Crystal form judgment method of silicon carbide single crystal polymorphic symbiotic region and application of crystal form judgment method

Abstract

The invention discloses a crystal form judgment method of a silicon carbide single crystal polymorphic symbiotic region and application, and belongs to the technical field of silicon carbide material detection. The determination method comprises the following steps: (1) testing: carrying out Raman test on silicon carbide single crystals to obtain a test spectrogram, and classifying characteristic peaks in the test spectrogram into first crystal form Raman characteristic peaks and second crystal form Raman characteristic peaks according to Raman characteristic peaks of different crystal forms; and (2) judgment: judging that the crystal form at the test point is the first crystal form, a symbiotic crystal form of the first crystal form and the second crystal form or the second crystal form according to the ratio of the peak intensity of the Raman characteristic peak of the first crystal form to the peak intensity of the Raman characteristic peak of the second crystal form. According to the method, Raman is adopted to test the silicon carbide single crystal material, and the crystal form at a test point is judged according to a test spectrogram, so that the crystal form of a multi-type symbiotic region of the silicon carbide single crystal material can be accurately distinguished and quantitatively characterized, and the method can be used for large-scale detection of a silicon carbide single crystal rod.

Description

Technical Field

[0001] The present application relates to a method for determining the crystal form of a polymorphic intergrowth region of a silicon carbide single crystal and its application, belonging to the technical field of silicon carbide material detection. Background Art

[0002] SiC single crystal has more than 200 isomorphic polymorphs. Due to the staggered growth temperature and pressure intervals of different crystal forms and the close stacking fault energy of different polymorphic SiC, polymorphic symbiosis is prone to occur during the growth of SiC single crystal using the PVT method, especially the edge of the silicon carbide single crystal rod is more prone to polymorphic symbiosis. In order to optimize the production process and facilitate subsequent processing and production, it is often necessary to test the completed silicon carbide single crystal material to determine the crystal form of the material.

[0003] Most of the existing testing equipment uses normal light or polarized light for differentiation. When normal light is irradiated to the conductive silicon carbide crystal rod, it presents different colors due to the different doping concentrations of the N element, which can achieve differentiation of the polytypes of the conductive silicon carbide crystal rod to a certain extent. However, for semi-insulating silicon carbide, normal light cannot distinguish the polytypes. The polarized light irradiation method is mainly used for the detection of silicon carbide substrates. For silicon carbide single crystal rods that have been flat-ground and rounded, the edge roughness changes, resulting in a shallow penetration depth of the polarized light source on the carbon surface and silicon surface, making it difficult to accurately determine the distribution position of the polytype on the side wall of the crystal rod. In addition, as the size and thickness of silicon carbide crystal rods on the market gradually increase, the above two test methods are more difficult to judge the polytype, and it is difficult to accurately distinguish the position of the polytype co-existence. Both of the above methods are difficult to accurately determine the crystal type in the polytype co-existence area on the side wall of the silicon carbide single crystal rod.

[0004] Although XRD can be used for polymorphic detection of silicon carbide single crystal rods, when XRD detects polymorphic co-growth areas, it is difficult to distinguish which crystal type is dominant in the polymorphic co-growth area because its detection spot covers a relatively large area, so the detection accuracy is low. In addition, during the XRD detection of silicon carbide single crystal rods, the crystal needs to be erected and fixed to detect the side wall of the crystal rod. The position of the crystal rod needs to be readjusted for each detection. In addition, the XRD itself needs to adjust the angle of the X-ray before testing, which makes the XRD detection time very long, making it difficult to achieve large-scale detection of silicon carbide crystal rods. Summary of the invention

[0005] In order to solve the above problems, a method and application of crystal form determination in polymorphic co-existence area of ​​silicon carbide single crystal is provided. The method adopts Raman to test silicon carbide single crystal material and determines the crystal form at the test point according to the test spectrum. The method can accurately distinguish and quantitatively characterize the crystal form in polymorphic co-existence area of ​​silicon carbide single crystal material, and can be used for large-scale detection of silicon carbide single crystal rods.

[0006] According to one aspect of the present application, a method for determining the crystal form of a polymorphic intergrowth region of a silicon carbide single crystal is provided, comprising the following steps:

[0007] (1) Testing: Performing Raman testing on a silicon carbide single crystal to obtain a test spectrum, and classifying characteristic peaks in the test spectrum into Raman characteristic peaks of the first crystal form and Raman characteristic peaks of the second crystal form according to Raman characteristic peaks of different crystal forms;

[0008] (2) Judgment: If RPS1 / RPS2≥10 and 0.5≤RPS2 / I Baseline ≤5, the crystal form at the test point is the first crystal form; if 0.1≤RPS1 / RPS2<10 and RPS1 / I Baseline ≥2, RPS2 / I Baseline ≥2, the crystal form at the test point is a co-existing crystal form of the first crystal form and the second crystal form; if RPS1 / RPS2<0.1, and 0.5≤RPS1 / I Baseline ≤5, the crystal form at the test point is the second crystal form, RPS1 is the peak intensity of the Raman characteristic peak of the first crystal form, RPS2 is the peak intensity of the Raman characteristic peak of the second crystal form, I Baseline is the baseline peak intensity.

[0009] The judgment basis of step (2) is the ratio of the peak intensity of the Raman characteristic peak of the first crystal form to the peak intensity of the Raman characteristic peak of the second crystal form, and the ratio of the peak intensity of the Raman characteristic peak to the peak intensity of the baseline. This is based on the different Raman activities of different polymorphs, which are reflected in the difference in peak intensity on the Raman spectrum. In SiC, the Raman characteristic peaks of different crystal forms represent the presence of polymorphs, and the peak intensity reflects the relative content of the polymorphs. The type and symbiotic ratio of the polymorphs can be determined by the peak intensity ratio of the characteristic peaks of different crystal forms. Therefore, it is more in line with the characteristics of Raman detection of silicon carbide single crystal materials, and the judgment results are more accurate, thereby improving the detection precision and accuracy of silicon carbide single crystal materials.

[0010] In addition to the peak intensity ratio of the Raman characteristic peaks of the first crystal form and the second crystal form, the above judgment conditions also introduce the ratio of the peak intensity of the Raman characteristic peak to the baseline peak intensity. This ratio is used to determine the peak intensity of the weaker Raman characteristic peak. If it is not within the above range, it means that the Raman characteristic peak is relatively weak, and the accuracy of peak search and fitting is also relatively weak. Therefore, this point is regarded as an interference peak and a miscellaneous peak signal, and there is no need for statistical calculation. Therefore, the judgment conditions that match the ratio of the Raman characteristic peaks of the two crystal forms and the ratio of the peak intensity of the Raman characteristic peak to the baseline peak intensity can improve the accuracy of the judgment method of this application.

[0011] Optionally, the first crystal form is one of the 4H crystal form, the 6H crystal form or the 15R crystal form, and the second crystal form is one of the 4H crystal form, the 6H crystal form or the 15R crystal form.

[0012] Optionally, the Raman characteristic peak of the 4H crystal form is 776.62±1.00cm -1 The Raman characteristic peak of the 6H crystal form is 788.05±1.00cm -1 The Raman characteristic peak of the 15R crystal form is 784.59±1.00cm -1 .

[0013] Optionally, the Raman test is a microscopic Raman test.

[0014] Since each test point in the Raman test needs to be focused before the test can continue, the test instrument needs to first determine whether it is focused. If it is not focused, the illumination or Raman test parameters need to be adjusted to refocus. The micro Raman can realize microscopic observation of the test point, improve the efficiency of judging whether the test point is focused during the detection process, and thus further improve the detection efficiency and accuracy.

[0015] Optionally, the laser wavelength range of the Raman test is 325nm-785nm, preferably 532nm-785nm.

[0016] During the detection process, when the focal length changes, the light intensity will change. When the Raman detection mechanism is used to achieve focusing, if there is no other dimming mechanism, focusing is achieved by adjusting the laser spot to the smallest and brightest. However, this focusing method has a certain focusing deviation compared to bright field focusing. If the laser wavelength is above 532nm, the focusing deviation can be ignored. Therefore, at a wavelength of 532nm-785nm, polymorphic quantitative detection can be achieved without dimming. However, if the laser wavelength is below 532nm, the focusing deviation will cause the detection point to still be in an abnormal focusing state, and the remaining dimming mechanisms need to be used for dimming to achieve detection.

[0017] Optionally, the step movement speed of the Raman test is 3000 μm / step-15000 μm / step.

[0018] The stride moving speed affects the test point density during the micro Raman mapping test, which affects the overall test efficiency on the one hand and the test accuracy of crystal form judgment and crystal form conversion on the other hand.

[0019] Optionally, the light spot of the Raman test is 1 μm-5 μm.

[0020] This indicator can affect the judgment of the test accuracy, especially in the process of polymorphic co-existence or crystal transformation, the test accuracy is relatively high when the spot is small. The spot of the Raman test used in this application is micron-level, while the test spot of XRD itself is millimeter-level, so the spot of the Raman test in this application is smaller than that of the XRD test spot. Although Raman and XRD can both measure multiple crystal forms of silicon carbide crystal rods at the same time, when the polymorphic co-existence area is measured, Raman and XRD will have multiple characteristic peaks of different crystal forms in their respective spectra. Since the test spot coverage area of ​​XRD is relatively large, it is difficult to distinguish which crystal form is dominant in the crystal co-existence area, so its test accuracy is low. The area of ​​the Raman test in this application is small, so the detection accuracy of silicon carbide single crystal materials is higher.

[0021] Optionally, the exposure time of the Raman test is 0.5s-10s.

[0022] On the one hand, the exposure time can affect the test efficiency. The longer the exposure time, the longer the single-point test time and thus the longer the test time. On the other hand, the exposure time affects the judgment of the peak position fitting accuracy and the crystal form conversion accuracy. The longer the exposure time, the stronger the peak intensity, thus the higher the relative peak position fitting accuracy within a certain range, and the more accurate the crystal form judgment when polymorphs coexist during the crystal form conversion process.

[0023] Optionally, the Z-axis automatic focusing height range of the Raman test is -100-+100 μm.

[0024] Since the side walls of the silicon carbide crystal rod have height fluctuations, the optimal signal strength is reflected, further improving the accuracy of the detection results.

[0025] According to another aspect of the present application, there is provided an application of the method for determining the crystal form of a polymorphic intergrowth region of a silicon carbide single crystal as described in any one of the above items in the detection of the crystal form of silicon carbide materials.

[0026] The beneficial effects of this application include but are not limited to:

[0027] 1. The method for determining the crystal form of the polymorphic co-existence area of ​​a silicon carbide single crystal of the present application uses Raman to scan the silicon carbide single crystal, and determines the crystal form based on the peak intensity ratio of the Raman characteristic peaks of the first crystal form and the second crystal form, thereby quantitatively and accurately obtaining the polymorphic distribution of the silicon carbide single crystal material, and feeding the determination result back to production or processing, which can optimize the production process and guide the adjustment of the processing technology.

[0028] 2. The method for determining the crystal form of polymorphic co-existence areas of silicon carbide single crystals of the present application has the characteristics of high detection efficiency, short detection time, low detection cost, and wide detection range. It can realize batch detection of silicon carbide single crystal materials and promote its use in industrialization.

[0029] 3. The method for determining the crystal form of polymorphic co-growth areas of silicon carbide single crystals of the present application has a wide detection range. It is not only suitable for polymorphic detection of the side walls of silicon carbide single crystal rods, but can also be used for polymorphic detection of silicon carbide substrates, thereby achieving quantitative characterization of silicon carbide single crystal materials.

[0030] 4. The method for determining the crystal type of the polymorphic co-existence area of ​​silicon carbide single crystal of the present application determines the specific crystal type at the test point based on the ratio of the peak intensities of the Raman characteristic peaks of different crystal types, which is more in line with the characteristics of silicon carbide single crystal materials, and therefore has higher detection accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0032] Figure 1 for Figure 3 Raman spectra of different crystal forms of silicon carbide crystal rods.

[0033] Figure 2 This is a Raman spectrum diagram of the simultaneous existence of 4H crystal form and 15R crystal form at a certain test point of the 4H-silicon carbide single crystal rod in Example 1 of the present application.

[0034] Figure 3 This is a Raman spectrum diagram of the simultaneous existence of 6H crystal form and 15R crystal form at a certain test point of the 4H-silicon carbide single crystal rod in Example 1 of the present application.

[0035] Figure 4 This is the polytype distribution diagram of the side wall of the 4H-silicon carbide single crystal rod in Example 1 of the present application. DETAILED DESCRIPTION

[0036] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0037] Unless otherwise specified, the method used in the embodiments of the present application is a conventional method in the prior art. In the following embodiments, a Raman test is performed on a silicon carbide single crystal rod. The basis for determining the crystal form according to the peak intensity ratio between the characteristic peaks of different crystal forms is that the Raman spectrum is a scattering spectrum. When a light beam is irradiated on a substance, part of the light will be scattered. In addition to the components with the same frequency as the incident light, the scattered light also has components that change with the frequency of the incident light. This change includes frequency increase and decrease. By analyzing the frequency and intensity of these scattered lights, the molecular vibration and rotation information of the substance can be obtained, thereby studying the structure and properties of the substance. In crystal form analysis, different crystal forms will cause the position, intensity and number of characteristic peaks in the Raman spectrum to be different due to the different molecular arrangement and symmetry rules, showing different Raman characteristic peak positions, and the intensity of the characteristic peak mainly reflects the degree of molecular vibration or rotation, and this intensity ratio can be used to describe the relative intensity relationship between different characteristic peaks.

[0038] Example 1

[0039] This embodiment relates to a method for determining the crystal form of a polymorphic intergrowth region of a silicon carbide single crystal rod, comprising the following steps:

[0040] (1) Test: A microscopic Raman test is performed on a silicon carbide single crystal to obtain a test spectrum. According to the Raman characteristic peaks of different crystal forms, the characteristic peaks in the test spectrum are classified into the first crystal form Raman characteristic peaks and the second crystal form Raman characteristic peaks. The wavelength of the Raman test is 325 nm, the step speed is 3000 μm / step, the spot is 1 μm, and the exposure time is 0.5 s. The dimming mechanism is used to assist in the Raman test to achieve precise focusing on each test point.

[0041] (2) Determination: If RPS1 / RPS2>0.7, the crystal form at the test point is the first crystal form; if 0.3≤RPS1 / RPS2≤0.7, the crystal form at the test point is a co-existing crystal form of the first crystal form and the second crystal form; if RPS1 / RPS2<0.3, the crystal form at the test point is the second crystal form, and RPS1 is the peak intensity of the Raman characteristic peak of the first crystal form, and RPS2 is the peak intensity of the Raman characteristic peak of the second crystal form.

[0042] In step (2), the first crystal form is one of the 4H crystal form, the 6H crystal form or the 15R crystal form, and the second crystal form is one of the 4H crystal form, the 6H crystal form or the 15R crystal form, and the first crystal form and the second crystal form are different in crystal type. The Raman characteristic peak of the 4H crystal form is 776.62±0.5cm -1 The Raman characteristic peak of the 6H crystal form is 788.05±0.5cm -1 The Raman characteristic peak of the 15R crystal form is 784.59±0.5cm -1 .

[0043] Figure 1 The Raman spectra of the reference peaks of the 4H, 6H and 15R crystal forms of the silicon carbide single crystal rod are used in this application as the basis for judgment. Since the characteristic peaks in the Raman test are affected by the stress of the substrate itself, the temperature and humidity of the test environment, and the surface roughness of the substrate, the characteristic peaks at the test points are offset relative to the reference peaks. Therefore, in step (2), for the 4H crystal form, 776.62±1.00cm -1 The peak at the position is taken as the Raman characteristic peak. For 6H crystal type, 788.05±1.00cm -1 The peak at the position is taken as the Raman characteristic peak. For 15R crystal type, 784.59±1.00cm -1 The peak at the position is taken as the Raman characteristic peak.

[0044] The method of Example 1 is used to test the 4H-silicon carbide single crystal rod and the 6H-silicon carbide single crystal rod respectively. Specifically, the 4H-silicon carbide single crystal rod and the 6H-silicon carbide single crystal rod to be tested after flat grinding and rounding are placed in the detection area respectively, and then the side walls are mapped and scanned according to steps (1) and (2) and each test point is judged.

[0045] Figure 2 This is the Raman spectrum of the 4H-SiC single crystal rod at a certain test point where the 4H crystal form and the 15R crystal form coexist. Figure 2 It can be seen that at this test point, RPS1 / 15R of 0.1≤4H has RPS2<10, and RPS1 / I of 4H has Baseline RPS2 / I ≥2, 15R Baseline ≥2, so the crystal form at this test point is determined to be a co-occurring crystal form of 4H and 15R. Figure 3 This is the Raman spectrum of the 6H and 15R crystal forms at a certain test point of the 4H-SiC single crystal rod. Figure 3 It can be seen that at this test point, RPS1 / 15R of 0.1≤6H has RPS2<10, and RPS1 / I of 6H Baseline RPS2 / I ≥2, 15R Baseline ≥2, so the crystal form at this test point is determined to be a co-existing crystal form of 6H and 15R.

[0046] After the 4H-SiC single crystal rod is tested and determined in the above steps (1) and (2), the polymorphic distribution of the side wall of the 4H-SiC single crystal rod is obtained according to the crystal type determination result of each test point. The test results are shown in Figure 4 , Figure 4 The green one is 6H crystal form, the blue one is 15R crystal form, and the red one is 4H crystal form. Figure 4The width of the 6H crystal measured in Figure (A) is 19246.8μm, and the width of the 15R crystal measured in Figure (B) is 7727.96μm.

[0047] The above test results prove that the method for determining the crystal form of silicon carbide single crystals of the present application can achieve quantitative characterization of the crystal form of silicon carbide single crystal materials.

[0048] Example 2

[0049] This embodiment relates to a method for determining the crystal form of a polymorphic co-growth region of a silicon carbide single crystal rod. The difference between this embodiment and Embodiment 1 is that the wavelength of the Raman test is 532 nm, the step moving speed is 15000 μm / step, the spot is 5 μm, the exposure time is 10 s, and a dimming mechanism is used to assist in the Raman test to achieve precise focusing on each test point. The rest is the same as Embodiment 1.

[0050] The method of this embodiment is used to test the side walls of 4H-silicon carbide single crystal rods and 6H-silicon carbide single crystal rods, respectively, to obtain the polymorphic distribution of the side walls of each silicon carbide single crystal rod.

[0051] Example 3

[0052] The difference between this embodiment and embodiment 1 is that the test wavelength is 785 nm, and the rest is the same as embodiment 1.

[0053] The method of this embodiment is used to test the side walls of 4H-silicon carbide single crystal rods and 6H-silicon carbide single crystal rods, respectively, to obtain the polymorphic distribution of the side walls of each silicon carbide single crystal rod.

[0054] Example 4

[0055] The difference between this embodiment and embodiment 1 is that microscopic Raman is not used, but ordinary Raman test is used, and the rest is the same as embodiment 1.

[0056] The method of this embodiment is used to test the side walls of 4H-silicon carbide single crystal rods and 6H-silicon carbide single crystal rods, respectively, to obtain the polymorphic distribution of the side walls of each silicon carbide single crystal rod.

[0057] Example 5

[0058] The difference between this embodiment and embodiment 1 is that the exposure time is 10 seconds, and the rest is the same as embodiment 1.

[0059] The method of this embodiment is used to test the side walls of 4H-silicon carbide single crystal rods and 6H-silicon carbide single crystal rods, respectively, to obtain the polymorphic distribution of the side walls of each silicon carbide single crystal rod.

[0060] Experimental example

[0061] The sidewall polymorphism of each silicon carbide single crystal rod in the above embodiment is tested by XRD test, and the XRD test method is as follows:

[0062] 1. First, use XRD to confirm the crystal phase of the SiC sidewall. The atoms in a single crystal are arranged in a three-dimensional periodic manner, which can be regarded as a series of parallel planes with a crystal plane spacing d. When a beam of monochromatic X-rays with a certain energy is incident on the plane in parallel, and the optical path difference between the X-rays and adjacent planes is n times its wavelength (n is an integer), diffraction will occur at this time, and the position where the diffraction occurs can determine the crystal phase of the crystal;

[0063] 2. According to the Bragg diffraction equation, nλ=2dsinθ, where θ is the angle between the incident light beam and the diffraction plane, λ is the X-ray wavelength, d is the crystal plane spacing, and n is the crystal plane spacing. When the X-ray diffracts on the corresponding crystal plane, the X-ray diffraction intensity reaches the highest;

[0064] 3. According to the crystal system to which different SiC crystal forms belong, such as the common 3C, 4H, 6H, 15R and other crystal forms, C, H, and R respectively indicate that their crystal structures belong to the cubic, hexagonal, and trigonal systems. The crystal orientation is calculated using the relationship between the interplanar spacing d and the crystal rod parameters a, c, and Miller indices h, k, and l;

[0065] 4. Adjust the position of the SiC sample to be tested so that the X-ray spot can be irradiated in the area to be tested. According to the approximate orientation of the crystal to be tested or by looking up the table, the standard reference 2θ Bragg diffraction angle of different crystal forms on different diffraction surfaces is compared and analyzed with the measured 2θ to obtain the crystal form in the area and the measured diffraction surface. The following Tables 1-3 are the 2θ angles of different diffraction surfaces of 4H single crystal, 6H single crystal, and 15R single crystal respectively:

[0066] Table 1 Correspondence between some crystal planes of 4H SiC and 2θ Bragg angle

[0067]

[0068] Table 2 Correspondence between some crystal planes of 6H SiC and 2θ Bragg angle

[0069]

[0070]

[0071] Table 3 Correspondence between some crystal planes of 15R SiC and 2θ Bragg angle

[0072]

[0073] According to Tables 1-3, when using XRD to test the SiC sidewall, the 2θ Bragg angles of the 4H, 6H and 15R crystal forms on the same diffraction surface are relatively close, so the detection accuracy of XRD is worse than that of the present application.

[0074] The deviation rate is used to represent the accuracy of the determination method of Examples 1-5, and the calculation formula of the deviation rate is: Deviation rate = (|crystal area calculated in Example - crystal area calculated by XRD| / crystal area calculated by XRD) × 100. For example, the 4H deviation rate in Example 1 = (|4H crystal area calculated in Example 1 - 4H crystal area calculated by XRD| / 4H crystal area calculated by XRD) × 100.

[0075] The test results of the deviation rate are shown in Table 4. The deviation rate in Table 4 refers to the average deviation rate of five silicon carbide crystal rods.

[0076] This experimental example is only to assist in verifying the accuracy of this application, so a certain deviation rate is calculated in Table 4. In fact, the polymorphic detection results of the silicon carbide crystal rod side wall obtained by quantitative testing in this application are more accurate than the XRD test results.

[0077] Table 4

[0078]

[0079]

[0080] Since the types of silicon carbide single crystal rods are different in each embodiment in Table 4, the deviation rate of the main crystal form of the silicon carbide single crystal rod of each crystal form is used as the basis for measuring the accuracy of the determination method. For example, in the above embodiment, the 4H-silicon carbide single crystal rod is mainly based on the 4H deviation rate, and the smaller the value, the more accurate the detection method of the embodiment is. In the 6H-silicon carbide single crystal rod, the 6H deviation rate is mainly used as the basis.

[0081] For 4H-SiC, 6H and 15R crystal forms are co-existing polymorphs, wherein 15R crystal form is a transitional crystal form in the process of transformation between 4H and 6H. In the XRD test, due to the large test spot, when 15R and 4H or 6H exist at the same time, 15R is easily identified as 4H or 6H. In the process of transition from 4H to 15R and 15R to 6H, different crystal characteristic peaks will appear in the same spectrum. Therefore, it is difficult to make an accurate judgment on the identification of 15R crystal form based on the peak intensity ratio of the characteristic peaks, and it is easy to be identified as 4H or 6H crystal form. Therefore, the 15R deviation rate of the 4H-silicon carbide single crystal rod measured in each embodiment is the highest, and the test conclusion is consistent with the actual crystal transformation process. Under the polymorphic co-existence of 4H-silicon carbide single crystal rod, the test method of the present application and the XRD test have a higher test deviation rate on the 15R crystal form, which can also prove that the detection method of the present application can more finely and quantitatively analyze the polymorphic co-existence of silicon carbide crystal rods than XRD.

[0082] The above is only the embodiment of the present application, and the protection scope of the present application is not limited by these specific embodiments, but is determined by the claims of the present application. For those skilled in the art, the present application can have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the technical ideas and principles of the present application should be included in the protection scope of the present application.

Claims

1. A method for determining the crystal form of polymorphic co-growth regions of a silicon carbide single crystal, characterized in that: The steps include: (1) Testing: Performing Raman testing on a silicon carbide single crystal to obtain a test spectrum, and classifying characteristic peaks in the test spectrum into Raman characteristic peaks of the first crystal form and Raman characteristic peaks of the second crystal form according to Raman characteristic peaks of different crystal forms; (2) Judgment: If RPS1 / RPS2≥10 and 0.5≤RPS2 / I Baseline ≤5, the crystal form at the test point is the first crystal form; if 0.1≤RPS1 / RPS2<10 and RPS1 / I Baseline ≥2, RPS2 / I Baseline ≥2, the crystal form at the test point is a co-existing crystal form of the first crystal form and the second crystal form; if RPS1 / RPS2<0.1, and 0.5≤RPS1 / I Baseline ≤5, the crystal form at the test point is the second crystal form, RPS1 is the peak intensity of the Raman characteristic peak of the first crystal form, RPS2 is the peak intensity of the Raman characteristic peak of the second crystal form, I Baseline is the baseline peak intensity.

2. The method for determining the crystal form of polymorphic co-growth regions of silicon carbide single crystal according to claim 1, characterized in that: The first crystal form is one of the 4H crystal form, the 6H crystal form or the 15R crystal form, and the second crystal form is one of the 4H crystal form, the 6H crystal form or the 15R crystal form.

3. The method for determining the crystal form of polymorphic co-growth regions of silicon carbide single crystal according to claim 2, characterized in that: The Raman characteristic peak of the 4H crystal form is 776.62±1.00cm -1 The Raman characteristic peak of the 6H crystal form is 788.05±1.00cm -1 The Raman characteristic peak of the 15R crystal form is 784.59±1.00cm -1 .

4. The method for determining the crystal form of polymorphic co-growth regions of silicon carbide single crystal according to claim 1, characterized in that: The Raman test is a microscopic Raman test.

5. The method for determining the crystal form of polymorphic co-growth regions of silicon carbide single crystal according to claim 1, characterized in that: The laser wavelength range of the Raman test is 325nm-785nm.

6. The method for determining the crystal form of polymorphic co-growth regions of silicon carbide single crystal according to claim 1, characterized in that: The step size of the Raman test is 3000 μm / step-15000 μm / step.

7. The method for determining the crystal form of polymorphic co-growth regions of a silicon carbide single crystal according to claim 1, characterized in that: The light spot of the Raman test is 1 μm-5 μm.

8. The method for determining the crystal form of polymorphic co-growth regions of a silicon carbide single crystal according to claim 1, characterized in that: The exposure time of the Raman test is 0.5s-10s.

9. The method for determining the crystal form of polymorphic co-growth regions of silicon carbide single crystal according to claim 1, characterized in that: The Z-axis autofocus height range of the Raman test is -100-+100 μm.

10. Application of the method for determining the crystal form of polymorphic intergrowth regions of a silicon carbide single crystal as claimed in any one of claims 1 to 9 in the detection of crystal form of silicon carbide materials.

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