Silicon carbide power device and preparation method thereof
By setting the obtuse anode angle structure and anchor hole structure in the passivation layer of the silicon carbide power device, the problem of prone to cracking of the passivation layer is solved and the reliability of the device is improved.
Patent Information
- Application Number
- CN202411949876.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-27
- Publication Date
- 2025-04-11
AI Technical Summary
The passivation layer of the silicon carbide power device is prone to cracking, resulting in a decrease in device reliability.
A silicon carbide power device is designed, the anode angle structure of the passivation layer is set at an obtuse angle, and an anchor hole is provided on the top of the front metal layer, so that the passivation layer extends into the anchor hole, thereby increasing the bonding force between the passivation layer and the metal layer.
By reducing the shear stress at the anode angle structure and increasing the bonding force between the passivation layer and the metal layer, the risk of passivation layer cracking is effectively alleviated or eliminated, and the reliability of silicon carbide power devices is improved.
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Figure CN119815845A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of semiconductor technology, and specifically, to a silicon carbide power device and a method for preparing the same. Background Art
[0002] In the booming development of modern power electronics technology, silicon carbide power devices have become the core components of many high-efficiency power conversion applications with their excellent performance advantages. However, the terminal area of silicon carbide power devices is extremely sensitive to the external environment and is easily affected by surface ion contamination, water vapor intrusion, etc., which will seriously inhibit the electrical characteristics of the device. Therefore, it is necessary to set a passivation layer on the surface of the terminal area to ensure the reliability of silicon carbide power devices.
[0003] However, the passivation layer of the current silicon carbide power device is prone to cracking, which reduces the reliability of the silicon carbide power device.
[0004] In view of the shortcomings of the existing methods, the present application proposes a silicon carbide power device and a preparation method thereof, so as to solve the technical problem that the passivation layer of the silicon carbide power device is prone to cracking.
[0005] In a first aspect, an embodiment of the present application provides a silicon carbide power device, including:
[0006] Silicon carbide substrate;
[0007] A front metal layer, disposed on one side of the silicon carbide substrate;
[0008] A passivation layer is arranged on a side of the front metal layer away from the silicon carbide substrate; the passivation layer comprises an anode angle structure for contacting the packaging structure, and the inner angle of the anode angle structure is an obtuse angle.
[0009] Optionally, the front metal layer includes a sidewall structure in contact with the passivation layer, and the sidewall structure includes at least one level of slope.
[0010] Optionally, the slope of at least one level is concave in shape.
[0011] Optionally, the top of the front metal layer includes at least one anchor hole, and the passivation layer extends into the anchor hole.
[0012] Optionally, in a plane parallel to the front metal layer, the anchor hole is ring-shaped; a plurality of the anchor holes are arranged outward in sequence along the center of the front metal layer.
[0013] Optionally, it comprises: an active area and a terminal area arranged at the periphery of the active area;
[0014] The silicon carbide device also includes:
[0015] A silicon carbide epitaxial layer, disposed on a side of the front metal layer close to the silicon carbide substrate;
[0016] a doped region disposed within the top of the silicon carbide epitaxial layer;
[0017] A field oxide layer is arranged on a side of the doped region away from the silicon carbide substrate, and the field oxide layer is located in the terminal region;
[0018] A Schottky contact metal layer is disposed between the doped region and the front metal layer; the Schottky metal layer is located in the active region and extends to the terminal region;
[0019] The back metal layer is arranged on a side of the silicon carbide substrate away from the silicon carbide epitaxial layer.
[0020] In a second aspect, an embodiment of the present application provides a method for preparing a silicon carbide power device based on the first aspect, comprising:
[0021] preparing a front metal layer on one side of the silicon carbide substrate;
[0022] A passivation layer is prepared on a side of the front metal layer away from the silicon carbide substrate, so that the anode angle structure of the passivation layer for contacting with the packaging structure is an obtuse angle.
[0023] Optionally, a front metal layer is prepared on one side of the silicon carbide substrate, comprising:
[0024] preparing an initial front metal layer on one side of the silicon carbide substrate;
[0025] Patterning the initial front metal layer n times to obtain an intermediate metal layer, so that the intermediate metal layer has a slope of n levels, wherein n is a natural integer greater than zero;
[0026] The top of the intermediate metal layer is patterned to obtain a front metal layer, so that the top structure of the front metal layer includes at least one anchor hole.
[0027] Optionally, before preparing the front metal layer on one side of the silicon carbide substrate, the method further includes:
[0028] forming a silicon carbide epitaxial layer on one side of the silicon carbide substrate;
[0029] Patterning and ion implantation are performed on the top of the silicon carbide epitaxial layer to obtain a doped region;
[0030] A field oxide layer is prepared in a terminal region on a side of the silicon carbide epitaxial layer away from the silicon carbide substrate, and then a Schottky contact metal layer is prepared in an active region, so that the Schottky contact metal layer extends to the terminal region.
[0031] Optionally, preparing a field oxide layer in a terminal region on a side of the silicon carbide epitaxial layer away from the silicon carbide substrate comprises:
[0032] Depositing a dielectric layer on a side of the silicon carbide epitaxial layer away from the silicon carbide substrate;
[0033] The dielectric layer located in the terminal area is masked, and the dielectric layer located in the active area is removed to form a field oxide layer.
[0034] The beneficial technical effects brought about by the technical solution provided by the embodiment of the present application include:
[0035] Setting the anode angle structure of the passivation layer to an obtuse angle can reduce the shear stress at the anode angle structure, thereby alleviating or eliminating passivation cracking. The top of the front metal layer includes at least one anchor hole, which can further increase the bonding force between the passivation layer and the front metal layer, thereby helping to reduce the risk of cracking of the passivation layer when the power device is subjected to temperature cycling, temperature shock testing or hot and cold shocks during actual application, and improve the reliability of silicon carbide power devices.
[0036] Additional aspects and advantages of the present application will be partially given in the following description, which will become apparent from the following description, or will be understood through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS
[0037] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:
[0038] Figure 1 A schematic diagram of the structure of a silicon carbide power device provided in an embodiment of the present application;
[0039] Figure 2 A schematic top view of a front metal layer provided in an embodiment of the present application;
[0040] Figure 3 A schematic diagram of a process for preparing a silicon carbide power device provided in an embodiment of the present application;
[0041] Figures 4 to 17 Schematic diagrams of various structures in a method for preparing a silicon carbide power device provided in an embodiment of the present application.
[0042] Description of reference numerals:
[0043] A-active area; B-terminal area;
[0044] 1-Silicon carbide substrate;
[0045] 2-Silicon carbide epitaxial layer;
[0046] 3- doped region;
[0047] 4-field oxide layer;
[0048] 5-Schottky contact metal layer;
[0049] 6-front metal layer; 61-slope; 62-anchor hole;
[0050] 7- passivation layer;
[0051] 8- back metal layer;
[0052] 101-first mask layer; 102-dielectric layer; 103-initial front metal layer; 1031-intermediate metal layer; 104-first etch stop layer; 105-second etch stop layer; 106-second mask layer; DETAILED DESCRIPTION
[0053] The embodiments of the present application are described below in conjunction with the drawings in the present application. It should be understood that the implementation methods described below in conjunction with the drawings are exemplary descriptions for explaining the technical solutions of the embodiments of the present application and do not constitute a limitation on the technical solutions of the embodiments of the present application.
[0054] It will be understood by those skilled in the art that, unless specifically stated, the "said" and "the" used herein may also include plural forms. It should be further understood that the term "including" used in the specification of the present application refers to the presence of the features, integers, steps, operations, elements and / or components, but does not exclude the implementation of other features, information, data, steps, operations, elements, components and / or combinations thereof supported by the present technical field. It should be understood that when we refer to an element as being "connected" or "coupled" to another element, the element may be directly connected or coupled to the other element, or may refer to the connection relationship between the element and the other element established through an intermediate element. In addition, the "connection" or "coupling" used herein may include wireless connection or wireless coupling. The term "and / or" used herein refers to at least one of the items defined by the term, for example, "A and / or B" may be implemented as "A", or as "B", or as "A and B".
[0055] In order to make the objectives, technical solutions and advantages of the present application clearer, the implementation methods of the present application will be further described in detail below with reference to the accompanying drawings.
[0056] The technical solution of the present application and how the technical solution of the present application solves the above-mentioned technical problems are described in detail below with specific embodiments. It should be noted that the following implementation modes can refer to, draw on or combine with each other, and the same terms, similar features and similar implementation steps in different implementation modes will not be described repeatedly.
[0057] The silicon carbide power devices in the present application include silicon carbide power diodes, silicon carbide power MOSFETs, silicon carbide power IGBTs and other silicon carbide power devices.
[0058] The present application embodiment provides a silicon carbide power device, the structural schematic diagram of the silicon carbide power device is as follows Figure 1 As shown, it includes: a silicon carbide substrate 1, a front metal layer 6 and a passivation layer 7. The front metal layer 6 is arranged on one side of the silicon carbide substrate 1. The passivation layer 7 is arranged on the side of the front metal layer 6 away from the silicon carbide substrate 1. The passivation layer 7 includes an anode angle structure for contacting with the packaging structure, and the inner angle of the anode angle structure is an obtuse angle.
[0059] In the related art, silicon carbide power devices are encapsulated by a packaging structure, that is, the packaging structure is arranged on the outer side of the passivation layer. The packaging structure generally uses epoxy molding compound (EMC) and is cured and encapsulated in a high temperature environment. However, because the thermal expansion coefficient of EMC is larger than that of silicon carbide, EMC shrinks more than silicon carbide power devices during cooling; and because the connection between the passivation layer and the packaging structure prevents the relative sliding of the two, shear stress is prone to occur at the contact interface between the passivation layer and the packaging structure. Further analysis shows that most of the shear stress is concentrated at the anode corner structure of the passivation layer. Due to the existence of shear stress, the anode corner structure is prone to passivation cracking. Contaminated ions (such as sodium ions, etc.) and water vapor will enter the terminal area through the crack position and directly affect the electric field distribution in the terminal area. In severe cases, the reverse leakage current of the silicon carbide power device is too large, which may eventually cause the silicon carbide power device to fail.
[0060] In this embodiment, the anode angle structure of the passivation layer 7 is set from a right angle to an obtuse angle, which can reduce the shear stress at the anode angle structure, thereby alleviating or eliminating passivation cracking, which is beneficial to improving the reliability of silicon carbide power devices.
[0061] It should be noted that the silicon carbide substrate 1 may be an N-type substrate, its diameter may be between 4 and 12 inches, its crystal form may be 4H-SiC, its thickness may be 350 um (micrometers), and its doping concentration may be 1e 18 / cm 3 To 1e 20 / cm 3 between.
[0062] Optionally, the front metal layer 6 includes a sidewall structure in contact with the passivation layer 7 , and the sidewall structure includes at least one level of slope 61 .
[0063] In this embodiment, the sidewall structure of the front metal layer 6 includes at least one level of slope 61, that is, the sidewall structure may include one level of slope 61, or two levels of slope 61, or multiple levels of slope 61. For example, Figure 1 As shown, the front metal layer 6 includes two levels of slopes 61. The passivation layer 7 is prepared in accordance with the shape of the front metal layer 6. When the sidewall structure of the front metal layer 6 is provided with at least one level of slope 61, the sidewall structure of the passivation layer 7 is also sloped, which can help the inner angle of the anode angle structure of the passivation layer 7 to form an obtuse angle, thereby reducing the contact shear stress of the anode angle structure of the passivation layer 7.
[0064] Optionally, at least one level of the slope 61 is concave in shape.
[0065] In this embodiment, the slope 61 is concave, which is beneficial to increase the bonding force between the passivation layer 7 and the front metal layer 6, thereby reducing the risk of deformation of the passivation layer 7, enhancing the structural strength, and is beneficial to improving the effectiveness and service life of the silicon carbide power device.
[0066] Alternatively, if Figure 1 As shown, the top of the front metal layer 6 includes at least one anchor hole 62 , and the passivation layer 7 extends into the anchor hole 62 .
[0067] In this embodiment, by extending the passivation layer 7 into the anchor hole 62, the bonding strength between the passivation layer 7 and the front metal layer 6 can be further increased, thereby helping to reduce the risk of cracking of the passivation layer 7 when the power device is subjected to temperature cycling, temperature shock testing or hot and cold shocks during actual application, thereby improving the reliability of the silicon carbide power device.
[0068] Alternatively, if Figure 2 As shown, in a plane parallel to the front metal layer 6, the anchor hole 62 is ring-shaped. A plurality of anchor holes 62 are sequentially arranged outward from the center of the front metal layer 6.
[0069] In this embodiment, the anchor hole 62 is arranged around the center of the front metal layer 6, which can increase the contact area between the passivation layer 7 and the front metal layer 6, thereby further increasing the bonding force between the passivation layer 7 and the front metal layer 6, which is beneficial to reducing the risk of cracking of the passivation layer 7.
[0070] Alternatively, if Figure 1 As shown, the silicon carbide device includes an active area A and a terminal area B arranged at the periphery of the active area A.
[0071] The silicon carbide device further includes: a silicon carbide epitaxial layer 2 , a doped region 3 and a field oxide layer 4 , as well as a Schottky contact metal layer 5 and a back metal layer 8 .
[0072] The silicon carbide epitaxial layer 2 is arranged on the side of the front metal layer close to the silicon carbide substrate 1. The doping region 3 is arranged in the top of the silicon carbide epitaxial layer 2. The field oxide layer 4 is arranged on the side of the doping region 3 away from the silicon carbide substrate 1, and the field oxide layer 4 is located in the terminal area B. The Schottky contact metal layer 5 is arranged between the doping region 3 and the front metal layer 6; the Schottky metal layer 5 is located in the active area A and extends to the terminal area B. The back metal layer 8 is arranged on the side of the silicon carbide substrate 1 away from the silicon carbide epitaxial layer 2.
[0073] In this embodiment, the main body of silicon carbide is formed by the cooperation of the silicon carbide substrate 1 and the silicon carbide epitaxial layer 2, providing a basic structure. The bottom of the silicon carbide power device is protected and supported by the back metal layer 8. The top of the silicon carbide power device is protected by the front metal layer 6. A sealed protection structure is formed by the passivation layer 7 to prevent water vapor and movable ions from entering the terminal area B. The doping region 3 of the terminal area B can be P+ type, and a field oxide layer 4 is provided above the doping region 3 of the terminal area B. The performance of the semiconductor is controlled by the doping region 3 of the terminal area B, and the communication conduction is controlled by the field oxide layer 4.
[0074] The Schottky metal layer 5 is located between the front metal layer 6 and the silicon carbide epitaxial layer 2, thereby forming a "Schottky barrier" between the front metal layer 6 and the silicon carbide epitaxial layer 2, which limits the charge diffusion while also giving it faster switching speed and better high-frequency performance.
[0075] Based on the same inventive concept, the present application embodiment provides a method for preparing a silicon carbide power device, the flow diagram of the method is as follows Figure 3 As shown, the method includes steps S1 and S2. Specifically, as follows:
[0076] S1: preparing a front metal layer 6 on one side of a silicon carbide substrate 1 .
[0077] In this embodiment, the silicon carbide substrate 1 may be an N-type substrate, the diameter of which may be between 4 and 12 inches, the crystal type may be 4H-SiC, the thickness may be 350 um, and the doping concentration may be 1e 18 / cm 3 To 1e 20 / cm 3 between.
[0078] Optionally, step S1 includes:
[0079] An initial front metal layer 103 is prepared on one side of the silicon carbide substrate 1, and the resulting structure is shown in FIG. Fig.10 shown.
[0080] The initial front metal layer 103 is patterned n times to obtain the intermediate metal layer 1031 , so that the intermediate metal layer 1031 has a slope 61 of n levels, wherein n is a natural integer greater than zero.
[0081] The top of the intermediate metal layer 1031 is patterned to obtain the front metal layer 6 , so that the top of the front metal layer 6 includes at least one anchor hole 62 .
[0082] In this embodiment, an initial front metal layer 103 is deposited on both the Schottky contact metal layer 5 and the field oxide layer 4, and this deposition can be performed by sputtering or evaporation. After deposition, a first etching stopper layer 104 can be formed on the initial front metal layer 103 by photolithography transfer pattern, exposing the initial front metal layer 103 to be etched. Then, a first level slope 61 in the sidewall structure is formed by a first photolithography and a first etching. Subsequently, a second etching stopper layer 105 is set on the top of the intermediate metal layer 1031, and then a two-level slope 61 in the sidewall structure is formed by a second photolithography and a second etching. The etching method can be dry etching, wet etching, or a combination of the two methods. The front metal layer 6 can be at least one of Al, Cu, Ag and Au. The thickness of the front metal layer 6 can be between 2-5um.
[0083] It is understandable that after n times of patterning, n levels of slopes 61 can be obtained. The specific number of times required can be determined according to actual conditions and is not limited here.
[0084] A second mask layer 106 is disposed on top of the intermediate metal layer 1031 to expose the anchor hole 62 region, and the anchor hole 62 is formed by etching. The etching method includes at least one of dry etching and wet etching. The depth of the anchor hole 62 can be between 100-1000 nm (nanometers), and the number of the anchor holes 62 can range from one to more. For example, Figure 2 As shown, the number of anchor holes 62 is three.
[0085] S2: preparing a passivation layer 7 on a side of the front metal layer 6 away from the silicon carbide substrate 1 , so that the anode angle structure of the passivation layer 7 for contacting with the packaging structure is an obtuse angle.
[0086] In this embodiment, the passivation layer 7 includes a first structure and a second structure, wherein the first structure includes at least one layer of PSG, SiOxNy, SIPOS, Si3N4, SiO2 and Al2O3. The material of the second structure includes polyimide. The second structure can block contamination ions and water vapor from entering the terminal area B.
[0087] Optionally, before step S1, the preparation method further comprises:
[0088] A silicon carbide epitaxial layer 2 is prepared on one side of a silicon carbide substrate 1, and the obtained structure is as follows Figure 4 shown.
[0089] Patterning and ion implantation are performed on the top of the silicon carbide epitaxial layer 2 to obtain a doped region 3. The obtained structure is as follows: Figure 6 shown.
[0090] A field oxide layer 4 is prepared in the terminal region B on the side of the silicon carbide epitaxial layer 2 away from the silicon carbide substrate 1, and then a Schottky contact metal layer 5 is prepared in the active region A, so that the Schottky contact metal layer 5 extends to the terminal region B. The obtained structure is as follows: Fig. 9 shown.
[0091] In this embodiment, the silicon carbide substrate 1 is subjected to RCA cleaning (industry standard wet cleaning process) to remove contamination before preparing the silicon carbide epitaxial layer 2. The silicon carbide epitaxial layer 2 can be grown on the silicon carbide substrate 1 by chemical vapor deposition or physical vapor deposition. The thickness of the silicon carbide epitaxial layer 2 is not less than 5 nanometers and not more than 30 nanometers. It is understood that the silicon carbide epitaxial layer 2 can be N-type.
[0092] Before preparing the doped region 3, the silicon carbide epitaxial layer 2 needs to be cleaned and etched to mark the position of the doped region 3 (marked), and then a first mask layer 101 is set on the top of the silicon carbide epitaxial layer 2 to expose the area to be doped. The resulting structural schematic diagram is shown in FIG. Figure 5 As shown. The area to be doped is etched and high-temperature ion implanted to form a doped region 3. The doped region 3 can be of P+ type. The shape of the doped region 3 of the active region A can be a strip, square, hexagonal or circular shape. The ion implantation can be one or more ion implantations. The implanted ions are activated by high-temperature annealing or other methods to form the doped region 3 of the terminal region. The first mask layer 101 is then removed by etching and cleaning methods.
[0093] An initial Schottky contact metal layer is deposited on the surface of the silicon carbide epitaxial layer 2 located in the active area A, and then annealed to obtain a Schottky contact metal layer 5. The deposition method includes sputtering or evaporation. The annealing temperature can be between 400-600°C (degrees Celsius), and the annealing time is within 30S-60min (minutes). The Schottky contact metal layer 5 includes at least one of Ti, TiN, Ni, Ag, W, Pt and Mo, and the thickness can be between 50-500nm.
[0094] Optionally, preparing the field oxide layer 4 in the terminal region B on a side of the silicon carbide epitaxial layer 2 away from the silicon carbide substrate 1 includes:
[0095] A dielectric layer 102 is deposited on the side of the silicon carbide epitaxial layer 2 away from the silicon carbide substrate 1, and the resulting structure is as shown in FIG. Figure 7 shown.
[0096] The dielectric layer 102 located in the terminal area B is masked, and the dielectric layer 102 located in the active area A is removed to form a field oxide layer 4. The obtained structure is as follows: Figure 8 shown.
[0097] In this embodiment, the material of the dielectric layer 102 may be silicon dioxide, and silicon dioxide is deposited on the surface of the silicon carbide epitaxial layer 2. A mask layer is provided on the surface of the dielectric layer 102 to expose the dielectric layer 102 located in the active area A to be etched. The dielectric layer 102 located in the active area A is etched to form a field oxide layer 4, and the active area A is exposed.
[0098] Optionally, after step S2 , the preparation method further comprises: preparing a back metal layer 8 on a side of the silicon carbide substrate 1 away from the silicon carbide epitaxial layer 2 .
[0099] In this embodiment, metal can be deposited on the back of the silicon carbide substrate 1 by sputtering or evaporation, and a back metal layer 8 can be formed by laser annealing. Specifically, the back metal layer 8 can be thinned on the back to remove scratches, stains and defects on the back of the silicon carbide substrate 1 and a certain thickness of the silicon carbide substrate 1, which is conducive to optimizing the forward conduction capability of the device. The material of the back metal layer 8 can be at least one of Ti, Ni, Ag, Au and Cu.
[0100] Those skilled in the art will appreciate that the various operations, methods, steps, measures, and schemes in the processes discussed in this application may be alternated, changed, combined, or deleted. Furthermore, other steps, measures, and schemes in the various operations, methods, and processes discussed in this application may also be alternated, changed, rearranged, decomposed, combined, or deleted. Furthermore, steps, measures, and schemes in the related art that are similar to those disclosed in this application may also be alternated, changed, rearranged, decomposed, combined, or deleted.
[0101] In the description of the present application, the directions or positional relationships indicated by words such as "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", and "outside" are based on the exemplary directions or positional relationships shown in the accompanying drawings. They are for the convenience of describing or simplifying the description of the embodiments of the present application, and do not indicate or imply that the referred device or component must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present application.
[0102] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise specified, "plurality" means two or more.
[0103] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.
[0104] In the description of this specification, specific features, structures, materials or characteristics may be combined in an appropriate manner in any one or more embodiments or examples.
[0105] The above is only a partial implementation method of the present application. It should be pointed out that for ordinary technicians in this technical field, without departing from the technical concept of the scheme of the present application, other similar implementation methods based on the technical ideas of the present application are also within the protection scope of the embodiments of the present application.
Claims
1. A silicon carbide power device, characterized in that: include: Silicon carbide substrate; A front metal layer, disposed on one side of the silicon carbide substrate; A passivation layer is arranged on a side of the front metal layer away from the silicon carbide substrate; the passivation layer comprises an anode angle structure for contacting the packaging structure, and the inner angle of the anode angle structure is an obtuse angle.
2. The silicon carbide power device according to claim 1, characterized in that: The front metal layer includes a sidewall structure in contact with the passivation layer, and the sidewall structure includes at least one level of slope.
3. The silicon carbide device according to claim 2, characterized in that: The shape of at least one level of the slope is concave.
4. The silicon carbide device according to any one of claims 1 to 3, characterized in that: The top of the front metal layer includes at least one anchor hole, and the passivation layer extends into the anchor hole.
5. The silicon carbide device according to claim 4, characterized in that: In a plane parallel to the front metal layer, the anchor hole is ring-shaped; a plurality of the anchor holes are sequentially arranged outward along the center of the front metal layer.
6. The silicon carbide device according to claim 1, characterized in that: include: An active region and a terminal region disposed at the periphery of the active region; The silicon carbide device also includes: A silicon carbide epitaxial layer, disposed on a side of the front metal layer close to the silicon carbide substrate; a doped region disposed within the top of the silicon carbide epitaxial layer; A field oxide layer is arranged on a side of the doped region away from the silicon carbide substrate, and the field oxide layer is located in the terminal region; A Schottky contact metal layer is disposed between the doped region and the front metal layer; the Schottky metal layer is located in the active region and extends to the terminal region; The back metal layer is arranged on a side of the silicon carbide substrate away from the silicon carbide epitaxial layer.
7. A method for preparing a silicon carbide power device according to any one of claims 1 to 6, characterized in that: include: preparing a front metal layer on one side of the silicon carbide substrate; A passivation layer is prepared on a side of the front metal layer away from the silicon carbide substrate, so that the anode angle structure of the passivation layer for contacting with the packaging structure is an obtuse angle.
8. The preparation method according to claim 7, characterized in that: A front metal layer is prepared on one side of the silicon carbide substrate, including: preparing an initial front metal layer on one side of the silicon carbide substrate; Patterning the initial front metal layer n times to obtain an intermediate metal layer, so that the intermediate metal layer has a slope of n levels, wherein n is a natural integer greater than zero; The top of the intermediate metal layer is patterned to obtain a front metal layer, so that the top structure of the front metal layer includes at least one anchor hole.
9. The preparation method according to claim 8, characterized in that: Before preparing a front metal layer on one side of the silicon carbide substrate, the method further includes: forming a silicon carbide epitaxial layer on one side of the silicon carbide substrate; Patterning and ion implantation are performed on the top of the silicon carbide epitaxial layer to obtain a doped region; A field oxide layer is prepared in a terminal region on a side of the silicon carbide epitaxial layer away from the silicon carbide substrate, and then a Schottky contact metal layer is prepared in an active region, so that the Schottky contact metal layer extends to the terminal region.
10. The preparation method according to claim 7, characterized in that: Preparing a field oxide layer in a terminal region on a side of the silicon carbide epitaxial layer away from the silicon carbide substrate comprises: Depositing a dielectric layer on a side of the silicon carbide epitaxial layer away from the silicon carbide substrate; The dielectric layer located in the terminal area is masked, and the dielectric layer located in the active area is removed to form a field oxide layer.