic layer, in this application, since the antiferromagnetic layer is located on the side of the ferromagnetic layer to be pinned, there is no need to set antiferromagnetic layers above or below the ferromagnetic layer to be pinned. This allows for the setting of additional layers, such as buffer layers, above and below the ferromagnetic layer to be pinned, without being affected by the antiferromagnetic layer. This prevents the pinning effect of the antiferromagnetic layer from being weakened due to lattice mismatch and material mixing at the interface, thereby improving the pinning effect and solving the problems of complex pinning structures and insignificant pinning effects in the prior art. Furthermore, because the antiferromagnetic layer surrounds and wraps the sides of the ferromagnetic layer to be pinned, it can protect the ferromagnetic layer to be pinned from the influence of the surrounding environment.

[0018] In one specific implementation, the electromagnetic device is a magnetic memory or a magnetic sensor to improve the effect of magnetic field pinning of the ferromagnetic layer to be pinned in the magnetic memory or magnetic sensor, while protecting the ferromagnetic layer to be pinned from the influence of the surrounding environment. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a pinned ferromagnetic layer structure provided in an embodiment of the present invention;

[0020] Figure 2 This is a schematic diagram of one step in the manufacturing process of a nailed ferromagnetic layer structure provided by an embodiment of the present invention;

[0021] Figure 3 This is a schematic diagram of sputtering an antiferromagnetic layer around a ferromagnetic layer to be pinned, provided by an embodiment of the present invention.

[0022] Figure 4 A flowchart illustrating a method for manufacturing a pinned ferromagnetic layer structure provided in an embodiment of the present invention;

[0023] Figure 5 This is a test structure diagram of a pinned ferromagnetic layer structure provided in an embodiment of the present invention;

[0024] Figure 6 A magnetization curve of a vertically anisotropic sample based on lateral pinning provided for an embodiment of the present invention;

[0025] Figure 7 This is a magnetization curve of an in-plane anisotropic sample based on lateral pinning, provided as an embodiment of the present invention.

[0026] Figure label:

[0027] 10-Substrate 20-Ferromagnetic layer to be pinned

[0028] 30-Antiferromagnetic layer 40-Conductive layer Detailed Implementation

[0029] 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.

[0030] To facilitate understanding of the pinned ferromagnetic layer structure provided in the embodiments of the present invention, the application scenarios of the pinned ferromagnetic layer structure provided in the embodiments of the present invention will be described first. This pinned ferromagnetic layer structure is applied in electromagnetic devices such as magnetic memory and magnetic sensors. The pinned ferromagnetic layer structure will be described in detail below with reference to the accompanying drawings.

[0031] refer to Figure 1 The pinned ferromagnetic layer structure provided in this embodiment of the invention includes a substrate 10, on which a ferromagnetic layer 20 to be pinned and an antiferromagnetic layer 30 are formed, and the magnetic moment direction of the antiferromagnetic layer 30 is parallel to the direction of the pinning magnetic field required by the ferromagnetic layer 20.

[0032] In the above-described scheme, an antiferromagnetic layer 30 is formed on the side of the ferromagnetic layer 20 to be pinned, and the magnetic moment direction of the antiferromagnetic layer 30 is parallel to the direction of the pinning magnetic field required for the ferromagnetic layer 20 to be pinned, thereby achieving pinning of the ferromagnetic layer 20 to be pinned. Compared with the multilayer film pinning method in the prior art, which uses a stacked arrangement of the ferromagnetic layer 20 to be pinned and the antiferromagnetic layer 30, in this application, since the antiferromagnetic layer 30 is located on the side of the ferromagnetic layer 20 to be pinned, there is no need to set an antiferromagnetic layer 30 above or below the ferromagnetic layer 20 to be pinned. This allows for the setting of other additional layers, such as buffer layers, above and below the ferromagnetic layer 20 to be pinned, without being affected by the antiferromagnetic layer 30. This prevents the pinning effect of the antiferromagnetic layer 30 from being weakened due to lattice mismatch and material mixing at the interface, thereby improving the pinning effect and solving the problems of complex pinning structures and insignificant pinning effects in the prior art. Furthermore, since the antiferromagnetic layer 30 surrounds and encloses the sides of the ferromagnetic layer 20 to be pinned, it can protect the ferromagnetic layer 20 from the influence of the surrounding environment. The following is a detailed description of each of the above structures with reference to the accompanying drawings.

[0033] When setting substrate 10, such as Figure 1 The substrate 10 shown serves as a structure supporting the ferromagnetic layer 20 to be pinned and the antiferromagnetic layer. Its primary material can be a silicon wafer structure made of silicon. Electrical structures, such as but not limited to word line structures, bit line structures, and electrode structures, can be formed on the substrate 10 to enable electrical connection with the ferromagnetic layer 20 to achieve functions such as storage, retrieval, testing, and computation.

[0034] When specifically setting the ferromagnetic layer 20 to be pinned, the ferromagnetic layer 20 includes at least one ferromagnetic layer. Specifically, the ferromagnetic layer 20 can consist of one ferromagnetic layer, or it can consist of at least two ferromagnetic layers, such as two, three, or four ferromagnetic layers. Other layer structures, such as, but not limited to, insulating layers and dielectric layers, can be set above or below the ferromagnetic layers, or even between different ferromagnetic layers. The material of the ferromagnetic layer can be CoFeB, Co, Ni, Fe, CoFe, NiFe, CoGd, CoTb, La1 x Sr x MnO3, MnSb, MnAs, MnGa, Gd, Tb, Dy, EuO, Y3Fe5O 12 The material can be any one of the materials or any alloy material composed of any of them. The thickness of the ferromagnetic layer 20 to be pinned can be any value between 0.2 nanometers and 500 micrometers, such as 0.2 nanometers, 2 nanometers, 20 nanometers, 200 nanometers, 2 micrometers, 20 micrometers, 200 micrometers, 500 micrometers, etc. The ferromagnetic layer 20 to be pinned can have perpendicular anisotropy or in-plane anisotropy, so that the ferromagnetic layer in the ferromagnetic layer 20 to be pinned has good ferromagnetic properties.

[0035] When setting the antiferromagnetic layer 30, refer to Figure 1 It is necessary to ensure that the antiferromagnetic layer 30 at least surrounds the side of at least one of the ferromagnetic layers, that is, there must be at least one ferromagnetic layer in the ferromagnetic layer 20 whose side is surrounded by the antiferromagnetic layer 30, so as to provide a pinning magnetic field to the ferromagnetic layer and improve the pinning effect of magnetic field pinning of the target ferromagnetic layer. Of course, if there are multiple ferromagnetic layers in the ferromagnetic layer 20 to be pinned, and it is necessary to pin multiple ferromagnetic layers, the side of each ferromagnetic layer to be pinned can be surrounded by the antiferromagnetic layer 30. In one embodiment, the entire side of the ferromagnetic layer 20 to be pinned can be wrapped with a counterferromagnetic layer. That is, the counterferromagnetic layer 30 not only wraps the side of the ferromagnetic layer 20, but also wraps the side of the non-ferromagnetic layer 20 when it contains a non-ferromagnetic layer. This increases the height of the counterferromagnetic layer 30, increases the bonding area between the counterferromagnetic layer 30 and the ferromagnetic layer 20, and thus improves the adhesion strength between them. Simultaneously, by wrapping the entire side of the ferromagnetic layer 20 with the counterferromagnetic layer 30, the wrapping space is larger, thus better protecting the ferromagnetic layer 20 from external influences.

[0036] Furthermore, the magnetic moment direction of the antiferromagnetic layer 30 needs to be adjusted so that it is parallel to the direction of the pinning magnetic field required for the pinning ferromagnetic layer 20. Specifically, the magnetic moment direction of the antiferromagnetic layer 30 can be parallel to the direction of the pinning magnetic field required for the pinning ferromagnetic layer 20, or it can be parallel to the direction of the pinning magnetic field required for the pinning ferromagnetic layer 20 in the opposite direction. This allows the antiferromagnetic layer 30 to provide a stable pinning magnetic field to the pinning ferromagnetic layer 20, achieving pinning of the pinning ferromagnetic layer 20 and improving the pinning effect.

[0037] For example, the ferromagnetic layer 20 to be pinned can be a magnetic tunnel junction formed by sequentially stacking a free layer, an insulating layer, and a reference layer, wherein the free layer and the reference layer are separated by an insulating layer, and both the free layer and the reference layer are ferromagnetic layers. Specifically, the free layer can be stacked on the substrate 10, followed by sequentially stacking an insulating layer on the free layer, and then stacking a reference layer on the insulating layer; alternatively, the reference layer can be stacked on the substrate 10, followed by sequentially stacking an insulating layer on the reference layer, and then stacking a free layer on the insulating layer. The specific stacking method can be selected based on the function of the ferromagnetic layer 20 in the entire electromagnetic device and the overall structural arrangement of the electromagnetic device. In this case, when setting the antiferromagnetic layer 30, the antiferromagnetic layer 30 can at least surround and enclose the sides of the free layer and / or the reference layer. That is, the antiferromagnetic layer 30 can be wrapped only around the side of the free layer; it can be wrapped only around the side of the reference layer; it can be wrapped around both the side of the free layer and the side of the reference layer; and it can be further wrapped around all sides of the free layer, the insulating layer, and the reference layer. Using the above configuration not only improves the pinning effect of the magnetic field pinning of the free layer or the reference layer, but also does not affect the application of other additional layers, such as buffer layers, on the surface of the free layer or the reference layer.

[0038] When determining the material of the antiferromagnetic layer 30, the material of the antiferromagnetic layer 30 can be CoO. x FeO x NiO x CrO x MnO x Cr, IrMn, CoFeO xThe antiferromagnetic layer 30 can be any material selected from PtMn, MnSe, MnS, MnTe, Mn2Au, and CuMnAs to give it good antiferromagnetic properties. When determining the thickness of the antiferromagnetic layer 30, the thickness of the antiferromagnetic layer 30 surrounding the ferromagnetic layer 20 to be pinned can range from 0.5 nanometers to 500 micrometers. It is important to note that this thickness refers to the thickness of the antiferromagnetic layer 30 surrounding the ferromagnetic layer 20, not its height. The height of the antiferromagnetic layer 30 is related to the thickness of the layer structure to be surrounded within the ferromagnetic layer 20. Specifically, the thickness of the antiferromagnetic layer 30 surrounding the ferromagnetic layer 20 can be set to any value between 0.5 nanometers and 500 micrometers, such as 0.5 nanometers, 5 nanometers, 50 nanometers, 500 nanometers, 5 micrometers, 50 micrometers, or 500 micrometers, to further improve the pinning effect and better protect the ferromagnetic layer 20 from the influence of the surrounding environment.

[0039] When determining the shapes of the ferromagnetic layer 20 and the antiferromagnetic layer 30 to be pinned, refer to Figure 1 The ferromagnetic layer 20 to be pinned can be shaped like a disk, meaning it is a "nanodot" structure. In this case, the antiferromagnetic layer 30 can be shaped like a ring, with the ring-shaped antiferromagnetic layer 30 completely surrounding the side of the disk-shaped ferromagnetic layer 20. Alternatively, the ferromagnetic layer 20 can be shaped like a cube, meaning it is a linear structure, similar to a "nanowire" structure. In this case, the antiferromagnetic layer 30 can be shaped like a rectangular ring, with the rectangular ring-shaped antiferromagnetic layer 30 completely surrounding the side of the cubic-shaped ferromagnetic layer 20. It should be understood that the shapes of the ferromagnetic layer 20 and the antiferromagnetic layer 30 are not limited to the above-described configurations; other shapes of the ferromagnetic layer 20 and the antiferromagnetic layer 30 can also be used. That is, as long as the antiferromagnetic layer 30 is arranged to surround and wrap around the side of the ferromagnetic layer 20 to be nailed, it is within the protection scope of this invention.

[0040] By forming an antiferromagnetic layer 30 on the side of the ferromagnetic layer 20 to be pinned, and ensuring that the magnetic moment direction of the antiferromagnetic layer 30 is parallel to the direction of the pinning magnetic field required for the ferromagnetic layer 20, pinning of the ferromagnetic layer 20 is achieved. Compared with the multilayer film pinning method in the prior art, which uses a stacked arrangement of the ferromagnetic layer 20 and the antiferromagnetic layer 30, in this application, since the antiferromagnetic layer 30 is located on the side of the ferromagnetic layer 20 to be pinned, there is no need to set an antiferromagnetic layer 30 above or below the ferromagnetic layer 20 to be pinned. This allows for the setting of other additional layers, such as buffer layers, above and below the ferromagnetic layer 20 to be pinned, without being affected by the antiferromagnetic layer 30. This prevents the pinning effect of the antiferromagnetic layer 30 from being weakened due to lattice mismatch and material mixing at the interface, thereby improving the pinning effect and solving the problems of complex pinning structures and insignificant pinning effects in the prior art. Furthermore, since the antiferromagnetic layer 30 surrounds and wraps around the side of the ferromagnetic layer 20 to be nailed, it can protect the ferromagnetic layer 20 from the influence of the surrounding environment.

[0041] In addition, embodiments of the present invention also provide a method for manufacturing a pinned ferromagnetic layer structure, referencing Figure 1 , Figure 2 and Figure 4 The manufacturing method includes:

[0042] S10: Provides a substrate 10;

[0043] S20: Forming a ferromagnetic layer 20 to be pinned on the substrate 10;

[0044] S30: Form an antiferromagnetic layer 30 surrounding and enclosing the ferromagnetic layer 20 to be pinned;

[0045] S40: Adjust the direction of the magnetic moment of the antiferromagnetic layer 30 so that the direction of the magnetic moment of the antiferromagnetic layer 30 is parallel to the direction of the pinning magnetic field required for the pinning ferromagnetic layer 20.

[0046] In the above-described scheme, an antiferromagnetic layer 30 is formed on the side of the ferromagnetic layer 20 to be pinned, and the magnetic moment direction of the antiferromagnetic layer 30 is parallel to the direction of the pinning magnetic field required for the ferromagnetic layer 20 to be pinned, thereby achieving pinning of the ferromagnetic layer 20 to be pinned. Compared with the multilayer film pinning method in the prior art, which uses a stacked arrangement of the ferromagnetic layer 20 to be pinned and the antiferromagnetic layer 30, in this application, since the antiferromagnetic layer 30 is located on the side of the ferromagnetic layer 20 to be pinned, there is no need to set an antiferromagnetic layer 30 above or below the ferromagnetic layer 20 to be pinned. This allows for the setting of other additional layers, such as buffer layers, above and below the ferromagnetic layer 20 to be pinned, without being affected by the antiferromagnetic layer 30. This prevents the pinning effect of the antiferromagnetic layer 30 from being weakened due to lattice mismatch and material mixing at the interface, thereby improving the pinning effect. Furthermore, since the antiferromagnetic layer 30 surrounds and wraps around the sides of the ferromagnetic layer 20 to be pinned, it can protect the ferromagnetic layer 20 from the influence of the surrounding environment. The following is a detailed description of each of the above steps with reference to the accompanying drawings.

[0047] First, refer to Figure 1 , Figure 2 and Figure 4 Provide a substrate 10. For example... Figure 1 The substrate 10 shown serves as a structure supporting the ferromagnetic layer 20 to be pinned and the antiferromagnetic layer. Its primary material can be a silicon wafer structure made of silicon. Electrical structures, such as but not limited to word line structures, bit line structures, and electrode structures, can be formed on the substrate 10 to enable electrical connection with the ferromagnetic layer 20 to achieve functions such as storage, retrieval, testing, and computation.

[0048] Next, refer to Figure 2 and Figure 4 A pinned ferromagnetic layer 20 is formed on the substrate 10. The pinned ferromagnetic layer 20 can be fabricated on the substrate 10 using various semiconductor manufacturing processes. For example, at least one ferromagnetic material layer can be grown on the substrate 10 first; then, through electron beam lithography and ion etching, the at least one ferromagnetic material layer can be patterned into a pinned ferromagnetic layer 20 containing at least one ferromagnetic layer. That is, the pinned ferromagnetic layer 20 contains at least one ferromagnetic layer. Specifically, the pinned ferromagnetic layer 20 can consist of one ferromagnetic layer, or it can consist of at least two ferromagnetic layers, such as two, three, or four ferromagnetic layers. Other layer structures, such as, but not limited to, insulating layers and dielectric layers, can be disposed above or below the ferromagnetic layers, or even between different ferromagnetic layers. Specifically, the fabrication of a pinned ferromagnetic layer 20 containing multiple ferromagnetic layers, such as the magnetic tunnel junction shown in the aforementioned structural section, can be performed using conventional methods in semiconductor manufacturing processes, which will not be elaborated further here.

[0049] The ferromagnetic layer can be made of materials such as CoFeB, Co, Ni, Fe, CoFe, NiFe, CoGd, CoTb, or La1. x Sr x MnO3, MnSb, MnAs, MnGa, Gd, Tb, Dy, EuO, Y3Fe5O 12 The material can be any one of the materials or any alloy materials composed of any of the above. The thickness of the ferromagnetic layer 20 to be pinned can be any value between 0.2 nanometers and 500 micrometers, such as 0.2 nanometers, 2 nanometers, 20 nanometers, 200 nanometers, 2 micrometers, 20 micrometers, 200 micrometers, and 500 micrometers. The ferromagnetic layer 20 to be pinned can have perpendicular anisotropy or in-plane anisotropy to give the ferromagnetic layer in the ferromagnetic layer 20 good ferromagnetic properties. When determining the shape of the ferromagnetic layer 20 to be pinned, refer to... Figure 1 The shape of the ferromagnetic layer 20 to be pinned can be set to a disk shape, that is, the ferromagnetic layer 20 to be pinned is a "nanodot" structure. Alternatively, the shape of the ferromagnetic layer 20 to be pinned can be set to a cube shape, that is, the ferromagnetic layer 20 to be pinned is a linear structure, similar to a "nanowire" structure. It should be understood that the shape of the ferromagnetic layer 20 to be pinned is not limited to the above-described configurations; other shapes of the ferromagnetic layer 20 can also be used.

[0050] Next, refer to Figure 1 , Figure 3 and Figure 4 An antiferromagnetic layer 30 is formed around the ferromagnetic layer 20 to be pinned. Specifically, various methods in semiconductor manufacturing processes can be used to process the antiferromagnetic layer 30 around the ferromagnetic layer 20 to be pinned, forming a layer that surrounds the sides of the ferromagnetic layer 20.

[0051] For example, when specifically forming an antiferromagnetic layer 30 surrounding the ferromagnetic layer 20 to be pinned, an antiferromagnetic material can be grown around the ferromagnetic layer 20 to be pinned, forming a ferromagnetic layer 20 to be pinned that at least surrounds the side of one of the at least one ferromagnetic layers. That is, the antiferromagnetic layer 30 at least surrounds the side of one of the at least one ferromagnetic layers, and there is at least one ferromagnetic layer in the ferromagnetic layer 20 whose side is surrounded by the antiferromagnetic layer 30, so as to provide a pinning magnetic field to the ferromagnetic layer, thereby improving the pinning effect of magnetic field pinning of the target ferromagnetic layer. Of course, if there are multiple ferromagnetic layers in the ferromagnetic layer 20 to be pinned, and it is necessary to pin multiple ferromagnetic layers, the side of each ferromagnetic layer to be pinned can be surrounded by the antiferromagnetic layer 30. In one embodiment, the entire side of the ferromagnetic layer 20 to be pinned can be wrapped with a counterferromagnetic layer. That is, the counterferromagnetic layer 30 not only wraps the side of the ferromagnetic layer 20, but also wraps the side of the non-ferromagnetic layer 20 when it contains a non-ferromagnetic layer. This increases the height of the counterferromagnetic layer 30, increases the bonding area between the counterferromagnetic layer 30 and the ferromagnetic layer 20, and thus improves the adhesion strength between them. Simultaneously, by wrapping the entire side of the ferromagnetic layer 20 with the counterferromagnetic layer 30, the wrapping space is larger, thus better protecting the ferromagnetic layer 20 from external influences.

[0052] An antiferromagnetic layer 30 can be formed around the ferromagnetic layer 20 to be pinned using a sputtering process. For details, refer to... Figure 3 Through sputtering, and during the sputtering process, the sputtering direction of the sputtered ions needs to be adjusted so that the incident angle between the sputtered ions and the surface of the substrate 10 is greater than 0 degrees and less than 90 degrees, an antiferromagnetic material is grown around the ferromagnetic layer 20 to be pinned, forming an antiferromagnetic layer 30. Specifically, the incident angle between the sputtered ions and the surface of the substrate 10 can be adjusted to a range greater than 0 degrees and less than 90 degrees, such as 1 degree, 5 degrees, 10 degrees, 20 degrees, 30 degrees, 40 degrees, 50 degrees, 60 degrees, 70 degrees, 80 degrees, and 89 degrees, to facilitate the generation of antiferromagnetic material around the ferromagnetic layer 20 to be pinned, improve the adhesion between the antiferromagnetic layer 30 and the side of the ferromagnetic layer 20 to be pinned, and prevent the antiferromagnetic layer 30 from detaching.

[0053] In addition, when the antiferromagnetic layer 30 surrounds at least one ferromagnetic layer in the ferromagnetic layer 20 to be pinned, but does not surround all sides of the ferromagnetic layer 20 to be pinned, the steps and processes can be adjusted in a way that is in semiconductor manufacturing process, so that only the sides of the ferromagnetic layer 20 to be pinned that need to be surrounded are surrounded, and the sides of the ferromagnetic layer 20 to be pinned that do not need to be surrounded are not surrounded. The specifics will not be elaborated here.

[0054] When determining the material of the antiferromagnetic layer 30, the material of the antiferromagnetic layer 30 can be CoO. x FeO x NiO x CrO x MnO x Cr, IrMn, CoFeO x The antiferromagnetic layer 30 can be any material selected from PtMn, MnSe, MnS, MnTe, Mn2Au, and CuMnAs to give it good antiferromagnetic properties. When determining the thickness of the antiferromagnetic layer 30, the thickness of the antiferromagnetic layer 30 surrounding the ferromagnetic layer 20 to be pinned can range from 0.5 nanometers to 500 micrometers. It is important to note that this thickness refers to the thickness of the antiferromagnetic layer 30 surrounding the ferromagnetic layer 20, not its height. The height of the antiferromagnetic layer 30 is related to the thickness of the layer structure to be surrounded within the ferromagnetic layer 20. Specifically, the thickness of the antiferromagnetic layer 30 surrounding the ferromagnetic layer 20 can be set to any value between 0.5 nanometers and 500 micrometers, such as 0.5 nanometers, 5 nanometers, 50 nanometers, 500 nanometers, 5 micrometers, 50 micrometers, or 500 micrometers, to further improve the pinning effect and better protect the ferromagnetic layer 20 from the influence of the surrounding environment.

[0055] The shape of the ferromagnetic layer 20 to be nailed is as follows: Figure 1 When the disk shape is shown, meaning the ferromagnetic layer 20 to be pinned is a "nanodot" structure, the antiferromagnetic layer 30 can be shaped as a ring, so that the ring-shaped antiferromagnetic layer 30 completely surrounds the side of the disk-shaped ferromagnetic layer 20 to be pinned. When the ferromagnetic layer 20 to be pinned is cubic, meaning the ferromagnetic layer 20 to be pinned is a linear structure, similar to a "nanowire" structure, the antiferromagnetic layer 30 can be shaped as a rectangular ring, so that the rectangular ring-shaped antiferromagnetic layer 30 completely surrounds the side of the cubic ferromagnetic layer 20 to be pinned. It should be understood that the shapes of the ferromagnetic layer 20 and the antiferromagnetic layer 30 are not limited to the above-shown arrangements. In addition, other shapes of the ferromagnetic layer 20 and the antiferromagnetic layer 30 can also be used. That is, as long as the arrangement ensures that the antiferromagnetic layer 30 surrounds the side of the ferromagnetic layer 20 to be pinned, it is within the protection scope of this invention.

[0056] Next, as Figure 4As shown, the magnetic moment direction of the antiferromagnetic layer 30 is adjusted so that it is parallel to the direction of the pinning magnetic field required for the pinning ferromagnetic layer 20. Specifically, the magnetic moment direction of the antiferromagnetic layer 30 can be parallel to the direction of the pinning magnetic field required for the pinning ferromagnetic layer 20, or it can be parallel to the direction of the pinning magnetic field required for the pinning ferromagnetic layer 20 in the opposite direction. This allows the antiferromagnetic layer 30 to provide a stable pinning magnetic field to the pinning ferromagnetic layer 20, achieving pinning of the pinning ferromagnetic layer 20 and improving the pinning effect.

[0057] When specifically adjusting the magnetic moment direction of the antiferromagnetic layer 30, the substrate 10 and the antiferromagnetic layer 30 can be vacuum annealed under the influence of an external magnetic field. The magnetic moment direction of the antiferromagnetic layer 30 can be adjusted by regulating the annealing temperature and the direction of the external magnetic field. Specifically, the annealing temperature needs to be adjusted to be higher than the Nieer temperature of the antiferromagnetic layer 30 material to transform the antimagnetic material into a paramagnetic material. Simultaneously, the direction of the external magnetic field should be parallel to the direction of the pinning magnetic field required for the pinning ferromagnetic layer 20. Specifically, the direction of the external magnetic field can be the same as or opposite to the direction of the pinning magnetic field required for the pinning ferromagnetic layer 20, thereby guiding the magnetic moment direction within the antiferromagnetic layer 30 to the same direction parallel to the pinning magnetic field required for the pinning ferromagnetic layer 20, thus providing a pinning magnetic field to the pinning ferromagnetic layer 20. Furthermore, the external magnetic field is applied throughout the annealing process until the antiferromagnetic layer 30 cools to room temperature, in order to adjust the direction of the magnetic moment of the antiferromagnetic layer 30 so that the direction of the magnetic moment within it is parallel to the direction of the pinning magnetic field required for the pinning ferromagnetic layer 20. Of course, in addition to the method of adjusting the direction of the magnetic moment of the antiferromagnetic layer 30 shown above, other methods can also be used to adjust the direction of the magnetic moment of the antiferromagnetic layer 30 so that the direction of the magnetic moment of the antiferromagnetic layer 30 is parallel to the direction of the pinning magnetic field required for the pinning ferromagnetic layer 20.

[0058] Afterwards, the external magnetic field can be removed, and the magnetization direction of the ferromagnetic layer 20 to be pinned can be measured to see if it is pinned by the antiferromagnetic layer 30, and the magnitude of the pinning magnetic field can be estimated, etc., for testing.

[0059] refer to Figures 5-7 This paper presents a test structure and test results for verifying the lateral pinning effect. First, refer to... Figure 5A multilayer film structure of Ta 8nm / CoFeB t / MgO 2nm / Ta 2nm was sputtered onto substrate 10, meaning the thickness of the conductive layer 40 formed by Ta is 8nm. The thickness of the pinned ferromagnetic layer 20 formed by CoFeB is t. When t = 0.8 nm, the pinned ferromagnetic layer 20 exhibits perpendicular anisotropy; when t = 2.5 nm, the pinned ferromagnetic layer 20 exhibits in-plane anisotropy. The sputtered sample was then processed by electron beam exposure and ion etching to prepare nanodots (i.e., disk-shaped pinned ferromagnetic layers 20) with a diameter of approximately 50 nm. Figure 5 As shown. Then, before the photoresist on the upper surface of the ferromagnetic layer 20 to be pinned is removed, a NiO layer approximately 50 nanometers thick is sputtered along the side. x An antiferromagnetic layer 30 is formed, so that the sides of the etched ferromagnetic layer 20 to be pinned are covered by NiO. x Package. NiO x On the one hand, it serves to protect the sides of the ferromagnetic layer 20 to be pinned; on the other hand, it serves to pin the antiferromagnetic layer. Afterward, the photoresist on top of the ferromagnetic layer 20 is removed. Then, the substrate 10, the ferromagnetic layer 20 formed thereon, and the antiferromagnetic layer 30 are placed together under an external magnetic field of 5 kOe and annealed at 350 degrees Celsius for 10 minutes. During the annealing heating and cooling process, the external magnetic field is maintained at 5 kOe until the substrate 10, the ferromagnetic layer 20, and the antiferromagnetic layer 30 cool to room temperature. The direction of the external magnetic field can be determined according to the direction of the pinning magnetic field required for the ferromagnetic layer 20. For example, for a ferromagnetic layer 20 to be pinned at t = 0.8 nm, the required pinning direction is perpendicular to the film surface, so the external magnetic field is applied in a direction perpendicular to the film surface of the ferromagnetic layer 20 to be pinned; for a ferromagnetic layer 20 to be pinned at t = 2.5 nm, the required pinning direction is parallel to the film surface, so the external magnetic field is applied in a direction parallel to the film surface of the ferromagnetic layer 20 to be pinned.

[0060] The lateral pinning effect can then be estimated by measuring the anomalous Hall effect and the nonlinear in-plane Hall effect. For the ferromagnetic layer 20 to be pinned at t = 0.8 nm, refer to... Figure 5 It can apply a 50 microamp current and measure the Hall voltage perpendicular to the current direction. Figure 6 A schematic diagram of the measured Hall voltage versus the vertical magnetic field is shown. This curve is not symmetrical around zero field, but rather shifted by approximately 15 Oe along the positive field direction, proving that the pinning field on this side is approximately 15 Oe. For the pinned ferromagnetic layer 20 at t = 2.5 nm, refer to... Figure 5 First, apply a +2 mA current, then apply a -2 mA current, and measure the Hall resistance (R) under the positive and negative currents respectively. H (I+ ) and R H (I - Calculate the difference ΔR between the Hall resistance values ​​under positive and negative currents. H = R H (I + ) - R H (I - ). Figure 7 The measured ΔR is shown. H The curve showing the variation of the in-plane and out-of-plane magnetic fields (along the direction of the pinning magnetic field). Similar to... Figure 6 The entire curve shifts approximately 10 Oe along the positive field direction, meaning that under this structure, the in-plane pinning field caused by lateral pinning is approximately 10 Oe. This demonstrates that the lateral pinning ferromagnetic structure provided in this embodiment of the invention has a good pinning effect.

[0061] By forming an antiferromagnetic layer 30 on the side of the ferromagnetic layer 20 to be pinned, and ensuring that the magnetic moment direction of the antiferromagnetic layer 30 is parallel to the direction of the pinning magnetic field required for the ferromagnetic layer 20, pinning of the ferromagnetic layer 20 is achieved. Compared with the multilayer film pinning method in the prior art, which uses a stacked arrangement of the ferromagnetic layer 20 and the antiferromagnetic layer 30, in this application, since the antiferromagnetic layer 30 is located on the side of the ferromagnetic layer 20 to be pinned, there is no need to set an antiferromagnetic layer 30 above or below the ferromagnetic layer 20 to be pinned. This allows for the setting of other additional layers, such as buffer layers, above and below the ferromagnetic layer 20 to be pinned, without being affected by the antiferromagnetic layer 30. This prevents the pinning effect of the antiferromagnetic layer 30 from being weakened due to lattice mismatch and material mixing at the interface, thereby improving the pinning effect and solving the problems of complex pinning structures and insignificant pinning effects in the prior art. Furthermore, since the antiferromagnetic layer 30 surrounds and wraps around the side of the ferromagnetic layer 20 to be nailed, it can protect the ferromagnetic layer 20 from the influence of the surrounding environment.

[0062] Furthermore, embodiments of the present invention also provide an electromagnetic device, see reference. Figure 1The electromagnetic device includes any of the above-mentioned pinned ferromagnetic layer structures. By forming an antiferromagnetic layer 30 on the side of the ferromagnetic layer 20 to be pinned, and by making the magnetic moment direction of the antiferromagnetic layer 30 parallel to the direction of the pinning magnetic field required for the ferromagnetic layer 20 to be pinned, the pinning of the ferromagnetic layer 20 can be achieved. Compared to the existing multilayer film pinning method that uses a stacked ferromagnetic layer 20 and an antiferromagnetic layer 30, in this application, since the antiferromagnetic layer 30 is located on the side of the ferromagnetic layer 20, there is no need to set an antiferromagnetic layer 30 above or below the ferromagnetic layer 20. This allows for the placement of additional layers, such as buffer layers, above and below the ferromagnetic layer 20 without being affected by the antiferromagnetic layer 30. This prevents the pinning effect of the antiferromagnetic layer 30 from being weakened due to lattice mismatch and material mixing at the interface, thereby improving the pinning effect and solving the problems of complex pinning structures and insignificant pinning effects in existing technologies. Furthermore, since the antiferromagnetic layer 30 surrounds the side of the ferromagnetic layer 20, it protects the ferromagnetic layer 20 from the influence of the surrounding environment.

[0063] When setting up the electromagnetic device, the electromagnetic device can be a magnetic storage device or a magnetic sensor to improve the effect of magnetic field pinning of the ferromagnetic layer 20 in the magnetic storage device or magnetic sensor, while protecting the ferromagnetic layer 20 from the influence of the surrounding environment. Of course, it should be noted that the electromagnetic device is not limited to the magnetic storage device or magnetic sensor shown above. In other application scenarios that require the use of the ferromagnetic layer 20, the pinning ferromagnetic layer structure shown in this application can be used. Correspondingly, the devices applied in such scenarios belong to the electromagnetic devices provided in the embodiments of this invention.

[0064] 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 stapled ferromagnetic layer structure, characterized in that, include: substrate; A ferromagnetic layer to be pinned is formed on the substrate; An antiferromagnetic layer surrounds the ferromagnetic layer to be pinned, and the direction of the magnetic moment of the antiferromagnetic layer is parallel to the direction of the pinning magnetic field required by the ferromagnetic layer to be pinned. Wherein, the ferromagnetic layer to be pinned is disc-shaped, the antiferromagnetic layer is annular-shaped, and the antiferromagnetic layer surrounds the side of the disc-shaped ferromagnetic layer to be pinned; or, The ferromagnetic layer to be pinned is cubic in shape, and the antiferromagnetic layer is rectangular in shape, with the antiferromagnetic layer surrounding and wrapping around the sides of the cubic ferromagnetic layer to be pinned.

2. The pinned ferromagnetic layer structure as described in claim 1, characterized in that, The ferromagnetic layer to be pinned includes at least one ferromagnetic layer, and the antiferromagnetic layer at least surrounds the side of one of the at least one ferromagnetic layers.

3. The pinned ferromagnetic layer structure as described in claim 2, characterized in that, The ferromagnetic layer to be pinned is a magnetic tunnel junction formed by sequentially stacking a free layer, an insulating layer, and a reference layer, wherein the free layer and the reference layer are separated by the insulating layer; Both the free layer and the reference layer are ferromagnetic layers, and the antiferromagnetic layer at least surrounds and encloses the side of the free layer and / or the reference layer.

4. The pinned ferromagnetic layer structure as described in claim 2, characterized in that, The ferromagnetic layer is made of CoFeB, Co, Ni, Fe, CoFe, NiFe, CoGd, CoTb, or La1. x Sr x MnO3, MnSb, MnAs, MnGa, Gd, Tb, Dy, EuO, Y3Fe5O 12 Any one of the materials or any alloy of several of them; The antiferromagnetic layer is made of CoO. x FeO x NiO x CrO x MnO x Cr, IrMn, CoFeO x Any one of the following materials: PtMn, MnSe, MnS, MnTe, Mn2Au, CuMnAs.

5. The pinned ferromagnetic layer structure as described in claim 1, characterized in that, The thickness of the antiferromagnetic layer surrounding the ferromagnetic layer to be pinned is from 0.5 nanometers to 500 micrometers.

6. A method for manufacturing a pinned ferromagnetic layer structure, characterized in that, include: Provide a substrate; A ferromagnetic layer to be pinned is formed on the substrate; An antiferromagnetic layer is formed around the ferromagnetic layer to be pinned; Adjust the direction of the magnetic moment of the antiferromagnetic layer so that the direction of the magnetic moment of the antiferromagnetic layer is parallel to the direction of the pinning magnetic field required by the ferromagnetic layer to be pinned; The ferromagnetic layer to be pinned is disc-shaped, the antiferromagnetic layer is annular, and the antiferromagnetic layer surrounds the side of the disc-shaped ferromagnetic layer to be pinned. Alternatively, the ferromagnetic layer to be pinned may be cubic in shape, and the antiferromagnetic layer may be rectangular in shape, with the antiferromagnetic layer surrounding and wrapping around the sides of the cubic ferromagnetic layer to be pinned.

7. The manufacturing method as described in claim 6, characterized in that, The formation of the antiferromagnetic layer surrounding the ferromagnetic layer to be pinned includes: An antiferromagnetic material is grown around the ferromagnetic layer to be pinned by means of a sputtering process, wherein the incident angle between the sputtered ions and the substrate surface is greater than 0 degrees and less than 90 degrees.

8. The manufacturing method as described in claim 6, characterized in that, Adjusting the magnetic moment direction of the antiferromagnetic layer so that it is parallel to the direction of the pinning magnetic field required by the ferromagnetic layer to be pinned includes: The substrate and the antiferromagnetic layer are vacuum annealed under the application of an external magnetic field; wherein the annealing temperature of the vacuum annealing is higher than the Nieer temperature of the antiferromagnetic layer, and the direction of the external magnetic field is parallel to the direction of the pinning magnetic field required for the pinning ferromagnetic layer.

9. An electromagnetic device, characterized in that, Includes the pinned ferromagnetic layer structure as described in any one of claims 1 to 5.

10. The electromagnetic device as described in claim 9, characterized in that, The electromagnetic device is a magnetic storage device or a magnetic sensor.

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