Methods and systems for epitaxial growth of crystals

Abstract

Embodiments of the present specification provide a method and system for epitaxial growth of a crystal. The method for epitaxial growth of a crystal includes growing an epitaxial layer on a carbon face of a silicon carbide seed wafer; growing a crystal on the epitaxial layer by a physical vapor transport method. The system for epitaxial growth of a crystal is configured to implement the method for epitaxial growth of a crystal, the system including an epitaxial growth module configured to grow an epitaxial layer on a carbon face of a silicon carbide seed wafer; a crystal growth module configured to grow a crystal on the epitaxial layer by a physical vapor transport method.

Description

Technical Field

[0001] This specification relates to the field of artificial crystal growth, and in particular to methods and systems for growing crystals via epitaxy. Background Technology

[0002] Crystals prepared by growing silicon carbide (SiC) seed crystals possess excellent mechanical and electrical properties, good thermal conductivity, and thermal stability, making them suitable for manufacturing high-frequency, high-power, and high-temperature resistant semiconductor devices. These devices are widely used in electric vehicles, electronic power systems, and aerospace applications. However, silicon carbide seed crystals are prone to various defects during growth, such as channel defects, microtube defects, carbon inclusions, spiral dislocations, and basal plane dislocations, which can affect the final crystal quality and device performance.

[0003] Therefore, it is necessary to provide methods and systems for growing crystals through epitaxial growth, so that the obtained crystals have high quality, stable overall performance, and few macroscopic defects. Summary of the Invention

[0004] This specification provides one or more embodiments of a method for growing crystals via epitaxial growth. The method includes growing an epitaxial layer on a carbon surface of a silicon carbide seed wafer and growing a crystal on the epitaxial layer using a physical vapor transport method.

[0005] In some embodiments, growing an epitaxial layer on the carbon surface of a silicon carbide seed wafer includes: determining a target doping concentration based on the silicon carbide seed wafer; determining a target doping parameter based on the target doping concentration; and controlling the growth environment of the epitaxial layer based on the target doping parameter.

[0006] In some embodiments, the dopant of the silicon carbide seed wafer is nitrogen gas, and the target doping parameter includes the doping flow rate of the nitrogen gas.

[0007] In some embodiments, determining the target doping parameter includes: determining the first doping parameter by growing a first reference epitaxial layer having a first doping concentration, wherein the first doping concentration is a doping concentration within the detection range of a target detection device; and determining the target doping parameter based on the target doping concentration and the first doping parameter.

[0008] In some embodiments, determining the first doping parameter by growing a first reference epitaxial layer with a first doping concentration includes: adjusting the doping parameter to grow the first reference epitaxial layer with the first doping concentration; and determining the doping parameter at this time as the first doping parameter in response to the doping uniformity of the first reference epitaxial layer being greater than a preset uniformity threshold.

[0009] In some embodiments, determining the target doping parameter based on the target doping concentration and the first doping parameter includes: calculating a reference ratio of the first doping concentration to the target doping concentration; determining the correlation between the first doping parameter and the target doping parameter based on the reference ratio; and determining the target doping parameter based on the correlation and the first doping parameter.

[0010] In some embodiments, determining the target doping parameter includes: acquiring growth data of growing a plurality of second reference epitaxial layers with a second doping concentration, wherein the difference between the second doping concentration and the target doping concentration is less than a preset value, and the growth data includes at least the second doping parameter for growing each second reference epitaxial layer and the doping situation corresponding to the second doping parameter; and determining the target doping parameter based on the growth data.

[0011] In some embodiments, the doping condition includes doping uniformity, and obtaining growth data for growing a plurality of second reference epitaxial layers with a second doping concentration includes: for each second reference epitaxial layer, obtaining a photoluminescence (PL) spectrum of the epitaxial wafer containing the second reference epitaxial layer; determining whether the photoluminescence spectrum includes a first characteristic region, the first characteristic region being a region with a brightness lower than a first brightness threshold; in response to the photoluminescence spectrum including the first characteristic region, obtaining a resistivity map of the epitaxial wafer, and based on the resistivity map and the first characteristic region, determining whether the doping uniformity of the second reference epitaxial layer meets a uniformity requirement; in response to the photoluminescence spectrum not including the first characteristic region, determining that the doping uniformity of the second reference epitaxial layer meets the uniformity requirement.

[0012] In some embodiments, determining whether the doping uniformity of the second reference epitaxial layer meets the uniformity requirement based on the resistivity map and the first feature region includes: determining a second feature region corresponding to the first feature region on the resistivity map, obtaining a first minimum resistivity within the second feature region and a second minimum resistivity outside the second feature region; and determining whether the doping uniformity meets the uniformity requirement based on the difference between the first minimum value and the second minimum value.

[0013] In some embodiments, the doping condition includes doping concentration; obtaining growth data for growing a plurality of second reference epitaxial layers having a second doping concentration includes: for each second reference epitaxial layer,

[0014] Obtain the photoluminescence spectrum and resistivity map of the epitaxial wafer containing the second reference epitaxial layer;

[0015] A third characteristic region of the photoluminescence spectrum is determined, wherein the third characteristic region is a region with a brightness higher than a second brightness threshold; a fourth characteristic region corresponding to the third characteristic region on the resistivity map is determined, and a third minimum value of resistivity within the fourth characteristic region is obtained; based on the third minimum value and a first preset reference range, it is determined whether the doping concentration meets the concentration requirements.

[0016] In some embodiments, growing an epitaxial layer on the carbon surface of a silicon carbide seed wafer further includes: determining the doping status of the silicon carbide seed wafer; determining whether the doping status meets the doping requirements; and growing the epitaxial layer on the carbon surface of the silicon carbide seed wafer in response to the doping status meeting the doping requirements.

[0017] In some embodiments, the doping condition includes doping uniformity, the doping requirement includes uniformity requirement, and determining whether the doping condition meets the doping requirement includes: acquiring a photoluminescence spectrum of the silicon carbide seed wafer; determining whether the photoluminescence spectrum includes a fifth feature region, the fifth feature region being a region with a brightness lower than a third brightness threshold; in response to the photoluminescence spectrum including the fifth feature region, acquiring a resistivity map of the silicon carbide seed wafer, and determining whether the doping uniformity meets the uniformity requirement based on the resistivity map and the fifth feature region; in response to the photoluminescence spectrum not including the fifth feature region, determining that the doping uniformity meets the uniformity requirement.

[0018] In some embodiments, determining whether the doping uniformity meets the uniformity requirement based on the resistivity map and the fifth feature region includes: determining a sixth feature region of the resistivity map, the sixth feature region being a region with resistivity lower than a first resistivity threshold; determining a contrast region corresponding to the sixth feature region on the photoluminescence spectrum, the brightness of the contrast region being higher than a fourth brightness threshold, the fourth brightness threshold being determined based on the first resistivity threshold; and determining whether the doping uniformity meets the uniformity requirement based on the shape of the contrast region and the shape of the sixth feature region.

[0019] In some embodiments, determining whether the doping uniformity meets the uniformity requirement based on the resistivity map and the fifth feature region includes: extracting the outline of the bright region outside the fifth feature region on the photoluminescence spectrum; extracting a set of resistivity contour lines on the resistivity map; determining whether there exists a target contour in the set of contours that meets a preset condition with the outline of the bright region; determining that the doping uniformity does not meet the uniformity requirement in response to the presence of the target contour in the set of contours; and determining that the doping uniformity meets the uniformity requirement in response to the absence of the target contour in the set of contours.

[0020] In some embodiments, the doping condition includes doping concentration, the doping requirement includes concentration requirement, and determining whether the doping condition meets the doping requirement includes: acquiring the photoluminescence spectrum and resistivity map of the silicon carbide seed wafer; determining a seventh feature region of the photoluminescence spectrum, wherein the seventh feature region is a region with a brightness higher than a fifth brightness threshold; determining an eighth feature region corresponding to the seventh feature region on the resistivity map, and acquiring a fourth minimum resistivity value within the eighth feature region; and determining whether the doping concentration meets the concentration requirement based on the fourth minimum value and a second preset reference range.

[0021] In some embodiments, growing an epitaxial layer on the carbon surface of a silicon carbide seed wafer further includes: determining the growth rate of the epitaxial layer on the carbon surface; and determining the growth time of the epitaxial layer based on the growth rate.

[0022] This specification provides one or more embodiments of a system for growing crystals via epitaxial growth. The system is configured to implement a method for growing crystals via epitaxial growth. The system includes an epitaxial growth module configured to grow an epitaxial layer on a carbon surface of a silicon carbide seed wafer and a crystal growth module configured to grow a crystal on the epitaxial layer using a physical vapor transport method. Attached Figure Description

[0023] This specification will be further described by way of exemplary embodiments, which will be described in detail with reference to the accompanying drawings. These embodiments are not limiting; in these embodiments, the same reference numerals denote the same structures, wherein:

[0024] Figure 1 This is a schematic diagram of the crystal structure shown in some embodiments of this specification;

[0025] Figure 2A This is a schematic diagram of a system for epitaxially growing crystals according to some embodiments of this specification;

[0026] Figure 2BThese are exemplary block diagrams of an exemplary processing apparatus shown in some embodiments of this specification;

[0027] Figure 3 This is an exemplary flowchart of an exemplary processing apparatus shown in some embodiments of this specification;

[0028] Figure 4 This is an exemplary flowchart illustrating the growth of an epitaxial layer on the carbon surface of a silicon carbide seed wafer according to some embodiments of this specification;

[0029] Figure 5A This is a photoluminescence spectrum of an epitaxial wafer shown in some embodiments of this specification;

[0030] Figure 5B yes Figure 5A Resistivity diagram of an epitaxial wafer;

[0031] Figure 5C This is a photoluminescence spectrum of an epitaxial wafer shown in some embodiments of this specification;

[0032] Figure 5D yes Figure 5C Resistivity diagram of an epitaxial wafer;

[0033] Figure 6 This is an exemplary flowchart illustrating the growth of an epitaxial layer according to some embodiments of this specification;

[0034] Figure 7A This is a photoluminescence spectrum of a silicon carbide seed wafer shown in some embodiments of this specification;

[0035] Figure 7B yes Figure 7A Resistivity diagram of medium silicon carbide seed wafer;

[0036] Figure 7C This is a photoluminescence spectrum of a silicon carbide seed wafer shown in some embodiments of this specification;

[0037] Figure 7D yes Figure 7C Resistivity diagram of medium silicon carbide seed wafer;

[0038] Figure 8 These are exemplary block diagrams of an exemplary processing apparatus shown in some embodiments of this specification;

[0039] Figure 9 This is an exemplary flowchart of an exemplary processing apparatus shown in some embodiments of this specification;

[0040] Figure 10 This is an exemplary flowchart illustrating, according to some embodiments of this specification, a determination of whether the doping condition meets the doping requirements;

[0041] Figure 11A This is a photoluminescence spectrum of a substrate wafer shown in some embodiments of this specification;

[0042] Figure 11B yes Figure 11A Resistivity diagram of the intermediate substrate;

[0043] Figure 11C This is a photoluminescence spectrum of a substrate wafer shown in some embodiments of this specification;

[0044] Figure 11D yes Figure 11C Resistivity diagram of the intermediate substrate. Detailed Implementation

[0045] To more clearly illustrate the technical solutions of the embodiments in this specification, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are merely some examples or embodiments of this specification. For those skilled in the art, these drawings can be applied to other similar scenarios without creative effort. Unless obvious from the context or otherwise specified, the same reference numerals in the drawings represent the same structures or operations.

[0046] It should be understood that the terms “system,” “device,” “unit,” and / or “module” used herein are one way to distinguish different components, elements, parts, sections, or assemblies at different levels. However, if other terms can achieve the same purpose, they may be replaced by other expressions.

[0047] As indicated in this specification and claims, unless the context clearly indicates otherwise, the words "a," "an," "an," and / or "the" do not specifically refer to the singular and may also include the plural. Generally speaking, the terms "comprising" and "including" only indicate the inclusion of expressly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements.

[0048] Flowcharts are used in this specification to illustrate the operations performed by the system according to embodiments of this specification. It should be understood that the preceding or following operations are not necessarily performed in exact order. Instead, the steps can be processed in reverse order or simultaneously. Furthermore, other operations can be added to these processes, or one or more steps can be removed from them.

[0049] Silicon carbide crystals possess superior properties, such as bandgap, drift velocity, breakdown voltage, and thermal conductivity, which are several times higher than those of traditional silicon. This gives them irreplaceable advantages in electronic applications such as high temperature, high pressure, high frequency, high power, optoelectronics, radiation resistance, and microwave performance.

[0050] Silicon carbide seed crystals are prone to various defects during growth, such as channel defects, microtube defects, carbon inclusions, spiral dislocations, and basal plane dislocations. These defects affect the quality and properties of the final silicon carbide crystal. Reducing the formation of defects in the seed crystal has become a major challenge.

[0051] To address the above problems, this specification proposes a method and system for epitaxial crystal growth. Figure 1 This is a schematic diagram of a crystal structure shown according to some embodiments of this specification. For example... Figure 1 As shown, the method for growing crystals via epitaxial growth includes growing an epitaxial layer 112 on the carbon surface 111 of a silicon carbide seed wafer 110; and growing a crystal on the epitaxial layer 112 using a physical vapor transport method. By setting the epitaxial layer 112, the inherent defects of the silicon carbide seed wafer 110 can be effectively reduced from extending to the crystal (i.e., ingot 120) ultimately generated on the epitaxial layer 112. Based on this, by cutting the crystal (i.e., ingot 120) generated by the aforementioned method and system for growing crystals via epitaxial growth to obtain a substrate 130, and then growing an epitaxial layer 132 on the silicon surface 131 of the substrate 130, an epitaxial wafer 140 with high crystal quality can be obtained. It is understood that doping uniformity is a very important indicator for measuring crystal quality, and accurate detection results are required. When the doping concentration of the silicon carbide seed wafer 110 is high, it may exceed the testing range of existing mercury probe detection equipment, making it impossible to determine the doping uniformity of the silicon carbide seed wafer 110 at high doping concentrations. Therefore, this specification also proposes that the doping concentration and doping uniformity of silicon carbide seed wafer 110 can be detected non-destructively and rapidly based on photoluminescence spectrum, which helps to obtain important parameters in the generation process (such as target doping parameters) to grow a high-doped epitaxial layer 112, and further obtain high-crystal-quality ingot 120, substrate 130 and epitaxial wafer 140.

[0052] Figure 2A This is a schematic diagram of a system for epitaxial crystal growth according to some embodiments of this specification. For example... Figure 2A As shown, the system 200 for epitaxial crystal growth may include a crystal growth apparatus 210, a processing device 220, a terminal 230, a network 240, and a storage device 250.

[0053] like Figure 2A As shown, the crystal growth apparatus 210 may include a seed crystal holder 211, a seed crystal connecting rod 212, a crucible 213, and a vacuum furnace 214.

[0054] The seed crystal holder 211 is used to fix the seed crystal. For example, the seed crystal holder 211 can be used to fix a silicon carbide seed crystal (e.g., a silicon carbide seed wafer 110). The seed crystal holder 211 can be made of graphite. The shape of the seed crystal holder 211 can be columnar, frustum-shaped, or other feasible shapes. The side of the seed crystal holder 211 that contacts the melt can be provided with a seed crystal bonding surface for bonding the seed crystal, and the seed crystal can be bonded to the seed crystal bonding surface of the seed crystal holder 211 under certain conditions (e.g., vacuuming, heating, etc.). During the epitaxial growth of crystals, the seed crystal bonding surface of the seed crystal holder 211 can contact the melt in the crucible to generate crystals, wherein the aforementioned melt can be formed by melting the raw materials and flux required for crystal generation at high temperature.

[0055] The seed crystal connecting rod 212 is used to connect to the seed crystal holder 211. One end of the seed crystal connecting rod 212 can be connected to the seed crystal holder 211. The other end of the seed crystal connecting rod 212 can be connected to the top wall of the crystal growth apparatus 210. The seed crystal connecting rod 212 can be connected to the seed crystal holder 211 in various ways. For example, the seed crystal connecting rod 212 can be threaded to the seed crystal holder 211. Another example is that the seed crystal connecting rod 212 can be snapped into place with the seed crystal holder 211. In some embodiments, the seed crystal connecting rod 212 can move axially along the seed crystal connecting rod 212, thereby causing the seed crystal holder 211 to move axially along the seed crystal connecting rod 212.

[0056] The crucible 213 is used to hold the melt for crystal growth. The crystal growth apparatus 210 can fully contact the seed crystal with the melt in the crucible 213, allowing the solute to be adsorbed onto the surface of the seed crystal and grow along the crystal lattice of the seed crystal to form a new crystal, such as an epitaxial layer (e.g., epitaxial layer 112, epitaxial layer 132) or a crystal formed after epitaxy (e.g., ingot 120). In some embodiments, the crystal growth apparatus 210 may also include an induction coil connected to a power source; when the induction coil is energized, it can inductively heat the crucible 213.

[0057] The vacuum furnace 214 provides a space for crystal growth reactions. It can be understood as a furnace chamber with a complete vacuum, so that there is no gas exchange between the equipment inside the furnace and the atmospheric environment. Seed crystal holder 211, seed crystal connecting rod 212, and crucible 213 can be set inside the vacuum furnace 214.

[0058] The processing device 220 can be installed inside the crystal growth apparatus 210 or outside the crystal growth apparatus 210 and connected to the various components of the crystal growth apparatus 210 via signals.

[0059] Processing device 220 is used to control various components of crystal growth apparatus 210. For example, processing device 220 can control heating components in crystal growth apparatus 210. Processing device 220 can also process data and / or information obtained from components of crystal growth apparatus 210 or other devices. Based on this data, information, and / or processing results, processing device 220 can control the components of crystal growth apparatus 210 to execute program instructions to perform one or more functions described in this specification. In some embodiments, processing device 220 may include one or more sub-processing devices (e.g., a single-core processing device or a multi-core multi-chip processing device). By way of example only, processing device 220 may include a central processing unit (CPU), graphics processing unit (GPU), reduced instruction set computer (RISC), microprocessor, or any combination thereof.

[0060] Terminal 230 is used to interact with the user. The user can issue operation commands to processing device 220 through terminal 230, so that processing device 220 can complete the specified operation. In some embodiments, terminal 230 can be one or any combination of mobile devices, tablet computers, laptop computers, desktop computers, and other devices with input and / or output functions.

[0061] Network 240 is used to connect the various components of the system and / or connect the system to external resources. Network 240 enables communication between the components and with other parts outside the system, facilitating the exchange of data and / or information. In some embodiments, one or more components in the system 200 for epitaxial crystal growth can send data and / or information to other components via network 240. In some embodiments, network 240 can be any one or more of a wired network or a wireless network.

[0062] Storage device 250 is used to store data or information. In some embodiments, storage device 250 is capable of storing data and / or information processed by processing device 220. Storage device 250 may include one or more storage components, each of which may be a separate device or part of another device. Storage device may be local or implemented via the cloud.

[0063] It should be noted that the above description is provided for illustrative purposes only and is not intended to limit the scope of this specification. Various changes and modifications can be made by those skilled in the art based on the content of this specification. Features, structures, methods, and other features of the exemplary embodiments described herein can be combined in various ways to obtain other and / or alternative exemplary embodiments.

[0064] Figure 2BThis is an exemplary block diagram of an exemplary processing apparatus according to some embodiments of this specification. In some embodiments, the processing apparatus 220 may include an epitaxial growth module 201 and a crystal growth module 202.

[0065] The epitaxial growth module 201 can be used to grow an epitaxial layer on the carbon surface of a silicon carbide seed wafer. For more information on growing the epitaxial layer, please refer to the description of step 310.

[0066] The epitaxial growth module 202 can be used to grow crystals on the epitaxial layer using the physical vapor transport method. For more information on crystal growth, please refer to the description of step 320.

[0067] In some embodiments, two modules in the processing device 220 can be combined into one module, which can perform the functions of the two modules. For example, the epitaxial growth module 201 and the crystal growth module 202 can be combined into one module, which can be used to grow an epitaxial layer on the carbon surface of a silicon carbide seed wafer and to grow a crystal on the epitaxial layer. In some embodiments, one module of the processing device 220 can be deleted, or one or more modules can be added to the processing device 220.

[0068] Figure 3 These are exemplary flowcharts of exemplary processing apparatuses shown according to some embodiments of this specification. Figure 3 As shown, process 300 includes the following steps. In some embodiments, process 300 may be performed by a processing apparatus 220 of a system 200 for epitaxial crystal growth (e.g., Figure 2B (One or more modules shown) are executed.

[0069] Step 310: An epitaxial layer is grown on the carbon surface of the silicon carbide seed wafer. In some embodiments, step 310 may be performed by the epitaxial growth module 201.

[0070] Silicon carbide seed wafers are single-crystal thin films formed from silicon carbide crystals through processes such as cutting, grinding, polishing, and cleaning. They are the starting material for silicon carbide crystal growth. For example, Figure 1 The silicon carbide seed wafer 110, etc. Silicon carbide seed wafers can be in various shapes, such as circular or hexagonal. Silicon carbide seed wafers can be in various sizes, such as 6 feet or 8 feet.

[0071] The carbon plane refers to the (000-1) crystal plane of a silicon carbide wafer, that is, the surface of the silicon carbide crystal cut along the negative direction of the c-axis of its growth direction, and the terminating atom of this surface is a carbon atom. For example, Figure 1 The carbon plane 111, etc. The silicon plane refers to the (0001) crystal plane of the silicon carbide wafer, that is, the surface of the crystal cut along the positive direction of the c-axis, and the terminating atom of this surface is the silicon atom.

[0072] An epitaxial layer refers to a single-crystal thin film, identical to the silicon carbide seed wafer, grown on the surface of the silicon carbide seed wafer. For example, Figure 1 Epitaxial layer 112, etc.

[0073] In some embodiments, the epitaxial growth module 201 can grow an epitaxial layer on the carbon surface of a silicon carbide seed wafer using an epitaxial growth device based on the growth parameters of the epitaxial layer. Growth parameters refer to relevant parameters of crystal growth, such as the growth thickness, growth temperature, growth pressure, and doping concentration of the epitaxial layer. Doping concentration refers to the concentration of doping elements in the crystal, such as the nitrogen doping concentration of the silicon carbide seed wafer. Growth parameters can be preset based on experience or requirements. In some embodiments, the growth thickness of the epitaxial layer can be 12 μm to 50 μm; the growth temperature can be 1580℃ to 1640℃; the growth pressure can be 100 mbar; and the doping concentration can be 6 × 10⁻⁶ mbar. 18 cm -3 ~1.5×10 19 cm -3 Epitaxial growth equipment refers to equipment used for growing epitaxial layers. Examples include horizontal epitaxial furnaces and vertical epitaxial furnaces. Epitaxial growth equipment can be selected based on experience or specific requirements.

[0074] In some embodiments, the epitaxial growth module 201 can determine the target doping concentration based on a silicon carbide seed wafer; determine the target doping parameters based on the target doping concentration; and control the growth environment of the epitaxial layer based on the target doping parameters. For more information on controlling the growth environment of the epitaxial layer, please refer to [link to relevant documentation]. Figure 4 And its related descriptions.

[0075] In some embodiments, the epitaxial growth module 201 can determine the growth rate of the epitaxial layer on the carbon surface. For example, the epitaxial growth module 201 can determine the reference growth rate of the reference epitaxial layer based on the reference growth thickness and reference growth time of the reference epitaxial layer; and determine the growth rate of the epitaxial layer on the carbon surface based on the reference growth rate. The reference epitaxial layer refers to an epitaxial layer test piece used for data reference. The reference epitaxial layer can adopt the same growth method, growth parameters, growth environment, etc. as the epitaxial layer on the carbon surface. It is understood that there is a linear relationship between growth thickness, growth time, and growth rate. For example, growth thickness can be expressed as the product of growth time and growth rate. Exemplarily, the epitaxial growth module 201 can prepare a reference epitaxial layer, determine the reference growth thickness of the reference epitaxial layer based on a growth thickness measurement device (e.g., Fourier transform infrared spectrometer, etc.), record the reference growth time of the reference epitaxial layer, and determine the reference growth rate of the reference epitaxial layer based on the aforementioned linear relationship. Since the reference epitaxial layer uses the same growth method, growth parameters, and growth environment as the epitaxial layer on the carbon surface, the epitaxial growth module 201 determines that the growth rate of the epitaxial layer on the carbon surface is the same as the reference growth rate.

[0076] Furthermore, the epitaxial growth module 201 can determine the growth time of the epitaxial layer based on the growth rate. For example, the epitaxial growth module 201 can determine the growth time of the epitaxial layer based on the growth rate, growth thickness, and the aforementioned linear relationship of the epitaxial layer on the carbon surface. The growth thickness can be preset based on experience or requirements.

[0077] In some embodiments of this specification, by determining the growth rate of the epitaxial layer on the carbon surface, and based on the growth rate, determining the growth time of the epitaxial layer, it is possible to determine the accurate growth time of the epitaxial layer based on the growth parameters of a reference epitaxial layer with the same process as the epitaxial layer.

[0078] Step 320: A crystal is grown on the epitaxial layer using a physical vapor transport method. In some embodiments, step 320 may be performed by the crystal growth module 202.

[0079] Understandably, the principle of physical vapor transport is to decompose and sublimate silicon carbide raw materials (e.g., silicon carbide powder) into gaseous components (e.g., Si gas, Si2C gas, SiC2 gas, etc.) at high temperatures. Under the action of temperature gradient, the gaseous components can be transported to a lower temperature region (e.g., at the seed crystal) and recrystallize to generate solid silicon carbide single crystals.

[0080] In some embodiments, the crystal growth module 202 can grow a crystal on the epitaxial layer using a crystal growth apparatus based on the physical vapor transport method. The crystal growth apparatus refers to equipment for growing silicon carbide crystals, such as a single crystal furnace. The grown crystal can be of a different form than the seed silicon carbide wafer. For example, Figure 1 Ingot 120, etc.

[0081] In some embodiments, before crystal growth, the crystal growth module 202 can preprocess the silicon carbide seed wafer with the epitaxial layer grown on it. The preprocessing may include cleaning, encapsulation, etc.

[0082] Understandably, traditional crystal growth methods involve growing ingots directly on seed crystals, which cannot avoid problems such as native channel defects, microtube defects, and carbon inclusions in the seed crystal, resulting in very limited crystal quality.

[0083] In some embodiments of this specification, by growing an epitaxial layer on the carbon surface of a silicon carbide seed wafer and growing a crystal on the epitaxial layer using a physical vapor transport method, a thin and high-quality epitaxial layer can be first grown on the carbon surface of the silicon carbide seed wafer, effectively avoiding the original defects of the silicon carbide seed wafer that extend to the epitaxial layer, and growing a crystal ingot with better crystal quality.

[0084] Figure 4This is an exemplary flowchart illustrating the growth of an epitaxial layer on the carbon surface of a silicon carbide seed wafer according to some embodiments of this specification. Figure 4 As shown, process 400 includes the following steps. In some embodiments, process 400 may be executed by epitaxial growth module 201.

[0085] Step 410: Determine the target doping concentration based on the silicon carbide seed wafer. In some embodiments, step 410 may be performed by the epitaxial growth module 201.

[0086] Target doping concentration refers to the final doping concentration that the epitaxial layer grown on the carbon surface of a silicon carbide seed wafer needs to achieve. For example, the target nitrogen doping concentration of the epitaxial layer. More information on doping concentration, silicon carbide seed wafers, carbon surfaces, and epitaxial layers can be found in [link to relevant documentation]. Figure 3 And related descriptions. In some embodiments, the target doping concentration is the same as or similar to the doping concentration of the silicon carbide seed wafer itself, and the epitaxial growth module 201 can determine the target doping concentration based on the doping concentration of the silicon carbide seed wafer. In some embodiments, the target doping concentration can be 6 × 10⁻⁶. 18 cm -3 ~1.5×10 19 cm -3 .

[0087] Step 420: Determine the target doping parameters based on the target doping concentration. In some embodiments, step 420 may be performed by the epitaxial growth module 201.

[0088] Target doping parameters refer to the doping parameters required during doping. Doping parameters are parameters related to the supply of dopant elements. Examples include actual doping concentration, target doping flow rate, and actual doping flow rate. Actual doping concentration refers to the actual doping concentration during doping. Target doping flow rate refers to a preset doping flow rate. Actual doping flow rate refers to the actual doping flow rate during doping. Doping flow rate refers to the injection flow rate of the dopant during doping. Examples include center-path doping flow rate and edge-path doping flow rate. Center-path doping flow rate refers to the doping flow rate injected into the central region of the carbon face of the silicon carbide seed wafer during epitaxial layer growth, while edge-path doping flow rate refers to the doping flow rate injected into the edge region of the carbon face of the silicon carbide seed wafer during epitaxial layer growth. The central region and edge region can be set based on experience or requirements. In some embodiments, the dopant of the silicon carbide seed wafer can be nitrogen, and the target doping parameters may include the nitrogen doping flow rate.

[0089] In some embodiments, the epitaxial growth module 201 can calculate and determine the target doping parameter based on the target doping concentration using historical data and statistical methods. The historical data includes multiple reference doping concentrations and their corresponding reference doping parameters. Statistical methods include descriptive statistical methods (statistical analysis of indicators such as mean, median, and mode), correlation analysis methods (linear correlation, etc.), etc. For example, the epitaxial growth module 201 can select multiple reference doping concentrations from the historical data whose mean is the target doping concentration, and determine the mean of their corresponding reference doping parameters as the target doping parameter.

[0090] To determine the target doping parameters, in some embodiments, the epitaxial growth module 201 can determine the first doping parameters by growing a first reference epitaxial layer with a first doping concentration. The first doping concentration refers to the doping concentration within the detection range of the target detection device. The target detection device refers to a device that detects the doping concentration, such as a mercury probe. When the target detection device is a mercury probe, the detection range is 1 × 10⁻⁶. 14 cm -3 ~1×10 17 cm -3 The first doping concentration can be set based on experience or requirements, according to the detection range of the target detection equipment. The first reference epitaxial layer refers to the reference epitaxial layer corresponding to the first doping concentration. The first doping parameter refers to the doping parameter corresponding to the first reference epitaxial layer. For example, the first doping flow rate corresponding to the first reference epitaxial layer (i.e., the preset doping flow rate when growing the first reference epitaxial layer), etc. For example, the epitaxial growth module 201 can record the doping parameters used to grow the first reference epitaxial layer with the first doping concentration and directly determine the first doping parameter.

[0091] For example, the epitaxial growth module 201 can adjust the doping parameters to grow a first reference epitaxial layer with a first doping concentration. For instance, the epitaxial growth module 201 can repeatedly adjust the central doping flow rate, the side-path doping flow rate, etc., until the grown first reference epitaxial layer has the first doping concentration. In response to the doping uniformity of the first reference epitaxial layer being greater than a preset uniformity threshold, the epitaxial growth module 201 can determine that the doping parameters at this time are the first doping parameters. Doping uniformity refers to a parameter characterizing the uniformity of the doping concentration distribution when doping elements are introduced. For example, when the doping uniformity of the first reference epitaxial layer is 3%, it means that the doping concentration variation in the first reference epitaxial layer is 3%. Doping uniformity can be calculated based on doping concentration. For example, doping uniformity can be calculated as the percentage of the difference between the maximum and minimum doping concentration values ​​to the average doping concentration. The preset uniformity threshold can be preset based on experience or requirements. In some embodiments, the preset uniformity threshold can be 3%. For example, the epitaxial growth module 201 can compare the doping uniformity of the first reference epitaxial layer with a preset uniformity threshold. If the doping uniformity is greater than the preset uniformity threshold, the doping parameter corresponding to the first reference epitaxial layer at this time is determined to be the first doping parameter. In some embodiments of this specification, by adjusting the doping parameter, a first reference epitaxial layer with a first doping concentration is grown; in response to the doping uniformity of the first reference epitaxial layer being greater than the preset uniformity threshold, the doping parameter at this time is determined to be the first doping parameter, and a first reference epitaxial layer with doping uniformity meeting the requirements can be grown and its corresponding first doping parameter determined.

[0092] Furthermore, the epitaxial growth module 201 can determine the target doping parameters based on the target doping concentration and the first doping parameter. For example, the epitaxial growth module 201 can calculate and determine the target doping parameters based on the target doping concentration, the first doping parameter, and the first doping concentration.

[0093] Specifically, the epitaxial growth module 201 can calculate a reference ratio between the first doping concentration and the target doping concentration. For example, the epitaxial growth module 201 can use the ratio of the first doping concentration to the target doping concentration as the reference ratio. Based on the reference ratio, the epitaxial growth module 201 can determine the correlation between the first doping parameter and the target doping parameter. For example, the epitaxial growth module 201 can determine the correlation between the first doping parameter and the target doping parameter as formula (1):

[0094] Based on the correlation and the first doping parameter, the epitaxial growth module 201 can determine the target doping parameter. For example, the epitaxial growth module 201 can calculate, based on formula (1), the ratio of the target doping flow rate in the target doping parameter to the product of the first doping flow rate and the target doping concentration in the first doping parameter, and the first doping concentration. In some embodiments of this specification, by calculating a reference ratio between the first doping concentration and the target doping concentration; based on the reference ratio, determining the correlation between the first doping parameter and the target doping parameter; and based on the correlation and the first doping parameter, determining the target doping parameter, the target doping parameter can be accurately determined based on the data correlation between the first reference epitaxial layer and the epitaxial layer.

[0095] Understandably, directly grown epitaxial layers have high doping concentrations, exceeding the detection range of a mercury probe, thus the doping concentration is not controlled during their growth. In some embodiments of this specification, a first doping parameter is determined by growing a first reference epitaxial layer with a first doping concentration; based on the target doping concentration and the first doping parameter, a target doping parameter is determined, enabling the growth of a reference test piece with a doping concentration within the detection range of the mercury probe; and then, based on the data correlation between the reference test piece and the epitaxial layer, an accurate target doping parameter is determined to ensure the doping uniformity of the epitaxial layer at high doping concentrations.

[0096] To determine the target doping parameters, in some embodiments, the epitaxial growth module 201 can acquire growth data of growing multiple second reference epitaxial layers with a second doping concentration. The second doping concentration refers to a doping concentration whose difference from the target doping concentration is less than a preset value. The preset value can be set based on experience or requirements. The second reference epitaxial layer refers to a reference epitaxial layer corresponding to the first doping concentration. Growth data refers to data related to the growth process of the second reference epitaxial layer. In some embodiments, the growth data may include the second doping parameters for growing each second reference epitaxial layer and the doping information corresponding to the second doping parameters. Doping information refers to relevant information and data that characterize the quality of doping in the wafer, such as doping uniformity and doping concentration.

[0097] To acquire growth data, for each second reference epitaxial layer, the epitaxial growth module 201 can acquire a photoluminescence (PL) spectrum of the epitaxial wafer containing the second reference epitaxial layer. For example, the epitaxial growth module 201 can acquire the photoluminescence spectrum of the epitaxial wafer containing the second reference epitaxial layer using a photoluminescence spectrometer. The epitaxial growth module 201 can determine whether the photoluminescence spectrum includes a first characteristic region. The first characteristic region refers to a region with a brightness lower than a first brightness threshold. The first brightness threshold is a threshold for identifying dark areas in the photoluminescence spectrum and can be set based on experience or requirements. Figure 5AThis is a photoluminescence spectrum of an epitaxial wafer shown in some embodiments of this specification. For example... Figure 5A As shown, the first feature region can be region A. For example, the epitaxial growth module 201 can traverse the brightness value (i.e., gray value) of each pixel in the photoluminescence spectrum. When the number of pixels with brightness values ​​lower than the first brightness threshold is greater than the preset number of pixels, the region formed by the aforementioned pixels is determined as the first feature region.

[0098] In response to the photoluminescence spectrum not including the first characteristic region, the epitaxial growth module 201 can determine that the doping uniformity of the second reference epitaxial layer meets the uniformity requirements.

[0099] In response to the photoluminescence spectrum including a first characteristic region, the epitaxial growth module 201 can acquire the resistivity map of the epitaxial wafer. For example, Figure 5B yes Figure 5A The resistivity map of the epitaxial wafer. Based on the resistivity map and the first characteristic region, the epitaxial growth module 201 can determine whether the doping uniformity of the second reference epitaxial layer meets the uniformity requirement. The uniformity requirement refers to the benchmark requirement for judging the doping concentration uniformity. When the doping uniformity meets the uniformity requirement, it is considered to be doped uniformly.

[0100] Specifically, the epitaxial growth module 201 can determine the second characteristic region corresponding to the first characteristic region on the resistivity map, and obtain the first minimum resistivity within the second characteristic region and the second minimum resistivity outside the second characteristic region. The second characteristic region refers to the region on the resistivity map corresponding to the position of the first characteristic region on the photoluminescence spectrum map. For example... Figure 5B As shown, the second feature region can be region B. The first minimum value refers to the minimum resistivity within the second feature region. The second minimum value refers to the minimum resistivity outside the second feature region. For example, the epitaxial growth module 201 can determine the corresponding second feature region on the resistivity map based on the position coordinates of the first feature region in the photoluminescence spectrum, and obtain the first minimum resistivity within the second feature region and the second minimum resistivity outside the second feature region based on the resistivity value annotations in the resistivity map.

[0101] Based on the difference between the first minimum value and the second minimum value, the epitaxial growth module 201 can determine whether the doping uniformity meets the uniformity requirements. For example, the epitaxial growth module 201 can set a preset difference based on experience or requirements, compare the difference between the first minimum value and the second minimum value with the preset difference, and if the difference is less than the preset difference, determine that the doping uniformity meets the uniformity requirements; if the difference is greater than the preset difference, determine that the doping uniformity does not meet the uniformity requirements.

[0102] Understandably, photoluminescence spectra can be used to determine doping uniformity based on brightness values. When brightness values ​​are generally consistent (e.g., uniformly bright), it indicates uniform doping. The presence of dark areas (i.e., the first characteristic region) could be due to non-uniform doping, internal defects, surface defects, or other factors, requiring further investigation. In this case, a resistivity map can be used to obtain the resistivity region corresponding to the dark area (i.e., the second characteristic region), the minimum resistivity value within this region (i.e., the first minimum value), and the minimum resistivity value outside this region (i.e., the second minimum value). If the dark area is caused by non-uniform doping, all minimum resistivity values ​​in the resistivity map will be located within the resistivity region; conversely, minimum resistivity values ​​will also be distributed outside the resistivity region. Comparing the difference between the two minimum values ​​indicates that the doping concentration is relatively consistent and the uniformity requirement is met when the difference is small; a large difference indicates a significant difference in doping concentration and the uniformity requirement is not met when the difference is large.

[0103] Neither a single photoluminescence spectrum nor a single resistivity map can directly reflect doping uniformity. Changes in brightness and resistivity values ​​in these two maps may be caused by other factors, such as internal defects. In some embodiments of this specification, by obtaining the photoluminescence spectrum of an epitaxial wafer containing a second reference epitaxial layer; determining whether the photoluminescence spectrum includes a first characteristic region; in response to the photoluminescence spectrum including the first characteristic region, obtaining the resistivity map of the epitaxial wafer; and based on the resistivity map and the first characteristic region, determining whether the doping uniformity of the second reference epitaxial layer meets the uniformity requirements; and in response to the photoluminescence spectrum not including the first characteristic region, determining that the doping uniformity of the second reference epitaxial layer meets the uniformity requirements, a comprehensive judgment can be made based on the photoluminescence spectrum and the resistivity map, which can more accurately determine the doping uniformity and effectively solve the problem of not being able to determine whether the doping is uniform at high doping concentrations.

[0104] To obtain growth data, in some embodiments, for each second reference epitaxial layer, the epitaxial growth module 201 can acquire a photoluminescence spectrum and a resistivity map of the epitaxial wafer containing the second reference epitaxial layer. For example, the epitaxial growth module 201 can acquire the photoluminescence spectrum of the epitaxial wafer containing the second reference epitaxial layer using a photoluminescence spectrometer, and acquire the resistivity map of the epitaxial wafer containing the second reference epitaxial layer using a resistivity meter. Figure 5C This is a photoluminescence spectrum of an epitaxial wafer shown in some embodiments of this specification. Figure 5D yes Figure 5C Resistivity diagram of an epitaxial wafer.

[0105] The epitaxial growth module 201 can determine the third characteristic region of the photoluminescence spectrum. The third characteristic region refers to the area with a brightness higher than a second brightness threshold. The second brightness threshold is the threshold for determining the bright area in the photoluminescence spectrum, and can be set based on experience or requirements. Figure 5C As shown, the third feature region can be region C. For example, the epitaxial growth module 201 can traverse the brightness value (i.e., gray value) of each pixel in the photoluminescence spectrum. When the number of pixels with brightness values ​​higher than the first brightness threshold is greater than the preset number of pixels, the region formed by the aforementioned pixels is determined as the third feature region.

[0106] The epitaxial growth module 201 can determine the fourth characteristic region corresponding to the third characteristic region on the resistivity map, and obtain the third minimum resistivity value within the fourth characteristic region. The fourth characteristic region refers to the area on the resistivity map corresponding to the position of the third characteristic region on the photoluminescence spectrum map. For example... Figure 5D As shown, the fourth feature region can be region D. The third minimum value refers to the minimum resistivity within the fourth feature region. For example, the epitaxial growth module 201 can determine the corresponding fourth feature region on the resistivity map based on the position coordinates of the third feature region in the photoluminescence spectrum, and obtain the third minimum resistivity within the fourth feature region based on the resistivity value annotations in the resistivity map.

[0107] The epitaxial growth module 201 can determine whether the doping concentration meets the concentration requirements based on a third minimum value and a first preset reference range. The first preset reference range refers to the threshold range of the minimum resistivity used to determine the doping concentration, and can be set based on experience or requirements. The concentration requirement refers to the benchmark requirement for judging the doping concentration; when the doping concentration meets the concentration requirement, it is considered that the doping concentration is moderate. For example, the epitaxial growth module 201 can compare the first minimum value with the first preset reference range. If the first minimum value is included within the first preset reference range, it is determined that the doping concentration meets the concentration requirements; if the first minimum value is not included within the first preset reference range, it is determined that the doping concentration does not meet the concentration requirements.

[0108] Understandably, photoluminescence spectra can be used to determine doping uniformity based on brightness values. When brightness values ​​are generally consistent (e.g., uniformly bright), it indicates uniform doping. The presence of bright areas (i.e., the third characteristic region) could be due to excessively high doping concentration, or it could be caused by internal defects, surface defects, or other factors, requiring further assessment. In this case, a resistivity map can be used to obtain the resistivity region corresponding to the aforementioned bright area (i.e., the fourth characteristic region), and the minimum resistivity value within this region (i.e., the third minimum value) can be obtained. If the bright area is caused by excessively high doping concentration, the minimum resistivity value in the resistivity region will be within a certain range (i.e., the first preset reference range); otherwise, the minimum resistivity value will exceed this range. Comparing the minimum resistivity value with the aforementioned range, if the minimum resistivity value is within the aforementioned range, the doping concentration is appropriate, and the doping concentration meets the requirements; if the minimum resistivity value exceeds the aforementioned range, the doping concentration is too high, and the doping concentration does not meet the requirements.

[0109] In some embodiments of this specification, by acquiring the photoluminescence spectrum and resistivity map of the epitaxial wafer containing the second reference epitaxial layer; determining the third characteristic region of the photoluminescence spectrum; determining the fourth characteristic region corresponding to the third characteristic region on the resistivity map; acquiring the third minimum value of resistivity in the fourth characteristic region; and determining whether the doping concentration meets the concentration requirements based on the third minimum value and the first preset reference range, a comprehensive judgment can be made based on the photoluminescence spectrum and resistivity map to accurately determine the doping concentration, effectively solving the problem of not being able to obtain the doping concentration under high doping concentration.

[0110] Furthermore, the epitaxial growth module 201 can determine the target doping parameters based on the growth data. For example, the epitaxial growth module 201 can obtain multiple sets of growth data through multiple experiments, find the maximum and minimum values ​​of the doping parameters corresponding to the growth data that meet the uniformity and concentration requirements, and use these values ​​as the target doping parameter range. The target doping parameters are then determined based on this range. Specifically, the determination method can be to randomly select values ​​within the target doping parameter range as the target doping parameters, etc.

[0111] It is understandable that the target doping parameters determined based on the first reference epitaxial layer are only theoretically calculated values, and differences are inevitable during the actual growth of the epitaxial layer. In some embodiments of this specification, by acquiring growth data of multiple second reference epitaxial layers with a second doping concentration, the difference between the second doping concentration and the target doping concentration is less than a preset value. The growth data includes at least the second doping parameters for each second reference epitaxial layer and the doping situation corresponding to the second doping parameters. Based on the growth data, the target doping parameters are determined, and multiple second doping parameters that are close to the target doping parameters and meet the doping uniformity requirements can be determined. This allows for the construction of a reasonable target doping parameter range, facilitating the acquisition of more accurate target doping parameters with satisfactory doping conditions.

[0112] Step 430: Control the growth environment of the epitaxial layer based on the target doping parameters. In some embodiments, step 430 may be performed by the epitaxial growth module 201.

[0113] The growth environment refers to the environment in which the epitaxial layer is grown. In some embodiments, the epitaxial growth module 201 can control the growth environment of the epitaxial layer by adjusting the doping equipment based on the target doping parameters. The doping equipment refers to doping-related equipment, such as the FC071 edge nitrogen flow meter and the FC074 middle nitrogen flow meter.

[0114] In some embodiments of this specification, by determining the target doping concentration based on the silicon carbide seed wafer, determining the target doping parameters based on the target doping concentration, and controlling the growth environment of the epitaxial layer based on the target doping parameters, the accurate target doping parameters can be determined based on the calculated relationship between the target doping concentration and the target doping parameters, so that the epitaxial layer growth process can proceed smoothly and an epitaxial layer matching the high nitrogen doping concentration of the silicon carbide seed wafer can be obtained.

[0115] Figure 6 This is an exemplary flowchart illustrating the growth of epitaxial layers according to some embodiments of this specification. Figure 6 As shown, process 600 includes the following steps. In some embodiments, process 600 may be executed by epitaxial growth module 201.

[0116] Step 610: Determine the doping status of the silicon carbide seed wafer. In some embodiments, step 610 can be performed by the epitaxial growth module 201. For example, the epitaxial growth module 201 can obtain the photoluminescence spectrum of the silicon carbide seed wafer. If the brightness values ​​of all pixels in the photoluminescence spectrum are within a preset brightness range, the doping status of the silicon carbide seed wafer is determined to be good; if the brightness values ​​of some pixels in the photoluminescence spectrum are not within the preset brightness range and the pixel values ​​exceed a preset pixel value, the doping status of the silicon carbide seed wafer is determined to be poor.

[0117] Step 620: Determine whether the doping condition meets the doping requirements. In some embodiments, step 620 may be performed by the epitaxial growth module 201. The doping requirements refer to the benchmark requirements for judging the quality of the doping condition; when the doping condition meets the doping requirements, it is considered to have a good doping condition.

[0118] In some embodiments, doping conditions may include doping uniformity, and doping requirements may also include uniformity requirements. The epitaxial growth module 201 can acquire the photoluminescence spectrum of the silicon carbide seed wafer. Figure 7A This is a photoluminescence spectrum of a silicon carbide seed wafer according to some embodiments of this specification. Further, the epitaxial growth module 201 can determine whether the photoluminescence spectrum includes a fifth characteristic region. The fifth characteristic region refers to a region with a brightness lower than a third brightness threshold. The third brightness threshold is a threshold for determining dark areas in the photoluminescence spectrum, and can be set based on experience or requirements. Figure 7A As shown, the first feature region can be region E. For example, the epitaxial growth module 201 can traverse the brightness value (i.e., gray value) of each pixel in the photoluminescence spectrum. When the number of pixels with brightness values ​​lower than the third brightness threshold is greater than the preset number of pixels, the region formed by the aforementioned pixels is determined as the fifth feature region.

[0119] In response to the photoluminescence spectrum including the fifth feature region, the epitaxial growth module 201 can acquire the resistivity map of the silicon carbide seed wafer. Figure 7B yes Figure 7A The resistivity map of the silicon carbide seed wafer. Based on the resistivity map and the fifth characteristic region, the epitaxial growth module 201 determines whether the doping uniformity meets the uniformity requirements. More information on doping uniformity and uniformity requirements can be found in [link to relevant documentation]. Figures 1-5D And related descriptions. In some embodiments, the epitaxial growth module 201 may determine that the doping uniformity meets the uniformity requirements in response to the photoluminescence spectrum not including the fifth feature region.

[0120] To determine whether the doping uniformity meets the uniformity requirements, in some embodiments, the epitaxial growth module 201 can identify a sixth characteristic region of the resistivity map. The sixth characteristic region refers to the area where the resistivity is below a first resistivity threshold. For example... Figure 7B As shown, the second feature region can be region F. The first resistivity threshold can be set based on experience or requirements. For example, the first resistivity threshold can be the value at the top A% of the resistivity values ​​in the resistivity map, sorted from largest to smallest. For instance, the epitaxial growth module 201 can obtain the resistivity of each region based on the resistivity values ​​marked in the resistivity map, and determine the region with a resistivity lower than the first resistivity threshold as the sixth feature region. Further, the epitaxial growth module 201 can determine the contrast region corresponding to the sixth feature region on the photoluminescence spectrum. The contrast region refers to the region with a brightness higher than the fourth brightness threshold. Figure 7A As shown, the comparison region can be region I. The fourth brightness threshold refers to the threshold for determining the bright area in the photoluminescence spectrum, which can be determined based on the first resistivity threshold. For example, the first resistivity threshold is the value at the top A% after sorting the resistance values ​​in the resistivity spectrum from largest to smallest. Then, the epitaxial growth module 201 can determine the fourth brightness threshold as the value at the top A% after sorting the brightness values ​​in the photoluminescence spectrum from largest to smallest, and thus determine the region in the photoluminescence spectrum with a brightness higher than the fourth brightness threshold as the comparison region corresponding to the sixth feature region. Further, the epitaxial growth module 201 can determine whether the doping uniformity meets the uniformity requirements based on the shape of the comparison region and the shape of the sixth feature region. For example, the epitaxial growth module 201 can compare the shape of the comparison region and the shape of the sixth feature region; if they are similar, it is determined that the doping uniformity does not meet the uniformity requirements; if they are not similar, it is determined that the doping uniformity meets the uniformity requirements.

[0121] For example, the epitaxial growth module 201 can determine the similarity between the shape of the comparison region and the shape of the sixth feature region. Similarity is a parameter representing the degree of similarity, which can be expressed as a percentage, etc. A higher similarity indicates a higher degree of similarity. The epitaxial growth module 201 can determine the similarity between the shape of the comparison region and the shape of the sixth feature region in various ways. For example, the epitaxial growth module 201 can determine the similarity between the shape of the comparison region and the shape of the sixth feature region by obtaining user input information. Another example is that the epitaxial growth module 201 can determine the similarity between the shape of the comparison region and the shape of the sixth feature region through machine learning models, preset algorithms, etc. Furthermore, the epitaxial growth module 201 can determine whether the doping uniformity meets the uniformity requirements based on the similarity. For example, the epitaxial growth module 201 can compare the similarity with a preset similarity threshold; if the similarity is greater than the preset similarity threshold, it is determined that the shape of the comparison region and the shape of the sixth feature region are similar, and the doping uniformity does not meet the uniformity requirements; if the similarity is less than the preset similarity threshold, it is determined that the shape of the comparison region and the shape of the sixth feature region are dissimilar, and the doping uniformity meets the uniformity requirements. The preset similarity threshold can be set based on experience or needs.

[0122] For example, the epitaxial growth module 201 can determine the overlap ratio between the shape of the comparison region and the shape of the sixth feature region. The overlap ratio refers to the proportion of overlap between the shapes. The epitaxial growth module 201 can determine the overlap ratio between the shape of the comparison region and the shape of the sixth feature region in various ways. For example, the epitaxial growth module 201 can determine the overlap ratio by obtaining user input information. Alternatively, the epitaxial growth module 201 can determine the overlap ratio between the shape of the comparison region and the shape of the sixth feature region using machine learning models, preset algorithms, etc. Furthermore, the epitaxial growth module 201 can determine whether the doping uniformity meets the uniformity requirements based on the overlap ratio. For example, the epitaxial growth module 201 can compare the overlap ratio with a preset overlap ratio threshold; if the overlap ratio is greater than the preset overlap ratio threshold, it is determined that the shape of the comparison region and the shape of the sixth feature region are similar, and the doping uniformity does not meet the uniformity requirements; if the overlap ratio is less than the preset overlap ratio threshold, it is determined that the shape of the comparison region and the shape of the sixth feature region are dissimilar, and the doping uniformity meets the uniformity requirements. The preset overlap ratio threshold can be set based on experience or needs.

[0123] Understandably, regions with excessively low resistivity in a resistivity map can be caused by excessively high doping concentration, uneven doping, or other defects. In some embodiments of this specification, a sixth characteristic region is determined in the resistivity map; this sixth characteristic region is a region with resistivity lower than a first resistivity threshold. A contrast region corresponding to the sixth characteristic region is determined in the photoluminescence spectrum; the brightness of the contrast region is higher than a fourth brightness threshold, which is determined based on the first resistivity threshold. Based on the shape of the contrast region and the shape of the sixth characteristic region, it is determined whether the doping uniformity meets the uniformity requirements. The similarity between the corresponding characteristic regions in the resistivity map and the photoluminescence spectrum can be analyzed. If the similarity is high, it can be concluded that the aforementioned characteristic region is caused by excessively high doping concentration or uneven doping. Furthermore, by determining the similarity and overlap ratio between the shape of the contrast region and the shape of the sixth characteristic region, it is determined whether the doping uniformity meets the uniformity requirements. The similarity between the characteristic regions in the photoluminescence spectrum and the resistivity map can be accurately determined, which helps to determine whether the doping is uniform.

[0124] To determine whether the doping uniformity meets the uniformity requirements, in some embodiments, the epitaxial growth module 201 can extract the contour of the bright region outside the fifth feature region on the photoluminescence spectrum. The bright region can refer to a region whose brightness value exceeds a reference brightness threshold. The reference brightness threshold can be set based on experience or requirements. For example, the epitaxial growth module 201 can process the photoluminescence spectrum using user annotation information, machine learning models, preset software, etc., to extract the contour of the bright region outside the fifth feature region. Further, the epitaxial growth module 201 can extract the contour set of resistivity contour lines on the resistivity map. A resistivity contour line is a closed curve connecting adjacent points with equal resistivity on the resistivity map. The contour set refers to the set composed of the contours of all resistivity contour lines. For example, the epitaxial growth module 201 can extract the contour set of resistivity contour lines on the resistivity map using user annotation information, machine learning models, preset software, etc.

[0125] Furthermore, the epitaxial growth module 201 can determine whether there exists a target contour in the contour set that satisfies a preset condition with the contour of the bright area. The preset condition can be based on experience or requirements. For example, the preset condition could be that the similarity between the target contour and the contour of the bright area is greater than a preset similarity threshold. For instance, the epitaxial growth module 201 can determine the similarity between the contours of each resistivity contour line in the contour set and the contour of the bright area using machine learning models, preset algorithms, etc., and compare the similarity with a preset similarity threshold. If there exists a contour in the contour set where the similarity between the resistivity contour line and the contour of the bright area is greater than the preset similarity threshold, then it is determined that there exists a target contour in the contour set that satisfies the preset condition with the contour of the bright area.

[0126] If a target contour exists in the contour set, the epitaxial growth module 201 can determine that the doping uniformity does not meet the uniformity requirements. If a target contour does not exist in the contour set, the epitaxial growth module 201 can determine that the doping uniformity meets the uniformity requirements. For more information on doping uniformity and uniformity requirements, please refer to [link to relevant documentation]. Figures 1-5D And its related descriptions.

[0127] Understandably, the presence of a target contour in the contour set can be considered as the existence of a feature region in the resistivity map that is highly similar to a bright area in the photoluminescence spectrum, which is likely caused by inhomogeneous doping. In some embodiments of this specification, by extracting the contour of the bright area outside the fifth feature region on the photoluminescence spectrum; extracting the contour set of resistivity contour lines on the resistivity map; determining whether there is a target contour in the contour set that meets the preset conditions with the contour of the bright area; in response to the presence of a target contour in the contour set, determining that the doping uniformity does not meet the uniformity requirements; in response to the absence of a target contour in the contour set, determining that the doping uniformity meets the uniformity requirements, it is possible to further quickly and accurately determine whether there is a feature region in the resistivity map that is similar to a bright area in the photoluminescence spectrum, which helps to accurately determine the doping uniformity.

[0128] Understandably, the photoluminescence spectrum can be used to determine the uniformity of doping based on the brightness value. When the brightness values ​​are basically consistent (e.g., uniformly bright), it indicates uniform doping. When there is a dark area (i.e., the fifth characteristic region), it may be caused by uneven doping, or it may be caused by internal defects, surface defects, or other factors, which require further judgment.

[0129] At this point, by combining the resistivity map, we can identify the characteristic region with low resistivity (i.e., the sixth characteristic region; the low resistivity region may have defects or uneven nitrogen doping). We can then determine the corresponding region in the photoluminescence spectrum (i.e., the comparison region). We can assess the similarity between the aforementioned characteristic region and the corresponding region. If the similarity is high, it indicates a high correlation, and the formation of the aforementioned characteristic region is most likely due to excessively high or uneven nitrogen doping concentration. If the similarity is low, it indicates a low correlation, and the formation of the aforementioned characteristic region is most likely not due to excessively high or uneven nitrogen doping concentration, meaning the uniformity requirement is met. We can also compare the outline of the bright area in the photoluminescence spectrum with the outline of the resistivity contour lines in the resistivity map to determine if there are similar characteristic regions, further determining the cause of the characteristic region's formation.

[0130] In some embodiments of this specification, the photoluminescence spectrum of a silicon carbide seed wafer is obtained; it is determined whether the photoluminescence spectrum includes the fifth characteristic region; in response to the photoluminescence spectrum including the fifth characteristic region, a resistivity map of the silicon carbide seed wafer is obtained; based on the resistivity map and the fifth characteristic region, it is determined whether the doping uniformity meets the uniformity requirement; in response to the photoluminescence spectrum not including the fifth characteristic region, it is determined that the doping uniformity meets the uniformity requirement. A comprehensive judgment can be made based on the photoluminescence spectrum and the resistivity map to more accurately determine whether the silicon carbide seed wafer is doped uniformly.

[0131] In some embodiments, doping conditions may include doping concentration, and doping requirements may include concentration requirements. In some embodiments, the epitaxial growth module 201 may acquire the photoluminescence spectrum and resistivity map of the silicon carbide seed wafer. For example, the epitaxial growth module 201 may acquire the photoluminescence spectrum of the silicon carbide seed wafer using a photoluminescence spectrometer and acquire the resistivity map of the silicon carbide seed wafer using a resistivity meter. Figure 7C This is a photoluminescence spectrum of a silicon carbide seed wafer shown in some embodiments of this specification. Figure 7D yes Figure 7C Resistivity diagram of silicon carbide seed wafers.

[0132] Furthermore, the epitaxial growth module 201 can determine the seventh characteristic region of the photoluminescence spectrum. The seventh characteristic region refers to the area with a brightness higher than the fifth brightness threshold. The fifth brightness threshold is the threshold for determining the bright areas in the photoluminescence spectrum, and can be set based on experience or requirements. Figure 7C As shown, the seventh feature region can be region G. For example, the epitaxial growth module 201 can traverse the brightness value (i.e., gray value) of each pixel in the photoluminescence spectrum. When the number of pixels with brightness values ​​higher than the fifth brightness threshold is greater than the preset number of pixels, the region formed by the aforementioned pixels is determined as the seventh feature region.

[0133] Furthermore, the epitaxial growth module 201 can determine the eighth feature region corresponding to the seventh feature region on the resistivity map, and obtain the fourth minimum resistivity value within the eighth feature region; the eighth feature region refers to the region in the resistivity map corresponding to the position of the seventh feature region in the photoluminescence spectrum map. For example... Figure 7D As shown, the eighth feature region can be region H. The fourth minimum value refers to the minimum resistivity within the eighth feature region. For example, the epitaxial growth module 201 can determine the eighth feature region corresponding to the position on the resistivity map based on the position coordinates of the seventh feature region in the photoluminescence spectrum, and obtain the fourth minimum resistivity within the eighth feature region based on the resistivity value annotations on the resistivity map.

[0134] Furthermore, the epitaxial growth module 201 can determine whether the doping concentration meets the concentration requirements based on a fourth minimum value and a second preset reference range. The second preset reference range refers to the threshold range of the minimum resistivity used to determine the doping concentration, and can be set based on experience or requirements. For example, the epitaxial growth module 201 can compare the fourth minimum value with the second preset reference range; if the fourth minimum value is included in the second preset reference range, it determines that the doping concentration meets the concentration requirements; if the fourth minimum value is not included in the second preset reference range, it determines that the doping concentration does not meet the concentration requirements.

[0135] Understandably, the photoluminescence spectrum can be used to determine the doping uniformity based on the brightness value. When the brightness values ​​are basically consistent (e.g., uniformly bright), it indicates uniform doping. When there is a bright area (i.e., the seventh characteristic region), it may be caused by excessive doping concentration, or it may be caused by internal defects, surface defects, or other factors, which require further judgment.

[0136] At this point, the resistivity map can be used to obtain the resistivity region corresponding to the aforementioned bright area (i.e., the eighth feature region), and the minimum resistivity value within this region (i.e., the fourth minimum value) can be obtained. If the aforementioned bright area is caused by excessively high doping concentration, the minimum resistivity value in the resistivity region will be within a certain range (i.e., the second preset reference range); otherwise, the minimum resistivity value will exceed the aforementioned certain range. Comparing the minimum resistivity value with the aforementioned certain range, if the minimum resistivity value is within the aforementioned certain range, the doping concentration is appropriate, and the doping concentration meets the concentration requirements; if the minimum resistivity value exceeds the aforementioned certain range, the doping concentration is too high, and the doping concentration does not meet the concentration requirements.

[0137] In some embodiments of this specification, by acquiring the photoluminescence spectrum and resistivity map of the silicon carbide seed wafer; determining the seventh characteristic region of the photoluminescence spectrum; determining the eighth characteristic region corresponding to the seventh characteristic region on the resistivity map; obtaining the fourth minimum value of resistivity within the eighth characteristic region; and determining whether the doping concentration meets the concentration requirements based on the fourth minimum value and the second preset reference range, a comprehensive judgment can be made based on the photoluminescence spectrum and resistivity map to accurately determine the doping concentration, effectively solving the problem of not being able to obtain the doping concentration under high doping concentration.

[0138] In some embodiments, doping conditions may include doping concentration and doping uniformity, and doping requirements may also include concentration requirements and uniformity requirements. The epitaxial growth module 201 can determine whether the doping concentration meets the concentration requirements and whether the doping uniformity meets the uniformity requirements. If both are met, the epitaxial growth module 201 can determine that the doping conditions meet the doping requirements.

[0139] Step 630: In response to the doping condition meeting the doping requirements, an epitaxial layer is grown on the carbon surface of the silicon carbide seed wafer. In some embodiments, step 630 may be performed by the epitaxial growth module 201. For more information on silicon carbide seed wafers, carbon surfaces, epitaxial layers, and specific growth methods, please refer to step 310 and its related description.

[0140] In some embodiments of this specification, by determining the doping status of the silicon carbide seed wafer and whether the doping status meets the doping requirements, an epitaxial layer is grown on the carbon surface of the silicon carbide seed wafer in response to the doping status meeting the doping requirements. This allows for accurate determination of the doping status of the silicon carbide seed wafer, thereby ensuring uniform doping of the silicon carbide seed wafer, avoiding its adverse effects on the generated epitaxial layer, reducing the influence of the silicon carbide seed wafer doping status when obtaining the photoluminescence spectrum of the epitaxial layer, and making the obtained photoluminescence spectrum of the epitaxial layer more consistent with the actual situation of the epitaxial layer.

[0141] Figure 8 This is an exemplary block diagram of an exemplary processing apparatus according to some embodiments of this specification. In some embodiments, the processing apparatus 220 may include a spectrum acquisition module 810, a doping determination module 820, and a growth module 830.

[0142] The spectrum acquisition module 810 can be used to acquire the photoluminescence spectrum of the substrate. For more information on how to acquire the photoluminescence spectrum, please refer to the description of step 910.

[0143] The doping determination module 820 can be used to determine the doping status of the substrate based on the photoluminescence spectrum. For more information on how to determine the doping status, please refer to the description of step 920.

[0144] The growth module 830 can be used to determine whether the doping conditions meet the doping requirements; in response to the doping conditions meeting the doping requirements, an epitaxial layer is grown on the substrate to obtain an epitaxial wafer. For more information on how the epitaxial layer is grown to obtain the epitaxial wafer, please refer to the description of step 930.

[0145] In some embodiments, two or more modules in the processing device 220 may be combined into one module, which can perform the functions of the two or more modules. For example, the spectrum acquisition module 810 and the doping determination module 820 may be combined into one module, which can be used to acquire the photoluminescence spectrum of the substrate and determine the doping status of the substrate. In some embodiments, one or more modules in the processing device 220 may be deleted, or one or more modules may be added to the processing device 220.

[0146] Figure 9 These are exemplary flowcharts of exemplary processing apparatuses shown according to some embodiments of this specification. Figure 9 As shown, process 900 includes the following steps. In some embodiments, process 900 may be performed by processing device 220 (e.g., Figure 8 (One or more modules shown) are executed.

[0147] Step 910: Obtain the photoluminescence spectrum of the substrate. In some embodiments, step 910 may be performed by the spectrum acquisition module 810.

[0148] A substrate is the basic material used in the manufacturing process of semiconductor devices to support and build other functional layers. For example, Figure 1 The substrate 130, etc. In some embodiments, the substrate can be a nitrogen-doped N-type substrate. In some embodiments, when the substrate is a nitrogen-doped N-type substrate, the substrate can have a first nitrogen doping concentration. The first nitrogen doping concentration refers to the doping concentration of nitrogen element in the substrate. In some embodiments, the first nitrogen doping concentration can be not less than 1 × 10⁻⁶. 18 cm -3 In some embodiments, the first nitrogen doping concentration may be 1 × 10⁻⁶. 18 cm -3 ~1×10 19 cm -3 In some embodiments, the first nitrogen doping concentration may also be 1.5 × 10⁻⁶. 18 cm -3 ~0.9×10 19 cm -3 In some embodiments, the first nitrogen doping concentration may also be 5 × 10⁻⁶. 18 cm -3 ~0.8×10 19 cm -3 . Figure 11C This is a photoluminescence spectrum of a substrate wafer according to some embodiments of this specification. In some embodiments, the spectrum acquisition module 810 can acquire the photoluminescence spectrum of the substrate wafer using a spectrum acquisition device. A spectrum acquisition device refers to a device capable of acquiring a photoluminescence spectrum, such as a photoluminescence spectrometer.

[0149] Step 920: Determine the doping status of the substrate based on the photoluminescence spectrum. In some embodiments, step 920 may be performed by the doping status determination module 820.

[0150] Doping characteristics refer to relevant information and data that characterize the quality of doping in a wafer. Examples include doping uniformity and doping concentration. Doping concentration refers to the concentration of the dopant element in a crystal. For example, the nitrogen doping concentration of a substrate. Doping uniformity refers to a parameter characterizing the evenness of the doping concentration distribution when a dopant element is introduced. For example, if the doping concentration variation in a substrate is 3%, then the doping uniformity of the substrate is 3%. In some embodiments, doping uniformity can be calculated based on doping concentration. For example, doping uniformity can be calculated as the percentage of the difference between the maximum and minimum doping concentration values ​​relative to the average doping concentration.

[0151] In some embodiments, the doping determination module 820 can determine the doping status of the substrate wafer based on the photoluminescence spectrum using various methods. For example, the doping determination module 820 can process the photoluminescence spectrum using machine learning models, preset algorithms, etc., to determine the doping status of the substrate wafer.

[0152] Step 930: Determine whether the doping conditions meet the doping requirements. In some embodiments, step 930 may be performed by the growth module 830.

[0153] Doping requirements refer to the benchmark requirements for judging the quality of doping. When the doping conditions meet the doping requirements, the doping conditions are considered to be good. In some embodiments, the growth module 830 can compare the doping conditions with the doping requirements. If the doping conditions meet the doping requirements, then the doping conditions are determined to meet the doping requirements. In some embodiments, the doping requirements can be preset based on experience or needs.

[0154] In some embodiments, doping conditions may include doping uniformity, and doping requirements may include uniformity requirements. Uniformity requirements refer to the baseline requirements for judging the degree of doping uniformity; when doping uniformity meets the uniformity requirements, it is considered that the doping is uniform. The growth module 830 can determine whether the photoluminescence spectrum includes a first brightness characteristic region; in response to the photoluminescence spectrum including the first brightness characteristic region, it acquires the resistivity map of the substrate, and based on the resistivity map and the first brightness characteristic region, determines whether the doping uniformity meets the uniformity requirements; in response to the photoluminescence spectrum not including the first brightness characteristic region, it determines that the doping uniformity meets the uniformity requirements. More information on determining whether doping uniformity meets the uniformity requirements can be found in [link to relevant documentation]. Figure 10 And its related descriptions.

[0155] In some embodiments, doping conditions include doping concentration, and doping requirements include concentration requirements. Concentration requirements refer to the baseline requirements for judging the magnitude of the doping concentration; when the doping concentration meets the concentration requirements, it is considered that the doping concentration is moderate. The growth module 830 can determine a second brightness characteristic region of the photoluminescence spectrum, which is a region whose brightness is higher than a second reference brightness threshold. The second brightness characteristic region refers to a region whose brightness is higher than the second reference brightness threshold. The second reference brightness threshold is a threshold for determining the bright areas in the photoluminescence spectrum, and can be set based on experience or requirements. Figure 11C As shown, the second brightness feature region can be region L. For example, the growth module 830 can traverse the brightness values ​​(i.e., gray values) of each pixel in the photoluminescence spectrum. When the number of pixels with brightness values ​​higher than the second reference brightness threshold is greater than a preset number of pixels, the region formed by the aforementioned pixels is determined as the second brightness feature region.

[0156] Furthermore, the growth module 830 can acquire a resistivity map of the substrate. Figure 11D yes Figure 11C The resistivity map of the intermediate substrate. The growth module 830 can determine the second resistivity feature region corresponding to the second brightness feature region on the resistivity map, and obtain the minimum resistivity value within the second resistivity feature region. The second resistivity feature region refers to the region in the resistivity map that corresponds to the position of the second brightness feature region in the photoluminescence spectrum. For example... Figure 11D As shown, the second resistivity feature region can be region M. For example, the growth module 830 can obtain the resistivity map of the substrate using a resistivity tester or other equipment, determine the corresponding second resistivity feature region on the resistivity map based on the position coordinates of the second brightness feature region in the photoluminescence spectrum map, and obtain the minimum resistivity value within the second resistivity feature region based on the resistivity value markings in the resistivity map.

[0157] Furthermore, the growth module 830 can determine whether the doping concentration meets the concentration requirements based on the minimum value and a third preset reference range. The third preset reference range refers to the threshold range of the minimum resistivity used to determine the doping concentration, and can be set based on experience or requirements. For example, the growth module 830 can compare the minimum value with the third preset reference range; if the minimum value is included in the third preset reference range, it determines that the doping concentration meets the concentration requirements; if the minimum value is not included in the third preset reference range, it determines that the doping concentration does not meet the concentration requirements.

[0158] Understandably, the photoluminescence spectrum can be used to determine the doping uniformity based on the brightness value. When the brightness values ​​are basically consistent (e.g., uniformly bright), it indicates uniform doping. When there is a bright area (i.e., the second brightness characteristic area), it may be caused by excessive doping concentration, or it may be caused by internal defects, surface defects, or other factors, which require further judgment.

[0159] At this point, the resistivity map can be used to obtain the resistivity region corresponding to the aforementioned bright area (i.e., the second resistivity characteristic region), and the minimum resistivity value within this region can be obtained. If the aforementioned bright area is caused by excessively high doping concentration, the minimum resistivity value in the resistivity region will be within a certain range (i.e., the third preset reference range); otherwise, the minimum resistivity value will exceed the aforementioned certain range. By comparing the minimum resistivity value with the aforementioned certain range, if the minimum resistivity value is within the aforementioned certain range, the doping concentration is appropriate, and the doping concentration meets the concentration requirements; if the minimum resistivity value exceeds the aforementioned certain range, the doping concentration is too high, and the doping concentration does not meet the concentration requirements.

[0160] In some embodiments of this specification, a second brightness characteristic region of the photoluminescence spectrum is determined, where the brightness of the second brightness characteristic region is higher than a second reference brightness threshold; a resistivity map of the substrate is obtained, and a second resistivity characteristic region corresponding to the second brightness characteristic region on the resistivity map is determined; the minimum resistivity value within the second resistivity characteristic region is obtained; based on the minimum value and a third preset reference range, it is determined whether the doping concentration meets the concentration requirements. A comprehensive judgment can be made based on the photoluminescence spectrum and the resistivity map, which can more accurately determine the doping concentration and effectively solve the problem of not being able to obtain the doping concentration under high doping concentration.

[0161] Step 940: In response to the doping condition meeting the doping requirements, an epitaxial layer is grown on the substrate to obtain an epitaxial wafer. In some embodiments, step 940 may be performed by the growth module 830.

[0162] An epitaxial layer refers to a single-crystal thin film grown on the surface of a substrate, identical to the substrate itself. For example, Figure 1 Epitaxial layer 132, etc. In some embodiments, when the substrate is a nitrogen-doped N-type substrate, the epitaxial layer may have a second nitrogen doping concentration. The second nitrogen doping concentration refers to the doping concentration of nitrogen element in the epitaxial layer. In some embodiments, the second nitrogen doping concentration may be 1 × 10⁻⁶. 14 cm -3 ~1×10 17 cm -3 In some embodiments, the second nitrogen doping concentration may also be 3 × 10⁻⁶. 14 cm -3 ~0.8×10 17 cm -3 In some embodiments, the second nitrogen doping concentration may also be 5 × 10⁻⁶. 14 cm -3 ~0.5×10 17 cm -3 In some embodiments, the first nitrogen doping concentration of the substrate may be greater than the second nitrogen doping concentration of the epitaxial layer.

[0163] An epitaxial wafer is a thin film material with a specific crystal structure and properties grown on a substrate using epitaxial growth technology. For example, Figure 1 Epitaxial wafers such as 140.

[0164] In some embodiments, the growth module 830 can grow an epitaxial layer on the silicon surface of a substrate using an epitaxial growth apparatus based on the growth parameters of the epitaxial layer. Growth parameters refer to relevant parameters for epitaxial layer growth. For example, the growth thickness, growth temperature, growth pressure, and doping concentration of the epitaxial layer. These growth parameters can be preset based on experience or requirements. In some embodiments, the growth thickness of the epitaxial layer can be 12 μm to 50 μm; the growth temperature can be 1580℃ to 1640℃; the growth pressure can be 100 mbar; and the doping concentration can be 6 × 10⁻⁶ mbar. 18 cm -3 ~1.5×10 19 cm -3 Epitaxial growth equipment refers to equipment used for growing epitaxial layers. Examples include horizontal epitaxial furnaces and vertical epitaxial furnaces. Epitaxial growth equipment can be configured based on experience or requirements. The silicon plane refers to the (0001) crystal plane of a silicon carbide wafer, that is, the surface of the crystal cut along the positive c-axis, where the terminating atom is a silicon atom. For example, Figure 1 Silicon surface 131, etc.

[0165] In some embodiments, the growth module 830 can grow an epitaxial layer on the carbon surface of a silicon carbide seed wafer. A silicon carbide seed wafer refers to a single-crystal thin film formed from silicon carbide crystals through processes such as cutting, grinding, polishing, and cleaning; it is the starting material for silicon carbide crystal growth. For example, Figure 1 The silicon carbide seed wafer 110, etc., is used in this process. The silicon carbide seed wafer can have various shapes, such as circular or hexagonal. It can also have various sizes, such as 6 feet or 8 feet. The carbon plane refers to the (000-1) crystal plane of the silicon carbide wafer, i.e., the surface of the silicon carbide crystal cut along the negative direction of the growth direction c-axis, where the terminating atom is a carbon atom. In some embodiments, the growth module 830 can grow an epitaxial layer on the carbon plane of the silicon carbide seed wafer using an epitaxial growth apparatus based on the growth parameters of the epitaxial layer. More information regarding growth parameters and epitaxial growth apparatus can be found in the foregoing descriptions.

[0166] Furthermore, the growth module 830 can grow crystals on the epitaxial layer using physical vapor transport (PVT). Understandably, the principle of PVT involves decomposing and sublimating silicon carbide raw materials (e.g., silicon carbide powder) into gaseous components (e.g., Si gas, Si2C gas, SiC2 gas, etc.) at high temperatures. Under the influence of a temperature gradient, these gaseous components can be transported to lower temperature regions (e.g., at the seed crystal), recrystallizing to form solid-phase silicon carbide single crystals.

[0167] Furthermore, the growth module 830 can cut the crystal to obtain a substrate. For example, as... Figure 1 As shown, the growth module 830 can grow crystals (such as crystals grown on epitaxial layers via physical vapor transport methods) on epitaxial layers. Figure 1 The ingot 120 is cut to obtain a substrate 130.

[0168] Understandably, the crystal quality of the substrate and epitaxial layer significantly affects the final growth quality of the epitaxial wafer. Doping concentration and doping uniformity are crucial indicators requiring accurate testing results. However, the high doping concentration of the substrate exceeds the testing range of existing mercury probe testing equipment, making it impossible to accurately determine the doping uniformity of the substrate at high doping concentrations.

[0169] In some embodiments of this specification, a photoluminescence spectrum of a substrate is obtained; based on the photoluminescence spectrum, the doping status of the substrate is determined; it is determined whether the doping status meets the doping requirements; in response to the doping status meeting the doping requirements, an epitaxial layer is grown on the substrate to obtain an epitaxial wafer. By combining the photoluminescence spectrum and resistivity map, the doping concentration and doping uniformity of the substrate can be detected non-destructively and rapidly, thereby contributing to the preparation of high-quality epitaxial wafers.

[0170] Figure 10 This is an exemplary flowchart illustrating, according to some embodiments of this specification, a method for determining whether doping conditions meet doping requirements. Figure 10 As shown, process 1000 includes the following steps. In some embodiments, process 1000 may be executed by growth module 830.

[0171] Step 1010: Determine whether the photoluminescence spectrum includes a first brightness characteristic region. In some embodiments, step 1010 may be performed by the growth module 830. Figure 11A This is a photoluminescence spectrum of a substrate wafer shown in some embodiments of this specification.

[0172] The first brightness characteristic region refers to the region whose brightness is lower than the first reference brightness threshold. The first reference brightness threshold is the threshold for determining the dark areas in the photoluminescence spectrum, and can be set based on experience or requirements. Figure 11A As shown, the first feature region can be region J.

[0173] For example, the growth module 830 can traverse the brightness value (i.e. gray value) of each pixel in the photoluminescence spectrum. When the number of pixels with brightness values ​​lower than the first reference brightness threshold is greater than the number of preset pixels, the area formed by the aforementioned pixels is determined as the first brightness feature area.

[0174] Step 1020: In response to the photoluminescence spectrum including a first brightness characteristic region, a resistivity map of the substrate is obtained. Based on the resistivity map and the first brightness characteristic region, it is determined whether the doping uniformity meets the uniformity requirements. In some embodiments, step 1020 may be performed by the growth module 830. Figure 11B yes Figure 11A Resistivity diagram of the intermediate substrate.

[0175] In some embodiments, the growth module 830 may determine a first resistivity characteristic region of the resistivity map. The first resistivity characteristic region refers to a region where the resistivity is lower than a first reference resistivity threshold. For example... Figure 11B As shown, the first resistivity characteristic region can be region K. The first reference resistivity threshold can be preset based on experience or requirements. For example, the first reference resistivity threshold can be the value at the top A% of the resistivity values ​​in the resistivity map, sorted from largest to smallest. For example, the growth module 830 can obtain the resistivity of each region based on the resistivity value annotations in the resistivity map, and determine the region with a resistivity lower than the first reference resistivity threshold as the first resistivity characteristic region.

[0176] Furthermore, the growth module 830 can determine a contrast region corresponding to the first resistivity characteristic region on the photoluminescence spectrum. The contrast region refers to a region whose brightness is higher than a second reference brightness threshold. For example... Figure 11A As shown, the comparison region can be region N. The second reference brightness threshold is the threshold for determining the bright area in the photoluminescence spectrum, which can be determined based on the first reference resistivity threshold. For example, the first reference resistivity threshold is the value at the top A% after sorting the resistance values ​​in the resistivity spectrum from largest to smallest. Then, the growth module 830 can determine the second reference brightness threshold as the value at the top A% after sorting the brightness values ​​in the photoluminescence spectrum from largest to smallest, and thus determine the region in the photoluminescence spectrum with a brightness higher than the second reference brightness threshold as the comparison region corresponding to the first resistivity feature region.

[0177] Furthermore, the growth module 830 can determine whether the doping uniformity meets the uniformity requirements based on the shape of the comparison region and the shape of the first resistivity characteristic region. For example, the growth module 830 can compare the shape of the comparison region with the shape of the first resistivity characteristic region; if they are similar, it is determined that the doping uniformity does not meet the uniformity requirements; if they are dissimilar, it is determined that the doping uniformity meets the uniformity requirements.

[0178] In some embodiments, the growth module 830 can determine the similarity between the shape of the comparison region and the shape of the first resistivity feature region. Similarity refers to a parameter representing the degree of similarity, which can be expressed as a percentage, etc. A higher similarity indicates a higher degree of similarity. In some embodiments, the growth module 830 can process the photoluminescence spectrum and resistivity map using machine learning models, preset algorithms, etc., to determine the similarity between the shape of the comparison region and the shape of the first resistivity feature region. In some embodiments, the growth module 830 can determine whether the doping uniformity meets the uniformity requirements based on the similarity. For example, the growth module 830 can compare the similarity with a preset similarity threshold; if the similarity is greater than the preset similarity threshold, it is determined that the shape of the comparison region and the shape of the first resistivity feature region are similar, and the doping uniformity does not meet the uniformity requirements; if the similarity is less than the preset similarity threshold, it is determined that the shape of the comparison region and the shape of the first resistivity feature region are dissimilar, and the doping uniformity meets the uniformity requirements. The preset similarity threshold can be set based on experience or requirements.

[0179] In some embodiments, the growth module 830 can determine the overlap ratio between the shape of the comparison region and the shape of the first resistivity characteristic region. The overlap ratio refers to the proportion of overlap between the shapes. The growth module 830 can process the photoluminescence spectrum and resistivity map using machine learning models, preset algorithms, etc., to determine the overlap ratio between the shape of the comparison region and the shape of the first resistivity characteristic region. In some embodiments, the growth module 830 can determine whether the doping uniformity meets the uniformity requirements based on the overlap ratio. For example, the growth module 830 can compare the overlap ratio with a preset overlap ratio threshold; if the overlap ratio is greater than the preset overlap ratio threshold, it is determined that the shape of the comparison region and the shape of the first resistivity characteristic region are similar, and the doping uniformity does not meet the uniformity requirements; if the overlap ratio is less than the preset overlap ratio threshold, it is determined that the shape of the comparison region and the shape of the first resistivity characteristic region are dissimilar, and the doping uniformity meets the uniformity requirements. The preset overlap ratio threshold can be set based on experience or requirements.

[0180] Understandably, regions with excessively low resistivity in a resistivity diagram can be caused by excessively high doping concentration, uneven doping, or other defects. In some embodiments of this specification, a first resistivity characteristic region is determined in the resistivity diagram; a corresponding contrast region is determined in the photoluminescence spectrum, where the brightness of the contrast region is higher than a second reference brightness threshold, which is determined based on the first reference resistivity threshold; based on the shape of the contrast region and the shape of the first resistivity characteristic region, it is determined whether the doping uniformity meets the uniformity requirements. A similarity analysis can be performed on the characteristic regions corresponding to the resistivity diagram and the photoluminescence spectrum. If the similarity is high, it can be concluded that the aforementioned characteristic region is caused by excessively high doping concentration or uneven doping.

[0181] In some embodiments, the growth module 830 can extract the outline of a bright region outside the first brightness feature region from the photoluminescence spectrum. The bright region may refer to a region whose brightness value exceeds a reference brightness threshold. The reference brightness threshold can be set based on experience or requirements. For example, the growth module 830 can process the photoluminescence spectrum using user annotation information, machine learning models, preset software, etc., to extract the outline of the bright region outside the first brightness feature region.

[0182] Furthermore, the growth module 830 can extract the contour set of resistivity contour lines from the resistivity map. A resistivity contour line is a closed curve connecting adjacent points of equal resistivity on the resistivity map. The contour set is the collection of the contours of all resistivity contour lines. For example, the growth module 830 can extract the contour set of resistivity contour lines from the resistivity map using user annotation information, machine learning models, preset software, etc.

[0183] Furthermore, the growth module 830 can determine whether there exists a target contour in the contour set that meets preset conditions with the contour of the bright area. These preset conditions can be based on experience or requirements. For example, a preset condition could be that the similarity between the target contour and the contour of the bright area is greater than a preset similarity threshold. For instance, the growth module 830 can determine the similarity between the contours of each resistivity contour line in the contour set and the contour of the bright area using a machine learning model or preset algorithm, compare the similarity with a preset similarity threshold, and if there exists a resistivity contour line in the contour set whose similarity to the contour of the bright area is greater than the preset similarity threshold, then it is determined that there exists a target contour in the contour set that meets the preset conditions with the contour of the bright area.

[0184] Furthermore, the growth module 830 can determine that the doping uniformity does not meet the uniformity requirement if the target contour exists in the contour set; and determine that the doping uniformity meets the uniformity requirement if the target contour does not exist in the contour set. More information on doping uniformity and uniformity requirements can be found in [link to relevant documentation]. Figures 8-11D And its related descriptions.

[0185] Understandably, the presence of a target contour in the contour set can be considered as the existence of a feature region in the resistivity map that is highly similar to a bright area in the photoluminescence spectrum, which is likely caused by inhomogeneous doping. In some embodiments of this specification, by extracting the contour of the bright area outside the first brightness feature region on the photoluminescence spectrum; extracting the contour set of resistivity contour lines on the resistivity map; determining whether there is a target contour in the contour set that meets preset conditions with the contour of the bright area: in response to the presence of a target contour in the contour set, determining that the doping uniformity does not meet the uniformity requirements; in response to the absence of a target contour in the contour set, determining that the doping uniformity meets the uniformity requirements, it is possible to further quickly and accurately determine whether there is a feature region in the resistivity map that is similar to a bright area in the photoluminescence spectrum, which helps to accurately determine the doping uniformity.

[0186] Step 1030: In response to the photoluminescence spectrum not including the first brightness characteristic region, determine that the doping uniformity meets the uniformity requirement. In some embodiments, step 1030 may be performed by the growth module 830.

[0187] Understandably, the photoluminescence spectrum can be used to determine the uniformity of doping based on the brightness value. When the brightness values ​​are basically consistent (e.g., uniformly bright), it indicates uniform doping. When there is a dark area (i.e., the first brightness characteristic area), it may be caused by uneven doping, or it may be caused by internal defects, surface defects, or other factors, which require further judgment.

[0188] At this point, the resistivity map can be used to identify the characteristic region with low resistivity (i.e., the first resistivity characteristic region; the low resistivity region may have defects or uneven nitrogen doping). The corresponding region in the photoluminescence spectrum (i.e., the comparison region) can then be determined. The similarity between the aforementioned characteristic region and the corresponding region can be assessed. If the similarity is high, it indicates a high correlation, and the formation of the aforementioned characteristic region is most likely due to excessively high or uneven nitrogen doping concentration. If the similarity is low, it indicates a low correlation, and the formation of the aforementioned characteristic region is most likely not due to excessively high or uneven nitrogen doping concentration, meaning the uniformity requirement is met. Furthermore, the outline of the bright area in the photoluminescence spectrum can be compared with the outline of the resistivity contour lines in the resistivity map to determine if there are similar characteristic regions, further determining the cause of the characteristic region's formation.

[0189] In some embodiments of this specification, by determining whether the photoluminescence spectrum includes a first brightness characteristic region; in response to the photoluminescence spectrum including the first brightness characteristic region, a resistivity map of the substrate is obtained; based on the resistivity map and the first brightness characteristic region, it is determined whether the doping uniformity meets the uniformity requirement; in response to the photoluminescence spectrum not including the first brightness characteristic region, it is determined that the doping uniformity meets the uniformity requirement. A comprehensive judgment can be made based on the photoluminescence spectrum and the resistivity map to more accurately determine whether the substrate is doped uniformly.

[0190] Furthermore, the growth module 830 can determine whether the doping uniformity meets the uniformity requirements based on the overlap ratio. For example, the growth module 830 can compare the overlap ratio with a preset overlap ratio threshold; if the overlap ratio is greater than the preset overlap ratio threshold, it is determined that the shape of the comparison area is similar to the shape of the sixth feature area, and the doping uniformity does not meet the uniformity requirements; if the overlap ratio is less than the preset overlap ratio threshold, it is determined that the shape of the comparison area is dissimilar to the shape of the sixth feature area, and the doping uniformity meets the uniformity requirements. The preset overlap ratio threshold can be set based on experience or requirements.

[0191] The basic concepts have been described above. Obviously, for those skilled in the art, the detailed disclosure above is merely illustrative and does not constitute a limitation of this specification. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and corrections to this specification. Such modifications, improvements, and corrections are suggested in this specification and therefore remain within the spirit and scope of the exemplary embodiments described herein.

[0192] Furthermore, this specification uses specific terms to describe embodiments thereof. For example, "an embodiment," "one embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic associated with at least one embodiment of this specification. Therefore, it should be emphasized and noted that references to "an embodiment," "one embodiment," or "an alternative embodiment" in different locations throughout this specification do not necessarily refer to the same embodiment. Moreover, certain features, structures, or characteristics in one or more embodiments of this specification can be appropriately combined.

[0193] Furthermore, unless expressly stated in the claims, the order of processing elements and sequences, the use of numbers and letters, or other names described in this specification are not intended to limit the order of the processes and methods described herein. Although various examples have been discussed in the foregoing disclosure of some embodiments of the invention that are currently considered useful, it should be understood that such details are for illustrative purposes only, and the appended claims are not limited to the disclosed embodiments; rather, the claims are intended to cover all modifications and equivalent combinations that conform to the spirit and scope of the embodiments described herein. For example, while the system components described above can be implemented using hardware devices, they can also be implemented solely using software solutions, such as installing the described system on existing servers or mobile devices.

[0194] Similarly, it should be noted that, in order to simplify the description disclosed herein and thus aid in the understanding of one or more embodiments of the invention, the foregoing description of embodiments in this specification may sometimes combine multiple features into a single embodiment, drawing, or description thereof. However, this method of disclosure does not imply that the subject matter of this specification requires more features than those mentioned in the claims. In fact, the embodiments contain fewer features than all the features of a single embodiment disclosed above.

[0195] In some embodiments, numbers describing the quantity of components and attributes are used. It should be understood that such numbers used in the description of embodiments are modified in some examples with the terms "approximately," "approximately," or "generally." Unless otherwise stated, "approximately," "approximately," or "generally" indicates that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximate values, which may be changed depending on the characteristics required by individual embodiments. In some embodiments, numerical parameters should take into account specified significant digits and employ a general method of digit reservation. Although the numerical ranges and parameters used to confirm their breadth of range in some embodiments of this specification are approximate values, in specific embodiments, such values ​​are set as precisely as feasible.

[0196] For each patent, patent application, patent application publication, and other material, such as articles, books, specifications, publications, and documents, referenced in this specification, the entire contents of which are incorporated herein by reference. This excludes historical application documents that are inconsistent with or conflict with the content of this specification, as well as documents that limit the broadest scope of the claims in this specification (currently or subsequently appended to this specification). It should be noted that in the event of any inconsistency or conflict between the descriptions, definitions, and / or terminology used in the supplementary materials to this specification and the content of this specification, the descriptions, definitions, and / or terminology used in this specification shall prevail.

[0197] Finally, it should be understood that the embodiments described in this specification are merely illustrative of the principles of the embodiments described herein. Other variations may also fall within the scope of this specification. Therefore, alternative configurations of the embodiments described herein are intended to be illustrative rather than limiting, and should be considered consistent with the teachings of this specification. Accordingly, the embodiments described herein are not limited to those explicitly introduced and described herein.

Claims

1. A method for epitaxial growth of crystals, characterized in that, include: An epitaxial layer is grown on the carbon surface of a silicon carbide seed wafer; and Crystals are grown on the epitaxial layer using physical vapor transport.

2. The method according to claim 1, characterized in that, The epitaxial layer grown on the carbon surface of the silicon carbide seed wafer includes: Based on the silicon carbide seed wafer, the target doping concentration is determined; Based on the target doping concentration, determine the target doping parameters; and The growth environment of the epitaxial layer is controlled based on the target doping parameters.

3. The method according to claim 2, characterized in that, The dopant for the silicon carbide seed wafer is nitrogen gas, and the target doping parameter includes the doping flow rate of the nitrogen gas.

4. The method according to claim 2, characterized in that, The determination of the target supply parameters includes: A first doping parameter is determined by growing a first reference epitaxial layer with a first doping concentration, wherein the first doping concentration is the doping concentration within the detection range of the target detection device; and The target doping concentration and the first doping parameter are used to determine the target doping parameter.

5. The method according to claim 4, characterized in that, The step of determining the first doping parameter by growing a first reference epitaxial layer with a first doping concentration includes: Adjust the doping parameters to grow the first reference epitaxial layer with the first doping concentration; and In response to the doping uniformity of the first reference epitaxial layer being greater than a preset uniformity threshold, the doping parameter at this time is determined to be the first doping parameter.

6. The method according to claim 4, characterized in that, The determination of the target doping parameter based on the target doping concentration and the first doping parameter includes: Calculate the reference ratio of the first doping concentration to the target doping concentration; Based on the reference ratio, the correlation between the first supply parameter and the target supply parameter is determined; and Based on the aforementioned correlation and the first supply parameter, the target supply parameter is determined.

7. The method according to claim 2, characterized in that, The determination of the target supply parameters includes: Acquire growth data for growing multiple second reference epitaxial layers with a second doping concentration, wherein the difference between the second doping concentration and the target doping concentration is less than a preset value, and the growth data includes at least a second doping parameter for growing each second reference epitaxial layer and the doping situation corresponding to the second doping parameter; and Based on the growth data, the target doping parameters are determined.

8. The method according to claim 7, characterized in that, The doping condition includes doping uniformity, and obtaining growth data for growing multiple second reference epitaxial layers with a second doping concentration includes: For each of the second reference epitaxial layers Obtain the photoluminescence (PL) spectrum of the epitaxial wafer containing the second reference epitaxial layer; Determine whether the photoluminescence spectrum includes a first characteristic region, wherein the first characteristic region is a region with a brightness lower than a first brightness threshold; In response to the photoluminescence spectrum including the first characteristic region, a resistivity map of the epitaxial wafer is obtained; based on the resistivity map and the first characteristic region, it is determined whether the doping uniformity of the second reference epitaxial layer meets the uniformity requirement; and In response to the photoluminescence spectrum not including the first characteristic region, it is determined that the doping uniformity of the second reference epitaxial layer meets the uniformity requirement.

9. The method according to claim 8, characterized in that, Determining whether the doping uniformity of the second reference epitaxial layer meets the uniformity requirement based on the resistivity map and the first characteristic region includes: Determine the second feature region corresponding to the first feature region on the resistivity map, and obtain the first minimum resistivity within the second feature region and the second minimum resistivity outside the second feature region; and Based on the difference between the first minimum value and the second minimum value, it is determined whether the doping uniformity meets the uniformity requirement.

10. The method according to claim 7, characterized in that, The doping condition includes the doping concentration; obtaining the growth data for growing multiple second reference epitaxial layers with a second doping concentration includes: For each of the second reference epitaxial layers Obtain the photoluminescence spectrum and resistivity map of the epitaxial wafer containing the second reference epitaxial layer; A third characteristic region is determined in the photoluminescence spectrum, wherein the third characteristic region is a region with a brightness higher than a second brightness threshold; Determine the fourth feature region corresponding to the third feature region on the resistivity map, and obtain the third minimum resistivity value within the fourth feature region; and Based on the third minimum value and the first preset reference range, it is determined whether the doping concentration meets the concentration requirements.

11. The method according to claim 1, characterized in that, The epitaxial layer growth on the carbon surface of the silicon carbide seed wafer further includes: Determine the doping status of the silicon carbide seed wafer; Determine whether the doping condition meets the doping requirements: and In response to the doping condition satisfying the doping requirements, the epitaxial layer is grown on the carbon surface of the silicon carbide seed wafer.

12. The method according to claim 11, characterized in that, The doping condition includes doping uniformity, the doping requirement includes uniformity requirement, and determining whether the doping condition meets the doping requirement includes: Obtain the photoluminescence spectrum of the silicon carbide seed wafer; Determine whether the photoluminescence spectrum includes a fifth feature region, wherein the fifth feature region is a region with a brightness lower than a third brightness threshold; In response to the photoluminescence spectrum including the fifth characteristic region, a resistivity map of the silicon carbide seed wafer is obtained. Based on the resistivity map and the fifth characteristic region, it is determined whether the doping uniformity meets the uniformity requirement; and In response to the photoluminescence spectrum not including the fifth feature region, it is determined that the doping uniformity meets the uniformity requirement.

13. The method according to claim 12, characterized in that, Determining whether the doping uniformity meets the uniformity requirement based on the resistivity map and the fifth characteristic region includes: A sixth characteristic region of the resistivity map is determined, wherein the sixth characteristic region is a region where the resistivity is lower than a first resistivity threshold; A contrast region corresponding to the sixth feature region is determined on the photoluminescence spectrum, the brightness of the contrast region being higher than a fourth brightness threshold, the fourth brightness threshold being determined based on the first resistivity threshold; and Based on the shape of the comparison region and the shape of the sixth feature region, it is determined whether the doping uniformity meets the uniformity requirement.

14. The method according to claim 12, characterized in that, Determining whether the doping uniformity meets the uniformity requirement based on the resistivity map and the fifth characteristic region includes: Extract the outline of the bright region outside the fifth feature region from the photoluminescence spectrum; Extract the contour set of resistivity contour lines from the resistivity map; Determine whether there exists a target contour in the contour set that satisfies a preset condition with the contour of the bright area; In response to the presence of the target contour in the contour set, it is determined that the doping uniformity does not meet the uniformity requirement; and In response to the absence of the target contour in the contour set, it is determined that the doping uniformity meets the uniformity requirement.

15. The method according to claim 11, characterized in that, The doping condition includes doping concentration, the doping requirement includes concentration requirement, and determining whether the doping condition meets the doping requirement includes: Obtain the photoluminescence spectrum and resistivity diagram of the silicon carbide seed wafer; A seventh characteristic region is determined in the photoluminescence spectrum, wherein the seventh characteristic region is a region with a brightness higher than a fifth brightness threshold; Determine the eighth feature region corresponding to the seventh feature region on the resistivity map, and obtain the fourth minimum resistivity value within the eighth feature region; and Based on the fourth minimum value and the second preset reference range, it is determined whether the doping concentration meets the concentration requirement.

16. The method according to claim 1, characterized in that, The epitaxial layer growth on the carbon surface of the silicon carbide seed wafer further includes: Determine the growth rate of the epitaxial layer on the carbon surface; and The growth time of the epitaxial layer is determined based on the growth rate.

17. A system for epitaxial growth of crystals, characterized in that, The system is configured to implement a method for epitaxial crystal growth, the system comprising: The epitaxial growth module is configured to grow an epitaxial layer on the carbon surface of a silicon carbide seed wafer; and The crystal growth module is configured to grow crystals on the epitaxial layer by physical vapor transport.

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