Preparation method of semiconductor epitaxial layer, semiconductor device and preparation method of semiconductor device
By using SiF2, which has more stable chemical bond energy, as the reaction source, the formation of Si clusters and polycrystalline carbides is suppressed, thus solving the problems of falling off and defects during the growth of SiC epitaxial layers and improving the quality and growth rate of epitaxial layers.
Patent Information
- Application Number
- CN202411143903.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-20
- Publication Date
- 2026-03-06
AI Technical Summary
In existing technologies, a large number of debris and gas nuclei are generated during the growth of SiC epitaxial layers, leading to an increase in surface defects and affecting the quality of the epitaxial layer.
By using gaseous Si-containing compounds with chemical bond energies greater than those between Cl and Si, such as SiF2, as the reaction source, the formation of Si clusters and polycrystalline carbides is suppressed, etching conditions are optimized, and the utilization efficiency of the Si source is improved.
It effectively reduces falling debris and gas nucleation, improves epitaxial layer quality, mitigates surface defects, and enhances growth rate and equipment operational stability.
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Figure CN121620097A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of semiconductor technology, and in particular to a method for preparing a semiconductor epitaxial layer, a semiconductor device, and the same method. Background Technology
[0002] As a representative of third-generation semiconductor materials, silicon carbide (SiC) possesses excellent physical and electrical properties. Compared to silicon, SiC has a larger bandgap and advantages such as high breakdown electric field, high thermal conductivity, high electron saturation velocity, and strong radiation resistance. Therefore, semiconductor devices fabricated using SiC can not only operate stably at higher temperatures but are also suitable for high-voltage and high-frequency applications.
[0003] In related technologies, the method for forming SiC epitaxial layers involves diluting a C source (e.g., C3H8) and a Si source (SiH4) with a carrier gas (H2) and introducing them into a reaction chamber, where they reach the heated SiC substrate surface and react to form a SiC epitaxial layer. The growth rate can be increased by increasing the flow rates of the C and Si source gases. However, during the formation of the SiC epitaxial layer, the Si atoms released by thermal decomposition are prone to agglomerate into nuclei after becoming supersaturated, forming Si clusters (nSi→Sin) and liquid Si droplets. These liquid Si droplets easily condense on the sidewalls and top of the reaction chamber, forming particulate matter that falls off, resulting in an increase in surface defects or a deterioration in surface roughness of the epitaxial layer. In addition, during the formation of the SiC epitaxial layer, a large amount of polycrystalline carbides (e.g., SiC) are also easily formed on the substrate in the reaction chamber. These polycrystalline carbides are very likely to fall onto the SiC substrate or the SiC epitaxial layer, resulting in an increase in surface defects or a deterioration in surface roughness of the epitaxial layer. Currently, HCl gas or Cl-containing compounds such as SiHCl3 (TCS) and SiCl4 are typically added to the SiC epitaxial layer growth system. Since Cl reacts with Si to form a relatively stable SiCl2 intermediate product, the introduction of Cl inhibits the formation of Si clusters and polycrystalline carbides on the substrate in the reaction chamber to some extent, improving Si source utilization efficiency and accelerating the growth rate by more than 10 times while enhancing film quality. However, a large number of debris defects still exist during epitaxial layer growth, resulting in numerous surface defects in the epitaxial layer. Furthermore, these surface defects become increasingly severe with each growth furnace cycle. Therefore, reducing debris formation during semiconductor epitaxial layer growth, minimizing vapor nucleation and parasitic deposition, and improving the quality of semiconductor epitaxial layers have become pressing technical problems that need to be addressed in this field. Summary of the Invention
[0004] This invention provides a method for preparing a semiconductor epitaxial layer, a semiconductor device, and the same method, to reduce debris formed during the growth of the semiconductor epitaxial layer, reduce gas nucleation and parasitic deposition during the epitaxial process, and improve the quality of the semiconductor epitaxial layer.
[0005] According to one aspect of the present invention, a method for preparing a semiconductor epitaxial layer is provided, comprising:
[0006] The substrate is placed in the epitaxial reaction chamber;
[0007] A reaction source for providing semiconductor epitaxial layer material is provided to the epitaxial reaction chamber to form a semiconductor epitaxial layer on one side of the substrate; wherein, the intermediate products in the formation process of the semiconductor epitaxial layer include at least one gaseous compound containing Si element with a chemical bond energy greater than that between Cl and Si.
[0008] Optionally, the reaction source includes a first compound containing element F;
[0009] Among the intermediate products formed, gaseous compounds containing Si with chemical bond energies greater than those between Cl and Si include SiF2.
[0010] Optionally, the material of the semiconductor epitaxial layer includes Si or SiC;
[0011] When the material of the semiconductor epitaxial layer includes Si, the first compound containing F element also contains Si;
[0012] When the material of the semiconductor epitaxial layer includes SiC, the first compound containing F element also contains at least one of Si element and C element.
[0013] Optionally, in the reaction source, the first compound containing element F includes SiF4, F4Si2, F6SSi2, Br3FSi, and C6H. 14 One or more of FSi, ClF3, SF6, CF4, C2F6, CHF3, C4F8, CH2F2, CH3F, NF3, FHS, CHClF2, and C3H4Cl3F3Si.
[0014] Optionally, when the material of the semiconductor epitaxial layer includes SiC, the reaction source includes a C source and a Si source; the reaction source for providing the semiconductor epitaxial layer material into the epitaxial reaction chamber includes:
[0015] A C source and a Si source are provided to the epitaxial reaction chamber, and the C source and the Si source are diluted by a carrier gas; wherein the carrier gas includes H2.
[0016] Optionally, before forming a semiconductor epitaxial layer on one side of the substrate, the method further includes:
[0017] The substrate is subjected to in-situ etching.
[0018] Optionally, the substrate is subjected to in-situ etching, including:
[0019] The temperature inside the epitaxial reaction chamber is heated to a higher than a preset value, and the substrate is etched in situ using H2.
[0020] Simultaneously and / or after in-situ etching of the substrate using H2, the process further includes:
[0021] The substrate is etched using a second compound containing element F.
[0022] Optionally, a semiconductor epitaxial layer is formed on one side of the substrate, comprising:
[0023] The semiconductor epitaxial layer is formed by chemical vapor deposition, physical vapor deposition, pulsed laser deposition, atomic layer deposition, or molecular beam epitaxy.
[0024] According to another aspect of the present invention, a method for fabricating a semiconductor device is provided, comprising:
[0025] Provide substrate;
[0026] A semiconductor epitaxial layer is formed on one side of the substrate using the semiconductor epitaxial layer preparation method described in any embodiment of the present invention;
[0027] The semiconductor epitaxial layer is processed to form a semiconductor device.
[0028] Optionally, the semiconductor epitaxial layer includes a buffer layer and a drift layer; the semiconductor epitaxial layer is formed on one side of the substrate, comprising:
[0029] A buffer layer is formed on one side of the substrate;
[0030] A drift layer is formed on the side of the buffer layer away from the substrate, wherein the doping concentration of the impurities in the buffer layer is greater than the doping concentration of the impurities in the drift layer.
[0031] Optionally, the material of the substrate is the same as the material of the semiconductor epitaxial layer, or the material of the substrate is different from the material of the semiconductor epitaxial layer;
[0032] The substrate material includes Si, 6H-SiC, 4H-SiC, 6H-SiC, or 3C-SiC;
[0033] The material of the semiconductor epitaxial layer includes Si, 6H-SiC, 4H-SiC, 6H-SiC, or 3C-SiC.
[0034] According to another aspect of the present invention, a semiconductor power device is provided, which is formed by the semiconductor power device fabrication method described in any embodiment of the present invention.
[0035] According to another aspect of the present invention, a power module is provided, comprising a substrate and at least one semiconductor power device as described in any embodiment of the present invention, wherein the substrate is used to support the semiconductor power device.
[0036] According to another aspect of the present invention, a power conversion circuit is provided, the power conversion circuit being used for one or more of current conversion, voltage conversion, and power factor correction;
[0037] The power conversion circuit includes a circuit board and at least one semiconductor device as described in any embodiment of the present invention, wherein the semiconductor device is electrically connected to the circuit board.
[0038] According to another aspect of the present invention, a vehicle is provided, including a load and a power conversion circuit as described in any embodiment of the present invention, the power conversion circuit being configured to convert alternating current to direct current, convert alternating current to alternating current, convert direct current to direct current, or convert direct current to alternating current and then input the power to the load.
[0039] This invention provides a method for preparing a semiconductor epitaxial layer, a semiconductor device, and the same method. The method includes: placing a substrate in an epitaxial reaction chamber; providing a reaction source for semiconductor epitaxial layer material into the reaction chamber to form a semiconductor epitaxial layer on one side of the substrate; wherein the intermediate product during the formation of the semiconductor epitaxial layer includes at least one gaseous compound containing Si with a chemical bond energy greater than that between Cl and Si. The technical solution provided by this invention, by adjusting the reaction source used to form the semiconductor epitaxial layer, ensures that the intermediate product during the formation of the semiconductor epitaxial layer includes at least one gaseous compound containing Si with a chemical bond energy greater than that between Cl and Si. This results in a Si-containing intermediate product that is chemically more stable and easier to form than SiCl2, further suppressing the formation of Si clusters. This effectively reduces the amount of debris and gaseous nucleation formed during the growth of the semiconductor epitaxial layer, as well as the formation of polycrystalline carbides on the substrate in the reaction chamber, thereby improving the quality of the semiconductor epitaxial layer.
[0040] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description
[0041] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0042] Figure 1 This is a flowchart of a method for preparing a semiconductor epitaxial layer according to an embodiment of the present invention;
[0043] Figure 2 This is a flowchart of another method for preparing a semiconductor epitaxial layer provided in an embodiment of the present invention;
[0044] Figure 3 This is a flowchart of another method for preparing a semiconductor epitaxial layer provided in an embodiment of the present invention;
[0045] Figure 4 This is a flowchart of another method for preparing a semiconductor epitaxial layer provided in an embodiment of the present invention;
[0046] Figure 5 This is a flowchart of a method for fabricating a semiconductor device according to an embodiment of the present invention;
[0047] Figure 6 This is a schematic diagram of the structure after the formation of a semiconductor epitaxial layer in a semiconductor device fabrication method provided in an embodiment of the present invention. Detailed Implementation
[0048] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.
[0049] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.
[0050] This invention provides a method for preparing a semiconductor epitaxial layer. Figure 1 This is a flowchart of a method for preparing a semiconductor epitaxial layer according to an embodiment of the present invention, see reference. Figure 1 ,include:
[0051] S110. Place the substrate in the epitaxial reaction chamber.
[0052] S120, A reaction source for providing semiconductor epitaxial layer material is provided into the epitaxial reaction chamber to form a semiconductor epitaxial layer on one side of the substrate; wherein, the intermediate product in the semiconductor epitaxial layer formation process includes at least one gaseous compound containing Si element whose chemical bond energy is greater than that between Cl and Si.
[0053] Specifically, the substrate material and the semiconductor epitaxial layer material can be the same, or the substrate material and the semiconductor epitaxial layer material can be different. The substrate material includes Si or SiC, where the SiC crystal form can be 6H-SiC, 4H-SiC, or 3C-SiC; the semiconductor epitaxial layer material includes Si or SiC, where the SiC crystal form can be 6H-SiC, 4H-SiC, or 3C-SiC. In one embodiment of the invention, an n-type SiC epitaxial layer can be prepared on a heterogeneous substrate, i.e., the substrate is a non-SiC substrate, and an n-type SiC epitaxial material is grown on the non-SiC substrate, such as growing an n-type 3C-SiC epitaxial material on a Si substrate. In another embodiment of the invention, an n-type SiC epitaxial layer can be prepared on other crystal form SiC substrates, such as epitaxially growing an n-type 4H-SiC epitaxial layer on a 6H-SiC substrate, or growing an n-type 4H-SiC epitaxial layer on a 3C-SiC substrate, or growing an n-type 3C-SiC epitaxial layer on a 4H-SiC substrate.
[0054] When the material of the semiconductor epitaxial layer includes SiC, the reaction source includes a C source and a Si source. The reaction source that provides the semiconductor epitaxial layer material to the epitaxial reaction chamber may include: providing a C source and a Si source to the epitaxial reaction chamber, and diluting the C source and Si source with a carrier gas; wherein the carrier gas includes H2. In related technologies, chlorine (Cl) is introduced into the reaction source of the semiconductor epitaxial layer to improve the growth rate of the semiconductor epitaxial layer and reduce the defect density in the semiconductor epitaxial layer. For example, common growth systems include SiH4+C3H8+HCl+H2, SiHCl3(TCS)+C2H4+H2, etc. This is because the chemical bond energy between Si and Cl is 381 kJ / mol, while the chemical bond energies for Si-H, Si-C, and Si-Si are 318 kJ / mol and 222 kJ / mol, respectively. The higher chemical bond energy between Si and Cl results in a more stable and readily formed intermediate product, SiCl2, which to some extent inhibits the formation of Si clusters and polycrystalline carbides on the spare parts in the reaction chamber. This improves the utilization efficiency of the Si source, accelerates the growth rate, and enhances the film quality. However, the introduction of Cl into the growth system still results in a large amount of debris, gas nucleation, and parasitic deposition during epitaxial layer growth, leading to less than ideal improvement in semiconductor epitaxial layer defects.
[0055] The semiconductor epitaxial layer preparation method provided in this invention adjusts the reaction source used to form the semiconductor epitaxial layer so that the intermediate products in the semiconductor epitaxial layer formation process include at least one gaseous compound containing Si elements with a chemical bond energy greater than that between Cl and Si. This allows for the acquisition of Si element-containing compounds that are chemically more stable and easier to form than SiCl2, further suppressing the formation of Si clusters and polycrystalline carbides on the spare parts in the reaction chamber, improving the utilization efficiency of the Si source, thereby effectively reducing the debris formed during the growth of the semiconductor epitaxial layer, reducing gas phase nucleation and parasitic deposition during the epitaxial process, and improving the quality of the semiconductor epitaxial layer.
[0056] The above is the core inventive concept of this invention. The preparation method of the semiconductor epitaxial layer is described in detail below.
[0057] Based on the above embodiments, optionally, the reaction source for forming the semiconductor epitaxial layer includes a first compound containing the element F; among the intermediate products formed, the gaseous compound containing the element Si, whose chemical bond energy is greater than that between Cl and Si, includes SiF2. Figure 2 This is a flowchart of another method for preparing a semiconductor epitaxial layer provided in an embodiment of the present invention, referred to [reference]. Figure 2 Methods for preparing semiconductor epitaxial layers include:
[0058] S210. Place the substrate in the epitaxial reaction chamber.
[0059] S220, A reaction source for providing semiconductor epitaxial layer material to the epitaxial reaction chamber is used to form a semiconductor epitaxial layer on one side of the substrate; wherein the reaction source includes a first compound containing element F, and the intermediate product generated during the formation of the semiconductor epitaxial layer includes SiF2.
[0060] Specifically, a first compound containing element F is used as a reaction source in the semiconductor epitaxial layer growth system. The chemical bond energy between F and Si is 565 kJ / mol, which can form the more stable intermediate product SiF2 compared to SiCl2. The gaseous SiF2 molecule has thermodynamic stability. The technical solution provided in this embodiment of the invention utilizes the characteristic that the chemical bond energy between F and Si is much greater than that of Si-Cl, Si-H, Si-C, and Si-Si. During the formation of the semiconductor epitaxial layer, it can further suppress Si gas-phase nucleation, Si droplet formation, and parasitic deposition, thereby improving the Si source utilization efficiency, increasing the growth rate of the semiconductor epitaxial layer, and improving the quality of the semiconductor epitaxial layer.
[0061] Furthermore, compared to Cl, F exhibits superior etching performance on Si. Incorporating an F-containing first compound as the reaction source optimizes etching and epitaxial conditions, effectively etching subsurface defects in the SiC substrate and defects generated during SiC epitaxial layer formation. This results in higher quality SiC epitaxial layers with lower crystal structure defect density and better surface quality. It also improves consistency and repeatability between batches, enhancing equipment efficiency. Moreover, using an F-containing first compound as the reaction source reduces the formation of solid particles in the epitaxial reaction chamber (e.g., solid particles formed by Si droplet condensation and polycrystalline carbides). This eliminates the problem of blockage in the epitaxial reaction chamber's inlet or outlet pipes, maintaining normal equipment operation and extending maintenance cycles.
[0062] Based on the above embodiments, optionally, the material of the semiconductor epitaxial layer includes Si, and the first compound containing F element further contains Si. This can be understood as the Si source being the first compound containing F element. Optionally, in other embodiments of the present invention, the Si source in the reaction source is not the same substance as the first compound containing F element. Here, the Si source can be understood as a material that provides Si element to the material of the semiconductor epitaxial layer.
[0063] Based on the above embodiments, optionally, the material of the semiconductor epitaxial layer includes SiC, and the first compound containing F element also contains at least one of Si element and C element.
[0064] Specifically, when the material of the semiconductor epitaxial layer is SiC, the reaction source includes a C source and a Si source. The C source can be a first compound containing the element F; or, the Si source can be a first compound containing the element F; or, the C source is a first compound containing the element F, and the Si source is a first compound containing the element F.
[0065] The Si source and the C source may be the same compound or they may not be the same compound. When the Si source and the C source are the same compound, the compound includes at least Si, C, and F elements. Optionally, in other embodiments of the present invention, the first compound containing F element may not be used as either the Si source or the C source.
[0066] Based on the above embodiments, the first compound containing the element F may optionally include, but is not limited to: SiF4, F4Si2, F6SSi2, Br3FSi, C6H 14 FSi, ClF3, SF6, CF4, C2F6, CHF3, C4F8, CH2F2, CH3F, NF3, FHS, CHClF2, or C3H4Cl3F3Si. The first compound containing element F in the reaction source forming the semiconductor epitaxial layer includes, but is not limited to: SiF4, F4Si2, F6SSi2, Br3FSi, C6H... 14 One or more of FSi, ClF3, SF6, CF4, C2F6, CHF3, C4F8, CH2F2, CH3F, NF3, FHS, CHClF2 and C3H4Cl3F3Si.
[0067] Based on the above embodiments, optionally, before forming a semiconductor epitaxial layer on one side of the substrate, the substrate is further subjected to in-situ etching to remove surface damage and scratches on the substrate surface. Figure 3 This is a flowchart of another method for preparing a semiconductor epitaxial layer provided in an embodiment of the present invention, referred to [reference]. Figure 3 Methods for preparing semiconductor epitaxial layers include:
[0068] S310. Place the substrate in the epitaxial reaction chamber.
[0069] S320, Perform in-situ etching on the substrate.
[0070] Specifically, various defects exist within the substrate, and these defects are often inherited during the epitaxial growth process of semiconductor epitaxial layers, severely impacting device performance. Before epitaxial growth on the silicon carbide substrate surface, in-situ etching can be performed on the silicon carbide substrate to remove surface damage and scratches.
[0071] In-situ etching of the substrate may specifically include: heating the temperature inside the epitaxial reaction chamber to a preset value, and then performing in-situ etching of the substrate using H2. For example, high-purity hydrogen gas is introduced into the epitaxial reaction chamber at a flow rate of 100 L / min to 120 L / min, such as 100 L / min, 110 L / min, or 120 L / min, to maintain the vacuum level of the epitaxial reaction chamber at 40 mbar to 150 mbar; the temperature of the epitaxial reaction chamber is then increased to stabilize at 1500℃ to 1700℃, and the silicon carbide substrate is etched in-situ for 2 to 5 minutes to remove surface damage and scratches on the silicon carbide substrate surface.
[0072] S330, A reaction source for providing semiconductor epitaxial layer material to the epitaxial reaction chamber is used to form a semiconductor epitaxial layer on one side of the substrate; wherein the reaction source includes a first compound containing element F, and the intermediate product generated during the formation of the semiconductor epitaxial layer includes SiF2.
[0073] Specifically, a semiconductor epitaxial layer can be formed on one side of a substrate using chemical vapor deposition, physical vapor deposition, pulsed laser deposition, atomic layer deposition, or molecular beam epitaxy. The formation process of the semiconductor epitaxial layer can be selected according to actual needs. The effect of setting the reaction source including a first compound containing element F can be referred to the above embodiments, and will not be repeated here.
[0074] Furthermore, the process of etching the substrate in situ with H2 simultaneously and / or afterward includes etching the substrate with a second compound containing the element F. Figure 4 This is a flowchart of another method for preparing a semiconductor epitaxial layer provided in an embodiment of the present invention, referred to [reference]. Figure 4 A method for preparing a semiconductor epitaxial layer, including: a method for preparing a semiconductor epitaxial layer, including:
[0075] S410. Place the substrate in the epitaxial reaction chamber.
[0076] S420. The substrate is etched in situ, and the substrate is etched using a second compound containing element F.
[0077] S430, A reaction source for providing semiconductor epitaxial layer material to the epitaxial reaction chamber is used to form a semiconductor epitaxial layer on one side of the substrate; wherein the reaction source includes a first compound containing element F, and the intermediate product generated during the formation of the semiconductor epitaxial layer includes SiF2.
[0078] Specifically, hydrogen (H) has a better etching effect on carbon (C), while sulfur (F) has a better etching effect on silicon (Si). Using a second compound containing sulfur (F) to etch the substrate can optimize etching and epitaxial conditions, further removing surface damage and scratches on the silicon carbide substrate surface, resulting in better quality SiC epitaxial layers with lower crystal structure defect density and better surface quality. Second compounds containing sulfur (F) include, but are not limited to: SiF4, F4Si2, F6SSi2, Br3FSi, and C6H. 14 FSi, ClF3, SF6, CF4, C2F6, CHF3, C4F8, CH2F2, CH3F, NF3, FHS, CHClF2 or C3H4Cl3F3Si.
[0079] Optionally, after in-situ etching of the substrate with H2, the substrate is then etched using a second compound containing F. In this case, the second compound containing F can be reused as the first compound containing F.
[0080] This invention also provides a method for fabricating a semiconductor device, comprising: providing a substrate; forming a semiconductor epitaxial layer on one side of the substrate using the semiconductor epitaxial layer fabrication method described in any embodiment of this invention; and processing the semiconductor epitaxial layer to form a semiconductor device.
[0081] Figure 5 This is a flowchart of a method for fabricating a semiconductor device according to an embodiment of the present invention, see reference. Figure 5 The methods for fabricating semiconductor devices include:
[0082] S510 provides a substrate.
[0083] S520. Place the substrate in the epitaxial reaction chamber.
[0084] S530, a reaction source for providing semiconductor epitaxial layer material is provided into the epitaxial reaction chamber to form a semiconductor epitaxial layer on one side of the substrate; wherein, the intermediate product in the semiconductor epitaxial layer formation process includes at least one gaseous compound containing Si element whose chemical bond energy is greater than that between Cl and Si.
[0085] S540. Process the semiconductor epitaxial layer to form a semiconductor device.
[0086] The semiconductor device fabrication method provided in this invention adjusts the reaction source used to form the semiconductor epitaxial layer so that the intermediate products in the semiconductor epitaxial layer formation process include at least one gaseous compound containing Si elements with a chemical bond energy greater than that between Cl and Si. This allows for the formation of Si element-containing compounds that are more chemically stable and easier to form than SiCl2, further suppressing the formation of Si clusters and polycrystalline carbides on the substrate in the reaction chamber. This improves the utilization efficiency of the Si source, thereby effectively reducing the debris formed during the growth of the semiconductor epitaxial layer, reducing gas phase nucleation and parasitic deposition during epitaxy, and improving the quality of the semiconductor epitaxial layer.
[0087] Optionally, in step S530, the reaction source includes a first compound containing the element F; among the intermediate products formed, the gaseous compound containing the element Si, whose chemical bond energy is greater than that between Cl and Si, includes SiF2.
[0088] Optionally, the material of the semiconductor epitaxial layer includes Si or SiC;
[0089] When the material of the semiconductor epitaxial layer includes Si, the first compound containing element F further contains Si; when the material of the semiconductor epitaxial layer includes SiC, the first compound containing element F further contains at least one of element Si and element C.
[0090] Optionally, the first compound containing the element F in the reaction source includes: SiF4, F4Si2, F6SSi2, Br3FSi, C6H 14 One or more of FSi, ClF3, SF6, CF4, C2F6, CHF3, C4F8, CH2F2, CH3F, NF3, FHS, CHClF2, and C3H4Cl3F3Si.
[0091] Optionally, the substrate material may be the same as the semiconductor epitaxial layer material, or the substrate material may be different from the semiconductor epitaxial layer material. The substrate material includes, but is not limited to, Si, SiC, 6H-SiC, 4H-SiC, 6H-SiC, or 3C-SiC; the semiconductor epitaxial layer material includes, but is not limited to, Si, SiC, 6H-SiC, 4H-SiC, 6H-SiC, or 3C-SiC. An n-type SiC epitaxial layer can be prepared on a heterogeneous substrate, i.e., the substrate is a non-SiC substrate, and an n-type SiC epitaxial material is grown on the non-SiC substrate, such as growing an n-type 3C-SiC epitaxial material on a Si substrate. An n-type SiC epitaxial layer can also be prepared on other crystalline SiC substrates, such as epitaxially growing an n-type 4H-SiC epitaxial layer on a 6H-SiC substrate, or an n-type 4H-SiC epitaxial layer on a 3C-SiC substrate, or an n-type 3C-SiC epitaxial layer on a 4H-SiC substrate.
[0092] Optionally, when the material of the semiconductor epitaxial layer includes SiC, the reaction source includes a C source and a Si source; the reaction source that provides the semiconductor epitaxial layer material into the epitaxial reaction chamber includes:
[0093] A C source and a Si source are provided to the epitaxial reaction chamber, and the C source and the Si source are diluted by a carrier gas, wherein the carrier gas includes H2.
[0094] Alternatively, a semiconductor epitaxial layer can be formed on one side of the substrate using chemical vapor deposition, physical vapor deposition, pulsed laser deposition, atomic layer deposition, or molecular beam epitaxy.
[0095] Optionally, a semiconductor epitaxial layer is formed on one side of the substrate, including: forming a buffer layer on one side of the substrate; and forming a drift layer on the side of the buffer layer away from the substrate.
[0096] Specifically, a SiC buffer layer is formed on a SiC substrate within the epitaxial reaction chamber, and an epitaxial growth is performed using a first compound containing element F as the reaction source; a SiC drift layer is formed on the SiC buffer layer within the epitaxial reaction chamber, and an epitaxial growth is performed using a first compound containing element F as the reaction source.
[0097] Figure 6 This is a schematic diagram of the structure after forming a semiconductor epitaxial layer in a semiconductor device fabrication method provided in an embodiment of the present invention. (Refer to...) Figure 6 The semiconductor epitaxial layer 20 includes a buffer layer 21 and a drift layer 22. The buffer layer 21 is located on one side of the substrate 10, and the drift layer 22 is located on the side of the buffer layer 21 away from the substrate 10. The doping type of the semiconductor epitaxial layer 20 can be either N-type or P-type. The doping concentration of the impurities in the buffer layer 21 is greater than the doping concentration of the impurities in the drift layer 22.
[0098] Optionally, before forming the semiconductor epitaxial layer on one side of the substrate in step S530, the method further includes: performing in-situ etching on the substrate. Specifically, performing in-situ etching on the substrate may include: heating the temperature inside the epitaxial reaction chamber to a preset value, and then performing in-situ etching on the substrate using H2.
[0099] Optionally, during and / or after in-situ etching of the substrate with H2, the method further includes etching the substrate with a second compound containing F.
[0100] Optionally, the processing of the semiconductor epitaxial layer in step S540 may include: performing ion implantation in the semiconductor epitaxial layer to form a well region and a source region; sequentially forming a gate insulating layer and a gate on the surface of the semiconductor epitaxial layer, or forming a gate trench on the surface of the semiconductor epitaxial layer away from the substrate, and then forming a gate insulating layer and a gate in the gate trench; forming a source electrode in contact with the source region on the surface of the semiconductor epitaxial layer; and forming a drain electrode on the back side of the substrate.
[0101] This invention also provides a semiconductor device formed by the semiconductor power device fabrication method described in any embodiment of this invention. It has the same technical effects and will not be repeated here. The semiconductor device can be a planar semiconductor device or a trench semiconductor device.
[0102] This invention also provides a power module, including a substrate and at least one semiconductor device as described in any embodiment of this invention, wherein the substrate is used to support the semiconductor device. It has the same technical effects and will not be described again here.
[0103] This invention also provides a power conversion circuit, which is used for one or more of current conversion, voltage conversion, and power factor correction. The power conversion circuit includes a circuit board and at least one semiconductor device as described in any embodiment of this invention, and the semiconductor device is electrically connected to the circuit board. It has the same technical effects and will not be described again here.
[0104] This invention also provides a vehicle, including a load and a power conversion circuit as described in any embodiment of the invention. The power conversion circuit is used to convert AC power to DC power, AC power to AC power, DC power to DC power, or DC power to AC power and then input it to the load. It has the same technical effects and will not be described again here.
[0105] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.
Claims
1. A method of producing a semiconductor epitaxial layer, characterized by, The method comprises: placing a substrate in an epitaxial reaction chamber; providing a reaction source of a semiconductor epitaxial layer material into the epitaxial reaction chamber to form a semiconductor epitaxial layer on one side of the substrate; wherein an intermediate product formed during the forming of the semiconductor epitaxial layer comprises at least one gaseous compound containing Si element with a bond energy greater than the bond energy between Cl and Si.
2. The method of producing a semiconductor epitaxial layer according to claim 1, wherein The reaction source comprises a first compound containing F element; In the intermediate product formed, the gaseous compound containing Si element with a bond energy greater than the bond energy between Cl and Si comprises SiF2.
3. The method of claim 2, wherein the step of growing the semiconductor epitaxial layer is performed by a method selected from the group consisting of a vapor phase epitaxy method, a liquid phase epitaxy method, and a molecular beam epitaxy method. The material of the semiconductor epitaxial layer comprises Si or SiC; In the case that the material of the semiconductor epitaxial layer comprises Si, the first compound containing F element further comprises Si; In the case that the material of the semiconductor epitaxial layer comprises SiC, the first compound containing F element further comprises at least one of Si element and C element.
4. The method according to claim 2, wherein, In the reaction source, the first compound containing the element F includes one or more of SiF4, F4Si2, F6SSi2, Br3FSi, C6H 14 FSi, ClF3, SF6, CF4, C2F6, CHF3, C4F8, CH2F2, CH3F, NF3, FHS, CHClF2, C3H4Cl3F3Si.
5. The method of producing a semiconductor epitaxial layer according to claim 1, wherein In the case that the material of the semiconductor epitaxial layer comprises SiC, the reaction source comprises a C source and a Si source; providing a reaction source of a semiconductor epitaxial layer material into the epitaxial reaction chamber comprises: providing a C source and a Si source into the epitaxial reaction chamber and diluting the C source and the Si source by a carrier gas; wherein the carrier gas comprises H2.
6. The method of claim 1, wherein the semiconductor epitaxial layer is formed by a method comprising: Before forming the semiconductor epitaxial layer on one side of the substrate, the method further comprises: performing in-situ etching treatment on the substrate.
7. The method of claim 6, wherein the step of growing the semiconductor epitaxial layer is performed by a method selected from the group consisting of a vapor phase epitaxy method, a liquid phase epitaxy method, and a molecular beam epitaxy method. The in-situ etching treatment on the substrate comprises: heating the temperature in the epitaxial reaction chamber to be higher than a preset value, and performing in-situ etching treatment on the substrate by H2; The in-situ etching treatment on the substrate by H2 is performed simultaneously and / or subsequently to, the method further comprises: performing etching treatment on the substrate by a second compound containing F element.
8. The method of producing a semiconductor epitaxial layer according to claim 1, wherein Forming the semiconductor epitaxial layer on one side of the substrate comprises: forming the semiconductor epitaxial layer by chemical vapor deposition, physical vapor deposition, pulsed laser deposition, atomic layer deposition or molecular beam epitaxy.
9. A method of manufacturing a semiconductor device, characterized by, The method comprises: providing a substrate; forming a semiconductor epitaxial layer on one side of the substrate by the method for preparing a semiconductor epitaxial layer according to any one of claims 1 to 8; performing treatment on the semiconductor epitaxial layer to form a semiconductor device.
10. The method of producing a semiconductor device according to Claim 9, wherein The semiconductor epitaxial layer comprises a buffer layer and a drift layer; forming the semiconductor epitaxial layer on one side of the substrate comprises: forming the buffer layer on one side of the substrate; forming the drift layer on a side of the buffer layer away from the substrate, wherein the doping concentration of the impurity doped in the buffer layer is greater than the doping concentration of the impurity doped in the drift layer.
11. The method according to claim 9, wherein: the material of the substrate is the same as the material of the semiconductor epitaxial layer, or the material of the substrate is different from the material of the semiconductor epitaxial layer; wherein the material of the substrate comprises Si, 6H-SiC, 4H-SiC, 6H-SiC or 3C-SiC. The material of the semiconductor epitaxial layer comprises Si, 6H-SiC, 4H-SiC, 6H-SiC or 3C-SiC.
12. A semiconductor power device, characterized by Formed by the method for manufacturing a semiconductor power device according to any one of claims 9 to 11.
13. A power module, characterized by A substrate for carrying the semiconductor power device according to claim 12.
14. A power conversion circuit, characterized by The power conversion circuit is used for one or more of current conversion, voltage conversion, power factor correction; The power conversion circuit comprises a circuit board and at least one semiconductor power device according to claim 12, and the semiconductor power device is electrically connected with the circuit board.
15. A vehicle characterized by comprising: A load and a power conversion circuit according to claim 14 are included, and the power conversion circuit is used for converting alternating current into direct current, converting alternating current into alternating current, converting direct current into direct current, or converting direct current into alternating current, and then inputting to the load.