Schottky diode, preparation method thereof and electronic device

Abstract

The Schottky diode, preparation method thereof and electronic device disclosed in the present invention include a substrate; a drift layer, located on one side of the substrate; a first dielectric layer, located on the side of the drift layer away from the substrate, the first dielectric layer including a groove running through its thickness; a regrown layer, located in the groove, the surface of the regrown layer away from the substrate and the surface of the first dielectric layer away from the substrate being coplanar; and a Schottky electrode, located on the side of the regrown layer and the first dielectric layer away from the substrate. Since the surface of the first dielectric layer away from the substrate and the surface away from the regrown layer are located on the same horizontal plane, there is no field plate corner on the surface of the drift layer for the Schottky electrode, which can reduce the electric field concentration phenomenon on the surface of the drift layer, thereby effectively improving the withstand voltage characteristics of the Schottky diode.

Description

Technical Field

[0001] The present disclosure relates to the field of semiconductor technology, and in particular to a Schottky diode, a preparation method thereof, and an electronic device. Background Art

[0002] In Schottky power devices, the electric field concentration effect at the edge of the Schottky electrode causes the device to break down prematurely at a voltage far below the theoretical breakdown voltage. To avoid premature breakdown of the device, a field plate structure can be used to alleviate the electric field concentration effect. The introduction of the field plate structure weakens the electric field peak at the surface of the drift layer, but there are still field plate corners on the surface of the drift layer, resulting in electric field concentration on the surface of the drift layer, which has limited effect on improving the withstand voltage of Schottky diode devices. Summary of the invention

[0003] In view of this, the embodiments of the present disclosure provide a Schottky diode, a preparation method thereof, and an electronic device, so as to improve the withstand voltage performance of the Schottky diode.

[0004] The Schottky diode, the preparation method thereof and the electronic device provided by the embodiments of the present disclosure are specifically described as follows:

[0005] In one aspect, an embodiment of the present disclosure provides a Schottky diode, comprising:

[0006] substrate;

[0007] A drift layer, located on one side of the substrate;

[0008] A first dielectric layer, located on a side of the drift layer away from the substrate, the first dielectric layer comprising a groove running through the thickness thereof;

[0009] a regrown layer, located in the groove, wherein a surface of the regrown layer away from the substrate is coplanar with a surface of the first dielectric layer away from the substrate;

[0010] The Schottky electrode is located on a side of the regrown layer and the first dielectric layer away from the substrate.

[0011] In some embodiments, in the above-mentioned Schottky diode provided in the embodiments of the present disclosure, a second dielectric layer is further included, and the second dielectric layer is stacked with a portion of the first dielectric layer;

[0012] The Schottky electrode covers a portion of the first dielectric layer and a portion of the second dielectric layer.

[0013] In some embodiments, in the above-mentioned Schottky diode provided by the embodiments of the present disclosure, the second dielectric layer covers the sidewalls of the first dielectric layer and the sidewalls of the drift layer.

[0014] In some embodiments, the Schottky diode provided in the embodiments of the present disclosure further includes an ohmic contact layer and an ohmic electrode; wherein,

[0015] The ohmic contact layer is located on a side of the substrate facing the drift layer, and the ohmic contact layer includes an edge portion that does not overlap with the drift layer; the ohmic electrode is electrically connected to the ohmic contact layer at the edge portion.

[0016] In some embodiments, in the above-mentioned Schottky diode provided by the embodiments of the present disclosure, the second dielectric layer covers a portion of the edge portion.

[0017] In some embodiments, in the above-mentioned Schottky diode provided in the embodiments of the present disclosure, the substrate is a diamond substrate, the drift layer is a p-diamond drift layer, the regrown layer is a p-diamond regrown layer, and the ohmic contact layer is a p+ diamond ohmic contact layer.

[0018] In some embodiments, in the above-mentioned Schottky diode provided by the embodiments of the present disclosure, the ohmic contact layer is an n+ silicon carbide ohmic contact layer.

[0019] In some embodiments, the Schottky diode provided in the embodiments of the present disclosure further includes an ohmic electrode located on a side of the substrate away from the drift layer.

[0020] In some embodiments, in the above-mentioned Schottky diode provided in the embodiments of the present disclosure, the substrate is a silicon carbide substrate, the drift layer is an n-silicon carbide drift layer, and the regrown layer is an n-silicon carbide regrown layer.

[0021] In some embodiments, the Schottky diode provided in the embodiments of the present disclosure further includes a transfer substrate located on a side of the substrate away from the drift layer.

[0022] On the other hand, an embodiment of the present disclosure provides a method for preparing the above-mentioned Schottky diode, comprising:

[0023] providing a substrate;

[0024] forming a drift layer, a first dielectric layer and a regrown layer on the substrate, wherein the first dielectric layer is located on a side of the drift layer away from the substrate, the first dielectric layer includes a groove running through the thickness thereof, the regrown layer is located in the groove, and a surface of the regrown layer away from the substrate is coplanar with a surface of the first dielectric layer away from the substrate;

[0025] A Schottky electrode is formed on a side of the regrown layer and the first dielectric layer away from the substrate.

[0026] In some embodiments, in the above preparation method provided in the embodiments of the present disclosure, the substrate is a diamond substrate, and a drift layer, a first dielectric layer and a regrown layer are formed on the substrate, specifically comprising:

[0027] forming a p-diamond drift layer on the diamond substrate;

[0028] forming a first dielectric layer on a side of the p-diamond drift layer away from the diamond substrate, wherein the first dielectric layer includes a groove running through the thickness thereof;

[0029] A p-diamond regrown layer is formed in the groove, and a surface of the p-diamond regrown layer away from the diamond substrate is coplanar with a surface of the first dielectric layer away from the diamond substrate.

[0030] In some embodiments, in the above preparation method provided by the embodiment of the present disclosure, after forming a p-diamond regrown layer in the groove and making the surface of the p-diamond regrown layer away from the diamond substrate coplanar with the surface of the first dielectric layer away from the diamond substrate, and before forming a Schottky electrode on the side of the regrown layer and the first dielectric layer away from the substrate, the method further includes:

[0031] A partial thickness of the diamond substrate is removed, and a transfer substrate is disposed on a side of the remaining diamond substrate away from the p-diamond drift layer.

[0032] In some embodiments, in the above preparation method provided by the embodiments of the present disclosure, removing a portion of the thickness of the diamond substrate, and setting a transfer substrate on the side of the remaining diamond substrate away from the p-diamond drift layer, specifically includes:

[0033] Using a femtosecond laser, focusing the laser on the inside of the diamond substrate, scanning continuously line by line, converting the phase on the scanning path into a graphite phase, and removing the graphite phase using an electrochemical etching technique;

[0034] The thinned surface of the diamond substrate away from the p-diamond drift layer and the surface of the transfer substrate to be combined with the diamond substrate are activated, and the activated surface of the diamond substrate and the activated surface of the transfer substrate are bonded.

[0035] In some embodiments, in the above preparation method provided in the embodiments of the present disclosure, after providing a substrate and before forming a p-diamond drift layer on the diamond substrate, the method further includes:

[0036] The diamond substrate is separated into at least two parts, and a transfer substrate is arranged on a side of one of the diamond substrates away from a p-diamond drift layer to be fabricated.

[0037] In some embodiments, in the above preparation method provided by the embodiments of the present disclosure, the diamond substrate is separated into at least two parts, and a transfer substrate is arranged on a side of one of the diamond substrates away from the p-diamond drift layer to be fabricated, specifically comprising:

[0038] Implanting ions to a predetermined depth of the diamond substrate;

[0039] epitaxially growing single crystal diamond of a preset thickness on the ion implantation surface of the diamond substrate;

[0040] Separating the diamond substrate of the preset depth from the ion implantation layer by electrochemical etching;

[0041] Depositing a first silicon carbide layer on a surface of the diamond substrate at the preset depth that is away from the single crystal diamond, and depositing a second silicon carbide layer on a surface of a transfer substrate to be bonded to the diamond substrate;

[0042] Activate the surfaces of the first silicon carbide layer and the second silicon carbide layer to be bonded, and bond the activated surface of the first silicon carbide layer and the activated surface of the second silicon carbide layer.

[0043] In some embodiments, in the above-mentioned preparation method provided in the embodiments of the present disclosure, the substrate is a silicon carbide substrate, and a drift layer, a first dielectric layer and a regrown layer are formed on the substrate, specifically comprising:

[0044] forming an integrated n-silicon carbide drift layer and an n-silicon carbide regrown layer on the silicon carbide substrate, wherein the n-silicon carbide regrown layer is located on a side of the n-silicon carbide drift layer away from the silicon carbide substrate;

[0045] A first dielectric layer is formed on a side of the n-silicon carbide drift layer away from the silicon carbide substrate, the first dielectric layer includes a groove running through the thickness of the n-silicon carbide regrown layer, and a surface of the first dielectric layer away from the silicon carbide substrate is coplanar with a surface of the n-silicon carbide regrown layer away from the silicon carbide substrate.

[0046] On the other hand, an embodiment of the present disclosure further provides an electronic device, including the above-mentioned Schottky diode provided by an embodiment of the present disclosure.

[0047] The beneficial effects of the present disclosure are as follows:

[0048] The Schottky diode, preparation method thereof and electronic device provided by the embodiments of the present disclosure include a substrate; a drift layer, located on one side of the substrate; a first dielectric layer, located on the side of the drift layer away from the substrate, the first dielectric layer including a groove running through its thickness; a regrown layer, located in the groove, the surface of the regrown layer away from the substrate is coplanar with the surface of the first dielectric layer away from the substrate; and a Schottky electrode, located on the side of the regrown layer and at least part of the first dielectric layer away from the substrate. The present disclosure arranges the regrown layer and the first dielectric layer on the drift layer, and arranges the Schottky electrode on the regrown layer and at least part of the first dielectric layer. Since the surface of the first dielectric layer away from the substrate is located on the same horizontal plane as the surface away from the regrown layer, when the Schottky diode is a diamond Schottky diode, there is no corner on the surface of the drift layer of the Schottky electrode, which can reduce the electric field concentration phenomenon on the surface of the drift layer, thereby effectively improving the withstand voltage characteristics of the Schottky diode. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 A schematic diagram of the structure of a Schottky diode provided in an embodiment of the present disclosure;

[0050] Figure 2 A schematic diagram of another structure of a Schottky diode provided in an embodiment of the present disclosure;

[0051] Figure 3 IV curves of three types of Schottky diodes provided in the embodiments of the present disclosure;

[0052] Figure 4 The electric field intensity distribution diagrams of different lateral positions of the Schottky contact surface of Schottky diodes with three structures are shown;

[0053] Figure 5 The electric field intensity distribution diagrams at different longitudinal positions of the Schottky electrode end in the three structures of Schottky diodes;

[0054] Figure 6 A flow chart of a method for preparing a Schottky diode provided in an embodiment of the present disclosure;

[0055] Figure 7 Another flow chart of the method for preparing a Schottky diode provided in an embodiment of the present disclosure;

[0056] Figure 8 Another flow chart of the method for preparing a Schottky diode provided in an embodiment of the present disclosure;

[0057] Figure 9a for Figure 1 A schematic diagram of the structure of a Schottky diode during the preparation process is shown;

[0058] Figure 9b for Figure 1Another structural schematic diagram of a Schottky diode during the preparation process is shown;

[0059] Fig.9c for Figure 1 Another structural schematic diagram of a Schottky diode during the preparation process is shown;

[0060] Figure 9d for Figure 1 Another structural schematic diagram of a Schottky diode during the preparation process is shown;

[0061] Fig.9e for Figure 1 Another structural schematic diagram of a Schottky diode during the preparation process is shown;

[0062] Figure 9f for Figure 1 Another structural schematic diagram of a Schottky diode during the preparation process is shown;

[0063] Figure 9g for Figure 1 Another structural schematic diagram of a Schottky diode during the preparation process is shown;

[0064] Figure 9h for Figure 1 Another structural schematic diagram of a Schottky diode during the preparation process is shown;

[0065] Figure 9i for Figure 1 Another structural schematic diagram of a Schottky diode during the preparation process is shown;

[0066] Figure 9j for Figure 1 Another structural schematic diagram of a Schottky diode during the preparation process is shown;

[0067] Fig.10 Another flow chart of the method for preparing a Schottky diode provided in an embodiment of the present disclosure;

[0068] Fig.11a A flow chart of separating a diamond substrate provided for an embodiment of the present disclosure;

[0069] Fig.11b for Fig.11a Flow chart of combining the separated diamond substrate with the transfer substrate;

[0070] Fig.12 Another flow chart of the method for preparing a Schottky diode provided in an embodiment of the present disclosure;

[0071] Fig.13 for Figure 1 Another structural schematic diagram of a Schottky diode during the preparation process is shown;

[0072] Fig.14 for Figure 1 Another structural schematic diagram of a Schottky diode during the preparation process is shown;

[0073] Fig.15 A schematic diagram of the structure of an electronic device provided in an embodiment of the present disclosure. DETAILED DESCRIPTION

[0074] In order to make the purpose, technical solution and advantages of the embodiment of the present disclosure clearer, the technical solution of the embodiment of the present disclosure will be clearly and completely described in conjunction with the drawings of the embodiment of the present disclosure. It should be noted that in the drawings, the thickness of the layer, film, panel, area, etc. is magnified for clarity. In the present disclosure, exemplary embodiments are described with reference to cross-sectional views of schematic diagrams of idealized embodiments. In this way, deviations from the shape of the figure as a result of, for example, manufacturing technology and / or tolerances will be expected. Therefore, the embodiments described in the present disclosure should not be interpreted as being limited to the specific shape of the area shown in the present disclosure, but include deviations in shape caused by, for example, manufacturing. For example, an area illustrated or described as flat may typically have rough and / or nonlinear features; the illustrated sharp corners may be rounded, etc. Therefore, the areas shown in the figures are schematic in nature, and their sizes and shapes are not intended to illustrate the exact shape of the area, do not reflect the true proportion, and the purpose is only to illustrate the content of the present disclosure. And in order to keep the following description clear and concise, the present disclosure omits detailed descriptions of known functions and known components.

[0075] Unless otherwise defined, the technical terms or scientific terms used herein shall have the usual meanings understood by persons of ordinary skill in the field to which the present disclosure belongs. The words "first", "second" and similar words used in the present disclosure specification and claims do not indicate any order, quantity or importance, but are only used to distinguish different components. Words such as "include" or "comprise" and the like mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Words such as "connect" or "connected" and the like are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Inside", "outside", "upper", "lower", etc. are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0076] In the following description, when an element or layer is referred to as being "on" or "connected to" another element or layer, the element or layer may be directly on, directly connected to, or there may be an intermediate element or intermediate layer. When an element or layer is referred to as being "disposed on one side of" another element or layer, the element or layer may be directly on one side of, directly connected to, or there may be an intermediate element or intermediate layer. However, when an element or layer is referred to as being "directly on" or "directly connected to" another element or layer, there are no intermediate elements or intermediate layers. The term "and / or" includes any and all combinations of one or more of the associated listed items.

[0077] The present disclosure provides a Schottky diode, such as Figure 1 and Figure 2 As shown, this may include:

[0078] Substrate 01, optionally, substrate 01 is a diamond substrate such as a single crystal diamond substrate, a single crystal diamond substrate doped with C ions, or substrate 01 is a silicon carbide SiC substrate.

[0079] The drift layer 02 is located on one side of the substrate 01 and is a lightly doped layer. In some embodiments, the drift layer 02 is a p-diamond drift layer located on one side of the diamond substrate and has a doping concentration of 10 14 cm -3 ~10 16 cm -3 , for example 10 14 cm -3 , 10 15 cm -3 , 10 16 cm -3 The thickness is 0.5 μm to 10 μm, such as 0.5 μm, 1 μm, 5 μm, 10 μm, etc. In other embodiments, the drift layer 02 is an n-silicon carbide drift layer located on one side of the silicon carbide substrate, and the doping concentration is 2×10 14 cm -3 ~10 16 cm -3 , for example, 2×10 14 cm -3 , 5×10 14 cm -3 , 10 15 cm -3 , 5×10 15 cm -3 , 10 16 cm -3The thickness is 10 μm to 40 μm, for example, 10 μm, 20 μm, 30 μm, 40 μm, etc.

[0080] The first dielectric layer 03 is located on the side of the drift layer 02 away from the substrate 01, and the first dielectric layer 03 includes a groove V running through its thickness; in some embodiments, the material of the first dielectric layer 03 includes at least one high-K material such as aluminum oxide, hafnium oxide, silicon nitride, etc., to reduce the risk of the first dielectric layer 03 being broken down.

[0081] The regrown layer 04 is located in the groove V, and the surface of the regrown layer 04 away from the substrate 01 is coplanar with the surface of the first dielectric layer 03 away from the substrate 01. In some embodiments, the material of the regrown layer 04 can be the same as that of the drift layer 02, for example, the drift layer 02 is a p-diamond drift layer, and the regrown layer 04 is a p-diamond regrown layer; for another example, the drift layer 02 is an n-silicon carbide drift layer, and the regrown layer 04 is an n-silicon carbide regrown layer. In some embodiments, the present disclosure can use the first dielectric layer 03 as a mask to grow a p-diamond regrown layer in the groove V, thereby reducing diamond surface defects caused by etching and reducing leakage. The present disclosure can also use a chemical mechanical polishing CMP process to make the upper surface of the p-diamond regrown layer and the upper surface of the first dielectric layer 03 located at the same horizontal plane. In addition, due to the limitations of process conditions or the influence of other factors such as measurement, the above-mentioned "coplanarity" may be exactly coplanar, or there may be some deviations. Therefore, as long as the "coplanarity" relationship between the above-mentioned features meets the error allowance, it belongs to the protection scope of the present disclosure.

[0082] The Schottky electrode 05 is located on the side of the regrown layer 04 and the first dielectric layer 03 away from the substrate 01. The Schottky electrode 05 is set as a field plate structure overlapping the first dielectric layer 03, which is conducive to reducing the electric field strength in the first dielectric layer 03, avoiding the early breakdown of the first dielectric layer 03, and finally improving the breakdown voltage of the device. In some embodiments, the material of the Schottky electrode 05 may include at least one metal such as Zr, Ni, and Au.

[0083] In the above-mentioned Schottky diode provided by the embodiment of the present disclosure, a regrown layer 04 and a first dielectric layer 03 whose upper surfaces are coplanar are provided on the drift layer 02, and a Schottky electrode 05 with a field plate structure is provided on the regrown layer 04 and the first dielectric layer 03. The upper surfaces of the first dielectric layer 03 and the regrown layer 04 are located at the same horizontal plane, so that there is no field plate corner between the surface of the drift layer 02 and the Schottky electrode 05, which can reduce the electric field concentration phenomenon on the surface of the drift layer 02; and, through the first dielectric layer 03 of high-K material and the field plate structure, the electric field strength in the first dielectric layer 03 is reduced, and the dielectric is prevented from being broken down prematurely, and finally the breakdown voltage of the device is improved.

[0084] In some embodiments, in the above-mentioned Schottky diode provided in the embodiments of the present disclosure, if Figure 1 As shown, it may also include an ohmic contact layer 06 and an ohmic electrode 07; wherein the ohmic contact layer 06 may be a heavily doped layer doped with boron (B), for example, the ohmic contact layer 06 is a p+ diamond ohmic contact layer located on the side of the diamond substrate facing the p-diamond drift layer, and the doping concentration is 10 19 cm -3 ~10 20 cm -3 , for example 10 19 cm -3 , 5×10 19 cm -3 , 10 20 cm -3 The thickness is 1 μm to 2 μm, such as 1 μm, 1.5 μm, 2 μm, etc.; or, the ohmic contact layer 06 is an n+ silicon carbide ohmic contact layer located on the side of the silicon carbide substrate facing the n- silicon carbide drift layer, and the doping concentration is 10 18 cm -3 ~5×10 19 cm -3 , for example 10 18 cm -3 , 5×10 18 cm -3 , 10 19 cm -3 , 5×10 19 cm -3 The thickness is 5μm~10μm, such as 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, etc. The ohmic electrode 07 may include a single layer or multiple layers of metal such as W, Ti / Pt / Au, Ti / Al / Ni / Au, etc. Different from the ohmic electrode 07 and the Schottky electrode 05 in the related art, which are separated on both sides of the substrate 01, the ohmic electrode 07 and the Schottky electrode 05 of the present disclosure are located on the same side of the substrate 01 (i.e., the side of the substrate 01 facing the drift layer 02), and the ohmic contact layer 06 corresponding to the ohmic electrode 07 is also located on the side of the substrate 01 facing the drift layer 02. And the ohmic contact layer 06 may include an edge portion 61 that does not overlap with the drift layer 02, so that the ohmic electrode 08 can be electrically connected to the ohmic contact layer 06 at the edge portion 61.

[0085] In some embodiments, the etching process of the drift layer 02 may cause over-etching, resulting in partial etching of the ohmic contact layer 06 (i.e., the edge portion 61) that does not overlap with the drift layer 02, and the thickness of the edge portion 61 is reduced. Figure 1 It can be known that in the present disclosure, the ohmic contact layer 06 may further include a middle portion 62 stacked with the drift layer 02 , and the thickness of the middle portion 62 is greater than the thickness of the edge portion 61 .

[0086] In some embodiments, in the above-mentioned Schottky diode provided in the embodiments of the present disclosure, if Figure 1 and Figure 2 As shown, a second dielectric layer 08 may also be included, and the material of the second dielectric layer 08 may include at least one high-K material such as aluminum oxide, hafnium oxide, silicon nitride, etc. In some embodiments, the second dielectric layer 08 does not overlap with the regrown layer 04, and is stacked with a portion of the first dielectric layer 03. The Schottky electrode 05 covers a portion of the first dielectric layer 03 close to the regrown layer 04, and a portion of the second dielectric layer 08 stacked with the first dielectric layer 03, so that the field plate corner of the Schottky electrode 05 is located at the step formed by the first dielectric layer 03 and the second dielectric layer 08, eliminating the field plate corner on the surface of the drift layer 02, transferring the electric field peak position from the surface of the drift layer 02 to the dielectric surface, and reducing the electric field strength in the dielectric through the high-K dielectric and field plate structure, avoiding premature breakdown of the dielectric, and ultimately increasing the breakdown voltage of the device.

[0087] In some embodiments, the edge portion 61 of the drift layer 03 and the ohmic contact layer 06 introduces a large number of surface states due to etching, which may cause leakage when high voltage is applied, thereby causing device failure. Figure 1 It can be seen that the second dielectric layer 08 disclosed in the present invention can extend to cover the side walls of the first dielectric layer 03, the side walls of the drift layer 03, and the partial edge portion 61 that does not overlap with the ohmic electrode 07, so that the etched surface can be passivated by the second dielectric layer 08, thereby reducing device surface leakage and improving device reliability.

[0088] In some embodiments, the substrate 01 is a diamond substrate such as a single crystal diamond substrate or a single crystal diamond substrate doped with C ions. However, the scarcity of large-size and high-quality single crystal diamond substrates leads to high costs. Figure 1 As shown, in the above-mentioned Schottky diode provided in the embodiment of the present disclosure, a transfer substrate 09 located on the side of the substrate 01 away from the drift layer 02 may also be included. Optionally, the transfer substrate 09 is a low-cost substrate such as Si, sapphire, or polycrystalline diamond. In some embodiments, a portion of the thickness of the substrate 01 may be removed, and a transfer substrate 09 may be set on the side of the retained substrate 01 away from the drift layer 02, so that the removed high-quality single crystal diamond substrate can be used to continue to prepare the device, thereby effectively reducing the cost. It should be understood that since the cost of the silicon carbide substrate is relatively low, the silicon carbide Schottky diode disclosed in the present disclosure may be provided with a transfer substrate 09 or may not be provided with a transfer substrate 09, which is not limited here.

[0089] In some embodiments, considering that the conductivity of the silicon carbide substrate can be very good, there is no need to set the ohmic contact layer 06, and the ohmic electrode 07 can be directly made on the back of the device. In other words, the Schottky diode provided in the embodiment of the present disclosure can also include an ohmic electrode 07 located on the side of the substrate 01 (e.g., silicon carbide substrate) away from the drift layer 02 (e.g., n-silicon carbide drift layer), such as Figure 2 shown.

[0090] The present disclosure also provides IV curves of the Schottky diode of the present disclosure, the Schottky diode with a common field plate, and the Schottky diode without a field plate, such as Figure 3 shown. Figure 4 The three structures of Schottky diodes are lateral to the Schottky contact surface (e.g. Figure 1 The electric field intensity distribution diagram at different positions in the I-I' direction, Figure 5 The longitudinal direction of the Schottky electrode end in the three structures of Schottky diodes (e.g. Figure 1 The electric field intensity distribution diagram at different positions in the II-II' direction. Figure 3 It can be seen that the voltage resistance performance of the Schottky diode without field plate, the ordinary Schottky diode with field plate, and the Schottky diode disclosed in the present invention is enhanced in turn. Figure 4 and Figure 5 It can be seen that the electric field peak of the present invention is located on the surface of the dielectric and is lower than the electric field peak of the Schottky diode without a field plate and the Schottky diode with a common field plate. This shows that the present invention transfers the electric field peak on the diamond surface to the dielectric surface, and the electric field strength in the dielectric is reduced, thereby avoiding premature breakdown of the dielectric and effectively improving the breakdown voltage of the device.

[0091] Based on the same inventive concept, an embodiment of the present disclosure provides a method for preparing the above-mentioned Schottky diode. Since the principle of solving the problem by the preparation method is similar to the principle of solving the problem by the above-mentioned Schottky diode, the implementation of the preparation method provided by the embodiment of the present disclosure can refer to the implementation of the above-mentioned Schottky diode provided by the embodiment of the present disclosure, and the repeated parts will not be repeated.

[0092] In some embodiments, the method for preparing a Schottky diode provided by the embodiments of the present disclosure is as follows: Figure 6 As shown, the following steps may be included:

[0093] S601, providing a substrate;

[0094] S602, forming a drift layer, a first dielectric layer and a regrown layer on a substrate, wherein the first dielectric layer is located on a side of the drift layer away from the substrate, the first dielectric layer includes a groove running through the thickness thereof, the regrown layer is located in the groove, and a surface of the regrown layer on a side away from the substrate is coplanar with a surface of the first dielectric layer on a side away from the substrate;

[0095] S603 , forming a Schottky electrode on a side of the regrown layer and the first dielectric layer away from the diamond substrate.

[0096] In some embodiments, in the above-mentioned preparation method provided in the embodiments of the present disclosure, the substrate is a diamond substrate, such as Figure 7 As shown, the above step S602 forms a drift layer, a first dielectric layer and a regrown layer on the substrate, which can be specifically implemented in the following manner:

[0097] S701, forming a p-diamond drift layer on a diamond substrate;

[0098] S702, forming a first dielectric layer on a side of the p-diamond drift layer away from the diamond substrate, wherein the first dielectric layer includes a groove running through the thickness thereof;

[0099] S703, forming a p-diamond regrown layer in the groove, and making the surface of the p-diamond regrown layer away from the diamond substrate coplanar with the surface of the first dielectric layer away from the diamond substrate.

[0100] In some embodiments, in the above-mentioned preparation method provided by the embodiment of the present disclosure, after performing the above-mentioned step S703 to form a p-diamond regrown layer in the groove, and making the surface of the p-diamond regrown layer away from the diamond substrate and the surface of the first dielectric layer away from the diamond substrate coplanar, and before performing the above-mentioned step S603 to form a Schottky electrode on the side of the regrown layer and the first dielectric layer away from the diamond substrate, in order to reduce costs, Figure 8 As shown, step S801 may also be performed to remove a portion of the thickness of the diamond substrate, and to arrange a transfer substrate on a side of the remaining diamond substrate away from the p-diamond drift layer.

[0101] In some embodiments, the above step S801 removes a portion of the thickness of the diamond substrate, and sets a transfer substrate on the side of the remaining diamond substrate away from the p-diamond drift layer, which can be specifically implemented in the following manner:

[0102] Using a femtosecond laser, the laser is focused inside the diamond substrate, and the laser is continuously scanned line by line to convert the diamond phase at the scanning path into a graphite phase, and the graphite phase is removed using electrochemical etching technology;

[0103] The surface of the thinned diamond substrate away from the p-diamond drift layer and the surface of the transfer substrate to be combined with the single crystal diamond substrate are activated, and the activated surface of the diamond substrate and the activated surface of the transfer substrate are bonded.

[0104] In order to better understand the technical solution of the above-mentioned preparation method provided by the embodiment of the present disclosure, the following takes the diamond Schottky diode as an example. Figure 1The preparation process of the Schottky diode shown is described in detail.

[0105] Step 1: Select a single crystal diamond substrate as substrate 01 and clean the surface of substrate 01. Specifically, place substrate 01 in 250°C HNO 3 :H 2 SO 4 The samples were cleaned in a (1:1) solution for 20 min, and then ultrasonically cleaned in acetone solution, anhydrous ethanol and deionized water for 15 min.

[0106] Step 2: epitaxially grow an ohmic contact layer 06 (eg, a p+ diamond ohmic contact layer) on the substrate 01. Figure 9a Specifically, MPCVD was used at 850°C, 9 kPa, and 1800 W to introduce 350 sccm of CH 4 , H 2 , BH 3 Mixed gas, CH 4 :H 2 (1:25), BH 3 Using H 2 Dilute to make B:C 1200ppm, grow for 1h, prepare B concentration of 10 20 cm -3 The p+ diamond ohmic contact layer has a thickness of 2μm.

[0107] Step 3, epitaxially growing a drift layer 02 (eg, a p-diamond drift layer) on the surface of the ohmic contact layer 06 (eg, a p+ diamond ohmic contact layer), such as Figure 9b Specifically, MPCVD was used at 950°C, 15 kPa, and 2000 W to introduce 500 sccm of CH 4 :H 2 :O 2 (10:1000:3) mixed gas, grown for 2h, to prepare a p-diamond drift layer with a thickness of 5μm.

[0108] Step 4: prepare an etching mask 10 on the surface of the drift layer 02 (eg, p-diamond drift layer), such as Fig.9c Specifically, a pre-reserved area is defined on the surface of the drift layer 02 (eg, p-diamond drift layer) using photoresist, a layer of metal Cr with a thickness of 100 nm is deposited on the surface of the drift layer 02 (eg, p-diamond drift layer) using electron beam evaporation, and then peeled off to form an etching mask 10.

[0109] Step 5, etching the drift layer 02 (eg, p-diamond drift layer) and part of the ohmic contact layer 06 (eg, p+diamond ohmic contact layer), such as Figure 9dSpecifically, the diamond is etched by ICP-RIE with the etching mask 10 of step 4 as shielding, and the ICP power and RF power are 900 W and 120 W, 45 sccm O respectively. 2 After etching for 40 min under the conditions of 10 Pa and 10 Pa, the etching mask 10 is removed.

[0110] Step 6, depositing a first dielectric layer 03 on the upper surface of the drift layer 02 (e.g., a p-diamond drift layer), and defining a Schottky contact region using a photoresist, exposing and developing to remove the photoresist outside the region, using the photoresist as a shield, etching to remove the first dielectric layer 03 in the Schottky contact region, and then stripping off the photoresist, such as Fig.9e If the material of the first dielectric layer 03 is SiNx, PECVD can be used at 300°C, 190W, 50Pa, and 100sccm of NH 3 :SiH 4 (4:3) mixed gas, deposited for 1.5 hours, to prepare a first dielectric layer 03 with a thickness of 600 nm.

[0111] Step 7, using the first dielectric layer 03 of step 6 as a mask, growing a regrown layer 04 (e.g., a p-diamond regrown layer) on the surface of the drift layer 02 (e.g., a p-diamond drift layer) in the Schottky contact region. Specifically, using MPCVD, at 950°C, 15 kPa, 2000 W, 500 sccm of CH 4 :H 2 :O 2 (10:1000:3) mixed gas, growth for 0.2h, prepared a p-diamond regrowth layer with a thickness of 700nm. And in 15kPa environment, using Cr 2 O 3 As an abrasive, CMP is performed for 0.5 h, so that the p-diamond regrown layer and the surface of the first dielectric layer 03 are located at the same level. Figure 9f shown.

[0112] Step 8, separating the device body portion up to step 7 from a portion of the substrate 01 (eg, a diamond substrate), such as Figure 9g As shown. Specifically, a femtosecond laser is used to focus the laser inside the diamond substrate, and the laser is continuously scanned line by line to convert the diamond phase at the scanning path into a graphite phase. The graphite phase is then removed by electrochemical etching technology to achieve separation. Removing a portion of the thickness of the diamond substrate in this way will not damage the main part of the device up to step 7, and the removed high-quality diamond substrate can also be used to continue to prepare the device, thereby effectively reducing costs.

[0113] Step 9, transferring the device to a low-cost transfer substrate 09 such as a silicon substrate, Figure 9hAs shown in FIG. 1 , the transfer substrate 09 can reduce the cost and, together with the retained diamond substrate, play a stable supporting role. Specifically, taking the silicon substrate as an example, in the case of 5×10 -7 The surfaces of the diamond substrate and the silicon substrate to be bonded were activated by Ar atomic beam irradiation at 1.5 kV and 1.5 mA under the condition of 1.5 GPa. After the surface activation, a pressure of 8 GPa was applied at room temperature to bond the diamond and silicon, and the diamond / silicon bonding interface was prepared by SAB.

[0114] Step 10, forming a second dielectric layer 08 on a portion of the upper surface of the first dielectric layer 03, the sidewall of the first dielectric layer 03, the sidewall of the drift layer 02 (e.g., the p-diamond drift layer), and a portion of the edge 61 of the ohmic contact layer 06 (e.g., the p+diamond ohmic contact layer), as shown in FIG. Figure 9i For details, refer to step 6.

[0115] Step 11: convert the surface of the regrown layer 04 (e.g., p-diamond regrown layer) into an oxygen terminal to enhance the Schottky contact effect between the p-diamond regrown layer and the subsequent Schottky electrode 05. Specifically, in an environment with an oxygen pressure of 25 kPa, using an illumination of 50 mW / cm 2 The samples were irradiated with ultraviolet light for 30 min.

[0116] Step 12, preparing an ohmic electrode 07 on the edge portion 61 of the ohmic contact layer 06 (eg, p+ diamond ohmic contact layer) not covered by the second dielectric layer 08, such as Figure 9j Specifically, Ti (20 nm) / Au (300 nm) metals were deposited in sequence by electron beam evaporation and annealed at 700°C for 2 min.

[0117] Step 13, a Schottky electrode 05 is prepared on the upper surface of the regrown layer 04 (eg, diamond regrown layer) not covered by the second dielectric layer 08 and a portion of the first dielectric layer 03, such as Figure 1 Specifically, the Schottky electrode 05 region is defined by photoresist, and 300nm of Au is deposited by electron beam evaporation. Figure 1 Preparation of the Schottky diode shown.

[0118] In some embodiments, in the above-mentioned preparation method provided by the embodiment of the present disclosure, in addition to the above-mentioned solution of adding a transfer substrate 09 in the preparation process of the Schottky diode, the present disclosure can also provide a transfer substrate 09 before preparing each film layer of the Schottky diode. Specifically, Fig.10As shown, after performing step S601 to provide a substrate (e.g., a diamond substrate), and before performing step S701 to form a p-diamond drift layer on the diamond substrate, step S1001 may be further performed to separate the diamond substrate into at least two parts, and to set a transfer substrate on a side of one of the diamond substrates away from the p-diamond drift layer to be formed.

[0119] In some embodiments, the above step S1001 separates the diamond substrate into at least two parts, and sets a transfer substrate on one side of the diamond substrate away from the p-diamond drift layer to be fabricated, which can be specifically achieved in the following manner:

[0120] implanting ions into a predetermined depth of the diamond substrate;

[0121] epitaxially growing single crystal diamond of a preset thickness on the ion implantation surface of the diamond substrate;

[0122] Separating a diamond substrate of a preset depth from the ion implantation layer by electrochemical etching;

[0123] Depositing a first silicon carbide layer on a surface of the diamond substrate at a preset depth away from the single crystal diamond, and depositing a second silicon carbide layer on a surface of the transfer substrate to be bonded to the diamond substrate;

[0124] The surfaces to be bonded of the first silicon carbide layer and the second silicon carbide layer are activated, and the activated surface of the first silicon carbide layer and the activated surface of the second silicon carbide layer are bonded.

[0125] Specifically, Fig.11a As shown, the ion implantation technique can be used to implant C ions into the substrate 01 (e.g., diamond substrate) at a depth of about 1.6 μm from the surface at an acceleration of 3 MeV. The ion implantation dose is 2×10 16 cm -2 Then, using MPCVD at 1130°C, 24 kPa, and 1800 W, 600 sccm of CH 4 :H 2 :N 2 (100:1000:1) mixed gas, growth for 2 hours, epitaxial growth of single crystal diamond with a thickness of 100 μm on the ion implantation surface. Electrochemical etching is used to separate the surface and interior of the substrate 01 (eg diamond substrate) from the ion implantation layer.

[0126] Then, if Fig.11b As shown, the surface of the separated substrate 01 (e.g., a diamond substrate) is partially transferred to a low-cost transfer substrate 09 such as a polycrystalline diamond substrate. Specifically, a SiC layer with a thickness of 15 nm is deposited on the polycrystalline diamond substrate and the separated diamond bonding surface by radio frequency sputtering.-7 The polycrystalline diamond substrate and the exfoliated diamond bonding surface were activated by Ar atomic beam irradiation at 1.5 kV and 1.5 mA under the condition of 1.5 GPa. After surface activation, a pressure of 8 GPa was applied at room temperature to bond the single crystal to the polycrystalline diamond.

[0127] After the substrate transfer is completed, a Schottky diode is prepared on the surface of the substrate 01 (eg, diamond substrate) away from the transfer substrate 09. The specific preparation steps are the same as the above steps 2 to 7 and steps 10 to 13, and are not described here.

[0128] In some embodiments, in the above-mentioned preparation method provided in the embodiments of the present disclosure, the substrate may also be a silicon carbide substrate, such as Fig.12 As shown, the above step S602 forms a drift layer, a first dielectric layer and a regrown layer on the substrate, which can also be implemented in the following manner:

[0129] S1201, forming an n-silicon carbide drift layer and an n-silicon carbide regrown layer integrally arranged on a silicon carbide substrate, wherein the n-silicon carbide regrown layer is located on a side of the n-silicon carbide drift layer away from the silicon carbide substrate;

[0130] S1202. Form a first dielectric layer on a side of the n-silicon carbide drift layer away from the silicon carbide substrate, wherein the first dielectric layer includes a groove running through the thickness of the n-silicon carbide regrown layer, and a surface of the first dielectric layer away from the silicon carbide substrate is coplanar with a surface of the n-silicon carbide regrown layer away from the silicon carbide substrate.

[0131] The following takes the silicon carbide Schottky diode as an example. Figure 1 The preparation process of the Schottky diode shown is described in detail.

[0132] Step 1: Select a single crystal silicon carbide substrate as substrate 01 and clean the surface of the silicon carbide substrate 01.

[0133] Step 2, such as Figure 9a As shown, the doping concentration of epitaxial growth on substrate 01 (such as a single crystal silicon carbide substrate) is The ohmic contact layer 06 (eg, n+ silicon carbide ohmic contact layer) has a thickness of 10 μm.

[0134] Step 3, such as Figure 9b As shown, the epitaxial growth doping concentration on the surface of the ohmic contact layer 06 (eg, n+ silicon carbide ohmic contact layer) is The drift layer 02 (eg, an n-silicon carbide drift layer) has a thickness of 30 μm.

[0135] Step 4, such as Fig.13As shown, the drift layer 02 (eg, an n-silicon carbide drift layer) and the ohmic contact layer 06 (eg, an n+ silicon carbide ohmic contact layer) are etched.

[0136] Next, prepare the first dielectric layer:

[0137] Step 5, such as Fig.14 As shown, the drift layer 02 (e.g., n-silicon carbide drift layer) for the first dielectric layer 03 to be deposited is etched to form a regrown layer 04 (e.g., n-silicon carbide regrown layer). Specifically, a pre-reserved area is defined on the surface of the drift layer 02 (e.g., n-silicon carbide drift layer) using photoresist, and a layer of metal Ni with a thickness of 100 mm is deposited on the drift layer 02 (e.g., n-silicon carbide drift layer) using electron beam evaporation. Silicon carbide is etched using ICP, and the etching gas is selected as , ICP power is 600W, etching for 10 minutes.

[0138] Step 6, such as Figure 9f As shown, a first dielectric layer 03 is deposited on the etched area of ​​the drift layer 02 (e.g., n-silicon carbide drift layer). Specifically, with the photoresist used as a mask in the previous step, PECVD is used at 300°C, 190W, and 50Pa, and 100sccm of The mixed gas was deposited for 1.5 hours to prepare a first dielectric layer 03 with a thickness of 1.5 μm.

[0139] At this point, the first dielectric layer has been prepared. It should be noted that the cost of the silicon carbide substrate itself is relatively low, so the silicon carbide Schottky diode disclosed in the present invention may not be provided with a transfer substrate 09. If a transfer substrate 09 is provided, reference may be made to steps 8 and 9 of the above-mentioned diamond Schottky diode, which will not be described in detail here. In addition, the implementation method of the second dielectric layer 08 is the same as step 10 of the above-mentioned diamond Schottky diode, which will not be described in detail here.

[0140] Electrode Steps:

[0141] Step 7, such as Figure 9j As shown, an ohmic electrode 07 is prepared on the edge 61 of the ohmic contact layer 06 (eg, n+ silicon carbide ohmic contact layer) not covered by the second dielectric layer 08. Specifically, metal Ni (200 nm) is deposited as the ohmic electrode by electron beam evaporation and RTP annealing is performed at 900°C.

[0142] Step 8, such as Figure 1As shown, Schottky electrodes are prepared on the upper surfaces of the regrown layer 04 (e.g., n-silicon carbide regrown layer), part of the first dielectric layer 03, and part of the second dielectric layer 08. Specifically, Mo-C alloy (150nm) and Au (200nm) are sequentially deposited as Schottky metals by radio frequency sputtering.

[0143] In some embodiments, Figure 2 The preparation process of the silicon carbide Schottky diode shown in Figure 1 The manufacturing steps 1, 3, 6 and 8 of the silicon carbide Schottky diode are shown, and an ohmic electrode 07 is adaptively prepared on a side of the silicon carbide substrate away from the n-silicon carbide drift layer.

[0144] It should be noted that in the above-mentioned preparation method provided in the embodiment of the present disclosure, the patterning process involved in forming each layer structure may include not only part or all of the process such as deposition, photoresist coating, mask template masking, exposure, development, etching, photoresist stripping, etc., but also other process, which is subject to the graphics of the required composition formed in the actual production process, and is not limited here. For example, a post-baking process may also be included after development and before etching. Among them, the deposition process may be chemical vapor deposition, plasma enhanced chemical vapor deposition or physical vapor deposition, which is not limited here; the mask used in the mask process may be a half-tone mask (Half Tone Mask), a single slit diffraction mask (Single Slit Mask) or a gray tone mask (Gray Tone Mask), which is not limited here; etching may be dry etching or wet etching, which is not limited here.

[0145] Based on the same inventive concept, the present disclosure also provides an electronic device, such as Fig.15 As shown, it includes the above-mentioned Schottky diode 001 provided in the embodiment of the present disclosure. The Schottky diode 001 can be used in electronic devices for high-frequency rectification, microwave communication, and high-speed logic control, etc. Since the principle of solving the problem by the electronic device is similar to the principle of solving the problem by the above-mentioned Schottky diode, the implementation of the electronic device provided in the embodiment of the present disclosure can refer to the implementation of the above-mentioned Schottky diode provided in the embodiment of the present disclosure, and the repeated parts will not be repeated.

[0146] Obviously, those skilled in the art can make various changes and modifications to the present disclosure without departing from the spirit and scope of the present disclosure. Thus, if these modifications and variations of the present disclosure fall within the scope of the claims of the present disclosure and their equivalents, the present disclosure is also intended to include these modifications and variations.

Claims

1. A Schottky diode, characterized in that: include: substrate; A drift layer, located on one side of the substrate; A first dielectric layer, located on a side of the drift layer away from the substrate, the first dielectric layer comprising a groove running through the thickness thereof; a regrown layer, located in the groove, wherein a surface of the regrown layer away from the substrate is coplanar with a surface of the first dielectric layer away from the substrate; A Schottky electrode, located on a side of the regrown layer and the first dielectric layer away from the substrate; a second dielectric layer, the second dielectric layer being stacked with a portion of the first dielectric layer; The Schottky electrode covers a portion of the first dielectric layer and a portion of the second dielectric layer.

2. The Schottky diode according to claim 1, characterized in that: The second dielectric layer covers the sidewalls of the first dielectric layer and the sidewalls of the drift layer.

3. The Schottky diode according to claim 1, characterized in that: It also includes an ohmic contact layer and an ohmic electrode; wherein, The ohmic contact layer is located on a side of the substrate facing the drift layer. The ohmic contact layer includes an edge portion that does not overlap with the drift layer. The ohmic electrode is electrically connected to the ohmic contact layer at the edge portion.

4. The Schottky diode according to claim 3, characterized in that: The second dielectric layer covers a portion of the edge portion.

5. The Schottky diode according to claim 3, characterized in that: The substrate is a diamond substrate, the drift layer is a p-diamond drift layer, the regrown layer is a p-diamond regrown layer, and the ohmic contact layer is a p+ diamond ohmic contact layer.

6. The Schottky diode according to claim 3, characterized in that: The ohmic contact layer is an n+ silicon carbide ohmic contact layer.

7. The Schottky diode according to claim 1, characterized in that: The invention also includes an ohmic electrode located at a side of the substrate away from the drift layer.

8. The Schottky diode according to claim 6 or 7, characterized in that: The substrate is a silicon carbide substrate, the drift layer is an n-silicon carbide drift layer, and the regrown layer is an n-silicon carbide regrown layer.

9. The Schottky diode according to any one of claims 1 to 6, characterized in that: The invention also includes a transfer substrate located at a side of the substrate away from the drift layer.

10. A method for preparing a Schottky diode according to any one of claims 1 to 9, characterized in that: include: providing a substrate; forming a drift layer, a first dielectric layer and a regrown layer on the substrate, wherein the first dielectric layer is located on a side of the drift layer away from the substrate, the first dielectric layer includes a groove running through the thickness thereof, the regrown layer is located in the groove, and a surface of the regrown layer away from the substrate is coplanar with a surface of the first dielectric layer away from the substrate; A Schottky electrode is formed on a side of the regrown layer and the first dielectric layer away from the substrate.

11. The preparation method according to claim 10, characterized in that: The substrate is a diamond substrate, and a drift layer, a first dielectric layer and a regrown layer are formed on the substrate, specifically comprising: forming a p-diamond drift layer on the diamond substrate; forming a first dielectric layer on a side of the p-diamond drift layer away from the diamond substrate, wherein the first dielectric layer includes a groove running through the thickness thereof; A p-diamond regrown layer is formed in the groove, and a surface of the p-diamond regrown layer away from the diamond substrate is coplanar with a surface of the first dielectric layer away from the diamond substrate.

12. The preparation method according to claim 11, characterized in that: After forming a p-diamond regrown layer in the groove and making the surface of the p-diamond regrown layer away from the diamond substrate coplanar with the surface of the first dielectric layer away from the diamond substrate, and before forming a Schottky electrode on the regrown layer and the first dielectric layer away from the substrate, the method further includes: A partial thickness of the diamond substrate is removed, and a transfer substrate is disposed on a side of the remaining diamond substrate away from the p-diamond drift layer.

13. The preparation method according to claim 12, characterized in that: Removing a portion of the thickness of the diamond substrate and arranging a transfer substrate on a side of the remaining diamond substrate away from the p-diamond drift layer specifically includes: Using a femtosecond laser, focusing the laser on the inside of the diamond substrate, scanning continuously line by line, converting the phase on the scanning path into a graphite phase, and removing the graphite phase using an electrochemical etching technique; The thinned surface of the diamond substrate away from the p-diamond drift layer and the surface of the transfer substrate to be combined with the diamond substrate are activated, and the activated surface of the diamond substrate and the activated surface of the transfer substrate are bonded.

14. The preparation method according to claim 11, characterized in that: After providing a substrate and before forming a p-diamond drift layer on the diamond substrate, the method further includes: The diamond substrate is separated into at least two parts, and a transfer substrate is arranged on a side of one of the diamond substrates away from a p-diamond drift layer to be fabricated.

15. The preparation method according to claim 14, characterized in that: The diamond substrate is separated into at least two parts, and a transfer substrate is arranged on a side of the diamond substrate away from the p-diamond drift layer to be fabricated, specifically comprising: Implanting ions to a predetermined depth of the diamond substrate; epitaxially growing single crystal diamond of a preset thickness on the ion implantation surface of the diamond substrate; Separating the diamond substrate of the preset depth from the ion implantation layer by electrochemical etching; Depositing a first silicon carbide layer on a surface of the diamond substrate at the preset depth that is away from the single crystal diamond, and depositing a second silicon carbide layer on a surface of a transfer substrate to be bonded to the diamond substrate; Activate the surfaces of the first silicon carbide layer and the second silicon carbide layer to be bonded, and bond the activated surface of the first silicon carbide layer and the activated surface of the second silicon carbide layer.

16. The preparation method according to claim 10, characterized in that: The substrate is a silicon carbide substrate, and a drift layer, a first dielectric layer and a regrown layer are formed on the substrate, specifically comprising: forming an integrated n-silicon carbide drift layer and an n-silicon carbide regrown layer on the silicon carbide substrate, wherein the n-silicon carbide regrown layer is located on a side of the n-silicon carbide drift layer away from the silicon carbide substrate; A first dielectric layer is formed on a side of the n-silicon carbide drift layer away from the silicon carbide substrate, the first dielectric layer includes a groove running through the thickness of the n-silicon carbide regrown layer, and a surface of the first dielectric layer away from the silicon carbide substrate is coplanar with a surface of the n-silicon carbide regrown layer away from the silicon carbide substrate.

17. An electronic device, characterized in that: Comprising the Schottky diode as described in any one of claims 1 to 9.

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