Semiconductor device and preparation method thereof, power module, power conversion circuit and vehicle

Abstract

The invention discloses a semiconductor device and a preparation method thereof, a power module, a power conversion circuit and a vehicle. The preparation method of the semiconductor device comprises the following steps: providing a semiconductor body; performing ion implantation on the first surface of the semiconductor body; forming a protective layer on the first surface of the semiconductor body; performing annealing treatment on the semiconductor body; processing the protection layer and the first surface of the semiconductor body, removing the protection layer and converting a part of the semiconductor body into a sacrificial layer; and removing the sacrificial layer. The method can prevent the first surface of the semiconductor body from being damaged when the protection layer is removed, and is simple in process, low in cost and high in reliability.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a semiconductor device and a preparation method thereof, a power module, a power conversion circuit and a vehicle. Background Art

[0002] After the ion implantation process is completed in the preparation of silicon carbide power devices, high-temperature annealing is required at a temperature greater than 1600 degrees Celsius. At such a high temperature, the surface of the silicon carbide wafer will degrade, making the surface roughness of the wafer larger, thus affecting the performance of the device. The industry usually deposits a protective layer of a certain thickness on the surface of the wafer to suppress the deterioration of roughness during high-temperature annealing, and then uses dry plasma etching technology to remove the protective layer. The removal of the protective layer uses dry plasma etching, which will damage the surface of the silicon carbide wafer to a certain extent, and the surface of the silicon carbide wafer still needs to be repaired later. Summary of the invention

[0003] The present invention provides a semiconductor device and a preparation method thereof, a power module, a power conversion circuit and a vehicle, so as to avoid damage to the first surface of the semiconductor body when removing a protective layer, with a simple process, low cost and high reliability.

[0004] According to one aspect of the present invention, an embodiment of the present invention provides a method for manufacturing a semiconductor device, comprising:

[0005] providing a semiconductor body;

[0006] Performing ion implantation on the first surface of the semiconductor body;

[0007] forming a protective layer on the first surface of the semiconductor body;

[0008] Annealing the semiconductor body;

[0009] Processing the protective layer and the first surface of the semiconductor body to remove the protective layer and convert a portion of the semiconductor body into a sacrificial layer;

[0010] The sacrificial layer is removed.

[0011] Optionally, processing the protective layer and the first surface of the semiconductor body to remove the protective layer and convert a portion of the semiconductor body into a sacrificial layer includes:

[0012] The protective layer and the first surface of the semiconductor body are oxidized to remove the protective layer and convert a portion of the semiconductor body into the sacrificial layer.

[0013] Optionally, performing oxidation treatment on the protective layer and the first surface of the semiconductor body, removing the protective layer and converting a portion of the semiconductor body into a sacrificial layer, comprises:

[0014] Performing oxidation treatment on the protective layer and the semiconductor body at the same time at a first temperature to remove the protective layer and convert a portion of the semiconductor body into the sacrificial layer;

[0015] Alternatively, the protective layer is first oxidized at the second temperature to remove the protective layer, and then the temperature is raised to the first temperature to oxidize the semiconductor body to form the sacrificial layer.

[0016] Optionally, the first temperature is greater than 1100°C, and the second temperature is 600°C-900°C.

[0017] Optionally, the oxidation treatment includes dry oxygen oxidation.

[0018] Optionally, the material used for the protective layer includes carbon, and the material used for the semiconductor body includes silicon carbide.

[0019] Optionally, after removing the sacrificial layer, the method further includes:

[0020] forming an electrode on the surface of the semiconductor body;

[0021] Performing ion implantation on the first surface of the semiconductor body comprises:

[0022] Ion implantation is performed on the first surface of the semiconductor body to form a well region and a first region, wherein the well region is arranged on a side of the first region away from the first surface.

[0023] Optionally, forming an electrode on the surface of the semiconductor body includes:

[0024] A gate, a source and a drain are formed on the surface of the semiconductor body.

[0025] According to another aspect of the present invention, an embodiment of the present invention further provides a semiconductor device, which is manufactured using the method for manufacturing a semiconductor device provided by any embodiment of the present invention.

[0026] According to another aspect of the present invention, an embodiment of the present invention further provides a power module, including a substrate and at least one semiconductor device provided by any embodiment of the present invention, wherein the substrate is used to carry the semiconductor device.

[0027] According to another aspect of the present invention, an embodiment of the present invention further provides a power conversion circuit, the power conversion circuit is used for one or more of current conversion, voltage conversion, and power factor correction;

[0028] The power conversion circuit includes a circuit board and at least one semiconductor device provided by any embodiment of the present invention, and the semiconductor device is electrically connected to the circuit board.

[0029] According to another aspect of the present invention, an embodiment of the present invention further provides a vehicle, comprising a load and a power conversion circuit provided by any embodiment of the present invention, wherein the power conversion circuit is used to convert AC power and / or DC power into AC power and / or DC power and input the converted power into the load.

[0030] In an embodiment of the present invention, ion implantation is performed on the first surface of the semiconductor body, a protective layer is formed on the first surface of the semiconductor body, the semiconductor body is subjected to high temperature treatment, the semiconductor body is subjected to high temperature treatment; the protective layer and the first surface of the semiconductor body are treated, the protective layer is removed and part of the semiconductor body is converted into a sacrificial layer; the sacrificial layer is removed; and an electrode is formed on the surface of the semiconductor body. In the present invention, the protective layer is removed and part of the semiconductor body is converted into a sacrificial layer by the same process. The sacrificial layer and the semiconductor body are made of different materials. When the sacrificial layer is removed, the semiconductor body will not be damaged, and damage to the semiconductor body when the protective layer is removed by a plasma etching process is avoided. The process is simple, the cost is low, and the reliability is high.

[0031] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0033] Figure 1 It is a flow chart of a method for preparing a semiconductor device provided by an embodiment of the present invention.

[0034] Figure 2 It is a schematic diagram of a semiconductor body.

[0035] Figure 3 This is the structure formed after ion implantation.

[0036] Figure 4 It is a schematic diagram of the structure after the protective layer is formed.

[0037] Figure 5 This is a structural diagram after the sacrificial layer is formed.

[0038] Figure 6 It is a schematic structural diagram of a semiconductor device provided by an embodiment of the present invention.

[0039] Figure 7 It is a schematic structural diagram of another semiconductor device provided by an embodiment of the present invention.

[0040] Figure 8 This is a flow chart of another method for preparing a semiconductor device provided by an embodiment of the present invention.

[0041] Fig. 9 This is a flow chart of another method for preparing a semiconductor device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0042] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0043] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, any variation of the terms "including" and "having" is intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0044] Figure 1 is a flow chart of a method for preparing a semiconductor device provided by an embodiment of the present invention. Figure 2-Figure 6 yes Figure 1 For the structural diagram corresponding to each step in Figure 1 , the method for preparing the semiconductor device comprises:

[0045] S110 . Provide a semiconductor body.

[0046] in, Figure 2 is a schematic diagram of the semiconductor body, see Figure 2The material used for the semiconductor body 1 is silicon carbide. The semiconductor body 1 includes a substrate 11 and an epitaxial layer 12. In some embodiments of the present invention, the semiconductor body 1 may also include only the epitaxial layer 12. In another embodiment of the present invention, the semiconductor body 1 may also include a substrate 1 and a semiconductor layer formed by other processes. Among them, the epitaxial layer 12 is a semiconductor layer formed by a single epitaxial process on the basis of the substrate 11. The epitaxial process includes chemical vapor epitaxy (CVE), molecular beam epitaxy (MBD) and atomic layer epitaxy (ALE) and other processes.

[0047] S120 , performing ion implantation on the first surface of the semiconductor body.

[0048] in, Figure 3 This is the structure formed after ion implantation, see Figure 3 A first region 10 and a well region 15 are formed on a first surface 101 of the semiconductor body 1 by an ion implantation process. The first region 10 includes a first active region 14 and a second active region 13. The conductivity type of the first active region 14 is different from that of the well region 15, and the conductivity type of the second active region 13 is the same as that of the first active region 14. Taking an N-type semiconductor device as an example, the first active region 14 is an N+ doped region, the second active region 13 is a P+ doped region, and the well region 15 is a P-body region.

[0049] S130 , forming a protection layer on the first surface of the semiconductor body.

[0050] in, Figure 4 is a schematic diagram of the structure after the protective layer is formed, see Figure 4 The protective layer 16 is used to prevent the roughness of the first surface 101 of the semiconductor body 1 from increasing during high temperature treatment. The material used for the protective layer 16 includes carbon. Exemplarily, the protective layer 16 is a carbon film. The protective layer 16 is formed on the first surface 101 of the semiconductor body 1 by a physical vapor deposition process, a chemical vapor deposition process, or a photoresist curing method.

[0051] S140, performing annealing treatment on the semiconductor body.

[0052] Among them, the annealing treatment is used to activate the ions injected into the semiconductor body, repair the crystal lattice of the semiconductor body, and improve the conductivity and electrical properties of the semiconductor body device.

[0053] S150, processing the protective layer and the first surface of the semiconductor body, removing the protective layer and converting a portion of the semiconductor body into a sacrificial layer.

[0054] in, Figure 5 This is the structural diagram after the sacrificial layer is formed, see Figure 4 and Figure 5The treatment may be an oxidation treatment or other treatments, wherein the protective layer is oxidized and removed, and a portion of the thickness of the semiconductor body 1 is converted into a sacrificial layer 17 different from the semiconductor body material. Exemplarily, the treatment is an oxidation treatment, the sacrificial layer 17 is a silicon oxide layer, and the oxidation treatment may include dry oxygen oxidation or wet oxygen oxidation.

[0055] S160, removing the sacrificial layer.

[0056] Among them, reference Figure 4-Figure 5 , the sacrificial layer 17 is removed by a wet etching process.

[0057] Specifically, by converting the protective layer 16 and part of the semiconductor body 1 into a sacrificial layer 17 of a material different from that of the semiconductor body 1, the semiconductor body 1 will not be damaged when the sacrificial layer 17 is removed, thereby avoiding damage to the first surface 101 of the semiconductor body 1 when removing the protective layer 16 using a plasma etching process.

[0058] In an embodiment of the present invention, ion implantation is performed on the first surface of the semiconductor body, a protective layer is formed on the first surface of the semiconductor body, the semiconductor body is subjected to high temperature treatment, the semiconductor body is subjected to high temperature treatment; the protective layer and the first surface of the semiconductor body are treated, the protective layer is removed, and a portion of the semiconductor body is converted into a sacrificial layer; and the sacrificial layer is removed. In the present invention, the protective layer is removed and a portion of the semiconductor body is converted into a sacrificial layer by the same process. The sacrificial layer and the semiconductor body are made of different materials. When the sacrificial layer is removed, no damage is caused to the semiconductor body, and damage to the semiconductor body when the protective layer is removed by a plasma etching process is avoided. The process is simple, the cost is low, and the reliability is high.

[0059] Optionally, after removing the sacrificial layer, the method further includes forming an electrode on the surface of the semiconductor body.

[0060] in, Figure 6 It is a schematic structural diagram of a semiconductor device provided by an embodiment of the present invention. Figure 7 is a schematic diagram of the structure of another semiconductor device provided by an embodiment of the present invention. Figure 4-Figure 6 The electrode includes a source 3, a gate structure 2 and a drain 4. The source 3 and the gate structure 2 are formed on the first surface 101 of the semiconductor body 1, and the drain 4 is formed on the second surface 102 of the semiconductor body 1. The gate structure 2 includes a gate oxide layer 20 and a gate polysilicon 21. The gate oxide layer 20 is located on the first surface 101 of the semiconductor body 1, and the gate polysilicon 21 is located on the side of the gate oxide layer 20 away from the first surface 101 of the semiconductor body 1. Alternatively, see Figure 7The semiconductor body 1 includes a trench 23, a gate oxide layer 20 and a gate polysilicon 21 are located in the trench 23, and the gate oxide layer 20 is located between the trench 23 and the gate polysilicon 21. In the embodiment of the present invention, an interlayer insulating layer 22 is further provided to insulate the gate polysilicon 21 and the source 3.

[0061] Figure 8 is a flowchart of another method for preparing a semiconductor device provided by an embodiment of the present invention, and Figure 1 The difference between the manufacturing method of the semiconductor device shown in the figure is that the protective layer and the first surface of the semiconductor body are oxidized, the protective layer is removed, and part of the semiconductor body is converted into a sacrificial layer, see Figure 8 , the method for preparing the semiconductor device comprises:

[0062] S110 . Provide a semiconductor body.

[0063] S120 , performing ion implantation on the first surface of the semiconductor body.

[0064] S130 , forming a protection layer on the first surface of the semiconductor body.

[0065] S140, performing annealing treatment on the semiconductor body.

[0066] S1501, performing oxidation treatment on the protective layer and the first surface of the semiconductor body, removing the protective layer and converting a portion of the semiconductor body into a sacrificial layer.

[0067] S160, removing the sacrificial layer.

[0068] S170, forming an electrode on the surface of the semiconductor body.

[0069] In an embodiment of the present invention, the protective layer and the first surface of the semiconductor body are oxidized so that the protective layer is converted into a gas and removed after oxidation, and part of the semiconductor body is converted into an oxide sacrificial layer different from the material of the semiconductor body. This avoids damage to the semiconductor body when removing the protective layer by a plasma etching process, and the process is simple and highly feasible.

[0070] On the basis of the above embodiment, optionally, the protective layer and the first surface of the semiconductor body are oxidized to remove the protective layer and convert a portion of the semiconductor body into a sacrificial layer, including:

[0071] Performing oxidation treatment on the protective layer and the semiconductor body at the same time at a first temperature to remove the protective layer and convert a portion of the semiconductor body into the sacrificial layer;

[0072] Alternatively, the protective layer is first oxidized at the second temperature to remove the protective layer, and then the temperature is raised to the first temperature to oxidize the semiconductor body to form the sacrificial layer.

[0073] Specifically, refer to Figure 4 and Figure 5 , directly using a higher first temperature to simultaneously oxidize the protective layer 16 and the semiconductor body 1, which can simultaneously remove the protective layer 16 and convert part of the thickness of the semiconductor body 1 into the sacrificial layer 17, with a fast processing speed, which can shorten the process time.

[0074] When the second lower temperature is used for oxidation, the semiconductor body 1 will not be oxidized, the protective layer 16 will be oxidized and removed first, and then when the temperature is raised to the first temperature, the surface of the semiconductor body 1 will be oxidized and converted into the sacrificial layer 17. By controlling the temperature in the same oxidation process, the step-by-step oxidation of the protective layer 16 and the semiconductor body 1 can be achieved, which can avoid the simultaneous oxidation of the protective layer 16 and the semiconductor body 1, which will generate more particles when the protective layer 16 is oxidized, resulting in the phenomenon of excessive particles.

[0075] The embodiment of the present invention realizes the removal of the protective layer 16 and partial oxidation of the semiconductor body 1 simultaneously through one oxidation process, which can reduce the tape-out time and save equipment costs.

[0076] Based on the above embodiment, optionally, the first temperature is greater than 1100°C and the second temperature is 600°C-900°C.

[0077] Specifically, when the temperature is between 600° C. and 900° C., the protective layer 16 is oxidized and removed, while the semiconductor body 1 is not oxidized. When the oxidation temperature is greater than 1100° C., both the protective layer 16 and part of the semiconductor body 1 may be oxidized.

[0078] See also Figure 4 and Figure 5 , Optionally, the oxidation treatment includes dry oxygen oxidation.

[0079] Specifically, by performing dry oxygen oxidation on the protective layer 16 and a portion of the first surface 101 of the semiconductor body 1 , the generated sacrificial layer 17 is made more uniform, and the dry oxygen oxidation process is simple, further reducing the process difficulty.

[0080] See also Figure 4 Optionally, the material used for the protective layer 16 includes carbon. In this way, during the annealing process, the protective layer 16 can better protect the semiconductor body 1 and avoid surface damage of the semiconductor body 1, thereby reducing material costs.

[0081] Optionally, the protective layer 16 is made of carbon material, so that CO2 gas is formed after oxidation treatment, which makes the removal process of the protective layer 16 simpler and further reduces the process cost.

[0082] See also Figure 4 and Figure 5 Optionally, the material used for the semiconductor body 1 includes silicon carbide.

[0083] Among them, the protective layer 16 is a carbon film. By oxidizing the carbon film and the silicon carbide semiconductor body 1, the carbon film is converted into carbon dioxide gas and removed. At the same time, part of the semiconductor body 1 is converted into a sacrificial layer 17 of silicon oxide. The removal process of the silicon oxide sacrificial layer is not easy to cause damage to the silicon carbide semiconductor body 1, and damage to the semiconductor body 1 can be avoided.

[0084] Fig. 9 is a flowchart of another method for preparing a semiconductor device provided by an embodiment of the present invention, and Figure 1 The difference between the semiconductor device manufacturing method shown in FIG. 1 and FIG. 2 is that ions are implanted into the first surface of the semiconductor body to form a well region and a first region. Fig. 9 , the method for preparing the semiconductor device comprises:

[0085] S110 . Provide a semiconductor body.

[0086] S1201. Perform ion implantation on a first surface of a semiconductor body to form a well region and a first region, wherein the well region is arranged on a side of the first region away from the first surface.

[0087] The preparation process and effect of S1201 refer to S120 and will not be described in detail here.

[0088] S130 , forming a protection layer on the first surface of the semiconductor body.

[0089] S140, performing annealing treatment on the semiconductor body.

[0090] S150, processing the protective layer and the first surface of the semiconductor body, removing the protective layer and converting a portion of the semiconductor body into a sacrificial layer.

[0091] S160, removing the sacrificial layer.

[0092] S1701, forming a gate, a source and a drain on the surface of the semiconductor body.

[0093] According to another aspect of the present invention, an embodiment of the present invention further provides a semiconductor device, which is manufactured using the method for manufacturing a semiconductor device provided by any embodiment of the present invention.

[0094] According to another aspect of the present invention, an embodiment of the present invention further provides a power module, comprising a substrate and at least one semiconductor device provided by any embodiment of the present invention, wherein the substrate is used to carry the semiconductor device.

[0095] According to another aspect of the present invention, an embodiment of the present invention further provides a power conversion circuit, the power conversion circuit is used for one or more of current conversion, voltage conversion, and power factor correction;

[0096] The power conversion circuit includes a circuit board and at least one semiconductor device provided by any embodiment of the present invention, and the semiconductor device is electrically connected to the circuit board.

[0097] According to another aspect of the present invention, an embodiment of the present invention further provides a vehicle, comprising a load and a power conversion circuit provided by any embodiment of the present invention, wherein the power conversion circuit is used to convert AC power and / or DC power into AC power and / or DC power and input the converted power into the load.

[0098] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0099] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a semiconductor device, characterized in that: include: providing a semiconductor body; Performing ion implantation on the first surface of the semiconductor body; forming a protective layer on the first surface of the semiconductor body; Annealing the semiconductor body; Processing the protective layer and the first surface of the semiconductor body to remove the protective layer and convert a portion of the semiconductor body into a sacrificial layer; The sacrificial layer is removed.

2. The method for preparing a semiconductor device according to claim 1, characterized in that , processing the protective layer and the first surface of the semiconductor body, removing the protective layer and converting a portion of the semiconductor body into a sacrificial layer comprises: The protective layer and the first surface of the semiconductor body are oxidized to remove the protective layer and convert a portion of the semiconductor body into the sacrificial layer.

3. The method for preparing a semiconductor device according to claim 2, characterized in that: The protective layer and the first surface of the semiconductor body are oxidized to remove the protective layer and convert a portion of the semiconductor body into a sacrificial layer, comprising: Performing oxidation treatment on the protective layer and the semiconductor body at the same time at a first temperature to remove the protective layer and convert a portion of the semiconductor body into the sacrificial layer; Alternatively, the protective layer is first oxidized at the second temperature to remove the protective layer, and then the temperature is raised to the first temperature to oxidize the semiconductor body to form the sacrificial layer.

4. The method for preparing a semiconductor device according to claim 3, wherein: The first temperature is greater than 1100°C, and the second temperature is 600°C-900°C.

5. The method for preparing a semiconductor device according to claim 2, wherein: The oxidation treatment includes dry oxygen oxidation.

6. The method for preparing a semiconductor device according to claim 1, wherein: The material used for the protection layer includes carbon, and the material used for the semiconductor body includes silicon carbide.

7. The method for preparing a semiconductor device according to claim 1, characterized in that: After removing the sacrificial layer, the method further comprises: forming an electrode on the surface of the semiconductor body; Performing ion implantation on the first surface of the semiconductor body comprises: Ion implantation is performed on the first surface of the semiconductor body to form a well region and a first region, wherein the well region is arranged on a side of the first region away from the first surface.

8. The method for preparing a semiconductor device according to claim 7, characterized in that: Forming an electrode on the surface of the semiconductor body comprises: A gate, a source and a drain are formed on the surface of the semiconductor body.

9. A semiconductor device, characterized in that: The semiconductor device is prepared by the method for preparing the semiconductor device according to any one of claims 1 to 8.

10. A power module, characterized in that: The method comprises a substrate and at least one semiconductor device according to claim 9, wherein the substrate is used for carrying the semiconductor device.

11. A power conversion circuit, characterized in that: The power conversion circuit is used for one or more of current conversion, voltage conversion, and power factor correction; The power conversion circuit includes a circuit board and at least one semiconductor device as claimed in claim 9, wherein the semiconductor device is electrically connected to the circuit board.

12. A vehicle, characterized in that: The invention comprises a load and a power conversion circuit as claimed in claim 11, wherein the power conversion circuit is used for converting alternating current and / or direct current into alternating current and / or direct current and then inputting the converted alternating current and / or direct current into the load.

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