A tunneling magnetoresistance, a manufacturing method thereof, and a tunneling magnetic device

Abstract

The present invention provides a tunnel magnetoresistor, a method for manufacturing the same, and a tunnel magnetic device. The tunnel magnetoresistor comprises: a pinned layer; a free layer disposed opposite the pinned layer, the free layer being a superparamagnetic layer with a thickness less than or equal to a critical thickness; a tunnel barrier layer located between the pinned layer and the free layer; and an underlying conductive structure located on the side of the free layer facing away from the tunnel barrier layer. The free layer in the tunnel magnetoresistor is a superparamagnetic layer with a thickness less than or equal to the critical thickness. During magnetization, the magnetic moments of the single-domain particles constituting the superparamagnetic layer can be oriented in the same direction to achieve magnetic saturation, resulting in a high magnetic susceptibility. Therefore, the tunnel magnetoresistor provided by the present invention has a large saturation field and high linearity.

Description

Technical Field

[0001] The present invention relates to the technical field of magnetic sensors, and in particular to a tunnel magnetoresistance, a manufacturing method thereof, and a tunnel magnetic device. Background Art

[0002] Magnetic sensing technology is widely used in new energy, intelligent transportation, industrial control, smart home appliances, and smart networks. TMR (Tunneling Magneto Resistance) technology is currently being widely promoted.

[0003] The mechanism of the tunnel magnetoresistance effect is the spin-related tunneling effect, and its core lies in the MTJ (Magnetic Tunnel Junction) device, which is also a magnetic tunnel junction device. The magnetic tunnel junction includes a pinned layer with a fixed magnetization orientation, a free layer whose magnetization orientation can be changed by a magnetic field and current, and a tunnel barrier layer located between the pinned layer and the free layer. An electrode is connected to each of the free layer and the pinned layer of the magnetic tunnel junction. The MTJ device has a tunnel magnetoresistance effect. When the magnetization orientation direction of the free layer is parallel to the magnetization orientation of the pinned layer under the action of a magnetic field or current, the tunnel magnetoresistance presents a low resistance state; when the magnetization orientation direction of the free layer is antiparallel to the magnetization orientation of the pinned layer under the action of a magnetic field or current, the tunnel magnetoresistance presents a high resistance state.

[0004] However, the saturation field of tunnel magnetoresistance is relatively small, with the absolute value of the saturation field generally less than 200 Gs, and the linearity within the saturation field is relatively poor, which limits its application in some open-loop designs or sensor applications with large saturation field requirements. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the problems of small saturation field and poor linearity of tunnel magnetoresistance in the prior art, thereby providing a tunnel magnetoresistance and a manufacturing method thereof, as well as a tunnel magnetic device.

[0006] The present invention provides a tunnel magnetoresistance, comprising: a pinned layer; a free layer arranged opposite to the pinned layer, wherein the free layer is a superparamagnetic layer and the thickness of the free layer is less than or equal to a critical thickness; a tunneling barrier layer located between the pinned layer and the free layer; and an underlying conductive structure located on a side of the free layer facing away from the tunneling barrier layer.

[0007] Optionally, the material of the free layer includes CoFe 40 B 20 or CoFe 60 B 20 .

[0008] Optionally, the thickness of the free layer is 1.0 nm to 1.4 nm.

[0009] Optionally, it further includes: a top conductive structure, the pinned layer, the free layer and the tunnel barrier layer are all located between the top conductive structure and the bottom conductive structure, and the pinned layer is located between the top conductive structure and the tunnel barrier layer.

[0010] Optionally, the bottom conductive structure includes a bottom conductive body and an interface layer, and the interface layer is located between the bottom conductive body and the free layer; the material of the interface layer includes Ta or Ru.

[0011] Optionally, the pinning layer includes: a first sub-pinning film, a second sub-pinning film, a third sub-pinning film and a fourth sub-pinning film, wherein the first sub-pinning film, the second sub-pinning film, the third sub-pinning film and the fourth sub-pinning film are sequentially stacked in a direction from the free layer tunneling barrier layer to the tunneling barrier layer free layer; the material of the first sub-pinning film includes CoFe 40 B 20 The thickness of the first pinning film is 1.4 nm to 3 nm; the material of the second pinning film includes Ru, and the thickness of the second pinning film is 0.7 nm to 1.0 nm; the material of the third pinning film includes CoFe 30 The thickness of the third pinning film is 1.5 nm to 2 nm; the material of the fourth pinning film includes PtMn 62 The thickness of the fourth sub-pinning film is 15 nm to 20 nm.

[0012] The present invention also provides a method for manufacturing a tunnel magnetoresistance, which is used to form the tunnel magnetoresistance of the present invention, comprising the following steps: forming an underlying conductive structure; forming a free layer on one side of the underlying conductive structure, wherein the thickness of the free layer is less than or equal to a critical thickness; forming a tunnel barrier layer on the side of the free layer facing away from the underlying conductive structure; forming a pinning layer on the side of the tunnel barrier layer facing away from the free layer; and performing annealing magnetization treatment on the free layer so that the free layer becomes a superparamagnetic layer.

[0013] Optionally, the method further includes: providing a substrate before forming the bottom conductive structure, on which the bottom conductive structure is formed; and forming a top conductive structure on a side of the pinning layer facing away from the substrate.

[0014] Optionally, the method for forming the bottom conductive structure includes: forming a bottom conductive body; forming an interface layer on one side of the bottom conductive body; and the interface layer is located between the bottom conductive body and the free layer.

[0015] Optionally, the annealing temperature of the annealing magnetization treatment is 330°C to 400°C, and the annealing time of the annealing magnetization treatment is 2 hours to 6 hours; the magnetic field direction of the annealing magnetization treatment is parallel to the surface opposite to the free layer and the pinned layer, and the magnetic field intensity of the annealing magnetization treatment is 4000Gs to 20000Gs.

[0016] The present invention also provides a tunnel magnetic device, comprising the tunnel magnetoresistance of the present invention.

[0017] Optionally, there are multiple tunnel magnetoresistors, and the tunnel magnetoresistors are connected in series.

[0018] The technical solution of the present invention has the following beneficial effects:

[0019] 1. The tunnel magnetoresistors provided by the technical solution of the present invention employ a superparamagnetic layer having a thickness less than or equal to a critical thickness as the free layer. During magnetization, the magnetic moments of the single-domain particles constituting the superparamagnetic layer can align in the same direction, reaching magnetic saturation and resulting in a high magnetic susceptibility. Therefore, the tunnel magnetoresistors provided by the present invention have a large saturation field and high linearity. The free layer is located between the underlying conductive structure and the tunnel barrier layer. Because the film structure is relatively flat before the free layer is formed, the free layer is not easily affected by the preceding film layer during formation, thereby easily obtaining a continuous and uniform free layer, making the process easier and more stable to control.

[0020] 2. Furthermore, the underlying conductive structure includes an underlying conductive body and an interface layer, wherein the interface layer is located between the underlying conductive body and the free layer; the interface layer is made of Ta or Ru. The interface layer effectively prevents diffusion of the free layer into the underlying conductive body, thereby ensuring the thermal stability of the free layer.

[0021] 3. The present invention provides a method for fabricating a tunnel magnetoresistor, wherein the thickness of the formed free layer is less than or equal to the critical thickness; the free layer is subjected to an annealing magnetization treatment, thereby transforming the free layer into a superparamagnetic layer. Because all the single-domain particles comprising the superparamagnetic layer can follow the direction of the external magnetic field and reach magnetic saturation, resulting in a high magnetic susceptibility, the tunnel magnetoresistor fabricated using this method exhibits a large saturation field and excellent linearity.

[0022] 4. The technical solution of the present invention provides a tunnel magnetic device, which is formed by connecting several tunnel magnetoresistors in series. The tunnel magnetic device can be applied to the field of sensors with large requirements for saturation fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0024] Figures 1 to 7 A schematic structural diagram of a tunnel magnetoresistance formation process according to an embodiment of the present invention;

[0025] Figure 8 A condition for annealing and magnetization treatment provided in one embodiment of the present invention;

[0026] Figure 9 is the TMR output curve of the tunnel magnetoresistance in the prior art;

[0027] Figure 10 A TMR output curve of a tunnel magnetoresistance provided by an embodiment of the present invention;

[0028] Figure 11 A schematic structural diagram of a tunnel magnetic device provided in one embodiment of the present invention. DETAILED DESCRIPTION

[0029] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0030] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0031] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; internal connections between two components; wireless connections or wired connections. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0032] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0033] This embodiment provides a method for manufacturing a tunnel magnetoresistance, comprising the following steps: forming an underlying conductive structure; forming a free layer on one side of the underlying conductive structure, wherein the thickness of the free layer is less than or equal to a critical thickness; forming a tunnel barrier layer on a side of the free layer facing away from the underlying conductive structure; forming a pinned layer on a side of the tunnel barrier layer facing away from the free layer; and performing an annealing magnetization treatment on the free layer so that the free layer becomes a superparamagnetic layer.

[0034] Figures 1 to 7 A structural schematic diagram of a tunnel magnetoresistance formation process provided by an embodiment of the present invention.

[0035] Please refer to Figure 1 , providing a substrate 1a.

[0036] The substrate 1a may be a silicon substrate or a glass substrate.

[0037] Please refer to Figure 2 , a bottom conductive structure 2a is formed on the surface of one side of the substrate 1a.

[0038] The steps of forming the bottom conductive structure 2a include: forming a bottom conductive body 201a on one surface of the substrate 1a; and forming an interface layer 202a on a surface of the bottom conductive body 201a facing away from the substrate 1a.

[0039] The material of the interface layer 202 a includes Ta or Ru.

[0040] The interface layer effectively prevents the free layer 5 a from diffusing into the underlying conductive body 201 a during the subsequent annealing and magnetization process, thereby ensuring the thermal stability of the free layer 5 a.

[0041] Please refer to Figure 3 A free layer 5a is formed on the surface of the interface layer 202a facing away from the underlying conductive body 201a.

[0042] The free layer 5 a in this embodiment has a single-layer structure.

[0043] In one embodiment, the material of the free layer 5a includes CoFe 40 B 20 In other embodiments, the material of the free layer 5a may also be CoFe 60 B 20 .

[0044] The thickness of the free layer 5a is less than or equal to the critical thickness. The thickness of the free layer 5a is 1.0 nm to 1.4 nm, for example, 1.0 nm, 1.2 nm, 1.3 nm or 1.4 nm.

[0045] The process for forming the free layer 5 a includes a magnetron sputtering process, using a dedicated magnetron sputtering device with a coating accuracy within 0.01 nm, ensuring that the free layer 5 achieves the required film thickness and accuracy.

[0046] Please refer to Figure 4 A tunnel barrier layer 4a is formed on the surface of the free layer 5a facing away from the interface layer 202a.

[0047] The material of the tunnel barrier layer 4 a includes MgO.

[0048] The thickness of the tunneling barrier layer 4a is 0.5 nm to 1.5 nm, for example, 0.5 nm, 1 nm, 1.2 nm or 1.5 nm. The thickness of the tunneling barrier layer 4a can be adjusted according to the actual resistance requirement of the tunnel magnetoresistance.

[0049] Please refer to Figure 5 A pinning layer 3a is formed on the surface of the tunneling barrier layer 4a facing away from the free layer 5a.

[0050] In this embodiment, the steps of forming the pinning layer 3a include: forming a first sub-pinning film 301a on the surface of the tunneling barrier layer 4a facing away from the free layer 5a; forming a second sub-pinning film 302a on the surface of the first sub-pinning film 301a facing away from the tunneling barrier layer 4a; forming a third sub-pinning film 303a on the surface of the second sub-pinning film 302a facing away from the first sub-pinning film 301a; and forming a fourth sub-pinning film 304a on the surface of the third sub-pinning film 303a facing away from the second sub-pinning film 302a.

[0051] In one embodiment, the material of the first sub-pinning film 301a includes CoFe 40 B 20 The thickness of the first sub-pinning film 301a is 1.4 nm to 3 nm, for example, 1.4 nm, 1.8 nm, 2 nm, 2.5 nm or 3 nm.

[0052] In one embodiment, the material of the second sub-pinning film 302 a includes Ru, and the thickness of the second sub-pinning film 302 a is 0.7 nm to 1.0 nm, for example, 0.7 nm, 0.85 nm, or 1 nm.

[0053] In one embodiment, the material of the third sub-pinning film 303a includes CoFe 30 The thickness of the third sub-pinning film 303a is 1.5 nm to 2 nm, for example, 1.5 nm, 1.6 nm, 1.8 nm or 2 nm.

[0054] In one embodiment, the material of the fourth sub-pinning film 304a includes PtMn 62 The thickness of the fourth sub-pinning film 304a is 15 nm to 20 nm, for example, 15 nm, 16 nm, 18 nm or 20 nm.

[0055] In one embodiment, PtMn 62 As the ferromagnetic layer, CoFe 40 B 20、 Ru and CoFe 30 Form an antiferromagnetic composite layer.

[0056] Please refer to Figure 6 A top conductive structure 6a is formed on the side of the pinned layer 3a, the tunneling barrier layer 4a and the free layer 5a facing away from the substrate 1a.

[0057] Specifically, a top conductive structure 6 a is formed on the surface of the pinning layer 3 a facing away from the tunneling barrier layer 4 a .

[0058] The steps of forming the top conductive structure 6a include: forming a first top conductive film on the surface of the pinning layer 3a facing away from the tunneling barrier layer 4a; forming a second top conductive film on the surface of the first top conductive film facing away from the pinning layer 3a; and forming a third top conductive film on the surface of the second top conductive film facing away from the first top conductive film.

[0059] In one embodiment, the material of the first top conductive film may be Ta, with a thickness of 4 nm to 6 nm, for example, 5 nm.

[0060] In one embodiment, the second top conductive film may be made of Ru, with a thickness of 8 nm to 12 nm, for example, 10 nm.

[0061] In one embodiment, the material of the third top conductive film may be Ta, with a thickness of 4 nm to 6 nm, for example, 5 nm.

[0062] Please refer to Figure 7The free layer 5a is subjected to annealing and magnetization treatment to make the free layer 5a a superparamagnetic layer. It should be noted that the annealing and magnetization treatment can be performed after the free layer 5a is fabricated and before the tunnel barrier layer 4a is fabricated, or after the entire tunnel magnetoresistance is fabricated.

[0063] Figure 8 An annealing condition for annealing the free layer 5a is provided. Figure 8 The horizontal axis is time, in hours; Figure 8 The longitudinal axis in the figure is the temperature used for annealing and magnetization treatment, in degrees Celsius. Figure 8 The longitudinal minor axis in is the magnetic field applied during the annealing magnetization treatment, and its unit is Gs.

[0064] In one embodiment, during the annealing magnetization process, the annealing temperature is between 330°C and 400°C, for example, 330°C, 350°C, 380°C, or 400°C. The annealing temperature is appropriately selected based on the material of the pinned layer 3a; generally, the annealing temperature should be higher than the Curie temperature of the material of the pinned layer 3a. Increasing the annealing temperature can promote crystallization of the free layer 5a, making the superparamagnetic effect of the free layer 5a more pronounced. This increases the saturation field of the tunnel magnetoresistance and improves the linearity within the saturation field. Excessively high annealing temperatures can affect the thermal stability of the magnetic material.

[0065] In one embodiment, during the annealing magnetization treatment, the annealing time is 2 hours to 6 hours, for example, 2 hours, 3 hours, 4 hours or 6 hours. If the annealing time is too short, the crystallization process of the pinned layer 3a and the free layer 5a cannot reach a stable state. When the pinned layer 3a and the free layer 5a reach a stable state, an excessively long annealing time is unnecessary. Prolonging the annealing time can promote the crystallization of the free layer 5a, making the superparamagnetic effect of the free layer 5a more obvious, thereby increasing the saturation field of the tunnel magnetoresistance and the better the linearity within the saturation field. If the time is too long, the process efficiency is reduced and the cost is increased.

[0066] In this embodiment, during the annealing magnetization process, the magnetization direction is parallel to the surface of the free layer 5a opposite to the pinned layer 3a. After the annealing magnetization process is completed, the pinned layer 3a forms a fixed magnetic moment, and the direction of the magnetic moment in the pinned layer 3a is parallel to the magnetization direction.

[0067] In one embodiment, during the annealing magnetization process, the applied magnetic field strength is 4000 Gs to 20000 Gs, for example, 4000 Gs, 10000 Gs, 15000 Gs, or 20000 Gs. Excessively high magnetic field strength is unnecessary, while excessively low magnetic field strength cannot effectively magnetize the pinned layer 3a. The magnetic field strength is appropriately selected based on the material and thickness of the pinned layer 3a.

[0068] During the annealing magnetization process, the linearity of the tunnel magnetic device can be increased by increasing the annealing temperature or extending the annealing time.

[0069] In this embodiment, because the interface layer 202a is located between the underlying conductive body 201a and the free layer 5a, the interface layer 202a can effectively prevent the diffusion of the free layer 5a during the annealing and magnetization process, thereby ensuring the thermal stability of the free layer 5a.

[0070] The annealing magnetization process crystallizes the free layer 5 a , and the free layer 5 a in the tunnel magnetoresistance becomes superparamagnetic.

[0071] The free layer 5a in the tunnel magnetoresistance (TMR) is a superparamagnetic layer with a thickness less than or equal to the critical thickness. During the annealing magnetization process, the magnetic moments of the single-domain particles that make up the superparamagnetic layer are able to align in the same direction, reaching magnetic saturation and a high magnetic susceptibility. Therefore, the tunnel magnetoresistance provided by this embodiment has a large saturation field and high linearity.

[0072] In this embodiment, the free layer 5a is located between the underlying conductive structure 2a and the tunneling barrier layer 4a. Because there are fewer film layer structures before the free layer 5a is formed and the underlying conductive structure 2a is relatively flat, when the free layer 5a is formed, it is not easily affected by the previous film layer, so it is easy to obtain a continuous and uniform free layer 5a film layer, making the process easier and more stable to control.

[0073] An embodiment of the present invention provides a tunnel magnetoresistance, please refer to Figure 7 , including: a pinned layer 3a; a free layer 5a arranged opposite to the pinned layer 3a, the free layer 5a being a superparamagnetic layer, and the thickness of the free layer 5a being less than or equal to the critical thickness; a tunneling barrier layer 4a located between the pinned layer 3a and the free layer 5a; and an underlying conductive structure 2a located on the side of the free layer 5a facing away from the tunneling barrier layer 4a.

[0074] The tunnel magnetoresistance further includes a substrate 1 a , which is located on a side of the free layer 5 a facing away from the tunnel barrier layer 4 a .

[0075] The substrate 1a may be a silicon substrate or a glass substrate.

[0076] In this embodiment, the tunnel magnetoresistance has a top conductive structure 6a, the pinned layer 3a, the free layer 5a and the tunneling barrier layer 4a are all located between the top conductive structure 6a and the bottom conductive structure 2a, and the pinned layer 3a is located between the top conductive structure 6a and the tunneling barrier layer 4a.

[0077] The bottom conductive structure 2a includes a bottom conductive body 201a and an interface layer 202a. The interface layer 202a is located between the bottom conductive body 201a and the free layer 5a. The material of the interface layer 202a includes Ta or Ru.

[0078] The material of the free layer 5a includes CoFe 40 B 20 In other embodiments, the material of the free layer 5a may also be CoFe 60 B 20 .

[0079] The free layer 5 a in this embodiment has a single-layer structure.

[0080] The free layer 5a is a superparamagnetic layer, and the thickness of the free layer 5a is less than or equal to the critical thickness. The thickness of the free layer 5a is 1.0 nm to 1.4 nm, for example, 1.0 nm, 1.2 nm, 1.3 nm or 1.4 nm.

[0081] The material of the tunnel barrier layer 4 a includes MgO.

[0082] The thickness of the tunneling barrier layer 4a is 0.5 nm to 1.5 nm, for example, 0.5 nm, 1 nm, 1.2 nm or 1.5 nm. The thickness of the tunneling barrier layer 4a can be adjusted according to the actual resistance requirement of the tunnel magnetoresistance.

[0083] The pinning layer 3a includes: a first sub-pinning film 301a, a second sub-pinning film 302a, a third sub-pinning film 303a and a fourth sub-pinning film 304a, and the first sub-pinning film 301a, the second sub-pinning film 302a, the third sub-pinning film 303a and the fourth sub-pinning film 304a are stacked in sequence in the direction from the free layer 5a to the tunneling barrier layer 4a.

[0084] In one embodiment, the material of the fourth sub-pinning film 304a includes PtMn 62 The thickness of the fourth sub-pinning film 304a is 15 nm to 20 nm, for example, 15 nm, 16 nm, 18 nm or 20 nm.

[0085] In one embodiment, the material of the third sub-pinning film 303a includes CoFe 30 The thickness of the third sub-pinning film 303a is 1.5 nm to 2 nm, for example, 1.5 nm, 1.6 nm, 1.8 nm or 2 nm.

[0086] In one embodiment, the material of the second sub-pinning film 302 a includes Ru, and the thickness of the second sub-pinning film 302 a is 0.7 nm to 1.0 nm, for example, 0.7 nm, 0.85 nm, or 1 nm.

[0087] In one embodiment, the material of the first sub-pinning film 301a includes CoFe 40 B 20 The thickness of the first sub-pinning film 301a is 1.4 nm to 3 nm, for example, 1.4 nm, 1.8 nm, 2 nm, 2.5 nm or 3 nm.

[0088] The top conductive structure 6a includes a first top conductive film, a second top conductive film, and a third top conductive film stacked sequentially from bottom to top.

[0089] In one embodiment, the material of the first top conductive film includes Ta, and the thickness is 4 nm to 6 nm, for example, 5 nm.

[0090] In one embodiment, the second top conductive film is made of Ru and has a thickness of 8 nm to 12 nm, for example, 10 nm.

[0091] In one embodiment, the material of the third top conductive film includes Ta, and the thickness is 4 nm to 6 nm, for example, 5 nm.

[0092] Please refer to Figure 9 , Figure 9 is the TMR output curve of the tunnel magnetoresistance in the prior art, Figure 9 The horizontal axis is the external magnetic field strength, in Gs; Figure 9 The vertical axis is the TMR rate, and the unit is %. Figure 9 The saturation field of the medium tunnel magnetoresistance is relatively small, with an absolute value of less than 300Gs, and the linearity of the change of the TMR rate with the external magnetic field is small.

[0093] Please refer to Figure 10 , Figure 10 The TMR output curve of the tunnel magnetoresistance provided in this embodiment is: Figure 10 The horizontal axis is the magnetic field intensity, in Gs; Figure 10 The vertical axis is the TMR rate, and the unit is %. Figure 10 The tunnel magnetoresistance in the embodiment adopts the superparamagnetic free layer 5, so the saturation field of the tunnel magnetoresistance is relatively large, with an absolute value of 2000Gs, and the linearity of the change of the TMR rate with the external magnetic field is large.

[0094] Another embodiment of the present invention further provides a tunnel magnetic device, including the above tunnel magnetoresistance, please refer to Figure 11 The number of tunnel magnetoresistors in the tunnel magnetic device is several, and the tunnel magnetoresistors are connected in series.

[0095] In this embodiment, the substrate 1a in each tunnel magnetoresistors is a whole surface, and adjacent tunnel magnetoresistors are electrically connected through the bottom conductive structure 2a or the top conductive structure 6a; the series connection can be electrically connected through the wire 7a.

[0096] Connecting several tunnel magnetoresistors in series to form a tunnel magnetic device can be used in sensor fields that require a large saturation field.

[0097] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A tunnel magnetoresistance, characterized in that include: pinning layer; A free layer disposed opposite the pinned layer, the free layer being a superparamagnetic layer, the thickness of the free layer being less than or equal to a critical thickness, the thickness of the free layer being 1.2 nm to 1.4 nm, the free layer being subjected to an annealing magnetization treatment to form a superparamagnetic layer, the annealing temperature of the annealing magnetization treatment being 330° C. to 400° C., the annealing time of the annealing magnetization treatment being 2 hours to 6 hours, the magnetic field direction of the annealing magnetization treatment being parallel to the surface of the free layer opposite to the pinned layer, and the magnetic field strength of the annealing magnetization treatment being 4000 Gs to 20000 Gs; a tunneling barrier layer located between the pinned layer and the free layer; The pinning layer includes a first sub-pinning film, a second sub-pinning film, a third sub-pinning film and a fourth sub-pinning film, and the first sub-pinning film, the second sub-pinning film, the third sub-pinning film and the fourth sub-pinning film are sequentially stacked in a direction from the free layer to the tunnel barrier layer; The material of the first sub-pinning film includes CoFe 40 B 20 , the thickness of the first sub-pinning film is 1.4nm~3nm; The material of the second sub-pinning film includes Ru, and the thickness of the second sub-pinning film is 0.7 nm to 1.0 nm; The material of the third sub-pinning film includes CoFe 30 , the thickness of the third sub-pinning film is 1.5nm~2nm; The material of the fourth sub-pinning film includes PtMn 62 , the thickness of the fourth sub-pinning film is 15nm~20nm; The bottom conductive structure is located on the side of the free layer facing away from the tunnel barrier layer.

2. The tunnel magnetoresistance according to claim 1, wherein The material of the free layer includes CoFe 40 B 20 or CoFe 60 B 20 .

3. The tunnel magnetoresistance according to claim 1, wherein Also includes: The top conductive structure, the pinned layer, the free layer and the tunnel barrier layer are all located between the top conductive structure and the bottom conductive structure, and the pinned layer is located between the top conductive structure and the tunnel barrier layer.

4. The tunnel magnetoresistance according to claim 1, wherein The bottom conductive structure includes a bottom conductive body and an interface layer, wherein the interface layer is located between the bottom conductive body and the free layer; The material of the interface layer includes Ta or Ru.

5. A method for manufacturing a tunnel magnetoresistance, for forming the tunnel magnetoresistance according to any one of claims 1 to 4, characterized in that: The steps include: forming a bottom conductive structure; forming a free layer on one side of the bottom conductive structure, wherein the thickness of the free layer is less than or equal to the critical thickness and the thickness of the free layer is 1.2 nm to 1.4 nm; forming a tunnel barrier layer on a side of the free layer facing away from the underlying conductive structure; A pinning layer is formed on a side of the tunnel barrier layer facing away from the free layer, wherein the forming of the pinning layer comprises: forming a fourth sub-pinning film, wherein the material of the fourth sub-pinning film comprises PtMn 62 The thickness of the fourth pinning film is 15nm to 20nm; a third pinning film is formed on one side surface of the fourth pinning film, and the material of the third pinning film includes CoFe 30 , the thickness of the third sub-pinning film is 1.5nm~2nm; a second sub-pinning film is formed on the surface of the third sub-pinning film on the side facing away from the fourth sub-pinning film, the material of the second sub-pinning film includes Ru, and the thickness of the second sub-pinning film is 0.7nm~1.0nm; a first sub-pinning film is formed on the surface of the second sub-pinning film on the side facing away from the third sub-pinning film, and the material of the first sub-pinning film includes CoFe 40 B 20 , the thickness of the first sub-pinning film is 1.4nm~3nm; The free layer is subjected to annealing and magnetization treatment so that the free layer becomes a superparamagnetic layer. The annealing temperature of the annealing and magnetization treatment is 330° C. to 400° C., and the annealing time of the annealing and magnetization treatment is 2 hours to 6 hours. The magnetic field direction of the annealing and magnetization treatment is parallel to the surface opposite to the free layer and the pinned layer, and the magnetic field intensity of the annealing and magnetization treatment is 4000 Gs to 20000 Gs.

6. The method for manufacturing a tunnel magnetoresistance according to claim 5, wherein: Also includes: Before forming the underlying conductive structure, providing a substrate, on which the underlying conductive structure is formed; A top conductive structure is formed on the side of the pinning layer facing away from the substrate.

7. The method for manufacturing a tunnel magnetoresistance according to claim 5, wherein: The method for forming the bottom conductive structure includes: forming a bottom conductive body; forming an interface layer on one side of the bottom conductive body; The interface layer is located between the bottom conductive body and the free layer.

8. A tunnel magnetic device, characterized in that: include: A tunnel magnetoresistance according to any one of claims 1 to 4.

9. The tunnel magnetic device according to claim 8, characterized in that: There are multiple tunnel magnetoresistors, and the tunnel magnetoresistors are connected in series.

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