A silicon carbide Schottky diode with a trench structure having a junction type P+ protection and a manufacturing method thereof

Abstract

The present invention provides a silicon carbide Schottky diode with a trench structure having junction type P+ protection and a manufacturing method thereof. The diode comprises an electrode metal layer, a Schottky unit, a trench MOS unit and a P+ type protection ring. The present invention provides a sandwich structure consisting of filled conductive polysilicon, an oxide dielectric layer and an insulating polysilicon layer in the trench, maintains the MOS structure of the trench sidewall, and forms a MOS-like parallel plate capacitor structure in the trench, greatly smoothes the electric field distribution at the edge of the main junction when the device is broken down, improves the reverse withstand voltage of the device, and also improves the forward conduction current of the device. In addition, a protection structure consisting of a P+ type protection ring is added at both ends of the trench, which, on the one hand, alleviates the peak electric field at the interface of the outer edge of the trench, and at the same time, the addition of the P+ type protection ring effectively suppresses the influence of the image force on the Schottky barrier, so that the device obtains a lower forward turn-on voltage and reverse leakage current.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor devices, and in particular to a silicon carbide Schottky diode with a trench structure having junction type P+ protection and a manufacturing method thereof. Background Art

[0002] Comparing the characteristics of silicon carbide and silicon materials, the band gap width nearly three times that of silicon and the higher melting point enable silicon carbide materials to adapt to higher operating temperatures. The critical breakdown electric field of silicon carbide is ten times that of silicon, which enables silicon carbide power devices to block higher voltages while ensuring forward conduction capability. The higher electron saturation drift velocity enables SiC power devices to be suitable for thousands of higher operating frequencies. The higher thermal conductivity reduces the thermal resistance of silicon carbide materials, making SiC power devices have stronger heat dissipation capabilities, thereby reducing the requirements for the heat dissipation system.

[0003] 4H-SiC SBD diode (Silicon Carbide Schottky Barrier Diode) is a diode made of a metal-semiconductor junction (Schottky junction) consisting of a low-concentration 4H-SiC drift region and an anode metal contact. Due to the existence of the metal-semiconductor junction, the 4H-SiC SBD diode has the advantages of small forward conduction voltage and large conduction current. In addition, since the 4H-SiC SBD diode is multi-electron conductive, the stored charge in the drift region is very small when forward biased, which significantly reduces the reverse peak current of the device when it is in the reverse recovery state. Therefore, the power loss of the device can be greatly reduced.

[0004] At present, 4H-SiC SBD diodes have been widely used in various low-voltage power electronic circuits. The 4HSiC junction barrier Schottky (JBS) diode adopts the JBS structure. In addition to inheriting the excellent characteristics of the 4H-SiC Schottky barrier diode, it also improves the problem that the 4H-SiC high barrier SBD is difficult to balance the reverse withstand voltage and forward voltage drop. The forward characteristics of the device have the characteristics of a multi-sub device, that is, the JBS device has the forward characteristics of a Schottky diode, but the reverse characteristics have the characteristics of a PiN diode, which not only significantly reduces the reverse leakage current, but also significantly increases the breakdown voltage.

[0005] In order to reduce the reverse leakage current of silicon carbide power semiconductor devices as much as possible, based on the above two reasons for the high reverse leakage current, two methods can be used. One is to reduce the defects on the surface of semiconductor power devices. However, reducing the defects on the surface of the device requires more stringent requirements for the device manufacturing process. The other is to reduce the high electric field of the Schottky interface of the semiconductor power device as much as possible. The commonly used solution currently available is to set a JBS structure or a trench structure in the Schottky area to transfer the high electric field from the Schottky interface to the corner of the P-type ion implantation area. But this is not enough, and a better solution is still needed to shield the high electric field on the surface of the Schottky area. However, compared with traditional silicon carbide Schottky devices, silicon carbide Schottky diodes with trenches may have a very high overshoot voltage during the turn-on process, causing serious degradation of the switching characteristics of the device.

[0006] In the existing technology, the conventional trench structured silicon carbide Schottky diode has a trench filled with conductive polysilicon, which does not have a good buffering capability for current during reverse operation and is prone to breakdown. The spike electric field generated at the outer edge interface of the trench structure will reduce the withstand voltage of the device. Summary of the invention

[0007] The object of the present invention is to provide a silicon carbide Schottky diode with a trench structure having junction P+ protection and a manufacturing method thereof, so as to solve the problems raised in the above-mentioned background technology.

[0008] To achieve the above object, the present invention provides the following technical solutions:

[0009] A silicon carbide Schottky diode with a trench structure having a junction type P+ protection comprises an electrode metal layer, a Schottky unit, a trench MOS unit and a P+ type protection ring, wherein:

[0010] The Schottky unit comprises a substrate layer, an epitaxial layer is arranged above the substrate layer, and at least two trenches are arranged at the upper end of the epitaxial layer;

[0011] The electrode metal layer includes a cathode metal and an anode metal, and the cathode metal covers the bottom of the substrate layer;

[0012] A group of trench MOS units are arranged in each trench, and the trench MOS units include an oxide layer attached to the inner sidewall of the trench, and the trench inside the oxide layer is filled with conductive polysilicon, an oxide dielectric layer and an insulating polysilicon layer from bottom to top in sequence;

[0013] The insulating polysilicon layer is covered with a barrier layer, and the insulating polysilicon layer and the epitaxial layer are interconnected with the anode metal through the barrier layer.

[0014] P+ type guard rings are arranged in the trenches on both sides of the trench MOS unit to reduce the edge electric field peak value below the anode metal, suppress the peak field intensity effect of the trench edge, and increase the breakdown voltage.

[0015] Furthermore, the material of the substrate layer is one of sapphire, silicon, silicon carbide and gallium nitride.

[0016] Furthermore, the material of the oxide dielectric layer is one of zirconium oxide, titanium oxide, magnesium oxide and silicon oxide.

[0017] Furthermore, the insulating polysilicon layer is made of a material selected from silicon oxide and silicon nitride.

[0018] Furthermore, the barrier metal used in the barrier layer is one of nickel, chromium and titanium.

[0019] Furthermore, the P+ type guard ring is formed by injecting Mg ions into the trench, and the P+ type guard ring is in contact with the trench MOS unit, and the distance between the upper part and the barrier layer is 1 to 3 μm.

[0020] Furthermore, the contact between the cathode metal and the bottom of the substrate layer is an ohmic contact.

[0021] The present invention further provides a method for manufacturing a Schottky diode, which is suitable for manufacturing the above-mentioned silicon carbide Schottky diode with a trench structure having a junction type P+ protection, and the specific steps include:

[0022] S1: performing the first oxidation on the epitaxial layer to form a thin film on its surface;

[0023] S2: etching the upper surface of the epitaxial layer to form a groove on the epitaxial layer;

[0024] S3: performing a second oxidation on the epitaxial layer after the trench is formed, so as to form a silicon oxide film on the inner side wall of the trench to form an oxide layer;

[0025] S4: filling the inside of the trench with a conductive polysilicon layer, an oxide dielectric layer, and an insulating polysilicon layer in sequence from bottom to top;

[0026] S5: performing photolithography on both sides of the trench to form a ring pattern, and injecting ions to form a P+ type guard ring;

[0027] S6: performing photolithography on the epitaxial layer to remove the thin film formed by the first oxidation;

[0028] S7: using a sputtering process to sputter a metal layer on the upper end surface of the epitaxial layer to form a barrier layer;

[0029] S8: adhering and connecting the upper end of the substrate layer and the lower end of the epitaxial layer;

[0030] S9: A magnetron sputtering process is used to deposit an anode metal on the barrier layer and a cathode metal on the bottom of the substrate layer.

[0031] Furthermore, the substrate layer and the epitaxial layer are adhered and connected by a defect layer, and the dielectric material of the defect layer is silicon oxide or silicon nitride.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] The present invention provides a sandwich structure consisting of filled conductive polysilicon, an oxide dielectric layer, and an insulating polysilicon layer in the groove, maintains the MOS structure of the groove sidewall, and also forms a MOS-like parallel plate capacitor structure in the groove, which greatly smoothes the electric field distribution at the edge of the main junction when the device breaks down, improves the reverse withstand voltage of the device, and also improves the forward conduction current of the device. In addition, a protection structure consisting of a P+ type guard ring is added at both ends of the groove, which, on the one hand, alleviates the peak electric field at the interface of the outer edge of the groove, and at the same time, due to the addition of the P+ type guard ring, effectively suppresses the influence of the image force on the Schottky barrier, so that the device obtains a lower forward turn-on voltage and reverse leakage current. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0035] Figure 2 It is a schematic diagram of the overall cross-sectional structure of the present invention;

[0036] Figure 3 It is a schematic structural diagram of the trench MOS unit in the present invention;

[0037] Figure 4 It is a structural schematic diagram of a Schottky diode in the prior art;

[0038] Figure 5 Current curves of reverse voltage applied to Schottky diodes of the present invention and the prior art;

[0039] Figure 6 Current curves of the Schottky diodes of the present invention and the prior art when a forward voltage is applied;

[0040] Figure 7 The figure is a schematic diagram of the process of manufacturing the Schottky diode of the present invention.

[0041] In the figure: electrode metal layer 10, cathode metal 11, anode metal 12, Schottky unit 20, substrate layer 21, epitaxial layer 22, trench 23, trench MOS unit 30, oxide layer 31, conductive polysilicon 32, oxide dielectric layer 33, insulating polysilicon layer 34, barrier layer 35, P+ type guard ring 40. DETAILED DESCRIPTION

[0042] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments.

[0043] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the present invention should be understood by people with ordinary skills in the field to which the present invention belongs. The "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words 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. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like 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.

[0044] Example:

[0045] See also Figures 1 to 3 , the present invention provides a technical solution:

[0046] A silicon carbide Schottky diode with a trench structure having a junction type P+ protection comprises an electrode metal layer 10, a Schottky unit 20, a trench MOS unit 30 and a P+ type protection ring 40, wherein:

[0047] The Schottky unit 20 includes a substrate layer 21 , an epitaxial layer 22 is disposed above the substrate layer 21 , and at least two trenches 23 are disposed at the upper end of the epitaxial layer 22 .

[0048] In this embodiment, the material of the substrate layer 21 is one of sapphire, silicon, silicon carbide, and gallium nitride. The main function of the substrate layer 21 is that the substrate layer acts as a buffer layer in the Schottky diode, which can reduce the stress caused by the lattice mismatch between the substrate and the epitaxial layer. It can also provide a path for electron transmission and provide mechanical support and stability for the Schottky diode, protecting the thin film material of the epitaxial layer.

[0049] The electrode metal layer 10 includes a cathode metal 11 and an anode metal 12. The cathode metal 11 covers the bottom of the substrate layer 21. The cathode metal 11 and the anode metal 12 are used for current injection and collection of the Schottky diode. The electrode metal layer of the Schottky diode is used for current injection and collection. The Schottky diode is connected to an external circuit through the electrode metal layer 10, so that current can enter and exit the device. The electrode metal layer acts as a conductive medium, providing a low resistance path to ensure effective injection and collection of current.

[0050] In this embodiment, the contact between the cathode metal 11 and the bottom of the substrate layer 21 is an ohmic contact. In the ohmic contact, the cathode metal 11 can form a good contact with the substrate layer 21, and the current can flow freely between the cathode metal 11 and the substrate layer 21 without significant voltage drop or contact resistance.

[0051] A group of trench MOS units 30 are disposed in each trench 23 , and the trench MOS unit 30 includes an oxide layer 31 attached to the inner side wall of the trench 23 . The thickness of the oxide layer 31 can be determined according to the depth of the trench 23 to be etched. The deeper the depth of the trench 23 , the thicker the oxide layer 31 .

[0052] The groove 23 inside the oxide layer 31 is filled with conductive polysilicon 32, oxide dielectric layer 33 and insulating polysilicon layer 34 from bottom to top. The conductive polysilicon 32, oxide dielectric layer 33 and insulating polysilicon layer 34 form a sandwich structure filled in the groove 23, which maintains the MOS structure of the side wall of the groove 23 and also forms a MOS-like parallel plate capacitor structure inside the groove 23, which greatly smoothes the electric field distribution at the edge of the main junction when the device breaks down, improves the reverse withstand voltage of the device, and also improves the forward conduction current of the device.

[0053] In this embodiment, the material of the oxide dielectric layer 33 is one of zirconium oxide, titanium oxide, magnesium oxide and silicon oxide, the material of the insulating polysilicon layer 34 is one of silicon oxide and silicon nitride, and the conductive polysilicon 32 can be made of polysilicon or polysilicon thin film.

[0054] The insulating polysilicon layer 34 is covered with a barrier layer 35, and the insulating polysilicon layer 34 and the epitaxial layer 22 are interconnected with the anode metal 12 through the barrier layer 35. The barrier height of the barrier layer 35 is relatively low. The Schottky diode in this embodiment has a shorter carrier transmission path and a faster carrier injection and extraction speed, which enables the Schottky diode in this embodiment to achieve faster switching speed and response time. In this embodiment, the barrier metal used in the barrier layer 35 is one of nickel, chromium and titanium.

[0055] P+ type guard rings 40 are arranged in the grooves 23 on both sides of the trench MOS unit 30, which are used to reduce the edge electric field peak below the anode metal 12, suppress the peak field strength effect of the groove edge, and improve the breakdown voltage. The protection structure formed by adding P+ type guard rings 40 at both ends of the groove 23, on the one hand, alleviates the peak electric field at the interface of the outer edge of the groove 23, and at the same time, due to the addition of the P+ type guard ring 40, the influence of the mirror force on the Schottky barrier is effectively suppressed, so that the device obtains a lower forward turn-on voltage and reverse leakage current.

[0056] In this embodiment, the P+ type guard ring 40 is formed by implanting Mg ions into the trench 23 . The P+ type guard ring 40 is in contact with the trench MOS unit 30 , and the distance between the upper portion and the barrier layer 35 is 1 to 3 μm.

[0057] This embodiment uses TCAD software to build Figure 2 and Figure 4 Device structure, applying voltage to cathode metal 11, obtains reverse voltage curve, such as Figure 5 As shown, the breakdown characteristic curves of the Schottky diode in the prior art and the Schottky diode in this embodiment are shown. Figure 5 It can be obtained that the breakdown voltage of the Schottky diode in the prior art is 596V, and the breakdown voltage of the Schottky diode in this embodiment is 808V. It can be seen that the breakdown voltage of the Schottky diode in this embodiment is increased by about 36.6% compared with the existing Schottky diode.

[0058] like Figure 6 As shown, the forward conduction characteristic curves of the Schottky diode in the prior art and the Schottky diode in this embodiment are shown. It can be seen that the forward voltage drop of the Schottky diode in this embodiment is reduced, the on-resistance is improved, and the forward conduction current is increased.

[0059] See also Figure 7 The present invention also provides a method for manufacturing a Schottky diode, which is suitable for manufacturing the above-mentioned silicon carbide Schottky diode with a trench structure having a junction type P+ protection, and the specific steps include:

[0060] S1: performing a first oxidation on the epitaxial layer 22 to form a primary thin film on its surface;

[0061] S2: etching the upper surface of the epitaxial layer 22 to form a groove 23 on the epitaxial layer 22;

[0062] S3: performing a second oxidation on the grooved epitaxial layer 22 to form a silicon oxide film on the inner side wall of the groove 23 to form an oxide layer 31;

[0063] S4: filling the inside of the trench 23 with a conductive polysilicon layer 32, an oxide dielectric layer 33 and an insulating polysilicon layer 34 in sequence from bottom to top;

[0064] S5: performing photolithography on both sides of the trench 23 to form a ring pattern, and injecting ions to form a P+ type guard ring 40;

[0065] S6: performing photolithography on the epitaxial layer 22 to remove the thin film formed by the first oxidation;

[0066] S7: using a sputtering process to sputter a metal layer on the upper end surface of the epitaxial layer 22 to form a barrier layer 35;

[0067] S8: Adhere and connect the upper end of the substrate layer 21 and the lower end of the epitaxial layer 22;

[0068] S9: A magnetron sputtering process is used to deposit the anode metal 12 on the barrier layer 35 and the cathode metal 11 on the bottom of the substrate layer 21.

[0069] In this embodiment, a defect layer is used to adhere and connect the substrate layer 21 and the epitaxial layer 22. The dielectric material of the defect layer is silicon oxide or silicon nitride. The purpose of the defect layer is to reduce the stress and defects caused by the lattice mismatch between the substrate layer 21 and the epitaxial layer 22, and to provide a smooth interface.

[0070] The above embodiments may be implemented in whole or in part by software, hardware, firmware or any other combination thereof. When implemented by software, the above embodiments may be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions or computer programs. When the computer instructions or computer programs are loaded or executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions may be transmitted from one website, computer, server or data center to another website, computer, server or data center by wired (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium may be any available medium that a computer can access or a data storage device such as a server or data center that contains one or more available media sets. The available medium may be a magnetic medium (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium. The semiconductor medium may be a solid-state hard disk.

[0071] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0072] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0073] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division of a waterway underwater terrain change analysis system and method. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0074] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0075] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0076] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application can be essentially or partly embodied in the form of a software product that contributes to the prior art. The computer software product is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM), random access memory (RAM), disk or optical disk, etc., various media that can store program codes.

[0077] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

[0078] Finally: The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A silicon carbide Schottky diode with a trench structure and junction type P+ protection, comprising an electrode metal layer (10), a Schottky unit (20), a trench MOS unit (30) and a P+ type protection ring (40), characterized in that: The Schottky unit (20) comprises a substrate layer (21), an epitaxial layer (22) is arranged above the substrate layer (21), and at least two grooves (23) are arranged at the upper end of the epitaxial layer (22); The electrode metal layer (10) comprises a cathode metal (11) and an anode metal (12), wherein the cathode metal (11) covers the bottom of the substrate layer (21); A group of trench MOS units (30) is disposed in each trench (23), the trench MOS unit (30) comprising an oxide layer (31) attached to the inner side wall of the trench (23), the trench (23) inside the oxide layer (31) being filled with conductive polysilicon (32), an oxide dielectric layer (33) and an insulating polysilicon layer (34) in sequence from bottom to top; The insulating polysilicon layer (34) is covered with a barrier layer (35), and the insulating polysilicon layer (34) and the epitaxial layer (22) are interconnected with the anode metal (12) via the barrier layer (35); P+ type protection rings (40) are provided in the grooves (23) on both sides of the groove MOS unit (30) to reduce the peak value of the edge electric field below the anode metal (12), suppress the peak field intensity effect at the groove edge, and increase the breakdown voltage; The P+ type protection ring (40) is formed by injecting Mg ions into the trench (23); the P+ type protection ring (40) is attached to the trench MOS unit (30); and the distance between the upper portion and the barrier layer (35) is 1 to 3 μm.

2. The silicon carbide Schottky diode with a trench structure having a junction type P+ protection according to claim 1, characterized in that: The material of the substrate layer (21) is one of sapphire, silicon, silicon carbide and gallium nitride.

3. The silicon carbide Schottky diode with a trench structure having a junction type P+ protection according to claim 1, characterized in that: The material of the oxide dielectric layer (33) is one of zirconium oxide, titanium oxide, magnesium oxide and silicon oxide.

4. The silicon carbide Schottky diode with a trench structure having a junction type P+ protection according to claim 1, characterized in that: The insulating polysilicon layer (34) is made of a material selected from the group consisting of silicon oxide and silicon nitride.

5. The silicon carbide Schottky diode with a trench structure having a junction type P+ protection according to claim 1, characterized in that: The barrier metal used in the barrier layer (35) is one of nickel, chromium and titanium.

6. The silicon carbide Schottky diode with a trench structure having a junction type P+ protection according to claim 1, characterized in that: The contact between the cathode metal (11) and the bottom of the substrate layer (21) is an ohmic contact.

7. A method for manufacturing a Schottky diode, characterized in that: The manufacturing method is applicable to manufacturing a silicon carbide Schottky diode with a junction P+ protection trench structure as claimed in any one of claims 1 to 6, and the specific steps include: S1: performing a first oxidation on the epitaxial layer (22) to form a primary thin film on its surface; S2: etching the upper surface of the epitaxial layer (22) to form a groove (23) on the epitaxial layer (22); S3: performing a second oxidation on the epitaxial layer (22) after the groove is formed, so as to form a silicon oxide film on the inner side wall of the groove (23), thereby forming an oxide layer (31); S4: filling the inside of the trench (23) with a conductive polysilicon layer (32), an oxide dielectric layer (33) and an insulating polysilicon layer (34) in sequence from bottom to top; S5: performing photolithography on both sides of the trench (23) to form a ring pattern, and injecting ions to form a P+ type guard ring (40); S6: performing photolithography on the epitaxial layer (22) to remove the thin film formed by the first oxidation; S7: using a sputtering process to sputter a metal layer on the upper end surface of the epitaxial layer (22) to form a barrier layer (35); S8: adhering and connecting the upper end of the substrate layer (21) and the lower end of the epitaxial layer (22); S9: A magnetron sputtering process is used to deposit an anode metal (12) on the barrier layer (35), and a cathode metal (11) is deposited on the bottom of the substrate layer (21).

8. The method for manufacturing a Schottky diode according to claim 7, characterized in that: The substrate layer (21) and the epitaxial layer (22) are adhered and connected by a defect layer, and the dielectric material of the defect layer is silicon oxide or silicon nitride.

Images