Method for distinguishing between 4h conductivity type silicon carbide ingot and silicon surface after lapping

Abstract

The application discloses a method for distinguishing carbon surface and silicon surface of 4H conductive type silicon carbide ingot after lapping, which comprises the following steps: S1: setting two end surfaces of the measured ingot as A surface and B surface respectively, and obtaining the average resistivity of the A surface and the B surface of the measured ingot; S2: obtaining the resistivity uniformity of the A surface and the B surface of the measured ingot according to the average resistivity, judging the carbon surface and the silicon surface of the measured ingot through the resistivity uniformity, and distinguishing the carbon surface and the silicon surface of the measured ingot; setting the resistivity uniformity of the A surface of the measured ingot as U A , the resistivity uniformity of the B surface as U B , if U A > U B , the A surface of the measured ingot is the carbon surface, and the B surface is the silicon surface; if U A < U B , the A surface of the measured ingot is the silicon surface, and the B surface is the carbon surface. The application can accurately distinguish the carbon surface and the silicon surface of the qualified ingot after lapping.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of silicon carbide ingot detection, in particular to a method for distinguishing 4H conductive type silicon carbide ingot and silicon surface after grinding. BACKGROUND

[0002] In the related art, silicon carbide (SiC) has a wide band gap, a high critical breakdown electric field, a high carrier saturation drift speed, a low relative dielectric constant and high temperature resistance, and is the most representative third-generation wide band gap semiconductor material. At present, the mainstream process technology for growing silicon carbide is the physical vapor transport method (PVT method), and the technical characteristics are that the silicon carbide seed crystal is bonded to the graphite seed crystal holder, then the graphite seed crystal holder is installed on the upper part of the graphite crucible, the raw material at the bottom of the crucible is heated to sublimate, and the C face is grown. The grown silicon carbide crystal can distinguish the C face and Si face of the ingot from the surface morphology and structure, but the morphology of the carbon face and the silicon face of the ingot after flat grinding and cylindrical grinding is consistent, and cannot be distinguished, and can only be distinguished by manual marking by the crystal processing personnel, but manual marking may miss the mark or have memory errors, resulting in incorrect carbon-silicon surface marking and subsequent processing problems. SUMMARY

[0003] The present application aims to solve at least one of the technical problems existing in the prior art. To this end, the present application proposes a method for distinguishing the carbon face and silicon face of 4H conductive type silicon carbide ingot after grinding, which can accurately determine the carbon face and silicon face of the qualified ingot after grinding.

[0004] According to the method for distinguishing the carbon face and silicon face of 4H conductive type silicon carbide ingot after grinding according to the present application, the following steps are included:

[0005] S1: assuming that the two end faces of the ingot to be measured are A face and B face, the average resistivity of the A face and B face of the ingot to be measured is obtained;

[0006] S2: the resistivity uniformity of the A face and B face of the ingot to be measured is obtained according to the average resistivity, the carbon face and silicon face of the ingot to be measured are determined by the resistivity uniformity, and the carbon face and silicon face of the ingot to be measured are distinguished:

[0007] assuming that the resistivity uniformity of the A face of the ingot to be measured is U A , and the resistivity uniformity of the B face is U B ,

[0008] if U A > U B , the A face of the ingot to be measured is the carbon face, and the B face is the silicon face;

[0009] if U A < U B , the A face of the ingot to be measured is the silicon face, and the B face is the carbon face.

[0010] The determination method of the present application is simple, fast and accurate.

[0011] In some embodiments, in step S2, if the difference between the uniformity of the resistivity of the A surface and the B surface of the to-be-tested ingot is less than or equal to M, step S3 is performed, which is: obtaining the resistivity map image of the to-be-tested ingot, and determining the carbon surface and the silicon surface of the to-be-tested ingot through the resistivity map image, so as to distinguish the carbon surface and the silicon surface of the to-be-tested ingot. The present embodiment further increases the accuracy of the determination.

[0012] In some embodiments, the specific method of step S1 of the present application is as follows: the two end surfaces of the to-be-tested ingot are A surface and B surface, respectively, the resistivity values of each point of the A surface and the B surface of the to-be-tested ingot are obtained by taking N points on the A surface and the B surface of the to-be-tested ingot, respectively, so as to obtain the average values of the resistivity of the A surface and the B surface, wherein N is a positive integer, and N≥55.

[0013] In some embodiments, the specific method of step S3 of the present application is as follows:

[0014] S3.1: The resistivity map image of the A surface and the B surface of the to-be-tested ingot is collected by the resistivity tester; if the lowest resistivity region of the resistivity map image of the A surface of the to-be-tested ingot is located at the edge position, and the lowest resistivity region of the resistivity map image of the B surface is located at the non-edge position, then the A surface of the to-be-tested ingot is the carbon surface, and the B surface is the silicon surface; otherwise, the A surface of the to-be-tested ingot is the silicon surface, and the B surface is the carbon surface; in the present embodiment, the carbon surface and the silicon surface of the silicon carbide ingot are distinguished by the position of the lowest region, and the distinguishing method is fast and accurate.

[0015] In some embodiments, the specific method of step S3 of the present application can also be:

[0016] S3.1: The resistivity map of the A surface or the B surface of the to-be-tested ingot is collected by the resistivity tester, and the map image of the to-be-tested ingot is transmitted to the control module;

[0017] S3.2: The control module transmits to the image comparison module, the image comparison module calls the pre-stored original carbon surface resistivity map and original silicon surface resistivity map of the ungrounded ingot, compares the received to-be-tested ingot map image, sets the comparison result as: the similarity of the to-be-tested ingot map image with the original carbon surface resistivity map is E, E≥0, and the similarity with the original silicon surface resistivity map is F, F≥0, the control module analyzes the comparison result, and judges whether the to-be-tested ingot map image is a carbon surface or a silicon surface: if E>F, the control module judges that the to-be-tested ingot image map is a carbon surface; if E<F, the control module judges that the to-be-tested ingot image map is a silicon surface; the control module transmits the judgment result to the display module for display. In the present embodiment, the carbon and silicon surfaces of the ingot are judged in an intelligent and automatic way, the judgment speed is fast, and the accuracy is high.

[0018] Compared with the prior art, the present application adopts the principle of small face spiral growth of silicon carbide, step flow growth of non-small face area, the characteristic that the resistivity increases or decreases with the increase of the thickness of the crystal ingot, detects the carbon face and the silicon face of the crystal ingot by using a crystal ingot resistivity tester, obtains the resistivity data of the carbon-silicon face, distinguishes the carbon face and the silicon face according to the resistivity uniformity, and if the resistivity uniformity cannot distinguish the carbon-silicon face, the carbon-silicon face of the crystal ingot can be distinguished according to the 3D or resistivity atlas of the two faces of the crystal ingot.

[0019] Additional aspects and advantages of the application will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following and / or can be learned by practice of the application. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a flow chart of a method for distinguishing the carbon face and the silicon face of a 4H conductive type silicon carbide crystal ingot after grinding according to an embodiment of the present application;

[0021] Figure 2 is a resistivity atlas image of the A face of a crystal ingot for distinguishing the carbon face and the silicon face of a 4H conductive type silicon carbide crystal ingot after grinding according to an embodiment of the present application;

[0022] Figure 3 is a resistivity atlas image of the B face of a crystal ingot for distinguishing the carbon face and the silicon face of a 4H conductive type silicon carbide crystal ingot after grinding according to an embodiment of the present application.

[0023] Figure 4 is a resistivity atlas image of the A face of a crystal ingot for distinguishing the carbon face and the silicon face of a 4H conductive type silicon carbide crystal ingot after grinding according to an embodiment of the present application;

[0024] Figure 5 is a resistivity atlas image of the B face of a crystal ingot for distinguishing the carbon face and the silicon face of a 4H conductive type silicon carbide crystal ingot after grinding according to an embodiment of the present application.

[0025] Figure 6 is a resistivity atlas image of the A face of a crystal ingot for distinguishing the carbon face and the silicon face of a 4H conductive type silicon carbide crystal ingot after grinding according to an embodiment of the present application;

[0026] Figure 7 is a resistivity atlas image of the B face of a crystal ingot for distinguishing the carbon face and the silicon face of a 4H conductive type silicon carbide crystal ingot after grinding according to an embodiment of the present application.

[0027] Figure 8This is a resistivity spectrum image of the four A-side of a silicon carbide ingot, which is used to distinguish the carbon and silicon surfaces of a 4H conductive silicon carbide ingot after grinding, according to an embodiment of the present invention.

[0028] Figure 9 This is a resistivity spectrum image of the four B surfaces of a silicon carbide ingot, which is used to distinguish the carbon surface and silicon surface of a 4H conductive silicon carbide ingot after grinding, according to an embodiment of the present invention.

[0029] Figure 10 This is a resistivity spectrum image of the five A surfaces of a silicon carbide ingot, which is used to distinguish between the carbon and silicon surfaces of a 4H conductive silicon carbide ingot after grinding, according to an embodiment of the present invention.

[0030] Figure 11 This is a resistivity spectrum image of the B-side of a silicon carbide ingot, which is used to distinguish the carbon and silicon surfaces of a 4H conductive silicon carbide ingot after grinding, according to an embodiment of the present invention.

[0031] Figure 12 Electrical schematic diagram of a resistivity tester, image comparison module, storage module, display module and control module for a method of distinguishing the carbon surface and silicon surface of a 4H conductive silicon carbide ingot after grinding, according to an embodiment of the present invention.

[0032] Figure 13 This is a resistivity spectrum image of the six B surfaces of a silicon carbide ingot, which is used to distinguish the carbon and silicon surfaces of a 4H conductive silicon carbide ingot after grinding, according to an embodiment of the present invention.

[0033] Figure 14 This is a resistivity spectrum image of the six A-side of a silicon carbide ingot, which is used in a method for distinguishing the carbon and silicon surfaces of a 4H conductive silicon carbide ingot after grinding, according to an embodiment of the present invention. Detailed Implementation

[0034] Embodiments of the present invention are described in detail below. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0035] The following disclosure provides numerous different embodiments or examples for implementing various structures of the invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the invention. Furthermore, reference numerals and / or letters may be repeated in different examples. Such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. Additionally, examples of various specific processes and materials are provided in this invention; however, those skilled in the art will recognize the applicability of other processes and / or the use of other materials.

[0036] The following is for reference. Figures 1 to 14The method for distinguishing the carbon surface and the silicon surface of the 4H conductive type silicon carbide ingot after polishing according to the present application will be described in detail. It should be understood that the following description is intended to explain the present application, and cannot be used as a limitation of the present application.

[0037] The method for distinguishing the carbon surface and the silicon surface of the 4H conductive type silicon carbide ingot after polishing according to the present application, as shown in the figure, comprises the following steps: Figure 1

[0038] S1: Obtain the average resistivity of the two end surfaces of the measured ingot, and the specific method is as follows:

[0039] The two end surfaces of the measured ingot are A surface and B surface respectively. The resistivity values of each point of the A surface and the B surface are obtained by taking N points on the A surface and the B surface of the measured ingot respectively, so as to obtain the average resistivity of each surface, wherein N is a positive integer, and N≥55.

[0040] The point taking method of the present embodiment is as follows: first, draw a "R" shape on the A surface and the B surface of the measured ingot respectively, then take 55 points along the "R" shape, and collect the resistivity of the N points on the A surface and the B surface of the measured ingot by using a resistivity tester.

[0041] S2: Obtain the resistivity uniformity of the A surface and the B surface of the measured ingot according to the average resistivity, judge the carbon surface and the silicon surface of the measured ingot by the resistivity uniformity, so as to distinguish the carbon surface and the silicon surface of the measured ingot, and the specific judging method is as follows:

[0042] Let the resistivity uniformity of the A surface of the measured ingot be U A , and the resistivity uniformity of the B surface be U B .

[0043] If U A > U B , the A surface of the measured ingot is the carbon surface, and the B surface is the silicon surface.

[0044] If U A < U B , the A surface of the measured ingot is the silicon surface, and the B surface is the carbon surface.

[0045] In the present scheme, the resistivity uniformity = standard deviation / average resistivity. Since the calculation method of the resistivity uniformity is known to those skilled in the art, it will not be described here.

[0046] Since the difference between the two end surfaces of the measured ingot is too small, the carbon surface and the silicon surface of the measured ingot are judged by the resistivity uniformity. In order to make the judgment more accurate, in some embodiments, if the resistivity uniformity difference between the two end surfaces of the measured ingot ≤M, step S3 is executed, specifically, if |U A -U B ​If |R|≤1%, step S3 is performed. The embodiment further increases the accuracy of judging the carbon surface and the silicon surface of the measured ingot.

[0047] S3: Obtain the resistivity map image of the measured ingot, and judge the carbon surface and the silicon surface of the measured ingot through the resistivity map image, so as to distinguish the carbon surface and the silicon surface of the measured ingot. Step S3 can be realized by the following two methods.

[0048] S3.1: Collect the resistivity map images of the A surface and the B surface of the measured ingot by the resistivity tester;

[0049] If the lowest resistivity region of the resistivity map image of the A surface of the measured ingot is located at the edge position, and the lowest resistivity region of the resistivity map image of the B surface is located at the non-edge position, the A surface of the measured ingot is the carbon surface, and the B surface is the silicon surface. Conversely, the A surface of the measured ingot is the silicon surface, and the B surface is the carbon surface. The principle of the embodiment is that the small surface is always located at the edge position of the carbon surface, and the resistivity of the small surface is the lowest region of the entire carbon surface. Therefore, the carbon surface can be found by finding the surface where the small surface is located.

[0050] Reference Figure 12 As shown in the figure, the second method of step S3 includes a resistivity tester, an image comparison module, a display module and a control module, and the resistivity tester, the image comparison module, the display module and the control module are electrically connected. The image comparison module pre-stores the original carbon surface resistivity map and the original silicon surface resistivity map of the ungrounded ingot. The specific method is as follows:

[0051] S3.1: Collect the resistivity map of the A surface or the B surface of the measured ingot by the resistivity tester, and transmit the resistivity map image of the measured ingot to the control module;

[0052] S3.2: Transmit the resistivity map of the measured ingot to the image comparison module through the control module. The image comparison module calls the pre-stored original carbon surface resistivity map and original silicon surface resistivity map of the ungrounded ingot, compares the received resistivity map image of the measured ingot, sets the comparison result as: the similarity between the resistivity map image of the measured ingot and the original carbon surface resistivity map is X, X≥0, and the similarity between the resistivity map image of the measured ingot and the original silicon surface resistivity map is Y, Y≥0, and the control module analyzes the comparison result and judges whether the resistivity map image of the measured ingot is the carbon surface or the silicon surface:

[0053] If X>Y, the control module judges that the resistivity map image of the measured ingot is the carbon surface, and the lowest resistivity region of the carbon surface is the small surface.

[0054] If XY, the control module judges that the resistivity map image of the measured ingot is the silicon surface.

[0055] The control module transmits the judgment result to the display module for display. The control module of the embodiment is an STM32 microcontroller, and the display module of the embodiment can be a display screen.

[0056] Example 1

[0057] This embodiment distinguishes the carbon face and silicon face of the polished ingot one, including the following steps:

[0058] S1: Obtain the resistivity value of each point of the A and B faces of the ingot one by taking 55 points on each face, thereby obtaining the average resistivity of each face, wherein N=55, as shown in Table 1, the average resistivity of the A face of the ingot one is 0.01751, and the average resistivity of the B face is 0.02044;

[0059] S2: Obtain the resistivity uniformity of the A and B faces of the ingot one by the average resistivity, as shown in Table 1, the resistivity uniformity of the A face of the ingot one is U A = 6.41%, and the resistivity uniformity of the B face is U B = 4.62%, and the carbon face and silicon face are distinguished by the resistivity uniformity:

[0060] If U A > U B , the A face of the ingot one is the carbon face, and the B face is the silicon face;

[0061] If U A < U B , the A face of the ingot one is the silicon face, and the B face is the carbon face.

[0062] Since U A > U B in this embodiment, the A face of the ingot one is the carbon face, as shown in reference Figure 2 , and the B face is the silicon face, as shown in reference Figure 3 , the position of the small face can be seen from the resistivity distribution in Figure 2 , that is, the blue area with the lowest resistivity. Figure 2 The arrow direction in

[0063] Example 2

[0064] This embodiment distinguishes the carbon face and silicon face of the polished ingot two, and the method of this embodiment is the same as that of Example 1, except that as shown in Table 1, the average resistivity of the A face of the ingot two in this embodiment is 0.02563, and the average resistivity of the B face is 0.02054, and the resistivity uniformity of the A face of the ingot two in this embodiment is U A = 1.05%, and the resistivity uniformity of the B face is U B = 4.56%.

[0065] Since U A < U B in this embodiment, the A face of the ingot two is the silicon face, as shown in referenceFigure 4 As shown in FIG. 6, the B face is a carbon face, and the reference Figure 5 As shown in FIG. 7, the B face is a silicon face, and the reference Figure 5 The position of the facet can be seen from the resistivity distribution in FIG. 8, i.e., the blue area with the lowest resistivity.

[0066] Example 3

[0067] In this example, the carbon face and the silicon face of the polished crystal ingot three are distinguished. The method of this example is the same as that of Example 1, except that, as shown in Table 1, the average resistivity of the A face of the crystal ingot three in this example is 0.02152, and the average resistivity of the B face is 0.02239. It is concluded from the average resistivity that the resistivity uniformity of the A face of the crystal ingot three in this example is U A = 5.09%, and the resistivity uniformity of the B face is U B = 1.24%.

[0068] Since U A > U B in this example, the A face of the crystal ingot three is a carbon face, and the reference Figure 7 As shown in FIG. 6, the B face is a silicon face, and the reference Figure 6 As shown in FIG. 7, the B face is a silicon face, and the reference

[0069] Table 1: Resistivity parameters of the two end faces of the silicon carbide crystal ingot

[0070]

[0071]

[0072]

[0073] Example 4

[0074] In this example, the carbon face and the silicon face of the polished crystal ingot four are distinguished. This example is generally consistent with Example 1, except that, in this example, the average resistivity of the A face of the crystal ingot four is 0.01943, and the average resistivity of the B face is 0.02251. The resistivity uniformity of the A face of the crystal ingot four is U A = 6.81%, and the resistivity uniformity of the B face is U B = 6.10%. Since |U A -U B | = 0.71% < 1% in this example, the method of step S3 is used to further determine the carbon face and the silicon face of the crystal ingot four to increase the accuracy of the determination, and the specific method is as follows:

[0075] S3.1 The resistivity tester is used to collect resistivity spectrum images of the A face and the B face of the crystal ingot four, respectively.

[0076] Reference is made to Figure 8 and Figure 9 As shown in the figure, the lowest resistivity area of the A-face resistivity map image collected in the embodiment is located at the edge position, and the lowest resistivity area of the B-face resistivity map image is located at a non-edge position. According to the principle that the small face position is the lowest resistivity area in the resistivity map image and is located at the edge position, the A-face is the carbon face, as shown in reference Figure 8 , and then the B-face is the silicon face, as shown in reference Figure 9 , the carbon face can be determined according to the small face position in the embodiment, in other words, the face where the small face is located is the carbon face.

[0077] In the embodiment, the carbon face is determined by finding the position of the small face in the resistivity map image, and the face where the small face is located is the carbon face. The method is simple, fast, and has high accuracy.

[0078] Embodiment 5

[0079] In the embodiment, the carbon face and the silicon face of the ground crystal ingot five are distinguished. The embodiment is basically the same as embodiment 1, and the difference is that the average resistivity of the A-face of the crystal ingot five in the embodiment is 0.02064, and the average resistivity of the B-face is 0.02252. According to the average resistivity, the resistivity uniformity of the A-face of the crystal ingot five in the embodiment is U A = 5.83%, and the resistivity uniformity of the B-face is U B = 5.05%.

[0080] Since |U A -U B | = 0.78% < 1% in the embodiment, therefore, the carbon face and the silicon face of the crystal ingot five need to be further judged by the method of step S3 to increase the accuracy of the judgment, as shown in reference Figure 12 , and the specific method is as follows:

[0081] S3.1 The resistivity of the A-face of the crystal ingot five is collected by the resistivity tester (referred to as "map image" hereinafter), and the map image is transmitted to the control module;

[0082] S3.2 The map image is transmitted to the image comparison module by the control module. The image comparison module calls the original carbon face resistivity map and the original silicon face resistivity map of the ungrounded crystal ingot pre-stored in the storage module, compares them with the received map image, and the similarity of the map image with the original carbon face resistivity map is X = 90%, and the similarity with the original silicon face resistivity map is Y = 8%. The control module analyzes the comparison result and judges whether the map image is a carbon face or a silicon face:

[0083] Since X > Y in the embodiment, the control module judges that the A-face of the crystal ingot five is a carbon face. Since the A-face of the crystal ingot five is a carbon face, as shown in reference Figure 10As shown, so its B face is silicon surface, reference Figure 11 As shown, and the results of the judgment to the display module display. From Figure 10 The position of the small face, that is, the blue area with the lowest resistivity, is located at the edge of the carbon surface, as can be seen from the resistivity distribution in

[0084] Example 6

[0085] In this embodiment, the carbon surface and silicon surface of the polished crystal ingot six are distinguished. This embodiment is basically the same as Example 1, except that the average resistivity of the A face of the crystal ingot six in this embodiment is 0.02365, and the average resistivity of the B face is 0.03238. The resistivity uniformity of the B face of the crystal ingot six in this embodiment is U A = 5.11%, and the resistivity uniformity of the B face is U B = 4.75%.

[0086] Since |U A -U B | = 0.36 < 1%, therefore, in order to increase the accuracy of the judgment, the carbon surface and silicon surface of the crystal ingot six need to be further judged by the method of step S3. The specific method of step S3 in this embodiment is as follows:

[0087] S3.1 The resistivity tester collects the resistivity pattern image of the B face of the crystal ingot six (referred to as "pattern image" hereinafter), and transmits the pattern image to the control module;

[0088] S3.2 The control module transmits to the image comparison module. The image comparison module calls the original carbon surface resistivity pattern and the original silicon surface resistivity pattern of the unpolished crystal ingot previously stored in the storage module, and compares them with the received pattern image. In this embodiment, the similarity of the B face pattern image of the crystal ingot six to the original carbon surface resistivity pattern is X = 16%, and the similarity to the original silicon surface resistivity pattern is Y = 89%. The control module analyzes the comparison result and judges whether the pattern image is a carbon surface or a silicon surface:

[0089] Since X < Y in this embodiment, the control module judges that the B face of the crystal ingot six is a silicon surface, reference Figure 13 As shown, because the B face of the crystal ingot six is a silicon surface, its A face is a carbon surface, reference Figure 14 As shown, and the display result is transmitted to the display module for display. From Figure 14 The position of the small face, that is, the blue area with the lowest resistivity, can be seen from the resistivity distribution in

[0090] Table 2: Resistivity parameters of the two end faces of the silicon carbide crystal ingot

[0091]

[0092]

[0093]

[0094] The above embodiments 5 and 6 do not need to determine the carbon surface by the position of the facet, but adopt the image comparison method, directly determine whether the collected image is the carbon surface or the silicon surface through intelligent analysis, and the automation and intelligence degree is high, the judgment result is fast and accurate, effectively improves the work efficiency, reduces the production cost of enterprises, and avoids the error of manual marking.

[0095] Other configurations of the method for distinguishing the carbon surface and the silicon surface of the 4H conductive type silicon carbide crystal ingot after grinding according to the embodiments of the present application, such as the resistivity tester and the control module, the display module, the image comparison module, and the operation are known to those skilled in the art, and will not be described in detail here.

[0096] In the description of the present application, it should be understood that the orientations or positional relationships indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0097] In addition, the terms "first", "second", "third" and the like are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" and the like can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly specified and limited.

[0098] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection", "fixing" and the like should be understood in a broad sense, for example, it can be fixed connection, or detachable connection, or integral; it can be mechanical connection, or electrical connection, or communication; it can be directly connected, or indirectly connected through an intermediate medium; it can be the communication or interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0099] In the present application, unless otherwise explicitly specified and limited, a first feature is "on" or "under" a second feature can mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature "over", "above" and "on top of" the second feature can mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is horizontally higher than the second feature. The first feature "under", "below" and "underneath" the second feature can mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is horizontally lower than the second feature.

[0100] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in one or more embodiments or examples. In addition, the person skilled in the art can combine and combine the different embodiments or examples described in the present specification and the features of the different embodiments or examples, without contradiction.

[0101] Although the embodiments of the present application have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, replacements and variations can be made to the embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the claims and their equivalents.

Claims

1. A method for distinguishing between carbon and silicon faces of a 4H conductivity type silicon carbide ingot carbon face after lapping, characterized by, The method comprises the following steps: S1: assuming that the two end faces of the measured ingot are A face and B face, obtaining the average resistivity of the A face and the B face of the measured ingot; S2: obtaining the resistivity uniformity of the A face and the B face of the measured ingot according to the average resistivity, judging the carbon face and the silicon face of the measured ingot through the resistivity uniformity, and distinguishing the carbon face and the silicon face of the measured ingot: Let the A-surface resistivity uniformity of the measured ingot A be U A , and the B-surface resistivity uniformity be U B , If U A > U B , then the A surface of the measured ingot is a carbon surface, and the B surface is a silicon surface. If U A If U B If U B If U B If U B If U B If U B If U B If U B If U If the difference between the resistivity uniformity of the A face and the B face of the measured ingot is less than or equal to M, step S3 is performed, which is: obtaining the resistivity map image of the measured ingot, and judging the carbon face and the silicon face of the measured ingot through the resistivity map image, thereby distinguishing the carbon face and the silicon face of the measured ingot, and the specific method is as follows: The first method: the resistivity tester is used to collect the resistivity map image of the A face and the B face of the measured ingot; if the lowest resistivity region of the resistivity map image of the A face of the measured ingot is located at the edge position, and the lowest resistivity region of the resistivity map image of the B face is located at the non-edge position, then the A face of the measured ingot is the carbon face, and the B face is the silicon face; otherwise, the A face of the measured ingot is the silicon face, and the B face is the carbon face; The second method: S3.1: the resistivity tester is used to collect the resistivity map of the A face or the B face of the measured ingot, and the measured ingot map image is transmitted to the control module; S3.2: the image comparison module is transmitted through the control module, the image comparison module calls the pre-stored original carbon face resistivity map and original silicon face resistivity map of the ungrounded ingot, compares the received measured ingot map image, and transmits the comparison result to the control module, assuming that the similarity of the measured ingot map image with the original carbon face resistivity map is E, E≥0, and the similarity with the original silicon face resistivity map is F, F≥0, the control module analyzes the comparison result, and judges whether the measured ingot map image is the carbon face or the silicon face: If E>F, the control module judges that the measured ingot image is the carbon face; If E<F, the control module judges that the measured ingot image is the silicon face; The control module transmits the judgment result to the display module for display.

2. The method for distinguishing the carbon face and silicon face of a 4H-conductivity-type silicon carbide ingot after lapping according to claim 1, characterized in that, The step S1 is specifically as follows: N points are taken from the A face and the B face of the measured ingot to obtain the resistivity value of each point of the A face and the B face of the measured ingot, thereby obtaining the average resistivity of the A face and the B face, wherein N is a positive integer, and N≥55.

3. The method for distinguishing the carbon face and silicon face of a 4H-conductivity-type silicon carbide ingot after lapping according to claim 1, characterized in that, The control module is an STM32 microcontroller, and the display module is a display screen.

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