Epitaxial structure, preparation method thereof and communication chip

Abstract

The invention provides an epitaxial structure, a preparation method thereof and a communication chip. The preparation method of the epitaxial structure comprises the following steps: providing a substrate; at least one magnetic layer is epitaxially grown on the substrate using a magnetic material. The manufacturing process of the permanent magnet is close to the manufacturing process of the chip, specifically, the magnetic material is adopted to epitaxially grow the magnetic layer on the substrate, the problem that the permanent magnet and the chip are incompatible in the manufacturing process is solved, and therefore the permanent magnet is integrated on the semiconductor chip.

Description

Technical Field

[0001] The present disclosure relates to the field of semiconductor technologies, and particularly to an epitaxial structure, a preparation method thereof, and a communication chip. Background Art

[0002] Permanent magnet materials, also known as hard magnetic materials, refer to magnetic materials that can still maintain most of the original magnetization direction under the action of a reverse magnetic field after being magnetized by an external magnetic field. Permanent magnet materials have advantages such as a high remanent magnetic induction intensity Br, a strong coercive force BHC, and a large magnetic energy product BH. According to different element compositions, permanent magnet materials can be divided into three categories: metal permanent magnets, ferrite permanent magnets, and rare earth permanent magnets. Metal permanent magnets are permanent magnet materials mainly composed of iron and iron-group elements (such as nickel, cobalt, etc.). Ferrite permanent magnets are made from strontium oxide or barium oxide and Fe2O3 or Fe3O4 as raw materials through ceramic processes. They are divided into sintered ferrite and bonded ferrite according to the process. Rare earth permanent magnets refer to permanent magnets added with rare earth elements or even mainly composed of rare earth elements as the substrate, mainly including neodymium-iron-boron permanent magnet materials, samarium-cobalt permanent magnet materials, rare earth iron-carbon materials, and rare earth iron-nitrogen materials.

[0003] High-performance neodymium-iron-boron permanent magnets can significantly improve the performance of motors. High-performance neodymium-iron-boron permanent magnets have high magnetic performance indicators, high remanence, and high coercive force, which can improve the electrical energy conversion efficiency of motors, generate a large torque at low speeds, and have a high power factor; at the same time, they can reduce the volume of the magnets and motors, and correspondingly reduce the volume of the equipment, making it convenient for maintenance and repair and saving other raw materials. High-performance neodymium-iron-boron motors have a small magnetic loss, resulting in high electrical energy conversion efficiency and low heat generation. Their high magnetic flux and large magnetic energy product can significantly improve the accuracy and sensitivity of motor control, and the speed regulation range can be greatly improved, reaching more than 1000:1, making the motor start more smoothly, control more precisely, and have less loss during frequent start-up and speed change.

[0004] Magnetic tiles are a type of permanent magnet used as tile-shaped magnets in permanent magnet micro-special motors. They are the core components of permanent magnet micro-special motors and generally serve as the motor stator. They are mainly applied in fields such as new energy generators, new energy vehicles, drones, aerospace, etc. and are the core components determining the system performance. Therefore, high-performance permanent magnets are also the core materials and components determining the system performance. In addition, the variable frequency requirements of industrial automation and household appliances have also promoted the development of micro-special motors. Household appliances are one of the most important application scenarios for permanent ferrite magnetic tiles. Currently, neodymium iron boron permanent magnets are the permanent magnetic materials with the highest comprehensive cost performance and occupy most of the market space in applications such as high-end high-performance motors. However, the Curie temperature (Tc) of neodymium iron boron permanent magnets is relatively low, only 310 - 510 °C. Therefore, the operating temperature of neodymium iron boron is usually below 150 °C, which can meet the requirements of most applications. The samarium element in samarium cobalt permanent magnets is extremely scarce in the earth's crust, so the cost is very high. Since the Curie temperature (Tc) of samarium cobalt permanent magnets reaches 700 - 800 °C, the operating temperature can reach below 250 °C. Also, since it contains almost no iron, it is not easily oxidized at high temperatures, making it suitable for harsh environments such as high-temperature and corrosion-prone conditions. Rare earth iron carbon (nitrogen) permanent magnets are the next-generation permanent magnets for future systems and are currently in the R & D stage and have not been industrialized yet.

[0005] Taking the magnetic tile applied in a micro-special motor as an example, as Figure 1 shown, the micro-special motor includes a stator housing 11, a stator magnetic tile 12, and a rotor 13. A coil is externally coated on the stator magnetic tile 12. Among them, the size of the stator magnetic tile is determined by the size of the micro-special motor, and its length and width are usually above 10 mm. While the chip is usually a layered structure, as Figure 2 shown, the thickness of each layer is approximately 100 nm - 3 μm. By using etching and masking processes to fabricate circuit structures on these layered structures, a chip can be obtained, and the entire chip area is generally within 5 mm × 5 mm. It can be seen that it is difficult to integrate the chips produced by the existing technology with permanent magnets.

[0006] The common manufacturing processes for permanent magnets are sintering and bonding. Sintered ferrite is manufactured by the ceramic process method, with a hard and brittle texture and is not easily demagnetized. It usually adopts a high-temperature and high-pressure forming method similar to ceramic materials and is mainly used in fields such as new energy vehicles, household appliances, and industrial automation. Bonded permanent ferrite is composed of permanent ferrite magnetic powder and various plastics, combining magnetic properties and plastic properties, and can be processed into various complex shapes, mainly used in specific fields such as sensors and toys.

[0007] The manufacturing process of the chip is as follows: First, a substrate is prepared, typically semiconductor materials such as GaAs, Si, SOI, SiC, GaN, etc. The substrate is sheet-shaped and finally thinned to 75 - 200 μm. The substrate will then be sent to an epitaxial factory, where layer upon layer of semiconductor materials are grown through an epitaxial growth process, with each layer having a thickness of approximately 100 nm - 3 μm, and doping is carried out, which can form an epitaxial wafer as shown in Figure 2 Subsequently, the epitaxial wafer will be sent to a chip manufacturing factory to produce chips. The manufacturing factory will perform operations such as spin coating, photolithography, development, and photoresist removal on the epitaxial wafer according to the chip design drawings provided by the customer to fabricate circuit patterns such as transistors on the epitaxial wafer, and then more metal layers, capacitors, resistors, pads, and other patterns and circuits will be fabricated on it in a layered manner. Finally, after anti-oxidation passivation protection and passing the inspection, it leaves the factory as a wafer.

[0008] It can be seen that the manufacturing of permanent magnets is similar to the ceramic sintering process, and the manufactured permanent magnets are relatively large in size, usually more than 10 mm. While chip manufacturing usually uses atomic-level or molecular-level epitaxial processes, the manufacturing process is very precise and the size is very small, with the epitaxial layer thickness usually being 100 nm - 3 μm. Therefore, permanent magnets and chips are completely incompatible in the manufacturing process, making it difficult to monolithically integrate permanent magnets on chips. Summary of the Invention

[0009] The technical problem to be solved by the present disclosure is to overcome the defect that permanent magnets are difficult to be integrated on chips in the prior art, and to provide an epitaxial structure, a preparation method thereof, and a communication chip.

[0010] The present disclosure solves the above technical problem through the following technical solutions:

[0011] The first aspect of the present disclosure provides a preparation method of an epitaxial structure, including the following steps:

[0012] Provide a substrate;

[0013] Epitaxially grow at least one magnetic layer on the substrate using a magnetic material.

[0014] Optionally, the preparation method further includes: growing at least one semiconductor layer on the substrate;

[0015] Wherein, at least one magnetic layer is located above the semiconductor layer or between two semiconductor layers.

[0016] Optionally, at least one magnetic layer is located on the back surface of the substrate.

[0017] Optionally, the preparation method further includes: growing a first insulating layer on the substrate;

[0018] Among them, the first insulating layer is located between the substrate and the magnetic layer on the back surface of the substrate.

[0019] Optionally, the preparation method further includes: growing at least one second insulating layer and at least one metal layer on the substrate;

[0020] Among them, the number of the second insulating layers is less than or equal to the number of the metal layers; each second insulating layer is located between a metal layer and a magnetic layer.

[0021] Optionally, the step of epitaxially growing at least one magnetic layer on the substrate using a magnetic material specifically includes: preparing at least one magnetic layer by using a molecular beam epitaxy growth process or a metal organic chemical vapor deposition epitaxy growth process.

[0022] Optionally, after the step of epitaxially growing at least one magnetic layer on the substrate using a magnetic material, it further includes: processing the magnetic layer by using a mask to obtain a magnetic layer with a specific shape.

[0023] Optionally, the magnetic material includes samarium and cobalt.

[0024] Optionally, the magnetic material further includes bismuth or other rare earth metals except samarium.

[0025] The second aspect of the present disclosure provides an epitaxial structure, and the epitaxial structure is prepared according to the preparation method described in the first aspect.

[0026] The third aspect of the present disclosure provides a communication chip, including the epitaxial structure described in the second aspect.

[0027] On the basis of conforming to the common knowledge in the art, the above optional conditions can be combined arbitrarily to obtain various preferred embodiments of the present disclosure.

[0028] The positive and progressive effect of the present disclosure is that: by bringing the manufacturing process of the permanent magnet closer to the manufacturing process of the chip, specifically, epitaxially growing a magnetic layer on the substrate using a magnetic material, the problem of incompatibility between the manufacturing processes of the permanent magnet and the chip is solved, thereby realizing the integration of the permanent magnet into the semiconductor chip. Description of the Drawings

[0029] Figure 1 It is a schematic structural diagram of a special micro-motor in the prior art.

[0030] Figure 2 It is a schematic diagram of the layered structure of an epitaxial wafer in the prior art.

[0031] Figure 3 It is a flowchart of a preparation method of an epitaxial structure provided in Embodiment 1 of the present disclosure.

[0032] Figure 4 Schematic diagram of the layered structure of an epitaxial structure provided in Embodiment 1 of the present disclosure. Detailed implementation manners

[0033] The following describes exemplary embodiments of the present disclosure with reference to the accompanying drawings. Various details of the embodiments of the present disclosure are included to assist understanding, and they should be considered merely exemplary. Therefore, those of ordinary skill in the art should recognize that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the present disclosure. Similarly, for clarity and conciseness, descriptions of well-known functions and structures are omitted in the following description.

[0034] It should be noted that the terms "first", "second", etc. involved in the present disclosure are used to distinguish similar objects and do not necessarily need to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances so that the embodiments of the present disclosure described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products, or devices.

[0035] Considering that the manufacturing process of chips involves complex and precise technologies such as lithography and epitaxy, it is difficult to approach the manufacturing process of permanent magnets. And for the manufacturing process of permanent magnets, even the most complex sintering process is relatively simple compared to the manufacturing process of chips. Therefore, the present disclosure solves the problem of incompatibility between the manufacturing processes of permanent magnets and chips by approaching the manufacturing process of permanent magnets to that of chips, thereby realizing the integration of permanent magnets onto semiconductor chips.

[0036] Further, after integrating the permanent magnet into the semiconductor chip, magnetic functional units can be fabricated on the semiconductor chip by utilizing the Faraday effect and the isogyric magnetism principle to obtain a communication chip. Among them, the magnetic functional unit is a unit structure that realizes specific functions by using magnetic materials or magnetic effects. For example, it can be a microwave device, and a microwave chip can be obtained by fabricating a microwave device on the above-mentioned semiconductor chip. Among them, the microwave device can be a microwave isolator, a microwave circulator, a microwave transceiver chip, etc. The microwave chip obtained by the present disclosure has the advantages of high integration, high performance, high reliability, etc., and can be applied to communication fields such as 5G (5th Generation Mobile Networks), Wifi 6 (the sixth generation of wireless local area network technology), C-V2X (Cellular Vehicle-to-Everything), NB-IoT (Narrowband Internet of Things).

[0037] Embodiment 1

[0038] Figure 3 It is a schematic flow chart of a preparation method of an epitaxial structure provided in this embodiment. As Figure 3 shown, the preparation method of the epitaxial structure provided in this embodiment may include the following steps S101 to S102:

[0039] Step S101, provide a substrate. In practical applications, a group III-V compound semiconductor can be selected as the substrate, such as GaAs, GaN, InP, SiC, etc., and a silicon-based compound semiconductor can also be selected as the substrate, such as bulk silicon CMOS and SOI substrates, etc.

[0040] Step S102, epitaxially grow at least one magnetic layer on the substrate by using a magnetic material. Among them, one magnetic layer can be epitaxially grown according to actual needs, or two or even more magnetic layers can be epitaxially grown. In practical applications, the magnetic layer can also be called a magnetic thin film. The epitaxial growth process can adopt methods such as molecular beam epitaxy (MBE) or metal-organic chemical vapor deposition (MOCVD).

[0041] The magnetic material refers to a substance with magnetism, and its internal atoms or molecules have magnetic moments and can generate magnetization phenomena under the action of an external magnetic field. In a specific implementation, the magnetic material may include samarium and cobalt, and the corresponding chemical elements are Sm and Co respectively. The magnetic material can specifically be SmCo5, Sm2Co 17 etc.

[0042] In an optional implementation manner, the above step S102 specifically includes: preparing at least one magnetic layer by using a molecular beam epitaxy growth process. In a specific implementation, metallic elements or compounds of growth materials such as samarium (Sm) and cobalt (Co) can be placed in an evaporation source furnace, and the Sm ions and Co ions are excited by means of high temperature and bombardment with an electron beam or a plasma beam, and are sputtered onto the surface of a rotating substrate under the action of an electric field and in a high-vacuum environment, where a chemical reaction occurs, and then it is cooled to form a magnetic layer with a required ratio. Specifically, for the magnetic material Sm, metallic Sm can be used as the evaporation source, or solid compounds of Sm such as samarium (II) oxide (SmO), samarium sulfide (SmS), samarium selenide (SmSe), and samarium telluride (SmTe) can be used as the evaporation source. For the magnetic material Co, metallic Co can be used as the evaporation source, or solid compounds of Co such as cobalt (II) oxide (CoO), cobalt spinel (Co3O4), and cobalt trifluoride (CoF3) can be used as the evaporation source. It should be noted that if a compound is used as the evaporation source, a reduction reaction needs to be realized in the reaction cavity.

[0043] In an optional implementation manner, the above step S102 specifically includes: preparing at least one magnetic layer by using a metalorganic chemical vapor deposition epitaxy growth process. In a specific implementation, metalorganic compounds, complexes, polymers (i.e., precursors) of growth materials such as Sm and Co, and reaction gases can be mixed at the inlet of the reaction chamber. The precursor gas and the reaction gas are mixed with precise flow rates and pressures, and the mixed gas flows to the heated substrate, where the precursor decomposes and undergoes a chemical reaction with the reaction gas according to a predetermined chemical formula to generate the required solid material and deposit it on the substrate. Specifically, organic compounds of Sm can be used as the precursor of Sm, such as trimethylsamarium ((CH3)3Sm), triethylsamarium ((C2H5)3Sm), tris(cyclopentadienyl)samarium ((C5H5)3Sm), tris(tetramethylcyclopentyl)samarium ([C9H 13 3Sm), etc., organic compounds of Co can be used as the precursor of Co, such as trimethylcobalt ((CH3)3Co), triethylcobalt ((C2H5)3Co), cobalt (II) acetate tetrahydrate (Co(CH3COO)2·4H2O), etc., and hydrogen, nitrogen, or other inert gases can be used as the reaction gas.

[0044] Since samarium is sparsely and evenly distributed in the earth's crust, the price of samarium is very expensive. In practical applications, in order to reduce costs, other elements can be used to partially replace samarium in the basic configuration of samarium-cobalt permanent magnets. In this implementation manner, the magnetic material includes not only samarium and cobalt, but also bismuth (Bi) or other rare earth metals except Sm, such as rare earth metals like lanthanum (La), ytterbium (Yb), and terbium (Tb).

[0045] In the example of partially substituting samarium (Sm) with lanthanum (La), the substitution scheme for the SmCo5 configuration can be Sm x La (1-x1) Co5, and for the Sm2Co 17 configuration, the substitution scheme can be Sm 2x1 La 2(1-x1) Co 17 , where x1 is the substitution ratio and ranges from 0 to 1.0. It should be noted that the substitution ratios of different substitution elements may vary.

[0046] In an alternative embodiment, the above preparation method further includes: growing at least one semiconductor layer on the substrate. In a specific implementation, at least one magnetic layer can be located above the semiconductor layer or between two semiconductor layers. In this embodiment, a magnetic layer can be fabricated above the semiconductor layer or between the semiconductor layers.

[0047] In another alternative embodiment, at least one magnetic layer is located on the back surface of the substrate. In this embodiment, a magnetic layer can be fabricated on the back surface of the substrate.

[0048] In an alternative embodiment, the above preparation method further includes: growing a first insulating layer on the substrate. In this embodiment, the first insulating layer is located between the substrate and the magnetic layer on the back surface of the substrate and can play an insulating role. In practical applications, the first insulating layer can directly adopt the superlattice buffer layer located above the substrate.

[0049] In an alternative embodiment, the above preparation method further includes: growing at least one second insulating layer and at least one metal layer on the substrate. Among them, the number of the second insulating layers is less than or equal to the number of the metal layers; each second insulating layer is located between a metal layer and a magnetic layer. In this embodiment, the second insulating layer located between the metal layer and the magnetic layer can play an insulating role. In practical applications, the second insulating layer can directly adopt the insulating layer located between two metal layers.

[0050] It should be noted that different numbers of metal layers can be grown according to actual requirements, and different numbers of second insulating layers can be grown according to the actual contact situation between the metal layers and the magnetic layers.

[0051] Figure 4 Used to show the layered structure of the epitaxial structure of the GaAs HBT process obtained by the above preparation method. In Figure 4In the example shown, a substrate structure of GaAs HBT is adopted, and magnetic layers are integrated on the top, between layers, and on the back of the semiconductor layer. From bottom to top, they are: back metal layer, magnetic layer metal buffer layer, magnetic layer, magnetic layer substrate buffer layer, semi-insulating GaAs substrate, AlGaAs superlattice buffer layer, collector and sub-collector layers, GaAs base layer, InGaP emitter layer, GaAs sub-emitter layer, GaAs ohmic contact layer, metal layer M1, interlayer insulating layer between metal layers M1 and M2, magnetic layer metal buffer layer, magnetic layer N2, magnetic layer metal buffer layer, metal layer M2, magnetic layer metal buffer layer, magnetic layer N1, and passivation layer. Among them, the interlayer insulating layer between metal layers M1 and M2 can use Si3N4. It can be seen that Figure 4 A total of three magnetic layers are integrated in the shown layered structure, and the magnetic layer substrate buffer layer between the substrate and the magnetic layer on the back of the substrate corresponds to the above-mentioned first insulating layer, and the magnetic layer metal buffer layers between the metal layer M1 and the magnetic layer N2 and between the metal layer M2 and the magnetic layer N1 both correspond to the above-mentioned second insulating layer. The AlGaAs superlattice buffer layer, collector and sub-collector layers, GaAs base layer, InGaP emitter layer, GaAs sub-emitter layer, GaAs ohmic contact layer, and metal layer all belong to the above-mentioned semiconductor layer. The passivation layer is a protective layer covering the surface of the semiconductor layer and is usually composed of insulating materials.

[0052] In an alternative embodiment, after the above step S102, it further includes: processing the magnetic layer using a mask to obtain a magnetic layer with a specific shape. The mask is short for "mask" and is an indispensable component in the lithography process. In this embodiment, the mask carries a design pattern with a specific shape. By projecting light onto the photoresist, a photoresist pattern is formed, and then through an etching process, the photoresist pattern is transferred to the magnetic layer, thereby forming a magnetic layer with a specific shape. Among them, the above-mentioned specific shape can be in various forms such as circular, square, transmission line, coplanar waveguide, etc.

[0053] This embodiment also provides an epitaxial structure prepared by using the above preparation method. Since it integrates a magnetic layer, it can realize magnetic functions in addition to the original functions and has a wide range of applications. For example, it can be applied to various communication fields.

[0054] Embodiment 2

[0055] This embodiment provides an epitaxial structure, including: a substrate; and at least one magnetic layer located on the substrate, and the magnetic layer is epitaxially grown using a magnetic material.

[0056] In practical applications, a group III-V compound semiconductor can be selected as the substrate, such as GaAs, GaN, InP, SiC, etc., and a silicon-based compound semiconductor can also be selected as the substrate, such as bulk silicon CMOS and SOI substrates, etc.

[0057] Among them, a magnetic layer can be epitaxially grown according to actual needs, or two or even more magnetic layers can be epitaxially grown. In practical applications, the magnetic layer can also be called a magnetic thin film. The epitaxial growth process can adopt methods such as molecular beam epitaxy or metal-organic chemical vapor deposition.

[0058] The magnetic material refers to a substance with magnetism, and its internal atoms or molecules have magnetic moments and can generate magnetization under the action of an external magnetic field. In a specific implementation, the magnetic material can include samarium and cobalt, and the corresponding chemical elements are Sm and Co respectively. Among them, the ratio of Sm x Co (1-x) , x = 0 to 0.49, for example, it can be SmCo5, Sm2Co 17 etc.

[0059] Since samarium is sparsely and evenly distributed in the earth's crust, the price of samarium is very expensive. In practical applications, in order to reduce costs, other elements can be used to partially replace samarium in the basic configuration of the samarium-cobalt permanent magnet. In this embodiment, the magnetic material includes not only samarium and cobalt, but also bismuth Bi or other rare earth metals except samarium Sm, such as rare earth metals such as lanthanum La, ytterbium Yb, terbium Tb, etc.

[0060] In the example of using lanthanum La to partially replace samarium Sm, the substitution scheme for the SmCo5 configuration can be Sm x La (1-x1) Co5, and the substitution scheme for the Sm2Co 17 configuration can be Sm 2x1 La 2(1-x1) Co 17 , where x1 is the substitution ratio and is between 0 and 1.0. It should be noted that the substitution ratios of different substitution elements will be different.

[0061] In an alternative embodiment, the epitaxial structure further includes at least one semiconductor layer; the at least one magnetic layer can be located on the semiconductor layer or between two semiconductor layers.

[0062] In another alternative embodiment, at least one magnetic layer is located on the back of the substrate.

[0063] In an alternative embodiment, the epitaxial structure further includes a first insulating layer, which is located between the substrate and the magnetic layer on the back surface of the substrate and can play an insulating role. In practical applications, the first insulating layer can directly adopt the superlattice buffer layer on the substrate.

[0064] In an alternative embodiment, the epitaxial structure further includes at least one second insulating layer and at least one metal layer; wherein, the number of the second insulating layers is less than or equal to the number of the metal layers; each second insulating layer is located between a metal layer and a magnetic layer. In this embodiment, the second insulating layer located between the metal layer and the magnetic layer can play an insulating role. In practical applications, the second insulating layer can directly adopt the insulating layer between two metal layers.

[0065] The epitaxial structure provided in this embodiment integrates a magnetic layer, so that on the basis of realizing the original functions, the magnetic function can also be realized, and it has a wide range of applications. For example, it can be applied to various communication fields.

[0066] Embodiment 3

[0067] This embodiment provides a communication chip, including the epitaxial structure provided in Embodiment 1 or 2.

[0068] Since the magnetic layer is integrated in the above epitaxial structure, a communication chip can be obtained by fabricating magnetic functional units in the above epitaxial structure by utilizing the Faraday effect and the isogyromagnetic principle. In practical applications, a microwave chip can be obtained by fabricating microwave devices in the above epitaxial structure, where the microwave device can be a microwave isolator, a microwave circulator, a microwave transceiver chip, etc. The microwave chip has the advantages of high integration, high performance, high reliability, etc., and can be applied to communication fields such as 5G, Wifi6, C-V2X, NB-IoT, etc.

[0069] It should be noted that other types of communication chips can be obtained by fabricating magnetic functional units other than microwave devices in the above epitaxial structure.

[0070] Although the specific embodiments of the present disclosure have been described above, those skilled in the art should understand that this is only an example, and the protection scope of the present disclosure is defined by the appended claims. Without departing from the principles and essence of the present disclosure, those skilled in the art can make various changes or modifications to these embodiments, but these changes and modifications all fall within the protection scope of the present disclosure.

Claims

1. A method for preparing an epitaxial structure, characterized in that, Comprising the following steps: Providing a substrate; Epitaxially growing at least one magnetic layer on the substrate using a magnetic material.

2. The preparation method according to claim 1, characterized in that, The preparation method further comprises: Growing at least one semiconductor layer on the substrate; Wherein, at least one magnetic layer is located above the semiconductor layer or between two semiconductor layers.

3. The preparation method according to claim 1, characterized in that, At least one magnetic layer is located on the back surface of the substrate.

4. The preparation method according to claim 3, characterized in that, The preparation method further comprises: Growing a first insulating layer on the substrate; Wherein, the first insulating layer is located between the substrate and the magnetic layer on the back surface of the substrate.

5. The preparation method according to claim 1, characterized in that, The preparation method further comprises: Growing at least one second insulating layer and at least one metal layer on the substrate; Wherein, the number of the second insulating layers is less than or equal to the number of the metal layers; each second insulating layer is located between a metal layer and a magnetic layer.

6. The preparation method according to claim 1, characterized in that, The step of epitaxially growing at least one magnetic layer on the substrate using a magnetic material specifically comprises: preparing at least one magnetic layer by using a molecular beam epitaxy growth process or a metal organic chemical vapor deposition epitaxy growth process; Or, after the step of epitaxially growing at least one magnetic layer on the substrate using a magnetic material, the method further comprises: processing the magnetic layer by using a mask template to obtain a magnetic layer with a specific shape.

7. The preparation method according to any one of claims 1-6, characterized in that, The magnetic material comprises samarium and cobalt.

8. The preparation method according to claim 7, characterized in that, The magnetic material further comprises bismuth or other rare earth metals except samarium.

9. An epitaxial structure, characterized in that, The epitaxial structure is prepared by the preparation method according to any one of claims 1-8.

10. A communication chip, characterized in that, Comprising the epitaxial structure according to claim 9.

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