Trench-gate-type silicon carbide power device, manufacturing method therefor and semiconductor structure

Abstract

The present disclosure provides a trench-gate-type silicon carbide power device, a manufacturing method therefor and a semiconductor structure. The device comprises: a substrate; an epitaxial layer, which is located on a surface of the substrate; a trench gate, which is at least located in the epitaxial layer; a first injection region, which is located in the epitaxial layer on at least one side of the trench gate and is in contact with part of a side wall of the trench gate, wherein the surface of the first injection region away from the substrate overlaps part of the surface of the epitaxial layer away from the substrate; a second injection region, which is located in the epitaxial layer on at least one side of the trench gate, is in contact with part of the side wall of the trench gate, and is further in contact with the surface of the first injection region close to the substrate; and a third injection region, which is located in the epitaxial layer and is in contact with part of the bottom of the trench gate, part of the side wall of the trench gate and part of the surface of the second injection region close to the substrate, respectively, wherein the conduction types of the epitaxial layer, the first injection region and the third injection region are the same and are different from the conduction type of doped ions of the second injection region, and the doping concentration of the third injection region is greater than the doping concentration of the epitaxial layer.

Description

Trench gate silicon carbide power device, manufacturing method thereof and semiconductor structure

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This disclosure claims priority to a Chinese patent application filed with the Patent Office of China on December 21, 2023, with application number 2023117697360, entitled “Trench-gate silicon carbide power device, its manufacturing method and semiconductor structure,” the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present disclosure relates to the field of semiconductor technology, and in particular to a trench-gate silicon carbide power device, a manufacturing method thereof, and a semiconductor structure. Background Art

[0004] The performance of power semiconductor devices profoundly impacts the efficiency and application of power electronics systems. Compared to silicon-based materials, SiC MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors) offer advantages such as high breakdown electric field strength, low on-resistance, and high operating frequency. They meet the performance requirements of high voltage, low conduction loss, and miniaturization, and are widely used in aerospace, electric vehicles, rail transit, and other fields.

[0005] Trench gate structures can reduce cell size, allowing for even smaller chips, and have become a research hotspot. Reducing the on-resistance of trench-gate SiC power devices is a pressing technical challenge.

[0006] Summary of the Invention

[0007] The main purpose of the present disclosure is to provide a trench-gate silicon carbide power device, a manufacturing method thereof, and a semiconductor structure, so as to at least solve the problem of high on-resistance of the trench-gate silicon carbide power device in the prior art.

[0008] To achieve the above objectives, according to one aspect of the present disclosure, a trench gate silicon carbide power device is provided, comprising: a substrate; an epitaxial layer located on a surface of the substrate; a trench gate located at least in the epitaxial layer; a first implantation region located in the epitaxial layer on at least one side of the trench gate and contacting a portion of the sidewall of the trench gate, wherein the surface of the first implantation region away from the substrate coincides with the surface of the epitaxial layer away from the substrate; a second implantation region located in the epitaxial layer on at least one side of the trench gate and contacting a portion of the sidewall of the trench gate, wherein the second implantation region also contacts a surface of the first implantation region close to the substrate; and a third implantation region located in the epitaxial layer and contacting a portion of the bottom of the trench gate, a portion of the sidewall of the trench gate, and a portion of the surface of the second implantation region close to the substrate, respectively; wherein the dopant ions of the epitaxial layer, the dopant ions of the first implantation region, and the dopant ions of the third implantation region are of the same conductivity type and different from the conductivity type of the dopant ions of the second implantation region, and the dopant concentration of the dopant ions of the third implantation region is greater than the dopant concentration of the dopant ions of the epitaxial layer.

[0009] Optionally, the trench gate type silicon carbide power device further includes: a fourth injection region, located in the epitaxial layer and in contact with a portion of the surface of the third injection region close to the substrate, the fourth injection region also in contact with a portion of the bottom of the trench gate, and the doped ions of the fourth injection region have a different conductivity type from the doped ions of the epitaxial layer.

[0010] Optionally, the fourth implantation region wraps around a bottom corner of the trench gate.

[0011] Optionally, the first injection region and the second injection region are both located on both sides of the trench gate and are in contact with portions of both side walls of the trench gate, respectively; the third injection region only covers one bottom corner of the trench gate and a portion of the side wall of the trench gate located on the same side of the bottom corner and the surface of the second injection region close to the substrate.

[0012] Optionally, the trench gate type silicon carbide power device further includes: an interlayer insulating layer, located on the surface of the trench gate and the first injection region away from the substrate; a source metal layer, located on the surface of the epitaxial layer and the interlayer insulating layer away from the substrate; and a drain metal layer, located on the surface of the substrate away from the epitaxial layer.

[0013] Optionally, the trench gate includes: a trench located in the epitaxial layer; a gate oxide layer located on the sidewalls of the trench, the bottom of the trench and a portion of the surface of the first injection region away from the substrate; and a gate located on the surface of the gate oxide layer away from the substrate, the surface of the gate away from the substrate being flush with the surface of the gate oxide layer away from the first injection region.

[0014] Optionally, the trench gate type silicon carbide power device further includes: a fifth injection region, located in the epitaxial layer on at least one side of the trench gate, contacting the surface of the first injection region away from the side wall of the trench gate, the fifth injection region also contacts the partial surface of the second injection region away from the substrate, the surface of the fifth injection region away from the substrate coincides with the partial surface of the epitaxial layer away from the substrate, the doped ions in the fifth injection region have the same conductivity type as the doped ions in the second injection region, and the doping concentration of the doped ions in the fifth injection region is greater than the doping concentration of the doped ions in the second injection region.

[0015] According to another aspect of the present disclosure, a method for manufacturing a trench gate silicon carbide power device is provided, comprising: providing a substrate and an initial epitaxial layer located on the substrate; forming a first initial injection region, a second initial injection region, and a third initial injection region in the initial epitaxial layer, wherein a surface of the first initial injection region away from the substrate coincides with a surface of the initial epitaxial layer away from the substrate, the second initial injection region is located on a surface of the first initial injection region close to the substrate, and the third initial injection region is located on a surface of the second initial injection region close to the substrate, and the doping ions of the initial epitaxial layer, the doping ions of the first initial injection region, and the third initial injection region are located. The conductivity type of the doped ions in the third initial injection region is the same as that of the doped ions in the second initial injection region, and is different from the conductivity type of the doped ions in the second initial injection region, and the doping concentration of the doped ions in the third initial injection region is greater than the doping concentration of the doped ions in the initial epitaxial layer; a trench gate is formed in the initial epitaxial layer, the trench gate sequentially passes through the first initial injection region and the second initial injection region, and part of the bottom of the trench gate is located in the third initial injection region, the remaining first initial injection region forms a first injection region, the remaining second initial injection region forms a second injection region, the remaining third initial injection region forms a third injection region, and the remaining initial epitaxial layer forms an epitaxial layer.

[0016] Optionally, a first initial injection region, a second initial injection region and a third initial injection region are formed in the initial epitaxial layer, including: forming a fourth initial injection region in the initial epitaxial layer, the fourth initial injection region has the same width as the initial epitaxial layer in the first direction, the fourth initial injection region has a width in the second direction smaller than the width of the initial epitaxial layer in the second direction, the doped ions in the fourth initial injection region have a different conductivity type from the doped ions in the initial epitaxial layer, the first direction is perpendicular to the stacking direction of the substrate and the initial epitaxial layer, and the second direction is parallel to the stacking direction; forming the first initial injection region in the fourth initial injection region, the first initial injection region has a width in the first direction smaller than the width of the fourth initial injection region in the first direction, the first initial injection region has a width in the second direction smaller than the width of the fourth initial injection region in the second direction, and the remaining fourth initial injection region forms the second initial injection region; forming a fifth initial injection region in the initial epitaxial layer, the fifth initial injection region is located on a portion of the surface of the second initial injection region close to the substrate, the doped ions in the fifth initial injection region are different from the doped ions in the initial epitaxial layer The conductive type of the doped ions is different; the third initial injection region is formed in the initial epitaxial layer and the fifth initial injection region, the third initial injection region is in contact with the surface of the second initial injection region close to the substrate, and the remaining fifth initial injection region forms an intermediate injection region, forming a trench gate located in the initial epitaxial layer, including: removing part of the first initial injection region, part of the second initial injection region, part of the third initial injection region and part of the intermediate injection region to form a trench with a partial bottom located in the third initial injection region and the remaining bottom in contact with the intermediate injection region, and the remaining The first initial injection region forms the first injection region, the remaining second initial injection region forms the second injection region, the remaining third initial injection region forms the third injection region, the remaining intermediate injection region forms the fourth injection region, and the remaining initial epitaxial layer forms the epitaxial layer; a gate oxide layer is covered in the trench and on a portion of the surface of the first injection region away from the substrate; a conductive material is filled in the remaining trench to form a gate, the surface of the gate away from the substrate is flush with the surface of the gate oxide layer away from the first injection region, and the gate and the gate oxide layer form the trench gate.

[0017] According to another aspect of the present disclosure, a semiconductor structure is provided, comprising: any one of the trench-gate silicon carbide power devices, or a trench-gate silicon carbide power device manufactured by the method described.

[0018] By applying the technical solution disclosed in the present invention, a third injection region having the same doping type of doping ions as that of the epitaxial layer is provided in the epitaxial layer at the bottom of the trench gate, and the doping concentration of the doping ions in the third injection region is higher than that of the epitaxial layer. Due to the presence of the third injection region, when a voltage is applied to the gate and source of the trench gate silicon carbide power device and the device threshold voltage is reached, a carrier path from the first injection region, through the second injection region, and the third injection region to the epitaxial layer is first formed, that is, the carriers pass through the first injection region, flow through the inversion layer channel formed by the second injection region, and then flow through the third injection region to the epitaxial layer and the substrate, thereby ensuring a low path resistance and effectively solving the technical problem of high on-resistance of the trench gate silicon carbide power device in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings, which constitute part of the present disclosure, are intended to provide a further understanding of the present disclosure. The exemplary embodiments of the present disclosure and their descriptions are intended to explain the present disclosure and do not constitute an improper limitation of the present disclosure. In the accompanying drawings:

[0020] FIG1 shows a schematic structural diagram of a trench gate silicon carbide power device provided in an embodiment of the present disclosure;

[0021] FIG2 is a schematic flow chart showing a method for manufacturing a trench gate silicon carbide power device according to an embodiment of the present disclosure;

[0022] 3 to 12 are schematic structural diagrams showing the structure obtained after each process step of the method for manufacturing a trench gate silicon carbide power device provided in accordance with an embodiment of the present disclosure.

[0023] The accompanying drawings include the following reference numerals:

[0024] 10. Substrate; 11. Epitaxial layer; 12. Trench gate; 13. First injection region; 14. Second injection region; 15. Third injection region; 16. Fourth injection region; 17. Interlayer insulating layer; 18. Source metal layer; 19. Drain metal layer; 20. Gate oxide layer; 21. Gate; 22. Initial epitaxial layer; 23. First initial injection region; 24. Second initial injection region; 25. Third initial injection region; 26. Fourth initial injection region; 27. Fifth initial injection region; 28. Trench; 29. ​​Sixth initial injection region; 30. Fifth injection region; 31. Intermediate injection region. DETAILED DESCRIPTION

[0025] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in the present disclosure may be combined with each other. The present disclosure will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0026] In order to enable those skilled in the art to better understand the solutions of the present disclosure, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings in the embodiments of the present disclosure. Obviously, the embodiments described are only part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present disclosure.

[0027] It should be noted that the terms "first," "second," and the like in the specification and claims of the present disclosure and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate for the embodiments of the present disclosure described herein. In addition, the terms "including" and "having," and any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units that are not explicitly listed or inherent to these processes, methods, products, or apparatus.

[0028] As introduced in the background technology, the on-resistance of trench-gate silicon carbide power devices in the prior art is relatively high. To solve the above technical problems, the embodiments of the present disclosure provide a trench-gate silicon carbide power device, a manufacturing method thereof, and a semiconductor structure.

[0029] The technical solutions in the embodiments of the present disclosure will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the present disclosure.

[0030] In this embodiment, a trench gate silicon carbide power device as shown in FIG1 is provided, specifically comprising:

[0031] substrate 10;

[0032] an epitaxial layer 11 located on the surface of the substrate 10;

[0033] Specifically, the materials of the substrate and the epitaxial layer are respectively silicon carbide. The conductive type of the doping ions of the substrate and the epitaxial layer is the same. For example, if the substrate is an n-type conductive substrate, the epitaxial layer is an n-type epitaxial layer. The doping concentration of the doping ions of the substrate is greater than the doping concentration of the doping ions of the epitaxial layer. Those skilled in the art can flexibly set the doping concentration values ​​of the doping ions of the substrate and the epitaxial layer according to actual design requirements. In an optional embodiment, the doping concentration of the doping ions of the substrate is E19 cm -3 ~E20cm -3 The doping concentration of the doping ions in the epitaxial layer is E15cm -3~E16cm -3 .

[0034] A trench gate 12 is located at least in the epitaxial layer 11;

[0035] a first implantation region 13 located in the epitaxial layer 11 on at least one side of the trench gate 12 and contacting a portion of a sidewall of the trench gate 12 , wherein a surface of the first implantation region 13 away from the substrate 10 overlaps with a portion of a surface of the epitaxial layer 11 away from the substrate 10 ;

[0036] Specifically, the first implant region may contact only a portion of one sidewall of the trench gate, or may contact portions of both sidewalls of the trench gate as shown in FIG1 . The first implant region extends from the surface of the epitaxial layer into the epitaxial layer. The depth of the first implant region is less than the depth of the epitaxial layer and also less than the depth of the trench gate in the epitaxial layer. The depth is a depth value in a direction parallel to the stacking direction of the substrate and the epitaxial layer.

[0037] a second implantation region 14 located in the epitaxial layer 11 on at least one side of the trench gate 12 and contacting a portion of the sidewall of the trench gate 12 , and further contacting a surface of the first implantation region 13 close to the substrate 10 ;

[0038] Specifically, the second implant region may contact only a portion of one sidewall of the trench gate, or may contact portions of both sidewalls of the trench gate as shown in FIG1 . In the case where the first implant region contacts only a portion of one sidewall of the trench gate, the second implant region and the first implant region are located on the same side of the trench gate. The total depth of the second implant region and the first implant region is less than or equal to the depth of the trench gate in the epitaxial layer.

[0039] a third implantation region 15 located in the epitaxial layer 11 and contacting a portion of the bottom of the trench gate 12, a portion of the sidewall of the trench gate 12, and a portion of the surface of the second implantation region 14 close to the substrate 10; that is, the third implantation region 15 at least wraps around the bottom corner of the trench gate 12;

[0040] Among them, the conductivity type of the doping ions of the epitaxial layer, the doping ions of the first injection region, and the doping ions of the third injection region are the same and different from the conductivity type of the doping ions of the second injection region, and the doping concentration of the doping ions of the third injection region is greater than the doping concentration of the doping ions of the epitaxial layer.

[0041] Specifically, the conductivity type of the doping ions in the second injection region is different from that in the epitaxial layer, the first injection region, and the third injection region. For example, when the conductivity type of the doping ions in the second injection region is p-type, the conductivity type of the doping ions in the epitaxial layer, the first injection region, and the third injection region are all n-type. Those skilled in the art can flexibly set the doping concentration of the doping ions in the third injection region according to actual design requirements. In this embodiment, the doping concentration of the doping ions in the third injection region is E17-E19 cm -3 .

[0042] Through the embodiment, a third injection region having the same doping type of doping ions as the epitaxial layer is provided in the epitaxial layer at the bottom of the trench gate, and the doping concentration of the doping ions in the third injection region is higher than that in the epitaxial layer. Due to the presence of the third injection region, when a voltage is applied to the gate and source of the trench gate silicon carbide power device and the device threshold voltage is reached, a carrier path from the first injection region, through the second injection region, and the third injection region to the epitaxial layer is first formed, that is, the carriers pass through the first injection region, flow through the inversion layer channel formed by the second injection region, and then flow through the third injection region to the epitaxial layer and the substrate, thereby ensuring a low path resistance and effectively solving the technical problem of high on-resistance of the trench gate silicon carbide power device in the prior art.

[0043] In another specific embodiment, the doping concentration of the doping ions in the first implantation region is greater than the doping concentration of the doping ions in the third implantation region. The doping concentration of the doping ions in the first implantation region may be specifically E19-E20 cm -3 .

[0044] In the prior art, because the dielectric constant of SiO2 is one-third that of SiC, the electric field in the gate oxide of the trench gate is approximately three times that of SiC. This can cause the electric field at the bottom of the gate of the trench gate silicon carbide power device to be too large in the reverse state, resulting in gate oxide breakdown, thereby reducing the breakdown voltage. To address this problem, in an optional embodiment of the present disclosure, as shown in Figure 1, the trench gate silicon carbide power device further includes: a fourth implantation region 16, located in the epitaxial layer 11 and in contact with a portion of the surface of the third implantation region 15 near the substrate 10, the fourth implantation region 16 also in contact with a portion of the bottom of the trench gate 12, and the dopant ions of the fourth implantation region 16 have a different conductivity type from the dopant ions of the epitaxial layer 11.

[0045] In the embodiment, a fourth implantation region having a different conductivity type from that of the doped ions in the epitaxial layer is provided at the bottom of the trench gate, so that the fourth implantation region contacts a portion of the bottom of the trench gate and the third implantation region, respectively. The fourth implantation region and the second implantation region respectively form PN junctions with the epitaxial layer. Thus, when a reverse voltage is applied to the trench-gate silicon carbide power device so that the device operates in a reverse state, the conductivity type of the doped ions in the second implantation region, the fourth implantation region, and the epitaxial layer is set so that the PN junction formed by the fourth implantation region and the epitaxial layer and the PN junction formed by the second implantation region and the epitaxial layer are in a reverse biased state. As the reverse voltage increases, the depletion layers of the two PN junctions gradually expand and connect, which can effectively solve the problem of electric field concentration at the bottom of the trench, ensure that the breakdown voltage of the trench-gate silicon carbide power device is high, and have good overall reliability.

[0046] Furthermore, the fourth injection region may only contact the bottom of the trench gate. To further ensure better device reliability, in the present disclosure, the fourth injection region wraps around the bottom corner of the trench gate. Since high electric fields are mainly concentrated at the bottom corners of the trench gate, wrapping the bottom corners by the fourth injection region forms a trench shielding structure for the trench gate, which can effectively protect the gate oxide layer at the bottom corners of the trench gate, further solving the problem of high electric field concentration at the bottom corners of the trench gate, and further improving the reliability of the trench gate.

[0047] In actual application, the doping concentration of the doping ions in the second injection region and the fourth injection region can be any appropriate concentration value. In a specific embodiment, the doping concentration of the doping ions in the second injection region and the fourth injection region is E17-E18 cm -3 .

[0048] According to another exemplary embodiment of the present disclosure, as shown in FIG1 , the first implantation region 13 and the second implantation region 14 are both located on both sides of the trench gate 12 and respectively contact portions of both sidewalls of the trench gate 12. The third implantation region 15 only covers one bottom corner of the trench gate 12, a portion of the sidewall of the trench gate 12 on the same side of the bottom corner, and a surface of the second implantation region 14 close to the substrate 10, and does not cover the other bottom corner of the trench gate 12 and the surface of the second implantation region 14 close to the substrate 10 on the other side thereof. In the embodiment, a plurality of conduction channels are formed by the first injection region, the second injection region, and the third injection region and the fourth injection region in contact with one of the second injection regions on both sides of the trench gate, wherein the plurality of conduction channels include: a conduction channel formed by the first injection region, the second injection region, the third injection region, and the epitaxial layer on one side of the trench gate, a conduction channel formed by the first injection region, the second injection region, and the epitaxial layer on the other side of the trench gate, and a conduction channel formed by the first injection region, the second injection region, the third injection region, the fourth injection region, and the epitaxial layer on one side of the trench gate, thereby further reducing the on-resistance of the device and improving the current density of the device.

[0049] In a specific application, as shown in FIG1 , the trench gate silicon carbide power device further includes: an interlayer insulating layer 17 located on the surface of the trench gate 12 and the first implantation region 13 away from the substrate 10; a source metal layer 18 located on the surface of the epitaxial layer 11 and the interlayer insulating layer 17 away from the substrate 10; and a drain metal layer 19 located on the surface of the substrate 10 away from the epitaxial layer 11. In this embodiment, the interlayer insulating layer is used to isolate and protect the trench gate; the source metal layer serves as the source of the device, and the drain metal layer serves as the drain of the device.

[0050] In the embodiments of the present disclosure, suitable materials can be selected as the materials of the interlayer insulating layer, such as silicon dioxide, silicon nitride, aluminum oxide, etc. Of course, in addition to the materials mentioned above, other insulating materials can also be selected as the materials of the interlayer insulating layer. Similarly, those skilled in the art can select any suitable conductive material as the material of the source metal layer and the drain metal layer, and the source metal layer and the drain metal layer can choose a single-layer conductive structure or a multi-layer conductive structure. In an optional scheme, the source metal layer is a multi-layer conductive structure, specifically including a first metal layer, a second metal layer and a third metal layer stacked in sequence in a direction away from the epitaxial layer, wherein the first metal layer is a Ni layer, the second metal layer is a Ti layer, and the third metal layer is an Al layer. The drain metal layer is also a multi-layer conductive structure, specifically including a fourth metal layer, a fifth metal layer, a sixth metal layer and a seventh metal layer stacked in sequence in a direction away from the substrate, wherein the fourth metal layer is Ni, the fifth metal layer is a Ti layer, the sixth metal layer is a Ni layer, and the seventh metal layer is an Ag layer. In this embodiment, the use of a stacked metal material as the drain metal layer and the source metal layer enables the drain metal layer to form a good ohmic contact with the substrate, and the source metal layer to form a good ohmic contact with the first injection region, further ensuring good overall performance of the semiconductor device. Of course, in addition to the aforementioned metal materials, the source metal layer and the drain metal layer of the present disclosure may also be made of other single conductive materials or alloy materials.

[0051] To further ensure better device performance of the trench-type silicon carbide power device, specifically, as shown in FIG1 , the trench-gate silicon carbide power device further includes: a fifth implantation region 30 located in the epitaxial layer 11 on at least one side of the trench gate 12. That is, the fifth implantation region 30 may be located only in the epitaxial layer on one side of the trench gate, or in the epitaxial layer on both sides of the trench gate. The fifth implantation region 30 contacts the surface of the first implantation region 13 away from the sidewall of the trench gate 12. The fifth implantation region 30 also contacts the portion of the surface of the second implantation region 14 away from the substrate 10. The surface of the fifth implantation region 30 away from the substrate 10 overlaps with the portion of the surface of the epitaxial layer 11 away from the substrate 10. The dopant ions in the fifth implantation region 30 and the dopant ions in the second implantation region 14 have the same conductivity type, and the dopant concentration of the dopant ions in the fifth implantation region 30 is greater than the dopant concentration of the dopant ions in the second implantation region 14. The fifth implantation region can prevent the parasitic transistor of the device from turning on.

[0052] In a specific embodiment, the doping concentration of the doping ions in the fifth implantation region may be E19-E21 cm -3 .

[0053] Those skilled in the art can select any suitable dopant ions to form the substrate, epitaxial layer, and implanted regions of the present disclosure by ion implantation or other doping methods. In the case of n-type doping, nitrogen ions and phosphorus ions can be selected as dopant ions, and in the case of p-type doping, aluminum ions and boron ions can be selected as dopant ions.

[0054] Optionally, as shown in Figure 1, the trench gate 12 includes: a trench (not shown in Figure 1), located in the epitaxial layer 11; a gate oxide layer 20, located on the sidewalls of the trench, the bottom of the trench and a portion of the surface of the first injection region 13 away from the substrate 10; a gate 21, located on the surface of the gate oxide layer 20 away from the substrate 10, and the surface of the gate 21 away from the substrate 10 is flush with the surface of the gate oxide layer 20 away from the first injection region 13.

[0055] The materials of the gate and the gate oxide layer can be any feasible materials in the prior art. In an exemplary embodiment, the material of the gate includes polysilicon, and the material of the gate oxide layer includes silicon oxide.

[0056] In an exemplary embodiment of the present disclosure, the gate oxide layer has a thickness ranging from 40 nm to 60 nm.

[0057] Specifically, taking the device structure in which the doping type of the doping ions of the epitaxial layer is n-type and the first implantation region, the second implantation region, and the fifth implantation region are all located in the epitaxial layer on both sides of the trench gate as an example, the working principle of the trench gate silicon carbide power device disclosed in the present invention is described as follows:

[0058] When a positive voltage (Vgs greater than 0) is applied to the gate-source region of a trench-gate silicon carbide power device, the surfaces of the p-type second and fourth implant regions near the gate oxide enter a weak inversion state. As the gate-source voltage increases and exceeds the device threshold voltage, the surfaces of the second and fourth implant regions near the gate oxide enter a strong inversion state, forming a conductive channel, and the device begins operation. Electrons first pass through the first implant region on the right side of the trench gate, flow through the N-type inversion layer channel formed by the second implant region on the right side of the trench gate, then flow through the third implant region, and then flow into the epitaxial layer and substrate. Then, as the gate-source voltage continues to increase, electrons simultaneously flow from the first implant region on the left side of the trench gate, through the N-type inversion layer channel formed by the second implant region on the left side of the trench gate, and then flow into the epitaxial layer and substrate. Thereafter, as the gate-source voltage continues to increase, electrons simultaneously flow through the N-type inversion layer channel formed by the first and second implant regions on the right side of the trench gate, and through the N-type inversion layer channel formed by the third and fourth implant regions, and then flow into the epitaxial layer and substrate. Among them, the channel composed of the first injection region, the second injection region, the third injection region, the epitaxial layer and the substrate on the right side of the trench gate is formed first. Due to the existence of the third injection region, the path resistance of the device is relatively small.

[0059] When the device operates in the reverse state, the PN junction formed by the fourth injection region and the epitaxial layer is in a reverse biased state, and the PN junction formed by the second injection region and the epitaxial layer is in a reverse biased state. As the reverse voltage increases, the PN depletion layers formed by them begin to expand and connect, which can avoid the high electric field concentration phenomenon at the bottom of the trench.

[0060] The structural layers can be formed by any suitable growth method, such as one or more of CVD (Chemical Vapor Deposition), ALD (Atomic Layer Deposition), PVD (Physical Vapor Deposition), thermal oxidation, molecular beam epitaxy, metal organic chemical vapor deposition, metal organic vapor phase epitaxy, hydride vapor phase epitaxy and / or other well-known crystal growth processes.

[0061] In this embodiment, a method for manufacturing the trench gate silicon carbide power device is provided. It should be noted that although a logical order is shown in the flowchart, in some cases, the steps shown or described may be performed in an order different from that shown here.

[0062] FIG2 is a flow chart of a method for manufacturing a trench gate silicon carbide power device according to an embodiment of the present disclosure. As shown in FIG2 , the method includes the following steps:

[0063] Step S201 , providing a substrate 10 as shown in FIG3 and an initial epitaxial layer 22 located on the substrate 10 ;

[0064] Specifically, the materials of the substrate and the initial epitaxial layer are respectively silicon carbide. The conductive type of the doping ions of the substrate and the initial epitaxial layer is the same. For example, if the substrate is an n-type conductive substrate, the initial epitaxial layer is an n-type initial epitaxial layer. The doping concentration of the doping ions of the substrate is greater than the doping concentration of the doping ions of the initial epitaxial layer. Those skilled in the art can flexibly set the doping concentration values ​​of the doping ions of the substrate and the doping ions of the initial epitaxial layer according to actual design requirements. In an optional embodiment, the doping concentration of the doping ions of the substrate is E19cm -3 ~E20cm -3 The doping concentration of the doping ions in the initial epitaxial layer is E15cm -3 ~E16cm -3 .

[0065] Step S202, forming a first initial injection region 23, a second initial injection region 24, and a third initial injection region 25 in the initial epitaxial layer 22 to obtain a structure as shown in FIG8 , wherein a surface of the first initial injection region 23 away from the substrate 10 coincides with a portion of the surface of the initial epitaxial layer 22 away from the substrate 10, the second initial injection region 24 is located on a surface of the first initial injection region 23 close to the substrate 10, and the third initial injection region 25 is located on a portion of the surface of the second initial injection region 24 close to the substrate 10, the doping ions of the initial epitaxial layer 22, the doping ions of the first initial injection region 23, and the doping ions of the third initial injection region 25 have the same conductivity type and are different from the conductivity type of the doping ions of the second initial injection region 24, and the doping concentration of the doping ions of the third initial injection region 25 is greater than the doping concentration of the doping ions of the initial epitaxial layer 22;

[0066] Specifically, the conductivity type of the doped ions in the second initial injection region is different from that in the initial epitaxial layer, the first initial injection region, and the third initial injection region. For example, when the conductivity type of the doped ions in the second initial injection region is p-type, the conductivity type of the doped ions in the initial epitaxial layer, the first initial injection region, and the third initial injection region are all n-type. Those skilled in the art can flexibly set the doping concentration of the doped ions in the third initial injection region according to actual design requirements. In this embodiment, the doping concentration of the doped ions in the third initial injection region is E17-E19 cm -3 .

[0067] In step S203, as shown in FIG11 , a trench gate 12 is formed in the initial epitaxial layer 22. The trench gate 12 sequentially passes through the first initial injection region 23 and the second initial injection region 24. Part of the bottom of the trench gate 12 is located in the third initial injection region 25. The remaining first initial injection region 23 forms the first injection region 13. The remaining second initial injection region 24 forms the second injection region 14. The remaining third initial injection region 25 forms the third injection region 15. The remaining initial epitaxial layer 22 forms the epitaxial layer 11, thereby obtaining the structure shown in FIG1 .

[0068] Specifically, the first initial injection region may only contact a portion of one sidewall of the trench gate, or may contact portions of both sidewalls of the trench gate. The first initial injection region extends from the surface of the initial epitaxial layer into the initial epitaxial layer. The depth of the first initial injection region is less than the depth of the initial epitaxial layer and less than the depth of the trench gate in the initial epitaxial layer. The depth is the depth value in a direction parallel to the stacking direction of the substrate and the initial epitaxial layer. The second initial injection region may only contact a portion of one sidewall of the trench gate, or may contact portions of both sidewalls of the trench gate. When the first initial injection region only contacts a portion of one sidewall of the trench gate, the second initial injection region and the first initial injection region are located on the same side of the trench gate. The total depth of the second initial injection region and the first initial injection region is less than or equal to the depth of the trench gate in the initial epitaxial layer.

[0069] According to the embodiment, a substrate and an initial epitaxial layer located on the substrate are first provided; then, adjacent first initial injection regions, second initial injection regions, and third initial injection regions are formed in the initial epitaxial layer in a direction close to the substrate, wherein the initial epitaxial layer, the first initial injection region, and the third initial injection region have the same conductivity type, which is different from the second initial injection region, and the third initial injection region has a higher doping concentration than the initial epitaxial layer; finally, a trench gate is formed which penetrates the first initial injection region and the second initial injection region and has a portion of its bottom located in the third initial injection region, so that the remaining first initial injection region, the second initial injection region, the third initial injection region, and the initial epitaxial layer form the first injection region, the second injection region, the third injection region, and the epitaxial layer correspondingly, thereby realizing the third injection region in the epitaxial layer at the bottom of the trench gate, wherein the doping type of the doped ions is the same as that of the epitaxial layer and the doping concentration is higher than that of the epitaxial layer. Due to the presence of the third injection region, when a voltage is applied to the gate and source of the trench-gate silicon carbide power device and the device threshold voltage is reached, a carrier path is first formed from the first injection region, through the second injection region, and the third injection region to the epitaxial layer. That is, the carriers pass through the first injection region, flow through the inversion layer channel formed by the second injection region, and then flow through the third injection region to the epitaxial layer and the substrate, thereby ensuring a small path resistance and effectively solving the technical problem of high on-resistance of trench-gate silicon carbide power devices in the prior art.

[0070] In an optional solution, the specific implementation of step S202: forming the first initial implantation region, the second initial implantation region, and the third initial implantation region in the initial epitaxial layer may include:

[0071] Step S2021: As shown in FIG3 and FIG4 , a fourth initial implantation region 26 is formed in the initial epitaxial layer 22. The fourth initial implantation region 26 has the same width as the initial epitaxial layer 22 in the first direction, and the width of the fourth initial implantation region 26 in the second direction is smaller than the width of the initial epitaxial layer 22 in the second direction. The dopant ions in the fourth initial implantation region 26 have a different conductivity type from the dopant ions in the initial epitaxial layer. The first direction is perpendicular to the stacking direction of the substrate 10 and the initial epitaxial layer 22, and the second direction is parallel to the stacking direction.

[0072] Specifically, the fourth initial implantation region may be formed in the initial epitaxial layer by high-temperature ion implantation, and the doping concentration of the doping ions in the fourth initial implantation region may be E17-E18 cm -3 The fourth initial implantation region has the same width as the initial epitaxial layer, and the implantation depth of the fourth initial implantation region is less than the thickness of the initial epitaxial layer.

[0073] Step S2022: As shown in FIG. 4 to FIG. 6 , forming the first initial injection region 23 in the fourth initial injection region 26, wherein the width of the first initial injection region 23 in the first direction is smaller than the width of the fourth initial injection region 26 in the first direction, and the width of the first initial injection region 23 in the second direction is smaller than the width of the fourth initial injection region 26 in the second direction, and the remaining fourth initial injection region 26 forms the second initial injection region 24;

[0074] Specifically, the first initial implantation region is formed in the fourth initial implantation region by high temperature ion implantation, and the doping concentration of the doping ions in the first initial implantation region may be E19cm -3 ~E20cm -3 The injection depth of the first initial injection region is smaller than the injection depth of the fourth initial injection region, and the injection width of the first initial injection region is also smaller than the injection width of the fourth initial injection region.

[0075] In the present disclosure, as shown in Figures 4 to 6, forming the first initial injection region 23 in the fourth initial injection region 26 may include the following steps: as shown in Figures 4 and 5, forming a sixth initial injection region 29 in the fourth initial injection region 26, and the remaining fourth initial injection region 26 forming the second initial injection region 24, thereby obtaining the structure shown in Figure 5, wherein the width of the sixth initial injection region 29 in the first direction is equal to the width of the fourth initial injection region 26 in the first direction, and the width of the sixth initial injection region 29 in the second direction is less than the width of the fourth initial injection region 26 in the second direction; forming an initial barrier layer on the exposed surface of the sixth initial injection region 29, and then removing the edge of the initial barrier layer by etching to form an injection window (not shown in the figure); ion implanting the sixth initial injection region 29 through the injection window to obtain a fifth injection region 30, and the remaining sixth initial injection region 29 forming the first initial injection region 23, thereby obtaining the structure shown in Figure 6. By forming the fifth injection region, the parasitic transistor of the device can be prevented from turning on.

[0076] Specifically, the sixth initial implantation region can be formed in the fourth initial implantation region by a high temperature ion implantation method, and the fifth implantation region can be formed in the sixth initial implantation region. The doping concentration of the doping ions in the sixth initial implantation region can be E19cm -3 ~E20cm -3 The doping concentration of the doping ions in the fifth implantation region may be E19cm -3 ~E21cm -3 .

[0077] Step S2023: As shown in FIG7 , a fifth initial implantation region 27 is formed in the initial epitaxial layer 22 . The fifth initial implantation region 27 is located on a portion of the surface of the second initial implantation region 24 close to the substrate 10 . The dopant ions in the fifth initial implantation region 27 are of a different conductivity type from the dopant ions in the initial epitaxial layer 22 .

[0078] Specifically, an initial barrier layer can be formed on the exposed surface of the initial epitaxial layer, and then a portion of the initial barrier layer can be removed by etching to form an injection window, through which high-temperature and high-energy ion implantation is performed to form the fifth initial implantation region. The conductivity type of the doped ions in the fifth initial implantation region can be E17cm -3 ~E18cm -3 .

[0079] Step S2024: As shown in Figure 8, the third initial injection region 25 is formed in the initial epitaxial layer 22 and the fifth initial injection region 27. The third initial injection region 25 is in contact with the second initial injection region 24 close to the surface of the substrate 10, and the remaining fifth initial injection region 27 forms an intermediate injection region 31.

[0080] Specifically, an initial barrier layer can be formed on the exposed surface of the initial epitaxial layer, and then a portion of the initial barrier layer can be removed by etching to form an injection window. The orthographic projection of the injection window on the substrate overlaps with the orthographic projection of the fifth initial injection region on the substrate. High-temperature and high-energy ion implantation is performed through the injection window to form the third initial injection region. The conductivity type of the doped ions in the third initial injection region can be E17cm -3 ~E19cm -3 .

[0081] On this basis, step S203: forming a trench gate in the initial epitaxial layer, including:

[0082] Step S2031: As shown in FIG8 and FIG9 , a portion of the first initial injection region 23, a portion of the second initial injection region 24, a portion of the third initial injection region 25, and a portion of the intermediate injection region 31 are removed to form a trench 28 with a portion of its bottom located in the third initial injection region 25 and the remaining bottom in contact with the intermediate injection region 31. The remaining first initial injection region 23 forms the first injection region 13, the remaining second initial injection region 24 forms the second injection region 14, the remaining third initial injection region 25 forms the third injection region 15, the remaining intermediate injection region 31 forms the fourth injection region 16, and the remaining initial epitaxial layer 22 forms the epitaxial layer 11.

[0083] Specifically, the depth of the trench is greater than the total injection depth of the first initial injection region and the second initial injection region, and less than the total injection depth of the first initial injection region, the second initial injection region, and the third initial injection region.

[0084] Step S2032: As shown in FIG9 and FIG10 , covering the trench 28 and a portion of the surface of the first implantation region 13 away from the substrate 10 with a gate oxide layer 20 ;

[0085] Specifically, the gate oxide layer may be grown in the trench by a high temperature oxidation method. The thickness of the gate oxide layer may be in the range of 40 to 60 nm.

[0086] Step S2033: As shown in Figure 11, a conductive material is filled in the remaining trench 28 to form a gate 21. The surface of the gate 21 away from the substrate 10 is flush with the surface of the gate oxide layer 20 away from the first injection region 13. The gate 21 and the gate oxide layer 20 form the trench gate 12.

[0087] Specifically, the conductive material can be deposited in the remaining grooves by a deposition method, and then the gate with the required morphology can be formed by photolithography and etching. The conductive material can be polysilicon or other conductive materials.

[0088] In the embodiment, a fourth implantation region having a conductivity type different from that of the doped ions of the epitaxial layer is provided at the bottom of the trench gate, so that the fourth implantation region contacts a portion of the bottom of the trench gate and the third implantation region, respectively, and the fourth implantation region and the second implantation region respectively form PN junctions with the epitaxial layer. Thus, when a reverse voltage is applied to the trench-gate silicon carbide power device so that the device operates in a reverse state, the conductivity type of the doped ions of the second implantation region, the fourth implantation region, and the epitaxial layer is set so that the PN junction formed by the fourth implantation region and the epitaxial layer and the PN junction formed by the second implantation region and the epitaxial layer are in a reverse biased state, and as the reverse voltage increases, the depletion layers of the two PN junctions gradually expand and connect, which can effectively solve the problem of electric field concentration at the bottom of the trench, ensure that the breakdown voltage of the trench-gate silicon carbide power device is high, and the overall reliability of the device is good.

[0089] Furthermore, the fourth injection region may only contact the bottom of the trench gate. To further ensure better device reliability, in the present disclosure, the fourth injection region wraps around the bottom corner of the trench gate. Since high electric fields are mainly concentrated at the bottom corners of the trench gate, wrapping the bottom corners by the fourth injection region forms a trench shielding structure for the trench gate, which can effectively protect the gate oxide layer at the bottom corners of the trench gate, further solving the problem of high electric field concentration at the bottom corners of the trench gate, and further improving the reliability of the trench gate.

[0090] After forming a trench gate in the initial epitaxial layer in step S203, the method further includes: forming an interlayer insulating layer 17 on the exposed surface of the trench gate 12 and on a portion of the exposed surface of the first implantation region 13, as shown in Figures 11 and 12; forming a source metal layer 18 on the exposed surface of the interlayer insulating layer 17 and on the exposed surface of the epitaxial layer 11, as shown in Figures 12 and 1; and forming a drain metal layer 19 on a surface of the substrate 10 away from the epitaxial layer 11. In this embodiment, the interlayer insulating layer is used to isolate and protect the trench gate; the source metal layer serves as the source of the device, and the drain metal layer serves as the drain of the device.

[0091] In the embodiments of the present disclosure, suitable materials can be selected as the material of the interlayer insulating layer, such as silicon dioxide, silicon nitride, aluminum oxide, etc. Of course, in addition to the aforementioned materials, other insulating materials can also be selected as the material of the interlayer insulating layer. Similarly, those skilled in the art can select any suitable conductive material as the material of the source metal layer and the drain metal layer. The source metal layer and the drain metal layer can be selected to have a single-layer conductive structure or a multi-layer conductive structure.

[0092] Specifically, the interlayer insulating layer can be grown by the LPCVD method. The process of forming the source metal layer can be: stacking a first metal layer, a second metal layer and a third metal layer in sequence on the exposed surface of the interlayer insulating layer and the exposed surface of the epitaxial layer, wherein the first metal layer is a Ni layer, the second metal layer is a Ti layer, and the third metal layer is an Al layer. The process of forming the drain metal layer can be: stacking a fourth metal layer, a fifth metal layer, a sixth metal layer and a seventh metal layer in sequence on the surface of the substrate away from the epitaxial layer, wherein the fourth metal layer is Ni, the fifth metal layer is a Ti layer, the sixth metal layer is a Ni layer, and the seventh metal layer is an Ag layer. The first metal layer, the second metal layer, the third metal layer, the fourth metal layer, the fifth metal layer, the sixth metal layer and the seventh metal layer can be obtained by metal sputtering.

[0093] According to another aspect of the present disclosure, a semiconductor structure is provided, comprising: any one of the trench-gate silicon carbide power devices, or a trench-gate silicon carbide power device manufactured by the method described.

[0094] The semiconductor structure includes the trench-gate silicon carbide power device, or a trench-gate silicon carbide power device obtained using the method. In this device, a third implantation region is provided in the epitaxial layer at the bottom of the trench gate, containing the same doping type as the epitaxial layer, and the doping concentration of the doping ions in the third implantation region is higher than that in the epitaxial layer. Due to the presence of the third implantation region, when a voltage is applied to the gate and source of the trench-gate silicon carbide power device and the device threshold voltage is reached, a carrier path is first formed from the first implantation region, through the second implantation region, and through the third implantation region to the epitaxial layer. That is, carriers pass through the first implantation region, flow through the inversion layer channel formed by the second implantation region, and then flow through the third implantation region to the epitaxial layer and substrate, thereby ensuring a low path resistance and effectively solving the technical problem of high on-resistance in trench-gate silicon carbide power devices in the prior art.

[0095] It should also be noted that the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, commodity, or apparatus that includes a series of elements includes not only those elements but also other elements not explicitly listed, or includes elements inherent to such process, method, commodity, or apparatus. In the absence of further limitations, an element defined by the phrase "comprises a ..." does not exclude the presence of other identical elements in the process, method, commodity, or apparatus that includes the element.

[0096] From the above description, it can be seen that the embodiments described in this disclosure achieve the following technical effects:

[0097] 1) In the trench gate type silicon carbide power device disclosed in the present invention, a third injection region is provided in the epitaxial layer at the bottom of the trench gate, in which the doping type of the doping ions is the same as that of the epitaxial layer, and the doping concentration of the doping ions in the third injection region is higher than that of the epitaxial layer. Due to the presence of the third injection region, when a voltage is applied to the gate and source of the trench gate type silicon carbide power device and the device threshold voltage is reached, a carrier path from the first injection region, through the second injection region, and the third injection region to the epitaxial layer is first formed, that is, the carriers pass through the first injection region, flow through the inversion layer channel formed by the second injection region, and then flow through the third injection region to the epitaxial layer and the substrate, thereby ensuring that the path resistance is small, and effectively solving the technical problem of high on-resistance of the trench gate type silicon carbide power device in the prior art.

[0098] 2) In the manufacturing method of the trench gate type silicon carbide power device disclosed in the present invention, a substrate and an initial epitaxial layer located on the substrate are first provided; then, adjacent first initial injection regions, second initial injection regions and third initial injection regions are formed in the initial epitaxial layer along the direction close to the substrate, wherein the initial epitaxial layer, the first initial injection region and the third initial injection region have the same conductivity type, which is different from the second initial injection region, and the third initial injection region has a higher doping concentration than the initial epitaxial layer; finally, a trench gate is formed that passes through the first initial injection region and the second initial injection region and has a part of its bottom located in the third initial injection region, so that the remaining first initial injection region, the second initial injection region, the third initial injection region and the initial epitaxial layer form the first injection region, the second injection region, the third injection region and the epitaxial layer correspondingly, thereby realizing the third injection region in the epitaxial layer at the bottom of the trench gate, whose doping type of doped ions is the same as that of the epitaxial layer and whose doping concentration is higher than that of the epitaxial layer. Due to the presence of the third injection region, when a voltage is applied to the gate and source of the trench-gate silicon carbide power device and the device threshold voltage is reached, a carrier path is first formed from the first injection region, through the second injection region, and the third injection region to the epitaxial layer. That is, the carriers pass through the first injection region, flow through the inversion layer channel formed by the second injection region, and then flow through the third injection region to the epitaxial layer and the substrate, thereby ensuring a small path resistance and effectively solving the technical problem of high on-resistance of trench-gate silicon carbide power devices in the prior art.

[0099] The foregoing description is merely a preferred embodiment of the present disclosure and is not intended to limit the present disclosure. Those skilled in the art will readily appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present disclosure shall be included within the scope of protection of the present disclosure.

Claims

1. A trench gate silicon carbide power device, wherein: include: substrate; an epitaxial layer located on the surface of the substrate; A trench gate, located at least in the epitaxial layer; a first implantation region, located in the epitaxial layer on at least one side of the trench gate and in contact with a portion of the sidewall of the trench gate, wherein a surface of the first implantation region away from the substrate overlaps with a portion of the surface of the epitaxial layer away from the substrate; a second implantation region, located in the epitaxial layer on at least one side of the trench gate and in contact with a portion of the sidewall of the trench gate, and the second implantation region is also in contact with a surface of the first implantation region close to the substrate; a third implantation region, located in the epitaxial layer, and respectively contacting a portion of the bottom of the trench gate, a portion of the sidewall of the trench gate, and a portion of the surface of the second implantation region close to the substrate; Among them, the conductivity type of the doping ions of the epitaxial layer, the doping ions of the first injection region and the doping ions of the third injection region is the same and different from the conductivity type of the doping ions of the second injection region, and the doping concentration of the doping ions of the third injection region is greater than the doping concentration of the doping ions of the epitaxial layer.

2. The trench gate silicon carbide power device according to claim 1, wherein: The trench gate silicon carbide power device further comprises: A fourth implantation region is located in the epitaxial layer and contacts a portion of the surface of the third implantation region close to the substrate. The fourth implantation region also contacts a portion of the bottom of the trench gate. The conductivity type of the doped ions in the fourth implantation region is different from that of the doped ions in the epitaxial layer.

3. The trench gate silicon carbide power device according to claim 2, wherein: The fourth implantation region wraps around a bottom corner of the trench gate.

4. The trench gate silicon carbide power device according to any one of claims 1 to 3, wherein: The first injection region and the second injection region are both located on both sides of the trench gate and are in contact with portions of two side walls of the trench gate respectively; the third injection region only covers a bottom corner of the trench gate and a portion of the side wall of the trench gate located on the same side of the bottom corner and a surface of the second injection region close to the substrate.

5. The trench gate silicon carbide power device according to any one of claims 1 to 3, wherein: The trench gate silicon carbide power device further comprises: An interlayer insulating layer, located on the surface of the trench gate and the first implantation region away from the substrate; A source metal layer, located on the surface of the epitaxial layer and the interlayer insulating layer away from the substrate; The drain metal layer is located on the surface of the substrate away from the epitaxial layer.

6. The trench gate silicon carbide power device according to any one of claims 1 to 3, wherein: The trench gate comprises: A trench located in the epitaxial layer; A gate oxide layer, located on the sidewalls of the trench, the bottom of the trench, and a portion of the surface of the first implantation region away from the substrate; The gate is located on a surface of the gate oxide layer away from the substrate, and the surface of the gate away from the substrate is flush with the surface of the gate oxide layer away from the first injection region.

7. The trench gate silicon carbide power device according to claim 1, wherein: The trench gate silicon carbide power device further comprises: A fifth injection region is located in the epitaxial layer on at least one side of the trench gate, and contacts the surface of the first injection region away from the side wall of the trench gate. The fifth injection region also contacts a portion of the surface of the second injection region away from the substrate. The surface of the fifth injection region away from the substrate coincides with a portion of the surface of the epitaxial layer away from the substrate. The doped ions of the fifth injection region have the same conductivity type as the doped ions of the second injection region, and the doping concentration of the doped ions of the fifth injection region is greater than the doping concentration of the doped ions of the second injection region.

8. A method for manufacturing a trench gate silicon carbide power device according to any one of claims 1 to 7, wherein: include: Providing a substrate and an initial epitaxial layer on the substrate; forming a first initial implantation region, a second initial implantation region and a third initial implantation region in the initial epitaxial layer, The surface of the first initial injection region away from the substrate coincides with a partial surface of the initial epitaxial layer away from the substrate, the second initial injection region is located on the surface of the first initial injection region close to the substrate, the third initial injection region is located on a partial surface of the second initial injection region close to the substrate, the doping ions of the initial epitaxial layer, the doping ions of the first initial injection region and the doping ions of the third initial injection region have the same conductivity type and are different from the conductivity type of the doping ions of the second initial injection region, and the doping concentration of the doping ions of the third initial injection region is greater than the doping concentration of the doping ions of the initial epitaxial layer; A trench gate is formed in the initial epitaxial layer, wherein the trench gate sequentially penetrates the first initial injection region and the second initial injection region, a portion of the bottom of the trench gate is located in the third initial injection region, the remaining first initial injection region forms a first injection region, the remaining second initial injection region forms a second injection region, the remaining third initial injection region forms a third injection region, and the remaining initial epitaxial layer forms an epitaxial layer.

9. The method according to claim 8, wherein: Forming a first initial implantation region, a second initial implantation region and a third initial implantation region in the initial epitaxial layer, comprising: forming a fourth initial implantation region in the initial epitaxial layer, wherein the fourth initial implantation region has the same width as the initial epitaxial layer in the first direction, the width of the fourth initial implantation region in the second direction is smaller than the width of the initial epitaxial layer in the second direction, the conductivity type of the doped ions in the fourth initial implantation region is different from that of the doped ions in the initial epitaxial layer, the first direction is perpendicular to the stacking direction of the substrate and the initial epitaxial layer, and the second direction is parallel to the stacking direction; forming the first initial injection region in the fourth initial injection region, wherein the width of the first initial injection region in the first direction is smaller than the width of the fourth initial injection region in the first direction, the width of the first initial injection region in the second direction is smaller than the width of the fourth initial injection region in the second direction, and the remaining fourth initial injection region forms the second initial injection region; forming a fifth initial implantation region in the initial epitaxial layer, the fifth initial implantation region being located on a portion of the surface of the second initial implantation region close to the substrate, and the doping ions of the fifth initial implantation region and the doping ions of the initial epitaxial layer having a different conductivity type; forming the third initial injection region located between the initial epitaxial layer and the fifth initial injection region, wherein the third initial injection region is in contact with the surface of the second initial injection region close to the substrate, and the remaining fifth initial injection region forms an intermediate injection region, Forming a trench gate in the initial epitaxial layer, comprising: Removing part of the first initial injection region, part of the second initial injection region, part of the third initial injection region and part of the intermediate injection region to form a trench with a part of the bottom located in the third initial injection region and the remaining bottom in contact with the intermediate injection region, the remaining first initial injection region forming the first injection region, the remaining second initial injection region forming the second injection region, the remaining third initial injection region forming the third injection region, the remaining intermediate injection region forming the fourth injection region, and the remaining initial epitaxial layer forming the epitaxial layer; Covering the trench and a portion of the surface of the first implantation region away from the substrate with a gate oxide layer; A conductive material is filled in the remaining trench to form a gate, wherein a surface of the gate away from the substrate is flush with a surface of the gate oxide layer away from the first injection region, and the gate and the gate oxide layer form the trench gate.

10. A semiconductor structure, wherein: include: A trench gate silicon carbide power device according to any one of claims 1 to 7, or a trench gate silicon carbide power device manufactured by the method according to claim 8 or 9.

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