Silicon carbide diode, power module, power conversion circuit, and vehicle

Abstract

The invention discloses a silicon carbide diode, a power module, a power conversion circuit and a vehicle, and belongs to the technical field of semiconductors. The silicon carbide diode includes a first electrode, a first conductivity type layer, and a second electrode. The first conductive type layer is arranged on the first electrode, the first conductive type layer comprises a first surface far away from the first electrode, the first surface is provided with a groove, the first conductive type layer further comprises a second conductive type region, the second conductive type region is arranged on the side wall and the bottom of the groove, and the second electrode is arranged in the groove. And the second conductive type region is covered. According to the technical scheme, the forward conduction capability of the silicon carbide diode is improved while the reverse voltage resistance of the silicon carbide diode is improved, so that the overall performance of the silicon carbide diode is improved.

Description

Technical Field

[0001] The present application belongs to the field of semiconductor technology, and in particular relates to a silicon carbide diode, a power module, a power conversion circuit, and a vehicle. Background Art

[0002] Silicon carbide diodes play a vital role in the field of semiconductor technology. Existing silicon carbide diode products are mainly junction barrier Schottky diodes (JBS) and merged PIN Schottky diodes (MPS). The manufacturing process of these two types of silicon carbide diodes usually forms a PN junction by injecting P-type ions into the surface of the N-type epitaxial layer, thereby reducing reverse leakage current and enhancing reverse voltage withstand capability. However, since this ion implantation doping method reduces the proportion of the Schottky area in the silicon carbide diode, the forward conduction capability of the silicon carbide diode will also decrease.

[0003] Based on this, how to improve the reverse voltage resistance of silicon carbide diodes while also enhancing their forward conduction capability has become an urgent problem to be solved in this field. Summary of the invention

[0004] The present application proposes a silicon carbide diode and a method for preparing the same, aiming to improve the reverse voltage withstand capability and forward conduction capability of the silicon carbide diode.

[0005] In a first aspect, an embodiment of the present application provides a silicon carbide diode, comprising a first electrode, a first conductive type layer, and a second electrode. The first conductive type layer is disposed on the first electrode, the first conductive type layer comprises a first surface away from the first electrode, the first surface is provided with a groove, and the first conductive type layer further comprises a second conductive type region, the second conductive type region is disposed on the sidewall and bottom of the groove, and the second electrode is disposed in the groove and covers the groove and the first surface of the first conductive type layer.

[0006] In the embodiment of the present application, a groove is provided on the first surface of the first conductive type layer of the silicon carbide diode, and a second conductive type region is provided on the sidewall and bottom of the groove, thereby increasing the actual effective area of ​​the PN junction formed by the second conductive type region and the first conductive type layer. By utilizing two-dimensional carrier depletion to realize charge coupling, the surface electric field can be introduced into a deeper depth in the epitaxial layer, thereby reducing the surface electric field of the silicon carbide diode, thereby weakening the Schottky barrier lowering effect, reducing the leakage current, and achieving a higher breakdown voltage, thereby improving the reverse withstand voltage performance of the silicon carbide diode.

[0007] In addition, the setting of the trench also improves the shielding efficiency of the PN junction depletion region and increases the actual effective area of ​​the PN junction. With the same area, the proportion of the forward Schottky region can be increased, thereby obtaining a higher forward conduction current density and better forward conduction capability.

[0008] In some embodiments, the second conductive type region includes a first conductive portion and a second conductive portion, the first conductive portion is located on the side wall of the trench, the second conductive portion is located at the bottom of the trench, and the distance from the side of the first conductive portion away from the first surface to the first surface is smaller than the distance from the side of the second conductive portion away from the first surface to the first surface.

[0009] In some embodiments, along the direction from the first electrode to the second electrode, the junction depth of the first conductive portion ranges from 0.4 micrometers to 1 micrometer, and the junction depth of the second conductive portion ranges from 0.1 micrometers to 0.5 micrometers.

[0010] In some embodiments, the sidewall of the trench has at least one step, and the second conductive type region is located on a surface of the at least one step.

[0011] In a second aspect, an embodiment of the present application also provides a method for preparing a silicon carbide diode, the method comprising: forming a first conductive type layer, the first conductive type layer comprising a first surface and a second surface relative to each other; forming a groove on the first surface; forming a second conductive type region, the second conductive type region being located at the sidewall and bottom of the groove; forming a second electrode, the second electrode being located in the groove and covering the second conductive type region; and forming a first electrode on the second surface.

[0012] In the embodiment of the present application, during the preparation process of the silicon carbide diode, a groove is formed on the first surface of the first conductive type layer, and a second conductive type region is formed on the sidewall and bottom of the groove, thereby increasing the actual effective area of ​​the PN junction formed by the second conductive type region and the first conductive type layer. By utilizing two-dimensional carrier depletion to achieve charge coupling, the surface electric field can be introduced into a deeper depth within the epitaxial layer, thereby reducing the surface electric field of the silicon carbide diode, thereby weakening the Schottky barrier lowering effect, reducing the leakage current, and achieving a higher breakdown voltage, thereby improving the reverse withstand voltage performance of the silicon carbide diode.

[0013] In addition, the formed grooves also improve the shielding efficiency of the PN junction depletion region and increase the actual effective area of ​​the PN junction. With the same area, the proportion of the forward Schottky region can be increased, thereby obtaining a higher forward conduction current density and better forward conduction capability, thereby improving the overall performance of the silicon carbide diode formed in this preparation process.

[0014] In some embodiments, before forming the groove, the above-mentioned preparation method also includes: forming a first mask layer on the first surface, the first mask layer having a first opening, performing a first ion implantation on the first conductive type layer through the first opening to form a first conductive portion in the first conductive type layer, forming a side wall on the side wall of the first opening, and forming a second opening on the inner side of the side wall.

[0015] The step of forming the groove is: etching the first conductive type layer through the second opening to form the groove, wherein the depth of the groove is less than or equal to the depth of the first ion implantation.

[0016] In some embodiments, the step of forming the second conductive type region is: performing a second ion implantation on the first conductive type layer through the second opening to form a second conductive portion at the bottom of the groove, wherein, compared to the first surface, the depth of the second ion implantation is greater than the depth of the first ion implantation, and the first conductive portion and the second conductive portion form a second conductive type region.

[0017] On the other hand, a power module is provided. The power module includes a substrate and a silicon carbide diode as described in any one of the above embodiments. The substrate is used for supporting the silicon carbide diode.

[0018] In another aspect, a power conversion circuit is provided, which is used for one or more of current conversion, voltage conversion, and power factor correction. The power conversion circuit includes a circuit board and a silicon carbide diode as described in any of the above embodiments, and the silicon carbide diode is electrically connected to the circuit board.

[0019] On the other hand, a vehicle is provided, which includes a load and a power conversion circuit as described in the above embodiment, 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.

[0020] The above-mentioned power module, power conversion circuit and vehicle have the same structure and beneficial technical effects as the silicon carbide diode provided in some of the above-mentioned embodiments, which will not be repeated here.

[0021] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0023] Figure 1 A schematic diagram of the structure of a silicon carbide diode provided in an embodiment of the present application;

[0024] Figure 2 A schematic diagram of the structure of another silicon carbide diode provided in an embodiment of the present application;

[0025] Figure 3 A schematic diagram of the process of preparing a silicon carbide diode in an embodiment of the present application;

[0026] Figures 4 to 12 A diagram showing the steps of preparing a silicon carbide diode in an embodiment of the present application;

[0027] Fig.13 A structural diagram of a power module provided in an embodiment of the present application;

[0028] Fig.14 A structural diagram of a power conversion circuit provided in an embodiment of the present application;

[0029] Fig.15 A structural diagram of a vehicle provided in an embodiment of the present application. DETAILED DESCRIPTION

[0030] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

[0031] The terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here, and the objects distinguished by "first", "second", etc. are generally of one type, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally indicates that the objects associated with each other are in an "or" relationship.

[0032] In the description of the present application, “plurality” means two or more.

[0033] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0034] The present application embodiment provides a silicon carbide diode, Figure 1 A schematic diagram of the structure of a silicon carbide diode provided in an embodiment of the present application is shown in FIG. Figure 1 As shown, the silicon carbide diode 1 includes a first electrode 10, a first conductive type layer 11 and a second electrode 14. The first conductive type layer 11 is arranged on the first electrode 10, and the first conductive type layer 11 includes a silicon carbide substrate 110 and an epitaxial layer 111 arranged in sequence, the first conductive type layer 11 includes a first surface 113 away from the first electrode 10, that is, the epitaxial layer 111 is away from the first surface 113 of the first electrode 10, the first surface 113 is provided with a groove 12, and the first conductive type layer 11 also includes a second conductive type region 13, the second conductive type region 13 is arranged on the sidewall and bottom of the groove 12, and the second electrode 14 is arranged in the groove 12, and covers the groove 12 and the first surface 113 of the first conductive type layer 11. The second electrode 14 is in Schottky contact with the first surface 113, so the second electrode 14 is also called a Schottky electrode.

[0035] In an embodiment of the present application, the first conductive type layer 11 and the second conductive type region 13 are type layers composed of different ion types. Exemplarily, the first conductive type layer 11 may be an N-type layer, and the second conductive type region 13 may be a P-type layer. P-type ions are implanted on the surface 113 of the first conductive type layer 11 to form the second conductive type region 13, so that a PN junction is formed in the contact area between the first conductive type layer 11 and the second conductive type region 13.

[0036] Due to the presence of the groove 12, charge coupling is achieved by utilizing two-dimensional carrier depletion, and the surface electric field can be introduced into a deeper depth in the epitaxial layer 111, so that the surface electric field of the silicon carbide diode 1 is reduced, thereby weakening the Schottky barrier lowering effect and reducing the leakage current to achieve a higher breakdown voltage, thereby improving the reverse withstand voltage performance of the silicon carbide diode 1.

[0037] Furthermore, the provision of the groove 12 also improves the shielding efficiency of the PN junction depletion region, increases the actual effective area of ​​the PN junction, and can increase the proportion of the forward Schottky region under the condition of the same area, thereby obtaining a higher forward conduction current density and better forward conduction capability.

[0038] In some embodiments, Figure 1 As shown, the second conductive type region 13 includes a first conductive portion 131 and a second conductive portion 132, the first conductive portion 131 is located on the side wall of the groove 12, and the second conductive portion 132 is located at the bottom of the groove 12, and the distance from the side of the first conductive portion 131 away from the first surface 113 to the first surface 113 is smaller than the distance from the side of the second conductive portion 132 away from the first surface 113 to the first surface 113, that is, taking the first surface 113 as a reference plane, the second conductive portion 132 is at least partially located below the first conductive portion 131 to increase the depth of the PN junction formed by the second conductive type region 13 and the first conductive type layer 11, so that a PN depletion region (shielding region) is formed when the silicon carbide diode 1 is reversed, and this depletion region can effectively disperse the electric field and reduce the risk of breakdown caused by excessive local electric field strength, thereby improving the reverse withstand voltage characteristics of the silicon carbide diode 1.

[0039] In some embodiments, Figure 1 As shown, along the Z direction from the first electrode 10 to the second electrode 14, the junction depth of the first conductive portion 131 ranges from 0.4 micrometers to 1.5 micrometers, for example, the junction depth of the first conductive portion 131 is 0.4 micrometers, 0.5 micrometers, 0.7 micrometers, 0.9 micrometers or 1 micrometer. The junction depth of the second conductive portion 132 ranges from 0.1 micrometers to 0.5 micrometers, for example, the junction depth of the second conductive portion 132 is 0.1 micrometers, 0.2 micrometers, 0.3 micrometers, 0.4 micrometers or 0.5 micrometers. By adjusting the junction depths of the first conductive portion 131 and the second conductive portion 132, the junction depth of the second conductive type region 13 can be adjusted, thereby adjusting the junction depth of the PN junction formed by the second conductive type region 13 and the first conductive type layer 11.

[0040] Figure 2 A schematic diagram of the structure of another silicon carbide diode provided in an embodiment of the present application.

[0041] In some embodiments, Figure 2 As shown, the side wall of the groove 12 has at least one step 121, and the second conductive type region 13 is located on the surface of at least one step 121. For example, when the side wall of the groove 12 has two steps, the second conductive type region 13 is located at the bottom of the groove 12 and the surface of the side wall having the two steps 121, forming a silicon carbide diode 1 with a multi-level trench structure.

[0042] The silicon carbide diode 1 with the multi-level trench structure has a larger contact area between the first conductive type layer 11 and the second conductive type region 13, and a larger contact area between the first surface 113 and the second electrode 14, so that the reverse withstand voltage capability and forward conduction capability of the silicon carbide diode 1 are more significantly improved. In addition, the setting of the multi-level trench can further reduce the electric field strength at the corner of the bottom of the trench and improve the structural reliability.

[0043] The present application also provides a method for preparing a silicon carbide diode 1. Figure 3 Schematic diagram of the process of preparing a silicon carbide diode in an embodiment of the present application. Figures 4 to 12 1 is a diagram of the steps for preparing a silicon carbide diode in an embodiment of the present application. Figure 3 As shown, the method includes the following steps S301 to S305:

[0044] Step S301: Figure 4 As shown, a first conductive type layer 11 is formed, and the first conductive type layer 11 includes a first surface 113 and a second surface 114 relative to each other. Specifically, an epitaxial layer 111 is formed on a silicon carbide substrate 110, and the silicon carbide substrate 110 and the epitaxial layer 111 together constitute the first conductive type layer 11. Exemplarily, an epitaxial layer 111 having the same ion type as the silicon carbide substrate 110 can be formed on the silicon carbide substrate 110 by chemical vapor deposition, and the ion type can be N-type.

[0045] Step S302: Figures 5 to 9 The steps for forming the groove 12 are shown in FIG. Figures 5 to 9 As shown, a groove 12 is formed on the surface 113 of the first conductive type layer 11, and a first conductive portion 131 is formed on the sidewall and bottom of the groove 12. Figure 3 Before forming the groove 12 in step S302, the above preparation method further includes the following steps S401 to S404:

[0046] Step S401: Figure 5 As shown, a first mask layer 15 is formed on the first surface 113 . Exemplarily, the first mask layer 15 may be a silicon oxide mask with a deposition thickness of 1.5 microns to 3 microns. The first mask layer 15 is etched to form a first opening 151 .

[0047] Step S402: Figure 6As shown, the first conductive type layer 11 is subjected to a first ion implantation through the first opening 151 to form a first conductive portion 131 in the first conductive type layer 11. Exemplarily, the ion type implanted in the first ion implantation may be aluminum (Al) or boron (B). The implantation is performed multiple times. The implantation energy ranges from 20Kev to 2000Kev. The implantation depth ranges from 0.4 microns to 1.5 microns, where "Kev" stands for "kiloelectron volts."

[0048] Step S403: Figure 7 As shown, a second mask layer 16 is deposited on the first mask layer 15, and the thickness of the second mask layer 16 is less than the thickness of the first mask layer 15. Exemplarily, the material of the second mask layer 16 can be the same as that of the first mask layer 15, which is also silicon oxide. The deposition thickness of the second mask layer 16 can be 500 angstroms to 2000 angstroms.

[0049] Step S404: Figure 8 As shown, the second mask layer 16 is etched by utilizing the anisotropy of dry etching, and the second mask layer 16 at the bottom of the first opening 151 is etched cleanly, and then a sidewall is formed on the sidewall of the first opening 151, and a second opening 161 is formed inside the sidewall.

[0050] After completing the above steps S401 to S404, Fig. 9 As shown, a groove 12 is formed on the surface 113 of the first conductive type layer 11, and the first conductive type layer 11 is etched through the second opening 161 to form a groove 12, wherein the depth of the groove 12 is less than or equal to the depth of the first ion implantation compared to the first surface 113. Exemplarily, the depth of the etched groove 12 is 0.1 microns to 1.5 microns. The provision of the groove 12 improves the shielding efficiency of the PN junction depletion region in the silicon carbide diode 1, increases the actual effective area of ​​the PN junction, and can increase the proportion of the forward Schottky region under the same area, thereby obtaining a higher forward conduction current density and better forward conduction capability.

[0051] In some embodiments, after completing the primary etching of the above-mentioned trench 12, a silicon oxide mask with a thickness of 500 angstroms to 2000 angstroms can be deposited on the sidewall and bottom of the trench 12 by plasma enhanced chemical vapor deposition (PECVD) or low pressure chemical vapor deposition (LPCVD), and then the silicon oxide at the bottom of the trench 12 is completely etched by dry etching, and the trench 12 is further etched by dry etching to a trench depth of 0.1 microns to 0.2 microns, thereby completing the secondary etching of the trench. After subsequent preparation steps, the following can be formed: Figure 2 The silicon carbide diode 1 shown has a multi-level trench structure.

[0052] In the embodiment of the present application, the process of forming the groove 12 can adopt a self-alignment method, and the self-alignment method can realize that the bottom and sidewalls of the groove 12 are completely surrounded by the second conductive type region 13, reducing the electric field strength of the sidewalls and the bottom of the groove 12, and improving the etching accuracy of the groove 12, thereby improving the reliability of the silicon carbide diode 1. The groove 12 formed by etching in a self-alignment method can further form a sidewall structure by a sidewall (spacer) deposition method, and further etching of the multi-stage groove 12 can be achieved, avoiding multiple photolithography, making the process steps simpler. The self-alignment method can also achieve precise control of the overlap (overlap) of the groove 12 and the second conductive type region 13, and the multi-stage groove structure can further reduce the electric field strength at the bottom corner of the groove 12 compared to the single groove structure, so as to improve the reliability of the silicon carbide diode 1.

[0053] Step S303: Figure 10-11 As shown, in the first conductive type layer 11 , a second conductive type region 13 is formed near a surface 113 of the first conductive type layer 11 , and the second conductive type region 13 is located on the sidewall and bottom of the trench 12 .

[0054] Exemplarily, the process of forming the second conductive type region 13 is as follows: Fig.10 As shown, the first conductive type layer 11 is subjected to a second ion implantation through the second opening 161, thereby forming a second conductive portion 132 at the bottom of the groove 12. The type of ions implanted during the second ion implantation is the same as the type of ions implanted during the first ion implantation. The depth of the second ion implantation is less than the depth of the first ion implantation. Exemplarily, the energy range of the implanted ions in the second ion implantation is 20Kev to 500Kev, and the implantation depth is 0.1 micrometer to 0.5 micrometer. The first conductive portion 131 and the second conductive portion 132 form a second conductive type region 13. Through the second ion implantation, the ion concentration at the bottom of the groove 12 can be further enhanced, and the actual effective area of ​​the PN junction formed by the second conductive type region 13 and the first conductive type layer 11 is increased, that is, charge coupling is achieved by using two-dimensional carrier depletion, and the surface electric field can be introduced into a deeper depth in the epitaxial layer 111, so that the surface electric field of the silicon carbide diode 1 is reduced, thereby weakening the Schottky barrier lowering effect, reducing the leakage current, so as to achieve a higher breakdown voltage, and then improve the reverse withstand voltage performance of the silicon carbide diode 1. The above is completed as shown in FIG. Fig.10 After the second ion implantation step shown, Fig.10 The remaining first mask layer 15 and the second mask layer 16 of the silicon carbide diode 1 are etched away to obtain Fig.11 The silicon carbide diode 1 is shown.

[0055] In some embodiments, Fig.11After the silicon carbide diode 1 is shown, a carbon film can be deposited on the surface 113 of the first conductive type layer 11 with a deposition thickness of 10 nanometers to 1000 nanometers. The silicon carbide diode 1 after the carbon film is deposited is then subjected to a high-temperature activation annealing treatment to smooth the surface 113 of the first conductive type layer 11, thereby improving the overall performance of the final silicon carbide diode 1. The carbon film is removed after the annealing is completed.

[0056] Step S304: Fig.12 As shown, a second electrode 14 is formed as the anode of the silicon carbide diode 1, wherein the second electrode 14 is located in the groove 12 and covers the second conductive type region 13, that is, covers the first conductive portion 131. Exemplarily, the second electrode 14 can be any one of titanium (Ti), titanium nitride (TiN) and aluminum (Al). After the second electrode 14 is formed, the first conductive type layer 11 can be ground and thinned on one side away from the second conductive type region 13, so that the thickness of the silicon carbide substrate 110 is thinned to 50 microns to 200 microns.

[0057] Step S305: forming a first electrode 10, wherein the first electrode 10 is located on a side of the first conductive type layer 11 away from the second conductive type region 13, that is, located on a side of the silicon carbide substrate 110 away from the second conductive type region 13. To form the first electrode 10, it is necessary to first deposit an ohmic metal layer on a side of the silicon carbide substrate 110 away from the second conductive type region 13. Exemplarily, the ohmic metal may be titanium (Ti) or nickel (Ni), and the deposition thickness ranges from 40 nanometers to 200 nanometers. The ohmic metal layer is then annealed, preferably by laser annealing. Next, a back metal layer is deposited on a side of the ohmic metal layer away from the first conductive type layer 11. Exemplarily, the back metal may be titanium (Ti), nickel (Ni), silver (Ag) or aluminum (Al), and the deposition thickness ranges from 1 micrometer to 5 micrometers. The ohmic metal layer and the back metal layer form the first electrode 10, which serves as the cathode of the silicon carbide diode 1. Finally, a structure such as the following is formed. Figure 1 The silicon carbide diode 1 is shown.

[0058] The embodiment of the present application further provides a power module, Fig.13 A structural diagram of a power module provided in an embodiment of the present application.

[0059] See also Fig.13 The power module 2 includes a substrate 21 and the silicon carbide diode 1 in any of the above embodiments, and the substrate 21 is used to support the silicon carbide diode 1.

[0060] Exemplarily, the power module 2 can be used as one of a power amplifier, a power converter, a power controller, a power management module, or a power regulator. The power amplifier is used to amplify the power of an electrical signal. The power converter is used to convert electrical energy from one form to another form. For example, the power converter can be an AC / DC converter or a DC / DC converter. The power controller is used to control the device of power flow. The power management module is used to manage the power supply to ensure that the power is stably and efficiently distributed to different parts of the electronic device. The power regulator is used to adjust the power output to meet the needs of a specific application.

[0061] The embodiment of the present application also provides a power conversion circuit, Fig.14 A structural diagram of a power conversion circuit provided in an embodiment of the present application.

[0062] See also Fig.14 The power conversion circuit 3 includes a circuit board 31 and a silicon carbide diode 1 in any of the above embodiments. The silicon carbide diode 1 is electrically connected to the circuit board 31. The power conversion circuit 3 can be used for current conversion, voltage conversion or power factor correction.

[0063] Exemplarily, the power conversion circuit 3 can be used as one of an AC / DC converter, an AC / AC converter, a DC / DC converter, a DC / AC inverter or a power factor correction (PFC) circuit, wherein the AC / DC converter is used to convert alternating current into direct current, the AC / AC converter is used to convert alternating current into alternating current, the DC / DC converter is used to convert direct current into direct current, the DC / AC inverter is used to convert direct current into alternating current, and the power factor correction circuit is used to improve the power factor of the power supply and reduce the harmonic pollution of the power grid.

[0064] An embodiment of the present application further provides a vehicle, Fig.15 A structural diagram of a vehicle provided in an embodiment of the present application.

[0065] See also Fig.15 The vehicle 4 includes a load 41 and the power conversion circuit 3 in the above embodiment, and the power conversion circuit 3 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 41 to power the load 41.

[0066] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. A silicon carbide diode, characterized in that: include: a first electrode; A first conductive type layer is disposed on one side of the first electrode; the first conductive type layer includes a first surface away from the first electrode, the first surface is provided with a groove; the first conductive type layer also includes a second conductive type region, the second conductive type region is disposed on the sidewall and bottom of the groove; A second electrode is disposed in the groove and covers the groove and the first surface of the first conductive type layer.

2. The silicon carbide diode according to claim 1, characterized in that: The second conductive type region includes a first conductive portion and a second conductive portion; The first conductive portion is located on a sidewall of the trench, and the second conductive portion is located at a bottom of the trench; A distance from a side of the first conductive portion away from the first surface to the first surface is smaller than a distance from a side of the second conductive portion away from the first surface to the first surface.

3. The silicon carbide diode according to claim 2, characterized in that: Along the direction from the first electrode to the second electrode, the junction depth of the first conductive portion ranges from 0.4 micrometers to 1 micrometer, and the junction depth of the second conductive portion ranges from 0.1 micrometers to 0.5 micrometers.

4. The silicon carbide diode according to claim 1, characterized in that: The sidewall of the groove has at least one step; The second conductive type region is located on a surface of the at least one step.

5. A method for preparing a silicon carbide diode, characterized in that: include: forming a first conductive type layer, the first conductive type layer comprising a first surface and a second surface opposite to each other; forming a groove on the first surface; forming a second conductive type region, wherein the second conductive type region is located on the sidewall and bottom of the trench; forming a second electrode, wherein the second electrode is located in the groove and covers the second conductive type region; A first electrode is formed on the second surface.

6. The preparation method according to claim 5, characterized in that: Before forming the groove, the preparation method further comprises: forming a first mask layer on the first surface, wherein the first mask layer has a first opening; Performing a first ion implantation on the first conductive type layer through the first opening to form a first conductive portion in the first conductive type layer; A side wall is formed on a side wall of the first opening, and a second opening is formed inside the side wall; Forming the groove comprises: The first conductive type layer is etched through the second opening to form the trench, wherein the depth of the trench is less than or equal to the depth of the first ion implantation.

7. The preparation method according to claim 6, characterized in that: Forming the second conductive type region includes: Performing a second ion implantation on the first conductive type layer through the second opening to form a second conductive portion at the bottom of the trench; Wherein, compared with the first surface, the depth of the second ion implantation is greater than the depth of the first ion implantation; The first conductive portion and the second conductive portion form the second conductive type region.

8. A power module, characterized in that: include: At least one silicon carbide diode according to any one of claims 1 to 4; A substrate is used to support the silicon carbide diode.

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 silicon carbide diode according to any one of claims 1 to 4, wherein the silicon carbide diode is electrically connected to the circuit board.

10. A vehicle, characterized in that: include: A load and a power conversion circuit as claimed 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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