Power device and preparation method, power module, power conversion circuit and vehicle

Abstract

The present invention discloses a power device and a preparation method, a power module, a power conversion circuit and a vehicle. The power device comprises: a semiconductor body, the semiconductor body comprises a first surface and a second surface arranged opposite to each other, the semiconductor body further comprises a contact area; the contact area is located on the first surface; an electrode structure, the electrode structure is located on the first surface and the second surface; the electrode structure comprises an electrode material layer and a piezoelectric material layer, the piezoelectric material layer is located on the side of the electrode material layer away from the semiconductor body; the piezoelectric material layer is provided with a plurality of cavities, the plurality of cavities penetrate the piezoelectric material layer; the electrode material layer covers the first surface and the second surface, and the electrode material layer fills the plurality of cavities. The present invention can reduce power consumption and improve the switching speed and conductivity of the device.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a power device and a preparation method thereof, a power module, a power conversion circuit and a vehicle. Background Art

[0002] Silicon carbide (SiC) is a typical third-generation wide bandgap semiconductor material with excellent characteristics such as high critical breakdown electric field, wide bandgap, high thermal conductivity and high electron saturation drift velocity. The critical breakdown electric field of SiC is nearly 10 times that of silicon (Si), the bandgap of SiC is nearly 3 times that of Si, and the thermal conductivity of SiC is nearly 3 times that of Si. When it is used as the channel material of power devices, the devices show advantages such as high breakdown voltage, low on-resistance, high current density, high heat dissipation and high switching speed. The industry's SiC power devices have epitaxial defects and interface defects, resulting in low mobility and slow switching speed. Summary of the invention

[0003] The present invention provides a power device and a preparation method thereof, a power module, a power conversion circuit and a vehicle, which can reduce power consumption and improve the switching speed and conductive performance of the device.

[0004] According to one aspect of the present invention, there is provided a power device, comprising:

[0005] A semiconductor body, the semiconductor body comprising a first surface and a second surface arranged opposite to each other, and the semiconductor body further comprising a contact region; the contact region is located on the first surface;

[0006] An electrode structure, wherein the electrode structure is located on a first surface and a second surface; the electrode structure includes an electrode material layer and a piezoelectric material layer, wherein the piezoelectric material layer is located on a side of the electrode material layer away from the semiconductor body; the piezoelectric material layer is provided with a plurality of cavities, and the plurality of cavities penetrate the piezoelectric material layer; the electrode material layer covers the first surface and the second surface, and the electrode material layer fills the plurality of cavities.

[0007] On the basis of the above embodiment, optionally, the electrode structure includes a first electrode layer and a second electrode layer, the first electrode layer is located on the first surface, and the second electrode layer is located on the second surface; the electrode material layer includes a first electrode material layer and a second electrode material layer, and the piezoelectric material layer includes a first piezoelectric material layer and a second piezoelectric material layer; the first electrode layer includes a first electrode material layer and a first piezoelectric material layer, the second electrode layer includes a second electrode material layer and a second piezoelectric material layer, and the plurality of cavities includes a plurality of first cavities and a plurality of second cavities;

[0008] The first piezoelectric material layer is located on a side of the first electrode material layer away from the first surface; the first piezoelectric material layer is provided with a plurality of first cavities, and the plurality of first cavities penetrate the first piezoelectric material layer; the first electrode material layer covers the first surface, and the first electrode material layer fills the plurality of first cavities;

[0009] The second piezoelectric material layer is located on a side of the second electrode material layer away from the second surface; the second piezoelectric material layer is provided with a plurality of second cavities, and the plurality of second cavities penetrate the second piezoelectric material layer; the second electrode material layer covers the second surface, and the second electrode material layer fills the plurality of second cavities.

[0010] Based on the above embodiment, optionally, the number of the contact regions is two, and the semiconductor body includes an epitaxial layer;

[0011] The contact region has a different conductivity type from the epitaxial layer.

[0012] Based on the above embodiment, optionally, the material of the electrode material layer includes graphene.

[0013] According to another aspect of the present invention, a power module is provided, comprising a substrate and a power device according to any embodiment of the present invention, wherein the substrate is used for carrying the power device.

[0014] According to another aspect of the present invention, there is provided a power conversion circuit, the power conversion circuit being used for one or more of current conversion, voltage conversion, and power factor correction;

[0015] The power conversion circuit comprises a circuit board and at least one power device according to any embodiment of the present invention, and the power body device is electrically connected to the circuit board.

[0016] According to another aspect of the present invention, a vehicle is provided, comprising a load and a power conversion circuit as described in any embodiment of the present invention, the power conversion circuit being used to convert alternating current into direct current, convert alternating current into alternating current, convert direct current into direct current, or convert direct current into alternating current and then input into the load.

[0017] According to another aspect of the present invention, there is provided a method for preparing a power device, which is used to prepare the power device according to any embodiment of the present invention, comprising:

[0018] A semiconductor body is provided, wherein the semiconductor body comprises a first surface and a second surface arranged opposite to each other, and the semiconductor body further comprises a contact region; the contact region is located on the first surface;

[0019] An electrode structure is formed on the first surface and the second surface; the electrode structure includes an electrode material layer and a piezoelectric material layer, the piezoelectric material layer is located on the side of the electrode material layer away from the semiconductor body; the piezoelectric material layer is provided with a plurality of cavities, and the plurality of cavities penetrate the piezoelectric material layer; the electrode material layer covers the first surface and the second surface, and the electrode material layer fills the plurality of cavities.

[0020] Based on the above embodiment, optionally, an electrode structure is formed on the first surface and the second surface, including:

[0021] forming a first electrode sublayer on the first surface; the first electrode sublayer covers the first surface;

[0022] forming a first piezoelectric material sublayer on a side of the first electrode sublayer away from the first surface; the first piezoelectric material sublayer covers the first electrode sublayer;

[0023] Etching the first piezoelectric material sublayer to form a plurality of first cavities to form a first piezoelectric material layer;

[0024] A second electrode sublayer is formed in the plurality of first cavities; the first electrode sublayer and the second electrode sublayer are a first electrode material layer, and the first electrode material layer and the first piezoelectric material layer are a first electrode layer;

[0025] forming a third electrode sublayer on the second surface; the third electrode sublayer covers the second surface;

[0026] forming a second piezoelectric material sublayer on a side of the third electrode sublayer away from the second surface; the second piezoelectric material sublayer covers the first electrode sublayer;

[0027] Etching the second piezoelectric material sublayer to form a plurality of second cavities to form a second piezoelectric material layer;

[0028] A fourth electrode sublayer is formed in the plurality of second cavities; the third electrode sublayer and the fourth electrode sublayer are second electrode material layers, the second electrode material layer and the second piezoelectric material layer are second electrode layers, and the first electrode layer and the second electrode layer are electrode structures.

[0029] On the basis of the above embodiment, optionally, a semiconductor body is provided, including:

[0030] An epitaxial layer is formed on one side of the substrate; a surface of the epitaxial layer away from the substrate is a first surface;

[0031] forming a contact region on the first surface;

[0032] After forming the second electrode sublayer in the plurality of first cavities, the method further includes:

[0033] Remove the substrate.

[0034] The power device provided by the technical solution of the embodiment of the present invention includes: a semiconductor body, the semiconductor body includes a first surface and a second surface arranged oppositely, and the semiconductor body also includes a contact area; the contact area is located on the first surface; an electrode structure, the electrode structure is located on the first surface and the second surface; the electrode structure includes an electrode material layer and a piezoelectric material layer, the piezoelectric material layer is located on the side of the electrode material layer away from the semiconductor body; the piezoelectric material layer is provided with a plurality of cavities, and the plurality of cavities penetrate the piezoelectric material layer; the electrode material layer covers the first surface and the second surface, and the electrode material layer fills a plurality of cavities. The embodiment of the present invention uses a piezoelectric material layer and an electrode material layer to replace the substrate, on the one hand, eliminating the substrate resistance and reducing the on-resistance; on the other hand, when a voltage is applied to the piezoelectric material layer, the piezoelectric material layer will be deformed, thereby increasing the mobility and conductivity of the charge carrier in the semiconductor structure, thereby increasing the switching speed and conductivity of the device. And due to the existence of the piezoelectric effect, when the piezoelectric material layer is subjected to an external force, an electric potential will be generated, which can realize the switching of the power device at an extremely low voltage, and even directly respond to mechanical stress, without the need for external voltage control, to realize self-driven power supply, thereby realizing a low-power power device.

[0035] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0037] Figure 1 It is a schematic diagram of the structure of a power device provided by an embodiment of the present invention.

[0038] Figure 2 It is a schematic diagram of the structure of another power device provided by an embodiment of the present invention.

[0039] Figure 3 It is a flow chart of a method for preparing a power device provided by an embodiment of the present invention.

[0040] Figure 4 yes Figure 3 A detailed flow chart included in S120.

[0041] Figure 5-Figure 8 It is a schematic diagram of an intermediate structure of a power device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0042] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings 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 should fall within the scope of protection of the present invention.

[0043] It should be noted that the terms "first", "second", etc. in the present invention are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention 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 inclusions, for example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products, or devices.

[0044] An embodiment of the present invention provides a power device. Figure 1 is a schematic diagram of a power device provided by an embodiment of the present invention, with reference to Figure 1 , power devices include:

[0045] The semiconductor body 10 includes a first surface 01 and a second surface 02 arranged opposite to each other. The semiconductor body 10 also includes a contact region 12. The contact region 12 is located on the first surface 01.

[0046] The electrode structure 20 is located on the first surface 01 and the second surface 02; the electrode structure 20 includes an electrode material layer 21 and a piezoelectric material layer 22, the piezoelectric material layer 22 is located on the side of the electrode material layer 21 away from the semiconductor body 10; the piezoelectric material layer 22 is provided with a plurality of cavities 03, and the plurality of cavities 03 penetrate the piezoelectric material layer 22; the electrode material layer 21 covers the first surface 01 and the second surface 02, and the electrode material layer 21 fills the plurality of cavities 03.

[0047] The power device may be a junction barrier Schottky (JBS) diode device; the conductivity type of the contact region 12 may be P-type, the material of the semiconductor body 10 may be SiC, the conductivity type of the semiconductor body may be N-type, and the N-type is lightly doped with N-type ions. The material of the electrode material layer 21 may include graphene; the material of the piezoelectric material layer 22 is all piezoelectric material, and the piezoelectric material has a piezoelectric effect, which refers to the phenomenon that the piezoelectric material will generate electric charge when subjected to mechanical stress, and will undergo mechanical deformation under the action of an electric field.

[0048] The piezoelectric material layer 22 is provided with a plurality of cavities 03, wherein the plurality of cavities 03 are a plurality of grooves arranged at intervals along a first direction and extending along a second direction, wherein the first direction is perpendicular to the direction of the semiconductor body 10 pointing to the electrode structure 20, and the second direction is perpendicular to the first direction and the direction of the semiconductor body 10 pointing to the electrode structure 20; or the plurality of cavities 03 are a plurality of through holes, and the plurality of through holes penetrate the piezoelectric material layer 22.

[0049] The embodiment of the present invention does not need to adopt the traditional substrate structure, but uses a piezoelectric material layer 22 and an electrode material layer 21 instead, so the device on-resistance is composed of contact resistance, channel resistance, and epitaxial resistance in series, and there is no substrate resistance in the on-resistance, thereby realizing a low on-resistance device and reducing the on-resistance; on the other hand, when a voltage is applied to the piezoelectric material layer 22, the piezoelectric material layer 22 will be deformed, thereby improving the mobility and conductivity of the charge carrier in the semiconductor structure; the embodiment of the present invention can dynamically adjust the transfer characteristics such as the mobility and conductivity of the charge carrier in the semiconductor structure through the piezoelectric effect, so it can effectively improve the response speed and sensitivity of the device to the input signal, thereby improving the switching speed and conductivity of the device. And due to the existence of the piezoelectric effect, when the piezoelectric material layer 22 is subjected to an external force, an electric potential will be generated, which can realize the switching of the power device at an extremely low voltage, and even directly respond to mechanical stress, without the need for external voltage control, to achieve self-driven power supply, thereby realizing a low-power power device.

[0050] The power device provided by the technical solution of the embodiment of the present invention includes: a semiconductor body 10, the semiconductor body 10 includes a first surface 01 and a second surface 02 arranged opposite to each other, and the semiconductor body 10 also includes a contact area 12; the contact area 12 is located on the first surface 01; an electrode structure 20, the electrode structure 20 is located on the first surface 01 and the second surface 02; the electrode structure 20 includes an electrode material layer 21 and a piezoelectric material layer 22, the piezoelectric material layer 22 is located on the side of the electrode material layer 21 away from the semiconductor body 10; the piezoelectric material layer 22 is provided with a plurality of cavities 03, and the plurality of cavities 03 penetrate the piezoelectric material layer 22; the electrode material layer 21 covers the first surface 01 and the second surface 02, and the electrode material layer 21 fills the plurality of cavities 03. The embodiment of the present invention uses the piezoelectric material layer 22 and the electrode material layer 21 to replace the substrate, on the one hand, eliminating the substrate resistance and reducing the on-resistance; on the other hand, when a voltage is applied to the piezoelectric material layer 22, the piezoelectric material layer 22 will be deformed, thereby improving the mobility and conductivity of the charge carriers in the semiconductor structure, thereby improving the switching speed and conductivity of the device. And due to the existence of the piezoelectric effect, when the piezoelectric material layer 22 is subjected to external force, an electric potential will be generated, which can realize the switching of power devices at extremely low voltages, and even directly respond to mechanical stress without external voltage control, thereby realizing self-driven power supply and realizing low-power power devices.

[0051] Based on the above embodiment, optionally, Figure 2 is a schematic diagram of the structure of another power device provided by an embodiment of the present invention, referring to Figure 1 and Figure 2 The electrode structure 20 includes a first electrode layer 201 and a second electrode layer 202, the first electrode layer 201 is located on the first surface 01, and the second electrode layer 202 is located on the second surface 02; the electrode material layer 21 includes a first electrode material layer 211 and a second electrode material layer 212, and the piezoelectric material layer 22 includes a first piezoelectric material layer 221 and a second piezoelectric material layer 222; the first electrode layer 201 includes a first electrode material layer 211 and a first piezoelectric material layer 221, and the second electrode layer 202 includes a second electrode material layer 212 and a second piezoelectric material layer 222, and the plurality of cavities 03 includes a plurality of first cavities 04 and a plurality of second cavities 05;

[0052] The first piezoelectric material layer 221 is located on a side of the first electrode material layer 211 away from the first surface 01; the first piezoelectric material layer 221 is provided with a plurality of first cavities 04, and the plurality of first cavities 04 penetrate the first piezoelectric material layer 221; the first electrode material layer 211 covers the first surface 01, and the first electrode material layer 211 fills the plurality of first cavities 04;

[0053] The second piezoelectric material layer 222 is located on a side of the second electrode material layer 212 away from the second surface 02 ; the second piezoelectric material layer 222 is provided with a plurality of second cavities 05 , and the plurality of second cavities 05 penetrate the second piezoelectric material layer 222 ; the second electrode material layer 212 covers the second surface 02 , and the second electrode material layer 212 fills the plurality of second cavities 05 .

[0054] Exemplarily, the contact region 12 may be a P-type conductive region, and the epitaxial layer 11 may be an N-type conductive region. The contact region 12 forms a PN junction with the epitaxial layer 11. The PN junction is formed in a Schottky structure. When the first electrode layer 201 is a cathode and the second electrode layer 202 is an anode, and the JBS diode is reverse biased, the depletion region formed by the PN junction will diffuse into the channel region. Under a certain reverse bias voltage, the depletion region will be connected, thereby forming a potential barrier in the channel region, so that the depletion layer will diffuse toward the second electrode layer 202 as the reverse bias increases. The depletion region of the PN junction shields the Schottky interface from the high field, avoiding the barrier lowering effect and greatly reducing the reverse leakage current. When the first electrode layer 201 is the anode and the second electrode layer 202 is the cathode, the Schottky barrier is lower than the junction barrier when the JBS diode is forward biased. The Schottky region provides a conductive channel for the current and has a very low turn-on voltage. Under high current conditions, after the junction is turned on, minority carriers are injected into the drift region to modulate the conductivity of the drift region, thereby reducing the on-state voltage drop and acting as a shunt bypass, and having a strong surge resistance capability.

[0055] Based on the above embodiments, Figure 1 and Figure 2 Optionally, the number of the contact regions 12 is two, and the semiconductor body 10 includes an epitaxial layer 11; the contact region 12 and the epitaxial layer 11 have different conductivity types.

[0056] Among them, the contact area 12 can be a P-type conductive type area, and the P-type conductive type area can be formed by injecting P-type ions at the position of the contact area 12; the epitaxial layer 11 can be an N-type conductive type area. Exemplarily, the material of the epitaxial layer 11 can be N-type SiC. The contact area 12 is different from the conductivity type of the epitaxial layer 11, and is used to form a PN junction in the device, thereby improving the performance of the device, so that the device has the advantages of high withstand voltage, low voltage drop, low leakage, good high-frequency characteristics, and strong resistance to overvoltage and surge current. The embodiment of the present invention does not need to adopt a traditional substrate structure, but instead uses a piezoelectric material layer 22 and an electrode material layer 21. Therefore, the on-resistance of the device is composed of contact resistance, channel resistance, and epitaxial resistance in series, and there is no substrate resistance in the on-resistance, thereby realizing a low on-resistance device and reducing the on-resistance;

[0057] Based on the above embodiment, optionally, refer to Figure 1 , the electrode material layer 21 includes graphene.

[0058] The electrode material layer 21 includes graphene, and the high conductivity of the graphene material can improve the electrode efficiency.

[0059] An embodiment of the present invention further provides a power module based on the above embodiment, comprising a substrate and the power device described in any embodiment of the present invention, wherein the substrate is used to carry the power device.

[0060] The power module provided by the technical solution of the embodiment of the present invention has the same beneficial effects as the power device described in any embodiment of the present invention.

[0061] An embodiment of the present invention further provides a power conversion circuit based on the above embodiments, and the power conversion circuit is used for one or more of current conversion, voltage conversion, and power factor correction; the power conversion circuit includes a circuit board and the power device described in any embodiment of the present invention, and the power device is electrically connected to the circuit board.

[0062] The power conversion circuit provided by the technical solution of the embodiment of the present invention has the same beneficial effects as the power device described in any embodiment of the present invention.

[0063] An embodiment of the present invention further provides a vehicle based on the above embodiments, including a load and the power conversion circuit described in any embodiment of the present invention, the power conversion circuit is used to convert AC power into DC power, convert AC power into AC power, convert DC power into DC power, or convert DC power into AC power and then input it into the load.

[0064] The vehicle provided by the technical solution of the embodiment of the present invention and the power device described in any embodiment of the present invention have the same beneficial effects.

[0065] An embodiment of the present invention provides a method for preparing a power device based on the above embodiment, which is used to prepare the power device described in any embodiment of the present invention. Figure 3 is a flow chart of a method for preparing a power device provided by an embodiment of the present invention, with reference to Figure 3 , the preparation method comprises:

[0066] S110, providing a semiconductor body, wherein the semiconductor body comprises a first surface and a second surface arranged opposite to each other, and the semiconductor body further comprises a contact region; the contact region is located on the first surface.

[0067] S120. An electrode structure is formed on the first surface and the second surface; the electrode structure includes an electrode material layer and a piezoelectric material layer, the piezoelectric material layer is located on a side of the electrode material layer away from the semiconductor body; the piezoelectric material layer is provided with a plurality of cavities, and the plurality of cavities penetrate the piezoelectric material layer; the electrode material layer covers the first surface and the second surface, and the electrode material layer fills the plurality of cavities.

[0068] The method for preparing a power device provided by the technical solution of the embodiment of the present invention adopts a piezoelectric material layer and an electrode material layer to replace the substrate. On the one hand, the substrate resistance is eliminated and the on-resistance is reduced; on the other hand, when a voltage is applied to the piezoelectric material layer, the piezoelectric material layer will deform, thereby improving the mobility and conductivity of the charge carriers in the semiconductor structure, thereby improving the switching speed and conductivity of the device. And due to the existence of the piezoelectric effect, when the piezoelectric material layer is subjected to an external force, an electric potential will be generated, which can realize the switching of the power device at an extremely low voltage, and even directly respond to mechanical stress, without the need for external voltage control, to achieve self-driven power supply, thereby realizing a low-power power device.

[0069] Based on the above embodiment, optionally, Figure 4 yes Figure 3 A detailed flow chart included in S120, Figure 5-Figure 8 is a schematic diagram of an intermediate structure of a power device provided by an embodiment of the present invention, with reference to Figure 4-Figure 8 , S120, forming an electrode structure on the first surface and the second surface, including:

[0070] S121, forming a first electrode sublayer on the first surface; the first electrode sublayer covers the first surface.

[0071] Among them, reference Figure 6 , a first electrode sublayer 06 can be formed on the first surface 01 by a sputtering process.

[0072] S122. Form a first piezoelectric material sublayer on a side of the first electrode sublayer away from the first surface; the first piezoelectric material sublayer covers the first electrode sublayer.

[0073] Among them, reference Figure 6 , a second piezoelectric material sublayer can be formed on a side of the first electrode sublayer 06 away from the first surface 01 through a bonding process.

[0074] S123, etching the first piezoelectric material sub-layer to form a plurality of first cavities, thereby forming a first piezoelectric material layer.

[0075] Among them, reference Figure 6 , the first piezoelectric material sublayer can be etched by dry etching to form a plurality of first cavities 04 and form a first piezoelectric material layer 221 .

[0076] S124, forming a second electrode sublayer in the plurality of first cavities; the first electrode sublayer and the second electrode sublayer are a first electrode material layer, and the first electrode material layer and the first piezoelectric material layer are a first electrode layer.

[0077] Among them, reference Figure 7 , a second electrode sublayer 07 can be formed in the plurality of first cavities 04 by a sputtering process.

[0078] S125, forming a third electrode sublayer on the second surface; the third electrode sublayer covers the second surface.

[0079] Among them, reference Figure 8 , a third electrode sublayer 08 can be formed on the second surface 02 by a sputtering process.

[0080] S126. Form a second piezoelectric material sublayer on a side of the third electrode sublayer away from the second surface; the second piezoelectric material sublayer covers the first electrode sublayer.

[0081] Among them, reference Figure 8 , a second piezoelectric material sublayer can be formed on a side of the third electrode sublayer 08 away from the second surface 02 through a bonding process.

[0082] S127, etching the second piezoelectric material sublayer to form a plurality of second cavities, thereby forming a second piezoelectric material layer.

[0083] Among them, reference Figure 8 , the second piezoelectric material sublayer can be etched by dry etching to form a plurality of second cavities 05 and form a second piezoelectric material layer 222 .

[0084] S128. Form a fourth electrode sublayer in the plurality of second cavities; the third electrode sublayer and the fourth electrode sublayer are second electrode material layers, the second electrode material layer and the second piezoelectric material layer are second electrode layers, and the first electrode layer and the second electrode layer are electrode structures.

[0085] Among them, reference Figure 1 and Figure 2 , a fourth electrode sublayer can be formed in the plurality of second cavities by a sputtering process; the third electrode sublayer and the fourth electrode sublayer are the second electrode material layer 212 , and the second electrode material layer and the second piezoelectric material layer are the second electrode layer 202 .

[0086] Based on the above embodiment, optionally, S110, providing a semiconductor body, including:

[0087] S111, forming an epitaxial layer on one side of the substrate; a surface of the epitaxial layer away from the substrate is a first surface;

[0088] Among them, reference Figure 5 An epitaxial layer 11 may be formed on one side of a substrate 13 by epitaxial growth. The substrate 13 may be an N+ silicon carbide substrate, and the epitaxial layer 11 may be an N- silicon carbide epitaxial layer.

[0089] S112, forming a contact area on the first surface.

[0090] Among them, reference Figure 5, a contact region 12 is formed by an ion implantation process; P-type ions may be implanted on one side of the first surface 01 to form the contact region 12 .

[0091] After forming the second electrode sublayer in the plurality of first cavities, the method further includes:

[0092] Remove the substrate.

[0093] Among them, reference Figure 7 and Figure 8 The substrate 13 can play a supporting role. After the second electrode sublayer 07 is formed in the plurality of first cavities 04, the substrate 13 can be removed by a conventional removal process, and a second electrode material layer is formed after the substrate 13 is removed.

[0094] The method for preparing a power device provided in an embodiment of the present invention has the same beneficial effects as the power device described in any embodiment of the present invention.

[0095] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0096] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a power device, characterized in that: include: A semiconductor body is provided, wherein the semiconductor body comprises a first surface and a second surface arranged opposite to each other, and the semiconductor body further comprises a contact region; the contact region is located on the first surface; An electrode structure is formed on the first surface and the second surface; the electrode structure comprises an electrode material layer and a piezoelectric material layer, and the piezoelectric material layer is located on a side of the electrode material layer away from the semiconductor body; The piezoelectric material layer is provided with a plurality of cavities, and the plurality of cavities penetrate the piezoelectric material layer; The electrode material layer covers the first surface and the second surface, and the electrode material layer fills the plurality of cavities.

2. The preparation method according to claim 1, characterized in that: An electrode structure is formed on the first surface and the second surface, comprising: forming a first electrode sublayer on the first surface; the first electrode sublayer covers the first surface; forming a first piezoelectric material sublayer on a side of the first electrode sublayer away from the first surface; the first piezoelectric material sublayer covers the first electrode sublayer; Etching the first piezoelectric material sublayer to form a plurality of first cavities to form a first piezoelectric material layer; forming a second electrode sublayer in the plurality of first cavities; the first electrode sublayer and the second electrode sublayer are first electrode material layers, and the first electrode material layer and the first piezoelectric material layer are first electrode layers; forming a third electrode sublayer on the second surface; the third electrode sublayer covers the second surface; forming a second piezoelectric material sublayer on a side of the third electrode sublayer away from the second surface; the second piezoelectric material sublayer covers the first electrode sublayer; Etching the second piezoelectric material sublayer to form a plurality of second cavities to form a second piezoelectric material layer; A fourth electrode sublayer is formed in the plurality of second cavities; the third electrode sublayer and the fourth electrode sublayer are second electrode material layers, the second electrode material layer and the second piezoelectric material layer are second electrode layers, and the first electrode layer and the second electrode layer are electrode structures.

3. The preparation method according to claim 2, characterized in that: Provide a semiconductor body, including: An epitaxial layer is formed on one side of a substrate; a surface of the epitaxial layer away from the substrate is a first surface; forming a contact area on the first surface; After forming the second electrode sublayer in the plurality of first cavities, the method further includes: The substrate is removed.

4. A power device, characterized in that: The method according to any one of claims 1 to 3 is used for preparation, comprising: A semiconductor body, the semiconductor body comprising a first surface and a second surface arranged opposite to each other, the semiconductor body further comprising a contact region; the contact region is located on the first surface; An electrode structure, wherein the electrode structure is located on the first surface and the second surface; the electrode structure includes an electrode material layer and a piezoelectric material layer, wherein the piezoelectric material layer is located on a side of the electrode material layer away from the semiconductor body; the piezoelectric material layer is provided with a plurality of cavities, wherein the plurality of cavities penetrate the piezoelectric material layer; the electrode material layer covers the first surface and the second surface, and the electrode material layer fills the plurality of cavities.

5. The power device according to claim 4, characterized in that: The electrode structure includes a first electrode layer and a second electrode layer, the first electrode layer is located on the first surface, and the second electrode layer is located on the second surface; the electrode material layer includes a first electrode material layer and a second electrode material layer, and the piezoelectric material layer includes a first piezoelectric material layer and a second piezoelectric material layer; the first electrode layer includes a first electrode material layer and a first piezoelectric material layer, the second electrode layer includes a second electrode material layer and a second piezoelectric material layer, and the plurality of cavities includes a plurality of first cavities and a plurality of second cavities; The first piezoelectric material layer is located on a side of the first electrode material layer away from the first surface; the first piezoelectric material layer is provided with a plurality of first cavities, and the plurality of first cavities penetrate the first piezoelectric material layer; the first electrode material layer covers the first surface, and the first electrode material layer fills the plurality of first cavities; The second piezoelectric material layer is located on a side of the second electrode material layer away from the second surface; The second piezoelectric material layer is provided with a plurality of second cavities, and the plurality of second cavities penetrate the second piezoelectric material layer; the second electrode material layer covers the second surface, and the second electrode material layer fills the plurality of second cavities.

6. The power device according to claim 4, characterized in that: The number of the contact regions is two, and the semiconductor body includes an epitaxial layer; The contact region and the epitaxial layer have different conductivity types.

7. The power device according to claim 4, characterized in that: The material of the electrode material layer includes graphene.

8. A power module, characterized in that: The invention comprises a substrate and at least one power device according to any one of claims 4 to 7, wherein the substrate is used for supporting the power device.

9. A power conversion circuit, characterized in that: The power conversion circuit is used for one or more of current conversion, voltage conversion, and power factor correction; The power conversion circuit comprises a circuit board and at least one power device as claimed in any one of claims 4 to 7, wherein the power device is electrically connected to the circuit board.

10. A vehicle, characterized in that: It includes a load and a power conversion circuit as described in claim 9, wherein the power conversion circuit is used to convert AC power into DC power, convert AC power into AC power, convert DC power into DC power, or convert DC power into AC power and then input it into the load.

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