A CoFeB-based magnetic multilayer film and preparation method thereof

Abstract

The present invention provides a CoFeB-based magnetic multilayer film and a preparation method thereof. The present invention introduces a TiC layer, which can effectively inhibit the diffusion of Ta, making the Ta / CoFeB interface smoother, which is conducive to obtaining perpendicular magnetic anisotropy; the TiC layer can effectively introduce C atoms into the multilayer film, and the introduction of C atoms can effectively regulate the orbital hybridization between Fe and O, and then can effectively drive the magnetic anisotropy of the multilayer film from in-plane to out-of-plane through the double-layer action of C and O double ions, that is, the magnetic multilayer film obtains perpendicular magnetic anisotropy; the present invention increases the degree of freedom of material regulation and improves the amplitude of performance regulation through the regulation of C and O double ions, greatly improves the regulation of the perpendicular magnetic anisotropy of the film from multiple angles, and further improves the thermal stability of the CoFeB-based magnetic multilayer film.

Description

Technical Field

[0001] The invention relates to the technical field of magnetic materials, and in particular to a CoFeB-based magnetic multilayer film and a preparation method thereof. Background Art

[0002] CoFeB based perpendicular anisotropic magnetic tunnel junction (CoFeB based p-MTJ) has the advantages of relatively high spin polarization rate and thermal stability, low magnetic damping coefficient and critical reversal current density, and is expected to be used in the next generation of ultra-high density magnetic random access memory (MRAM). Spintronics devices (STT-MRAM) based on its structure are also developing rapidly, and its storage density has reached Gbit from Mbit level. Therefore, improving the perpendicular magnetic anisotropy of CoFeB / MgO based multilayer films is crucial for future applications.

[0003] At present, the research on the regulation of magnetic anisotropy of CoFeB-based thin film materials focuses on regulating the perpendicular magnetic anisotropy of thin films by selecting different oxide layer materials, applying stress and strain, introducing external electric fields, etc. These methods mainly focus on regulating the magnetic anisotropy of ferromagnetic multilayer film materials by single ions; in addition, in order to maintain good perpendicular magnetic anisotropy, annealing treatment is usually required. High-temperature annealing will cause diffusion of the bottom layer of the multilayer film system, thereby reducing the perpendicular magnetic anisotropy of the CoFeB / oxide multilayer film, and even causing the disappearance of the perpendicular magnetic anisotropy, which is not conducive to practical application.

[0004] Therefore, it is of great significance to effectively regulate the perpendicular magnetic anisotropy of CoFeB / oxide multilayer films and improve the thermal stability of their perpendicular magnetic anisotropy. Summary of the invention

[0005] The present invention provides a CoFeB-based magnetic multilayer film and a preparation method thereof, so as to solve or at least partially solve the defects existing in the prior art.

[0006] In a first aspect, the present invention provides a CoFeB-based magnetic multilayer film, comprising:

[0007] substrate;

[0008] A buffer layer, which is located on the surface of the substrate;

[0009] A TiC layer, which is located on a surface of the buffer layer away from the substrate;

[0010] A CoFeB layer, which is located on a surface of the TiC layer away from the substrate;

[0011] an oxide layer, which is located on a surface of the CoFeB layer away from the substrate;

[0012] A protection layer is located on a surface of the oxide layer away from the substrate.

[0013] Preferably, the material of the buffer layer includes any one of Ta, Ti, and Ru;

[0014] And / or, the material of the protective layer includes any one of Ta, Ti, and Ru;

[0015] and / or, the oxide layer is a MgO layer;

[0016] And / or, the substrate includes any one of a glass substrate, a silicon substrate, and a polymer substrate.

[0017] Preferably, the thickness of the substrate is 0.5-0.7 mm;

[0018] and / or, the thickness of the buffer layer is 40 to 50 Å;

[0019] And / or, the thickness of the TiC layer is 1 to 10 Å;

[0020] And / or, the thickness of the CoFeB layer is 10-15 Å;

[0021] and / or, the thickness of the oxide layer is 20 to 25 Å;

[0022] And / or, the thickness of the protective layer is 20 to 50 Å.

[0023] Preferably, a SiO2 oxide layer is further provided on the surface of the substrate, and the buffer layer is located on the surface of the SiO2 oxide layer away from the substrate.

[0024] Preferably, the thickness of the SiO2 oxide layer is 200-400 nm.

[0025] Preferably, the molar ratio of Co, Fe and B in the CoFeB layer is (39.5~40.5):(39.5~40.5):(19.5~20.5).

[0026] In a second aspect, the present invention further provides a method for preparing the CoFeB-based magnetic multilayer film, comprising the following steps:

[0027] S1. providing a substrate;

[0028] S2, depositing a buffer layer, a TiC layer, a CoFeB layer, an oxide layer, and a protective layer on the substrate in sequence;

[0029] S3. Under a vacuum environment, heat-treat the substrate having the multilayer film formed in S2 to obtain a CoFeB-based magnetic multilayer film.

[0030] Preferably, the heat treatment temperature is 200-450° C. and the time is 25-35 min.

[0031] Preferably, a buffer layer, a TiC layer, a CoFeB layer, an oxide layer, and a protective layer are sequentially deposited on the substrate by magnetron sputtering;

[0032] In the process of depositing the buffer layer by magnetron sputtering, the sputtering power is controlled to be 45-55W and the sputtering temperature is controlled to be 20-25°C;

[0033] In the process of depositing the TiC layer by magnetron sputtering, the sputtering power is controlled to be 45~55W and the sputtering temperature is controlled to be 20~25℃;

[0034] In the process of depositing the CoFeB layer by magnetron sputtering, the sputtering power is controlled to be 25~35W and the sputtering temperature is controlled to be 20~25℃;

[0035] In the process of depositing the oxide layer by magnetron sputtering, the sputtering power is controlled to be 180~220W and the sputtering temperature is controlled to be 20~25℃;

[0036] In the process of depositing the protective layer by magnetron sputtering, the sputtering power is controlled to be 45~55W and the sputtering temperature is controlled to be 20~25℃;

[0037] The background vacuum of the sputtering chamber during sputtering is 1×10 -5 ~3×10 -5 Pa, the working pressure of argon is 0.3~0.6Pa.

[0038] Preferably, the substrate S2 having the multilayer film formed thereon is subjected to heat treatment in a vacuum environment, wherein the vacuum degree of the vacuum environment is 1×10 -5 ~3×10 -5 Pa.

[0039] The present invention has the following beneficial effects compared with the prior art:

[0040] 1. The CoFeB-based magnetic multilayer film of the present invention comprises a substrate, a buffer layer, a TiC layer, a CoFeB layer, an oxide layer, and a protective layer which are sequentially stacked; wherein the TiC layer can effectively inhibit the diffusion of Ta, making the Ta / CoFeB interface smoother, which is conducive to obtaining perpendicular magnetic anisotropy; on the other hand, the TiC layer can effectively introduce C atoms into the multilayer film, thereby effectively regulating the electronic coordination environment of Fe at the Ta / CoFeB interface and improving the out-of-plane orbital electron occupancy of Fe atoms, that is, the introduction of C atoms can effectively regulate the orbital hybridization between Fe and O, and further can effectively drive the magnetic anisotropy of the multilayer film from in-plane to out-of-plane through the double-layer action of C and O double ions, that is, the magnetic multilayer film obtains perpendicular magnetic anisotropy;

[0041] 2. The preparation method of the CoFeB-based magnetic multilayer film of the present invention, by introducing a TiC layer, the TiC layer can effectively introduce C atoms into the multilayer film, the introduction of C atoms can effectively regulate the orbital hybridization between Fe and O, and then can effectively drive the magnetic anisotropy of the multilayer film from in-plane to out-plane through the double-layer action of C and O double ions, that is, the magnetic multilayer film obtains perpendicular magnetic anisotropy; the present invention increases the degree of freedom of material regulation and improves the amplitude of performance regulation through the regulation of C and O double ions, greatly improves the regulation of the perpendicular magnetic anisotropy of the film from multiple angles, and further improves the thermal stability of the CoFeB-based magnetic multilayer film. The CoFeB-based magnetic multilayer film of the present invention can improve the power consumption, storage density and stability of electronic devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 A schematic diagram of the structure of a CoFeB-based magnetic multilayer film in one embodiment of the present invention;

[0043] Figure 2 A schematic diagram of the structure of a CoFeB-based magnetic multilayer film in another embodiment of the present invention;

[0044] Figure 3 Schematic diagram of the structure of the CoFeB-based magnetic multilayer film in Comparative Examples 1-2;

[0045] Figure 4 is the hysteresis loop of the CoFeB-based magnetic multilayer film prepared in Comparative Example 1;

[0046] Figure 5 is the hysteresis loop of the CoFeB-based magnetic multilayer film prepared in Example 1;

[0047] Figure 6 is the hysteresis loop of the CoFeB-based magnetic multilayer film prepared in Comparative Example 2;

[0048] Figure 7 : is the hysteresis loop of the CoFeB-based magnetic multilayer film prepared in Example 2. DETAILED DESCRIPTION

[0049] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0050] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0051] In the description of the present invention, it should be understood that the directions or positions indicated by “upper” and the like are based on the directions or positions shown in the accompanying drawings, or are the directions or positions in which the product of the invention is usually placed when in use, or are directions or positions commonly understood by those skilled in the art. These directions or positions are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0052] The following are described in detail. It should be noted that the order of description of the following embodiments is not intended to limit the preferred order of the embodiments. In addition, in the description of the present application, the term "including" means "including but not limited to". Various embodiments of the present invention may exist in the form of a range; it should be understood that the description in the form of a range is only for convenience and simplicity, and should not be understood as a rigid limitation on the scope of the present invention; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single values ​​within the range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the numbered ranges, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated in this article, it is meant to include any quoted numbers (fractions or integers) within the indicated range.

[0053] The present invention provides a CoFeB-based magnetic multilayer film, such as Figure 1 As shown, including:

[0054] Base 1;

[0055] A buffer layer 2, which is located on the surface of the substrate 1;

[0056] A TiC layer 3, which is located on the surface of the buffer layer 2 away from the substrate 1;

[0057] A CoFeB layer 4, which is located on the surface of the TiC layer away from the substrate 1;

[0058] An oxide layer 5, which is located on a surface of the CoFeB layer away from the substrate 1;

[0059] The protection layer 6 is located on the surface of the oxide layer 5 away from the substrate 1 .

[0060] The CoFeB-based magnetic multilayer film of the present invention comprises a substrate 1, a buffer layer 2, a TiC layer 3, a CoFeB layer 4, an oxide layer 5, and a protective layer 6 which are sequentially stacked; wherein the TiC layer 3 can effectively inhibit the diffusion of Ta, so that the Ta / CoFeB interface is smoother, which is conducive to obtaining perpendicular magnetic anisotropy; on the other hand, the TiC layer 3 can effectively introduce C atoms into the multilayer film, thereby effectively regulating the electronic coordination environment of Fe at the Ta / CoFeB interface and improving the out-of-plane orbital electron occupancy of Fe atoms, that is, the introduction of C atoms can effectively regulate the orbital hybridization between Fe and O, and further can effectively drive the magnetic anisotropy of the multilayer film from in-plane to out-of-plane conversion through the double-layer action of C and O double ions, that is, the magnetic multilayer film obtains perpendicular magnetic anisotropy.

[0061] In some embodiments, the material of the buffer layer 2 includes any one of Ta, Ti, and Ru.

[0062] In some embodiments, the material of the protection layer 6 includes any one of Ta, Ti, and Ru.

[0063] Preferably, the material of the buffer layer 2 and the protective layer 6 is Ta.

[0064] In some embodiments, the oxide layer 5 is a MgO layer, and preferably, the multilayer film is a Ta / TiC / CoFeB / MgO / Ta multilayer film.

[0065] In some embodiments, the substrate 1 includes any one of a glass substrate, a silicon substrate, and a polymer substrate.

[0066] Specifically, the silicon substrate includes a Si substrate and a Si / SiO2 substrate, and the substrate may also include an inorganic substrate such as a SiC substrate; the polymer substrate may be an organic flexible substrate such as a polyethylene substrate, a polypropylene substrate, a polystyrene substrate, a polyethylene terephthalate substrate, a polyimide substrate, and a polycarbonate substrate.

[0067] In some embodiments, the thickness of the substrate 1 is 0.5-0.7 mm.

[0068] In some embodiments, the thickness of the buffer layer 2 is 40-50 Å.

[0069] In some embodiments, the thickness of the TiC layer 3 is 1-10 Å.

[0070] In some embodiments, the thickness of the CoFeB layer 4 is 10-15 Å.

[0071] In some embodiments, the thickness of the oxide layer 5 is 20-25 Å.

[0072] In some embodiments, the thickness of the protective layer 6 is 20 to 50 Å.

[0073] Specifically, 1 Å = 10 -10 m=0.1 nm.

[0074] In some embodiments, Figure 2 As shown, a SiO2 oxide layer 11 is also provided on the surface of the substrate 1, and the buffer layer is located on the surface of the SiO2 oxide layer 11 away from the substrate, that is, the substrate is a Si / SiO2 substrate.

[0075] In some embodiments, the thickness of the SiO2 oxide layer is 200-400 nm.

[0076] In some embodiments, the molar fractions of Co, Fe, and B in the CoFeB layer are not limited. Preferably, the molar ratio of Co, Fe, and B in the CoFeB layer is (39.5-40.5):(39.5-40.5):(19.5-20.5). More preferably, the molar ratio of Co, Fe, and B in the CoFeB layer is 40:40:20. In this case, the CoFeB layer is Co 40 Fe 40 B 20 layer.

[0077] Based on the same inventive concept, the present invention also provides a method for preparing the above-mentioned CoFeB-based magnetic multilayer film, comprising the following steps:

[0078] S1. providing a substrate;

[0079] S2, sequentially depositing a buffer layer, a TiC layer, a CoFeB layer, an oxide layer, and a protective layer on the substrate;

[0080] S3. Under a vacuum environment, heat-treat the substrate having the multilayer film formed in S2 to obtain a CoFeB-based magnetic multilayer film.

[0081] In some embodiments, the heat treatment temperature is 200-450° C. and the time is 25-35 min. After the heat treatment, the film is naturally cooled to room temperature to obtain a CoFeB-based magnetic multilayer film.

[0082] In some embodiments, a buffer layer, a TiC layer, a CoFeB layer, an oxide layer, and a protective layer are sequentially deposited on a substrate by magnetron sputtering.

[0083] In some embodiments, during the process of depositing the buffer layer by magnetron sputtering, the sputtering power is controlled to be 45-55 W and the sputtering temperature is controlled to be 20-25° C.

[0084] In some embodiments, during the process of depositing the TiC layer by magnetron sputtering, the sputtering power is controlled to be 45-55 W and the sputtering temperature is controlled to be 20-25° C.

[0085] In some embodiments, during the process of depositing the CoFeB layer by magnetron sputtering, the sputtering power is controlled to be 25-35 W and the sputtering temperature is controlled to be 20-25° C.

[0086] In some embodiments, during the process of depositing the oxide layer by magnetron sputtering, the sputtering power is controlled to be 180-220 W and the sputtering temperature is controlled to be 20-25° C.

[0087] In some embodiments, during the process of depositing the protective layer by magnetron sputtering, the sputtering power is controlled to be 45-55 W and the sputtering temperature is controlled to be 20-25° C.

[0088] In some embodiments, when a buffer layer, a TiC layer, a CoFeB layer, an oxide layer, and a protective layer are sequentially deposited on a substrate by magnetron sputtering, the background vacuum degree of the sputtering chamber during sputtering is 1×10 -5 ~3×10 -5 Pa, the working pressure of argon is 0.3~0.6 Pa.

[0089] In some embodiments, the substrate S2 having the multilayer film formed thereon is subjected to heat treatment in a vacuum environment, wherein the vacuum degree of the vacuum environment is 1×10 -5 ~3×10 -5 Pa.

[0090] Specifically, when each layer is obtained by magnetron sputtering, the target material corresponding to the material of the layer is used for sputtering deposition; for example, if the buffer layer and the protective layer are both Ta, the Ta target material is used for sputtering deposition; the TiC (titanium carbide) target material is used for sputtering deposition to obtain the TiC layer; the CoFeB target material is used for sputtering deposition to obtain the CoFeB layer; and the MgO target material is used for sputtering deposition to obtain the oxide layer. Argon is used as the working gas during sputtering deposition, and the working gas pressure of argon is 0.3~0.6 Pa.

[0091] In some embodiments, before depositing each layer on the substrate, the substrate is also cleaned. Specifically, the substrate is cleaned with acetone, anhydrous ethanol, and deionized water in sequence, and then blown dry with high-purity nitrogen.

[0092] The preparation method of the CoFeB-based magnetic multilayer film of the present invention introduces a TiC layer, and the TiC layer can effectively introduce C atoms into the multilayer film. The introduction of C atoms can effectively regulate the orbital hybridization between Fe and O, and then can effectively drive the magnetic anisotropy of the multilayer film from in-plane to out-plane through the double-layer action of C and O double ions, that is, the magnetic multilayer film obtains perpendicular magnetic anisotropy; the present invention increases the degree of freedom of material regulation and improves the amplitude of performance regulation through the regulation of C and O double ions, greatly improves the regulation of the perpendicular magnetic anisotropy of the film from multiple angles, and further improves the thermal stability of the CoFeB-based magnetic multilayer film. The CoFeB-based magnetic multilayer film of the present invention can improve the power consumption, storage density and stability of electronic devices.

[0093] The following further describes the CoFeB-based magnetic multilayer film and its preparation method of the present application with specific examples. This section further describes the content of the present invention in conjunction with specific examples, but should not be construed as limiting the present invention. Unless otherwise specified, the technical means used in the examples are conventional means known to those skilled in the art. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0094] Example 1

[0095] The present application embodiment provides a CoFeB-based magnetic multilayer film, such as Figure 2 As shown, including:

[0096] A substrate having a SiO2 oxide layer on its surface;

[0097] A buffer layer, which is located on the surface of the SiO2 oxide layer away from the substrate;

[0098] A TiC layer located on a surface of the buffer layer away from the substrate;

[0099] A CoFeB layer located on a surface of the TiC layer away from the substrate;

[0100] An oxide layer, which is located on the surface of the CoFeB layer away from the substrate;

[0101] a protective layer, which is located on the surface of the oxide layer away from the substrate;

[0102] Wherein, the material of the buffer layer is Ta;

[0103] The material of the protective layer is Ta;

[0104] The oxide layer is a MgO layer;

[0105] CoFeB layer is Co 40 Fe 40 B 20 layer;

[0106] The substrate is a Si substrate, the thickness of the Si substrate is 0.6 mm, and the thickness of the SiO2 oxide layer is 300 nm;

[0107] The thickness of the buffer layer is 50 Å;

[0108] The thickness of the TiC layer is 1 Å;

[0109] The thickness of the CoFeB layer is 10Å;

[0110] The thickness of the oxide layer is 20 Å;

[0111] The thickness of the protective layer is 20 Å.

[0112] The method for preparing the CoFeB-based magnetic multilayer film comprises the following steps:

[0113] S1. Provide a substrate (i.e., a Si / SiO2 substrate, with a Si thickness of 0.6 mm and a SiO2 thickness of 300 nm);

[0114] S2, using Ta target, TiC target, CoFeB target (the molar ratio of Co, Fe and B in the target is 40:40:20), MgO target and Ta target, respectively, to deposit a buffer layer, a TiC layer, a CoFeB layer, an oxide layer and a protective layer on a substrate by magnetron sputtering to form a Ta / TiC / CoFeB / MgO / Ta multilayer film;

[0115] S3, heat-treating the substrate with the multilayer film formed in S2 under a vacuum environment to obtain a CoFeB-based magnetic multilayer film;

[0116] In the process of depositing the buffer layer by magnetron sputtering in S2, the sputtering power was controlled to be 50W and the sputtering temperature to be 25°C;

[0117] During the magnetron sputtering process of depositing the TiC layer, the sputtering power was controlled to be 50 W and the sputtering temperature to be 25 °C;

[0118] During the deposition of the CoFeB layer by magnetron sputtering, the sputtering power was controlled to be 30 W and the sputtering temperature to be 25 °C;

[0119] In the process of depositing the oxide layer by magnetron sputtering, the sputtering power was controlled to be 200 W and the sputtering temperature to be 25°C;

[0120] In the process of depositing the protective layer by magnetron sputtering, the sputtering power was controlled to be 50W and the sputtering temperature to be 25°C;

[0121] When the buffer layer, TiC layer, CoFeB layer, oxide layer and protective layer are deposited on the substrate in sequence by magnetron sputtering, the background vacuum degree of the sputtering chamber is 1×10-5 Pa, the working pressure of argon is 0.4 Pa;

[0122] The vacuum degree of the vacuum environment in S3 is 1×10 -5 pa, heat treatment temperature is 250℃ and time is 30min.

[0123] Example 2

[0124] The present application embodiment provides a CoFeB-based magnetic multilayer film, such as Figure 2 As shown, including:

[0125] A substrate having a SiO2 oxide layer on its surface;

[0126] A buffer layer, which is located on the surface of the SiO2 oxide layer away from the substrate;

[0127] A TiC layer located on a surface of the buffer layer away from the substrate;

[0128] A CoFeB layer located on a surface of the TiC layer away from the substrate;

[0129] An oxide layer, which is located on the surface of the CoFeB layer away from the substrate;

[0130] a protective layer, which is located on the surface of the oxide layer away from the substrate;

[0131] Wherein, the material of the buffer layer is Ta;

[0132] The material of the protective layer is Ta;

[0133] The oxide layer is a MgO layer;

[0134] CoFeB layer is Co 40 Fe 40 B 20 layer;

[0135] The substrate is a Si substrate, the thickness of the Si substrate is 0.6 mm, and the thickness of the SiO2 oxide layer is 300 nm;

[0136] The thickness of the buffer layer is 50 Å;

[0137] The thickness of the TiC layer is 1 Å;

[0138] The thickness of the CoFeB layer is 10Å;

[0139] The thickness of the oxide layer is 20 Å;

[0140] The thickness of the protective layer is 20 Å.

[0141] The method for preparing the CoFeB-based magnetic multilayer film comprises the following steps:

[0142] S1. Provide a substrate (i.e., a Si / SiO2 substrate, with a Si thickness of 0.6 mm and a SiO2 thickness of 300 nm);

[0143] S2, using Ta target, TiC target, CoFeB target (the molar ratio of Co, Fe and B in the target is 40:40:20), MgO target and Ta target, respectively, to deposit a buffer layer, a TiC layer, a CoFeB layer, an oxide layer and a protective layer on a substrate by magnetron sputtering to form a Ta / TiC / CoFeB / MgO / Ta multilayer film;

[0144] S3, heat-treating the substrate with the multilayer film formed in S2 under a vacuum environment to obtain a CoFeB-based magnetic multilayer film;

[0145] In the process of depositing the buffer layer by magnetron sputtering in S2, the sputtering power was controlled to be 50W and the sputtering temperature to be 25°C;

[0146] During the magnetron sputtering process of depositing the TiC layer, the sputtering power was controlled to be 50 W and the sputtering temperature to be 25 °C;

[0147] During the deposition of the CoFeB layer by magnetron sputtering, the sputtering power was controlled to be 30 W and the sputtering temperature to be 25 °C;

[0148] In the process of depositing the oxide layer by magnetron sputtering, the sputtering power was controlled to be 200 W and the sputtering temperature to be 25°C;

[0149] In the process of depositing the protective layer by magnetron sputtering, the sputtering power was controlled to be 50W and the sputtering temperature to be 25°C;

[0150] When the buffer layer, TiC layer, CoFeB layer, oxide layer and protective layer are deposited on the substrate in sequence by magnetron sputtering, the background vacuum degree of the sputtering chamber is 1×10 -5 Pa, the working pressure of argon is 0.4 Pa;

[0151] The vacuum degree of the vacuum environment in S3 is 1×10 -5 pa, heat treatment temperature is 450℃ and time is 30min.

[0152] Comparative Example 1

[0153] This comparative example provides a CoFeB-based magnetic multilayer film, which is the same as Example 1, but does not contain a TIC layer, such as Figure 3 As shown, including:

[0154] A substrate having a SiO2 oxide layer on its surface;

[0155] A buffer layer, which is located on the surface of the SiO2 oxide layer away from the substrate;

[0156] A CoFeB layer located on a surface of the buffer layer away from the substrate;

[0157] An oxide layer, which is located on the surface of the CoFeB layer away from the substrate;

[0158] a protective layer, which is located on the surface of the oxide layer away from the substrate;

[0159] Wherein, the material of the buffer layer is Ta;

[0160] The material of the protective layer is Ta;

[0161] The oxide layer is a MgO layer;

[0162] CoFeB layer is Co 40 Fe 40 B 20 layer;

[0163] The substrate is a Si substrate, the thickness of the Si substrate is 0.6 mm, and the thickness of the SiO2 oxide layer is 300 nm;

[0164] The thickness of the buffer layer is 50 Å;

[0165] The thickness of the CoFeB layer is 10Å;

[0166] The thickness of the oxide layer is 20 Å;

[0167] The thickness of the protective layer is 20 Å.

[0168] The method for preparing the CoFeB-based magnetic multilayer film comprises the following steps:

[0169] S1. Provide a substrate (i.e., a Si / SiO2 substrate, with a Si thickness of 0.6 mm and a SiO2 thickness of 300 nm);

[0170] S2, using Ta target, CoFeB target (the molar ratio of Co, Fe and B in the target is 40:40:20), MgO target and Ta target respectively, a buffer layer, a CoFeB layer, an oxide layer and a protective layer are sequentially deposited on a substrate by magnetron sputtering to form a Ta / CoFeB / MgO / Ta multilayer film;

[0171] S3, heat-treating the substrate with the multilayer film formed in S2 under a vacuum environment to obtain a CoFeB-based magnetic multilayer film;

[0172] In the process of depositing the buffer layer by magnetron sputtering in S2, the sputtering power was controlled to be 50W and the sputtering temperature to be 25°C;

[0173] During the deposition of the CoFeB layer by magnetron sputtering, the sputtering power was controlled to be 30 W and the sputtering temperature to be 25 °C;

[0174] In the process of depositing the oxide layer by magnetron sputtering, the sputtering power was controlled to be 200 W and the sputtering temperature to be 25°C;

[0175] In the process of depositing the protective layer by magnetron sputtering, the sputtering power was controlled to be 50W and the sputtering temperature to be 25°C;

[0176] When the buffer layer, CoFeB layer, oxide layer and protective layer are deposited on the substrate in sequence by magnetron sputtering, the background vacuum degree of the sputtering chamber is 1×10 -5 Pa, the working pressure of argon is 0.4 Pa;

[0177] The vacuum degree of the vacuum environment in S3 is 1×10 -5 pa, heat treatment temperature is 250℃ and time is 30min.

[0178] Comparative Example 2

[0179] This comparative example provides a CoFeB-based magnetic multilayer film, which is the same as Example 2, except that it does not contain a TIC layer, such as Figure 3 As shown, including:

[0180] A substrate having a SiO2 oxide layer on its surface;

[0181] A buffer layer, which is located on the surface of the SiO2 oxide layer away from the substrate;

[0182] A CoFeB layer located on a surface of the buffer layer away from the substrate;

[0183] An oxide layer, which is located on the surface of the CoFeB layer away from the substrate;

[0184] a protective layer, which is located on the surface of the oxide layer away from the substrate;

[0185] Wherein, the material of the buffer layer is Ta;

[0186] The material of the protective layer is Ta;

[0187] The oxide layer is a MgO layer;

[0188] CoFeB layer is Co 40 Fe 40 B 20 layer;

[0189] The substrate is a Si substrate, the thickness of the Si substrate is 0.6 mm, and the thickness of the SiO2 oxide layer is 300 nm;

[0190] The thickness of the buffer layer is 50 Å;

[0191] The thickness of the CoFeB layer is 10Å;

[0192] The thickness of the oxide layer is 20 Å;

[0193] The thickness of the protective layer is 20 Å.

[0194] The method for preparing the CoFeB-based magnetic multilayer film comprises the following steps:

[0195] S1. Provide a substrate (i.e., a Si / SiO2 substrate, with a Si thickness of 0.6 mm and a SiO2 thickness of 300 nm);

[0196] S2, using Ta target, CoFeB target (the molar ratio of Co, Fe and B in the target is 40:40:20), MgO target and Ta target respectively, a buffer layer, a CoFeB layer, an oxide layer and a protective layer are sequentially deposited on a substrate by magnetron sputtering to form a Ta / CoFeB / MgO / Ta multilayer film;

[0197] S3, heat-treating the substrate with the multilayer film formed in S2 under a vacuum environment to obtain a CoFeB-based magnetic multilayer film;

[0198] In the process of depositing the buffer layer by magnetron sputtering in S2, the sputtering power was controlled to be 50W and the sputtering temperature to be 25°C;

[0199] During the deposition of the CoFeB layer by magnetron sputtering, the sputtering power was controlled to be 30 W and the sputtering temperature to be 25 °C;

[0200] In the process of depositing the oxide layer by magnetron sputtering, the sputtering power was controlled to be 200 W and the sputtering temperature to be 25°C;

[0201] In the process of depositing the protective layer by magnetron sputtering, the sputtering power was controlled to be 50W and the sputtering temperature to be 25°C;

[0202] When the buffer layer, CoFeB layer, oxide layer and protective layer are deposited on the substrate in sequence by magnetron sputtering, the background vacuum degree of the sputtering chamber is 1×10 -5 Pa, the working pressure of argon is 0.4 Pa;

[0203] The vacuum degree of the vacuum environment in S3 is 1×10 -5 Pa, heat treatment temperature is 450℃, time is 30min.

[0204] Performance Testing

[0205] Figure 4 : is the hysteresis loop of the CoFeB-based magnetic multilayer film prepared in Comparative Example 1.

[0206] Figure 5 : is the hysteresis loop of the CoFeB-based magnetic multilayer film prepared in Example 1.

[0207] from Figure 4 It can be seen that the CoFeB-based magnetic multilayer film prepared in Comparative Example 1 exhibits in-plane magnetic anisotropy (IMA). Figure 5 It can be seen that after the TiC layer is introduced in Example 1, the in-plane magnetic anisotropy (IMA) when the TiC layer is not introduced is transformed into the perpendicular magnetic anisotropy (PMA).

[0208] Figure 6 This is the hysteresis loop of the CoFeB-based magnetic multilayer film prepared in Comparative Example 2.

[0209] Figure 7 : is the hysteresis loop of the CoFeB-based magnetic multilayer film prepared in Example 2.

[0210] from Figure 6 It can be seen that the CoFeB-based magnetic multilayer film prepared in Comparative Example 2 exhibits in-plane magnetic anisotropy (IMA). Figure 7 It can be seen that after the TiC layer is introduced in Example 2 and after annealing at 450°C, the CoFeB-based magnetic multilayer film still maintains perpendicular magnetic anisotropy (PMA). Compared with the case where the TiC layer is not introduced, the temperature for maintaining perpendicular magnetic anisotropy is increased, and the thermal stability of the Ta / CoFeB / MgO / Ta system is greatly improved.

[0211] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A CoFeB-based magnetic multilayer film, characterized in that: include: substrate; A buffer layer, which is located on the surface of the substrate; A TiC layer, which is located on a surface of the buffer layer away from the substrate; A CoFeB layer, which is located on a surface of the TiC layer away from the substrate; an oxide layer, which is located on a surface of the CoFeB layer away from the substrate; A protective layer, which is located on a surface of the oxide layer away from the substrate; The material of the buffer layer is Ta; The material of the protective layer is Ta; The oxide layer is a MgO layer; The thickness of the substrate is 0.5-0.7 mm; A SiO2 oxide layer is also provided on the surface of the substrate, and the buffer layer is located on the surface of the SiO2 oxide layer away from the substrate; The thickness of the SiO2 oxide layer is 200-400 nm; The thickness of the buffer layer is 40 to 50 Å; The thickness of the TiC layer is 1 Å; The thickness of the CoFeB layer is 10-15 Å; The thickness of the oxide layer is 20 to 25 Å; The thickness of the protective layer is 20 to 50 Å; The molar ratio of Co, Fe and B in the CoFeB layer is (39.5-40.5):(39.5-40.5):(19.5-20.5); The method for preparing the CoFeB-based magnetic multilayer film comprises the following steps: S1. providing a substrate; S2, depositing a buffer layer, a TiC layer, a CoFeB layer, an oxide layer, and a protective layer on the substrate in sequence; S3, heat-treating the substrate with the multilayer film formed in S2 under a vacuum environment to obtain a CoFeB-based magnetic multilayer film; The heat treatment temperature is 250~450℃ and the time is 25~35min; A buffer layer, a TiC layer, a CoFeB layer, an oxide layer, and a protective layer are sequentially deposited on the substrate by a magnetron sputtering method; In the process of depositing the buffer layer by magnetron sputtering, the sputtering power is controlled to be 45-55W and the sputtering temperature is controlled to be 20-25°C; In the process of depositing the TiC layer by magnetron sputtering, the sputtering power is controlled to be 45~55W and the sputtering temperature is controlled to be 20~25℃; In the process of depositing the CoFeB layer by magnetron sputtering, the sputtering power is controlled to be 25~35W and the sputtering temperature is controlled to be 20~25℃; In the process of depositing the oxide layer by magnetron sputtering, the sputtering power is controlled to be 180~220W and the sputtering temperature is controlled to be 20~25℃; In the process of depositing the protective layer by magnetron sputtering, the sputtering power is controlled to be 45~55W and the sputtering temperature is controlled to be 20~25℃; The background vacuum of the sputtering chamber during sputtering is 1×10 -5 ~3×10 -5 Pa, the working pressure of argon is 0.3~0.6 Pa.

2. The CoFeB-based magnetic multilayer film according to claim 1, characterized in that: The substrate includes any one of a glass substrate, a silicon substrate, and a polymer substrate.

3. A method for preparing a CoFeB-based magnetic multilayer film according to any one of claims 1 to 2, characterized in that: The following steps are involved: S1. providing a substrate; S2, depositing a buffer layer, a TiC layer, a CoFeB layer, an oxide layer, and a protective layer on the substrate in sequence; S3, heat-treating the substrate with the multilayer film formed in S2 under a vacuum environment to obtain a CoFeB-based magnetic multilayer film; The heat treatment temperature is 250~450℃ and the time is 25~35min; A buffer layer, a TiC layer, a CoFeB layer, an oxide layer, and a protective layer are sequentially deposited on the substrate by a magnetron sputtering method; In the process of depositing the buffer layer by magnetron sputtering, the sputtering power is controlled to be 45-55W and the sputtering temperature is controlled to be 20-25°C; In the process of depositing the TiC layer by magnetron sputtering, the sputtering power is controlled to be 45~55W and the sputtering temperature is controlled to be 20~25℃; In the process of depositing the CoFeB layer by magnetron sputtering, the sputtering power is controlled to be 25~35W and the sputtering temperature is controlled to be 20~25℃; In the process of depositing the oxide layer by magnetron sputtering, the sputtering power is controlled to be 180~220W and the sputtering temperature is controlled to be 20~25℃; In the process of depositing the protective layer by magnetron sputtering, the sputtering power is controlled to be 45~55W and the sputtering temperature is controlled to be 20~25℃; The background vacuum of the sputtering chamber during sputtering is 1×10 -5 ~3×10 -5 Pa, the working pressure of argon is 0.3~0.6 Pa.

4. The method for preparing a CoFeB-based magnetic multilayer film according to claim 3, characterized in that: The substrate S2 having a multilayer film is subjected to heat treatment in a vacuum environment, wherein the vacuum degree of the vacuum environment is 1×10 -5 ~3×10 -5 Pa.

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