Method for obtaining BPD (Bipolar Phosphorus Distortion) BPD (Boron Distortion) vector of

Abstract

The invention relates to a method for obtaining a BPD (Bipolar Phosphorus Distortion) BPO vector of a hexagonal crystal system material, and belongs to the technical field of crystal analysis and characterization. The method comprises the following steps: preparing a detection sample of the hexagonal system semiconductor material; a plurality of diffraction vectors are obtained through screening according to the phase condition of X-ray diffraction, one diffraction vector does not meet the extinction principle, and the other diffraction vectors meet the principle; according to the diffraction vectors obtained through screening, corresponding detection parameters are calculated, X-ray morphology detection is conducted on the detection sample according to the detection parameters, and a defect morphology graph of the detection sample is obtained; by comparing defect morphology graphs of different diffraction vectors at the same position of a detection sample, a BPD BP vector is obtained. According to the invention, based on an X-ray morphology detection system and a dislocation extinction principle, different diffraction vectors are ingeniously selected to realize lossless characterization of a crystal material, and by judging the extinction conditions of dislocation under different diffraction geometries, the BPD BP vector can be reliably and accurately judged.

Description

Technical Field

[0001] The invention belongs to the technical field of crystal analysis and characterization, and relates to a method for obtaining a BPD Burgers vector of a hexagonal crystal material. Background Art

[0002] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention, and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art.

[0003] Hexagonal materials include SiC, AlN and GaN, which can be used as semiconductor substrates. In particular, hexagonal SiC materials have outstanding characteristics such as high thermal conductivity, high breakdown electric field strength and wide bandgap, which enable them to show excellent performance in high temperature, high pressure and high frequency application environments, and are particularly suitable for key technical fields such as electric vehicles, power conversion and radio frequency devices. However, there is still a high density of basal plane dislocations (BPDs) in the current commercial hexagonal SiC substrates, which has a significant adverse effect on the electrical properties and reliability of semiconductor devices. As a crystal defect, BPD will increase the recombination of carriers and reduce the conductivity and stability of the device. In addition, the presence of BPD may also cause the inhomogeneity of the local electric field, which in turn affects the switching characteristics and breakdown voltage of the device. The Burgers vector of BPD describes the size and direction of the displacement or lattice dislocation of BPD. Understanding the Burgers vector of BPD can grasp the slip mode and stress distribution of BPD, so as to deeply understand the microscopic mechanism of plastic deformation of the material and provide guidance for material design. Therefore, accurately identifying the characteristics of BPD and the distribution patterns of BPDs with different Burgers vectors in the substrate has important guiding significance for understanding the movement mechanism and transformation behavior of BPD and feedback optimization of single crystal growth technology.

[0004] Currently, the commonly used characterization methods for hexagonal SiC dislocations include KOH etching, white light interferometry, photoluminescence spectroscopy (PL), convergent beam electron diffraction (CBED), and X-ray topography (XRT). However, each of them has its own limitations: KOH etching is a destructive and irreversible defect characterization method for SiC wafers, which will destroy the surface structure and chemical composition of SiC crystals. Generally speaking, KOH etching can only obtain the distribution law of dislocations, and cannot accurately identify the Burgers vector of BPD; white light interferometry and photoluminescence spectroscopy (PL) are both non-destructive characterizations, but neither of these two characterization methods can determine the Burgers vector of BPD in SiC; although the convergent beam electron diffraction (CBED) method can determine the Burgers vector of dislocations through high-order Laue ring diffraction patterns, it is difficult to clearly observe the splitting of high-order Laue rings in the bright field disk, resulting in the size and test area of ​​the tested sample being limited; XRT has the advantages of non-destructive characterization, large characterization range, and high resolution, but the current research based on XRT is still relatively preliminary, especially in the application of XRT technology and in-depth analysis of crystal defects. The practical application of XRT technology in dislocation evolution analysis still faces many challenges. Therefore, it is urgent to develop an efficient method to obtain the BPD Burgers vector of hexagonal SiC wafers. Summary of the invention

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a method for obtaining the Burgers vector of the BPD of hexagonal materials. Based on the imaging results of the X-ray morphology detection system (XRT) under different diffraction vectors in the same area of ​​the same SiC crystal, the Burgers vector of the BPD with different dislocation line directions is identified, and then its Burgers vector is obtained.

[0006] In order to achieve the above object, the technical solution of the present invention is:

[0007] A method for obtaining the BPD Burgers vector of a hexagonal material comprises the following steps:

[0008] S1. preparing a test sample of hexagonal semiconductor material;

[0009] S2. Screening and obtaining multiple diffraction vectors according to the phase condition of X-ray diffraction, wherein one of the diffraction vectors does not satisfy the extinction principle, and the other diffraction vectors satisfy the principle;

[0010] S3, calculating the corresponding detection parameters according to the diffraction vectors obtained by screening, and performing X-ray morphology detection on the detection sample according to the detection parameters to obtain a defect morphology map of the detection sample;

[0011] S4. The Burgers vector of BPD is obtained by comparing the defect morphology images of different diffraction vectors at the same position of the detected sample.

[0012] Optionally, in S1, the hexagonal semiconductor material is hexagonal SiC, AlN or GaN.

[0013] Optionally, in S1, the hexagonal SiC is 4H-SiC or 6H-SiC.

[0014] Optionally, in S1, the hexagonal SiC is an unintentionally doped SiC substrate; or, is a conductive SiC substrate or a semi-insulating SiC substrate.

[0015] Optionally, in S1, the detection sample is a substrate or an epitaxial material.

[0016] Optionally, in S1, the plane size of the test sample is less than 12 inches, and the thickness is less than 2 mm; preferably, the plane size of the test sample is 4 to 8 inches, and the thickness is less than 1 mm.

[0017] Optionally, in S1, the depth of the surface scratches of the test sample does not exceed 0.5 μm, and the number of scratches with a length exceeding 10 mm does not exceed 5; preferably, the depth of the surface scratches of the test sample does not exceed 0.1 μm, and the number of scratches with a length exceeding 10 mm does not exceed 2.

[0018] Optionally, in S2, if the BPD is a spiral BPD, the extinction principle of the spiral BPD is Among them, δ is the extinction effect, is the diffraction vector, is the Burgers vector;

[0019] The diffraction vectors that do not satisfy the extinction principle are selected from the diffraction vectors perpendicular to the crystal plane family {hhil}, and the diffraction vectors that satisfy the extinction principle are selected from the diffraction vectors perpendicular to the crystal plane family The diffraction vector.

[0020] Optionally, in S2, if the BPD is a blade-shaped BPD, the extinction principle of the blade-shaped BPD is and Among them, δ is the extinction effect, is the diffraction vector, is the Burgers vector, is the dislocation line direction;

[0021] The diffraction vectors that do not satisfy the extinction principle are selected from the diffraction vectors perpendicular to the crystal plane family {000l}, and the diffraction vectors that satisfy the extinction principle are selected from the diffraction vectors perpendicular to the crystal plane family {000l}. The diffraction vector.

[0022] Optionally, in S3, the detection parameters are calculated based on the diffraction vector using the Bragg diffraction and Laue diffraction principles.

[0023] Optionally, in S3, the detection parameters include: an X-ray incident angle, an X-ray exit angle and a sample stage rotation angle of an X-ray topography detection system (XRT).

[0024] Optionally, in S3, during the X-ray morphology detection process, the X-ray incident angle is -90° to 70°, the X-ray exit angle is 20° to 150°, and the sample stage rotation angle is -180° to 180°.

[0025] Optionally, in S3, after obtaining the detection parameters, continue to optimize the test parameters, including: cyclically optimizing the rocking curve (RC) and the rotation angle of the sample stage 3-7 times; preferably, performing a base plane correction omega scan on the detection sample crystal, and performing small area snap defect morphology imaging, and judging whether to continue to optimize the current detection parameters based on the imaging quality; after the optimization is completed, performing a curvature correction scan on the detection sample, and then imaging the crystal defect morphology of the detection sample to obtain a defect morphology diagram of the detection sample.

[0026] Optionally, the imaging range is 2 to 20 mm and the scanning speed is 1 to 200 mm / min.

[0027] Optionally, in S4, if the number of the selected diffraction vectors capable of extinction is one, the Burgers vector is deduced based on the extinction principle and the basic properties of the Burgers vector; if the number of the selected diffraction vectors capable of extinction is two, and the two diffraction vectors are not parallel to each other, the Burgers vector is obtained by cross product of the two diffraction vectors;

[0028] Specifically, if a BPD is not extinguished in the imaging of the first diffraction vector, but is extinguished in the imaging of the second diffraction vector, the Burgers vector of the BPD is obtained according to the second diffraction vector; if a BPD is not extinguished in the imaging of the third diffraction vector, but is extinguished in the imaging of the fourth diffraction vector and is extinguished in the imaging of the fifth diffraction vector, and the fourth diffraction vector and the fifth diffraction vector are not parallel, the Burgers vector of the BPD is obtained according to the cross product of the fourth diffraction vector and the fifth diffraction vector.

[0029] The beneficial effects of the present invention are:

[0030] The present invention proposes a method for obtaining the BPD Burgers vector of hexagonal crystal materials. Based on the X-ray morphology detection system and the dislocation extinction principle, different diffraction vectors are cleverly selected to realize non-destructive characterization of crystal materials. By judging the extinction of dislocations under different diffraction geometries, the Burgers vector of BPD can be reliably and accurately judged, and the Burgers vectors of all BPDs in the crystal material can be simply and accurately determined. There is no requirement for the conductivity type of SiC material, no corrosion pits in wet etching are generated, and the dislocation type can be accurately judged. The characterization method does not destroy the surface structure of the SiC crystal, and the SiC sample after the test can be applied to various other scenarios, reducing the test cost. The test method is direct and efficient, and does not require hardware such as large-scale line stations of synchrotron radiation light sources. It can be carried out in the laboratory using XRT equipment. After obtaining the original image, no special processing is required. Only the dislocation extinction under different diffraction vectors needs to be compared to deduce the Burgers vector corresponding to the dislocation, which has the advantage of batch determination of all basal plane dislocation Burgers vectors in SiC wafers. It is highly universal and has a wide range of applications. It is also applicable to a variety of materials in the hexagonal crystal system, such as SiC, AlN and GaN. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0032] Figure 1 It is a schematic diagram of the hexagonal crystallographic coordinate system of the present invention.

[0033] Figure 2 : is a comparison diagram of BPD morphologies under different diffraction vectors in Example 1 of the present invention, where (a) is The image below, (b) is The following image.

[0034] Figure 3 : is a comparison diagram of BPD morphologies under different diffraction vectors in Example 2 of the present invention, where (a) is The image below, (b) is The image below, (c) is The following image.

[0035] Figure 4 3 is a comparison diagram of BPD morphologies under different diffraction vectors in Example 3 of the present invention, where (a) is The image below, (b) is The following image. DETAILED DESCRIPTION

[0036] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0037] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0038] Basal plane dislocation (BPD) refers to a dislocation along the basal plane in a crystal. In a crystal, the basal plane refers to the most densely packed plane in the crystal and is also the largest plane of the crystal. Basal plane dislocation is one of the most common types of dislocations in crystals and has an important influence on the physical and mechanical properties of crystals.

[0039] The Burgers vector, also known as the Burgers vector, is a method used to represent the distortion of a crystal caused by a dislocation.

[0040] The diffraction vector refers to the vector difference between the incident ray and the reflected ray when a beam of X-ray is reflected by a crystal plane. The Mie symbol is used in the present invention. In the hexagonal crystal system, the diffraction vector is expressed as a four-digit number without brackets; the crystal plane family is represented by curly brackets {}, the crystal plane is represented by small brackets (), the crystal direction family is represented by angle brackets <>, and the crystal direction is represented by square brackets [], as shown in the attached figure. Figure 1 As shown, Figure 1 In the equation, a1, a2, and a3 represent three axes in the four-axis coordinate system, and the fourth axis is perpendicular to the first three axes. Figure 1 (a) and (b) in the figure respectively represent the positions of multiple different crystal planes in the four-axis coordinate system. The coordinate system in the following embodiments of the present invention is based on Figure 1 The coordinate system shown; Figure 1 The mark in is the crystal plane in this coordinate system. The diffraction geometric direction used in the present invention is parallel to the normal direction of the crystal plane with the same number, for example, g=0008 is perpendicular to the (0008) crystal plane; is perpendicular to Crystal face.

[0041] Extinction means that a dislocation that can be imaged under certain diffraction vectors has a significantly reduced contrast or even no image when imaged under another diffraction vector.

[0042] A method for obtaining the BPD Burgers vector of a hexagonal material comprises the following steps:

[0043] S1. preparing a test sample of hexagonal semiconductor material;

[0044] S2. A plurality of diffraction vectors (also known as diffraction geometry) are obtained by screening according to the phase condition of X-ray diffraction, wherein one of the diffraction vectors does not satisfy the extinction principle, and the other diffraction vectors satisfy the principle;

[0045] S3, calculating the corresponding detection parameters according to the diffraction vectors obtained by screening, and performing X-ray morphology detection on the detection sample according to the detection parameters to obtain a defect morphology map of the detection sample;

[0046] S4. The Burgers vector of BPD is obtained by comparing the defect morphology images of different diffraction vectors at the same position of the detected sample.

[0047] Through the above method, the Burgers vector of BPD can be obtained through the extinction of dislocations when imaging under different diffraction geometries. The characterization method is not limited by the conductivity type of the SiC crystal and is lossless and efficient.

[0048] Optionally, in S1, the hexagonal semiconductor material is hexagonal SiC, AlN or GaN, which is suitable for being a crystalline material that can be imaged by X-ray topography (XRT) method.

[0049] Optionally, in S1, the hexagonal SiC is 4H-SiC or 6H-SiC.

[0050] Optionally, in S1, the hexagonal SiC is an unintentionally doped SiC substrate, a semi-insulating SiC substrate; or, an N-type SiC substrate or a P-type SiC substrate.

[0051] Optionally, in S1, the test sample is a substrate or an epitaxial material, which is suitable for testing commercial products.

[0052] Optionally, in S1, the plane size of the test sample is less than 15 inches and the thickness is less than 2 mm; preferably, the plane size of the test sample is 2 to 12 inches and the thickness is less than 1.5 mm

[0053] Optionally, in S1, the surface of the test sample is mechanically polished, the scratch depth does not exceed 0.5 μm, and the number of scratches exceeding 10 mm in length does not exceed 5; preferably, the scratch depth of the surface of the test sample does not exceed 0.1 μm, and the number of scratches exceeding 10 mm in length does not exceed 2; this is because scratches will leave traces during the imaging process, thereby affecting the identification of dislocations in the imaging.

[0054] Optionally, in S2, if the number of selected diffraction vectors capable of extinction is 1, the Burgers vector is deduced based on the extinction principle; if the number of selected diffraction vectors capable of extinction is 2, and the two diffraction vectors are not parallel to each other, the Burgers vector is obtained by the cross product of the two diffraction vectors.

[0055] Optionally, in S2, if the BPD is a spiral BPD, the extinction principle of the spiral BPD is Among them, δ is the extinction effect, is the diffraction vector, is the Burgers vector;

[0056] Then the diffraction vectors that do not satisfy the extinction principle are selected from the diffraction vectors perpendicular to the crystal plane family {hhil}, for example or And the diffraction vector that satisfies the extinction principle is selected from the family perpendicular to the crystal plane The diffraction vector, for example or These diffraction vectors are selected by the extinction principle of spiral BPD and edge BPD.

[0057] Optionally, in S2, if the BPD is a blade-shaped BPD, the extinction principle of the blade-shaped BPD is and Among them, δ is the extinction effect, is the diffraction vector, is the Burgers vector, is the dislocation line direction;

[0058] The diffraction vectors that do not satisfy the extinction principle are selected from the diffraction vectors perpendicular to the crystal plane family {0001}, such as 0008, 00016 (the last digit is 16), and the diffraction vectors that satisfy the extinction principle are selected from the diffraction vectors perpendicular to the crystal plane family {0001}. The diffraction vector, for example These diffraction vectors are selected by the extinction principle of spiral BPD and edge BPD.

[0059] Optionally, in S3, the Bragg diffraction principle "2dsinθ=nλ" is used to calculate the detection parameters according to the specific diffraction vector. The detection parameters are used to realize imaging under the set diffraction vector on the XRT device. In the Bragg diffraction principle, d is the crystal plane spacing and λ is the wavelength. Different d will correspond to different materials and diffraction vectors. On the other hand, different target materials will also have different λ, so as to calculate θ.

[0060] Optionally, in S3, the detection parameters include: the X-ray incident angle (theta_s), the X-ray exit angle (theta_d) and the rotation angle of the sample stage (phi) of the X-ray morphology detection system (XRT), and the required diffraction vector imaging results are obtained by operating the equipment parameters.

[0061] Optionally, in S3, during the X-ray morphology detection process, the X-ray incident angle is -90° to 70°, the X-ray exit angle is 20° to 150°, and the sample stage rotation angle is -180° to 180°.

[0062] Optionally, in S3, after obtaining the detection parameters, continue to optimize the test parameters, including: cyclically optimizing the rocking curve (RC) and the rotation angle of the sample stage 3-7 times; preferably, performing a base plane correction omega scan on the detection sample crystal (the optimization is completed when an obvious diffraction peak appears); performing small area snap defect morphology imaging, and judging whether to continue to optimize the current detection parameters based on the imaging quality (the defects can be clearly distinguished); after the optimization is completed, performing a curvature correction scan on the detection sample, and then imaging the crystal defect morphology of the detection sample to obtain a defect morphology diagram of the detection sample.

[0063] Optionally, the imaging range is 2 to 20 mm and the scanning speed is 1 to 200 mm / min.

[0064] Optionally, in S4, if a certain BPD is not extinguished in the imaging of the first diffraction vector but is extinguished in the imaging of the second diffraction vector, the Burgers vector of the BPD is obtained according to the second diffraction vector; if a certain BPD is not extinguished in the imaging of the third diffraction vector but is extinguished in the imaging of the fourth diffraction vector and is extinguished in the imaging of the fifth diffraction vector, and the fourth diffraction vector and the fifth diffraction vector are not parallel, the Burgers vector of the BPD is obtained according to the cross product of the fourth diffraction vector and the fifth diffraction vector;

[0065] Specifically, when the first diffraction vector and the second diffraction vector are selected, it is determined which Burgers vector and the second diffraction vector are equal to 0 in the six types of Burgers vectors (the determination method of the six types of Burgers vectors is a conventional technology in the art), that is, the desired Burgers vector is determined; that is, if a BPD is in the first diffraction vector There is no extinction in the imaging, but in the second diffraction vector Extinction in imaging; due to the Burgers vector of BPD theory For one of the Burgers vectors, verify The Burgers vector of the BPD is determined as

[0066] Alternatively, when the third diffraction vector, the fourth diffraction vector and the fifth diffraction vector are selected, the desired Burgers vector is obtained directly through the cross product result of the fourth diffraction vector and the fifth diffraction vector;

[0067] That is: if a BPD is in the third diffraction vector There is no extinction in the imaging, but in the fourth diffraction vector and the fifth diffraction vector The extinction in the imaging, and and Not parallel, due to the BPD theory Burgers vector For one of the Burgers vectors, verify and and The Burgers vector of the BPD is determined as

[0068] Since the diffraction geometry and the Burgers vector in the present invention are both in the hexagonal system, they are both expressed in a four-axis coordinate system.

[0069] Example 1

[0070] S1. A 6-inch diameter and 350μm thick N-type conductive 4H-SiC substrate wafer was selected for BPD Burgers vector discrimination. In the prepared samples, the scratch depth of the base plane did not exceed 0.5μm, and the number of scratches exceeding 10mm in length did not exceed 5.

[0071] S2. If a BPD is in the first diffraction vector There is no extinction in the imaging, but in the second diffraction vector Extinction in imaging; due to the Burgers vector of BPD theory For one of the Burgers vectors, verify The Burgers vector of the BPD is determined as Among them, according to the extinction principle, Two diffraction vectors, in In diffraction geometry, BPD does not extinct. Partial extinction of spiral BPD in diffraction geometry.

[0072] S3. According to the diffraction vector obtained by screening, the test parameters corresponding to the two diffraction geometries are calculated according to Bragg diffraction and Laue diffraction to obtain the corresponding detection parameters, including the X-ray incident angle (theta_s), the X-ray exit angle (theta_d) and the sample stage (phi) rotation angle. The equipment is adjusted to the required diffraction vector by operating the equipment parameters. Then, the X-ray morphology detection system is used to perform rocking curve RC scanning and sample stage rotation phi scanning and perform five-step optimization, including: the first step is to perform a rough scan optimization of omega within the range of ±5° of the current parameters, the second step is to perform a rough scan optimization of phi within the range of ±40° of the current parameters, the third step is to perform a fine scan optimization of omega within the range of ±2° of the current parameters, the fourth step is to perform a fine scan optimization of phi within the range of ±15° of the current parameters, and the fifth step is to perform a final scan optimization of omega within the range of ±1° of the current parameters.

[0073] 5mm*5mm small area snap imaging is selected to determine whether the current detection parameters need to be further optimized through imaging quality; when the current small area snap imaging quality is good and the dislocation lines in the small area can be clearly distinguished, 10*20 points are evenly selected on the 6-inch SiC substrate for curvature correction (CC) scanning, and defect morphology imaging is performed. The imaging size is -80mm~80mm and the scanning speed is 50mm / min.

[0074] S4. By comparing the defect morphology of different diffraction vectors at the same position of the test sample, the Burgers vector of BPD is obtained. The horizontal line BPD imaged under the diffraction vector ( Figure 2 (a) in Figure 1), No image is formed under the diffraction vector ( Figure 2 (b) in Figure 1), that is, It is not matte, and The corresponding Burgers vector is The straight horizontal line BPD is the Burgers vector The pure spiral BPD, the relatively curved horizontal line BPD is the Burgers vector Mixed BPD.

[0075] Example 2

[0076] S1. A P-type conductive 6H-SiC epitaxial material with a diameter of 8 inches and a thickness of 550 μm is selected for BPD Burgers vector discrimination. In the prepared samples, the scratch depth of the base plane does not exceed 0.5 μm, and the number of scratches with a length exceeding 10 mm does not exceed 5.

[0077] S2. If a BPD is in the third diffraction vector There is no extinction in the imaging, but in the fourth diffraction vector and the fifth diffraction vector In the imaging of extinction, due to the Burgers vector of BPD theory For one of the Burgers vectors, verify and and The Burgers vector of the BPD is determined as Among them, according to the extinction principle, and Three diffraction vectors, among which In diffraction geometry, BPD does not extinct. and Partial extinction of spiral BPD in diffraction geometry.

[0078] S3. According to the diffraction vector obtained by screening, the test parameters corresponding to the two diffraction geometries are calculated according to Bragg diffraction and Laue diffraction to obtain the corresponding detection parameters, including the X-ray incident angle (theta_s), the X-ray exit angle (theta_d) and the sample stage (phi) rotation angle. The equipment is adjusted to the required diffraction vector by operating the equipment parameters. Then, the X-ray morphology detection system is used to perform rocking curve RC scanning and sample stage rotation phi scanning and perform three-step optimization, including: the first step is to perform a rough scan optimization of omega within the range of ±3° of the current parameters, the second step is to perform a rough scan optimization of phi within the range of ±30° of the current parameters, and the third step is to perform a fine scan optimization of omega within the range of ±1° of the current parameters for final scanning. 4mm*4mm small area snap imaging is selected to determine whether the current detection parameters need to be further optimized through imaging quality; when the current small area snap imaging quality is good and the dislocation lines in the small area can be clearly distinguished, 12*24 points are evenly selected on the 8-inch SiC epitaxial material for curvature correction (CC) scanning, and defect morphology imaging is performed. The imaging size is -110mm~110mm, and the scanning speed is 80mm / min.

[0079] S4. By comparing the defect morphology of different diffraction vectors at the same position of the test sample, the Burgers vector of BPD is obtained. The " / "-shaped BPD with no extinction under the diffraction vector ( Figure 3 (a) in Figure 1), and Complete or partial extinction under the diffraction vector ( Figure 2 (b) and (c) in Figure 1), because The corresponding Burgers vector The straight “ / ” shaped BPD is the Burgers vector The pure spiral BPD and the more curved “ / ” shaped BPD are Burgers vectors. Mixed BPD.

[0080] Example 3

[0081] S1. A 7-inch diameter non-intentionally doped 4H-SiC substrate was selected for BPD Burgers vector discrimination. In the prepared samples, the scratch depth of the base plane did not exceed 0.5 μm, and the number of scratches with a length exceeding 10 mm did not exceed 5.

[0082] S2. Selection based on the extinction principle of blade-type BPD and screw-type BPD Two diffraction vectors, where Under diffraction geometry, both spiral BPD and blade BPD are not extinct. Under diffraction geometry, the spiral BPD is completely extinct and the blade BPD is not extinct.

[0083] S3. According to the diffraction vector obtained by screening, the test parameters corresponding to the two diffraction geometries are calculated according to Bragg diffraction and Laue diffraction to obtain the corresponding detection parameters, including the X-ray incident angle (theta_s), the X-ray exit angle (theta_d) and the sample stage (phi) rotation angle. The equipment is adjusted to the required diffraction vector by operating the equipment parameters. Then, the X-ray morphology detection system is used to perform rocking curve RC scanning and sample stage rotation phi scanning and perform five-step optimization, including: the first step is to perform a rough scan optimization of omega within the range of ±7° of the current parameters, the second step is to perform a rough scan optimization of phi within the range of ±50° of the current parameters, the third step is to perform a fine scan optimization of omega within the range of ±4° of the current parameters, the fourth step is to perform a fine scan optimization of phi within the range of ±20° of the current parameters, and the fifth step is to perform a final scan optimization of omega within the range of ±2° of the current parameters. 5mm*5mm small area snap imaging is selected to determine whether the current detection parameters need to be further optimized through imaging quality; when the current small area snap imaging quality is good and the dislocation lines in the small area can be clearly distinguished, 8*16 points are evenly selected on the 7-inch 4H-SiC substrate for curvature correction (CC) scanning, and defect morphology imaging is performed. The imaging size is -85mm~85mm, and the scanning speed is 35mm / min.

[0084] S4. By comparing the defect morphology of different diffraction vectors at the same position of the test sample, the Burgers vector of BPD is obtained. and The extinction principle and the uniqueness of the Burgers vector are used to determine the Burgers vector of the SiC basal plane dislocation. There is no extinction in diffraction geometry, but Extinction in diffraction geometry: Figure 4 The graph (a) in is not extinct and in Figure 4If the light is extinct in (b), the BPD is a screw BPD, and the Burgers vector is parallel to the dislocation line. There is no extinction in diffraction geometry, and If there is no extinction under diffraction geometry, the BPD is an edge-type BPD, and the direction of its Burgers vector is perpendicular to the direction of the dislocation line. Figure 4 The Burgers vector of the edge-shaped BPD shown in the red box

[0085] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for obtaining the BPD Burgers vector of a hexagonal material, characterized in that: The following steps are involved: S1. preparing a test sample of hexagonal semiconductor material; S2. Screening and obtaining multiple diffraction vectors according to the phase condition of X-ray diffraction, wherein one of the diffraction vectors does not satisfy the extinction principle, and the other diffraction vectors satisfy the principle; S3, calculating the corresponding detection parameters according to the diffraction vectors obtained by screening, and performing X-ray morphology detection on the detection sample according to the detection parameters to obtain a defect morphology map of the detection sample; S4. The Burgers vector of BPD is obtained by comparing the defect morphology images of different diffraction vectors at the same position of the detected sample.

2. The method for obtaining the BPD Burgers vector of hexagonal material according to claim 1, characterized in that: In S1, the hexagonal semiconductor material is hexagonal SiC, AlN or GaN.

3. The method for obtaining the BPD Burgers vector of a hexagonal material according to claim 1, It is characterized in that, in S1, the hexagonal SiC is 4H-SiC or 6H-SiC; Optionally, in S1, the hexagonal SiC is an unintentionally doped SiC substrate; or, is a conductive SiC substrate or a semi-insulating SiC substrate; Optionally, in S1, the detection sample is a substrate or an epitaxial material.

4. The method for obtaining the BPD Burgers vector of hexagonal material according to claim 1, characterized in that: In S1, the plane size of the test sample is less than 5 mm, and the thickness is less than 2 mm; preferably, the plane size of the test sample is 2 to 12 inches, and the thickness is less than 1.5 mm; Optionally, in S1, the depth of the surface scratches of the test sample does not exceed 0.5 μm, and the number of scratches with a length exceeding 10 mm does not exceed 5; preferably, the depth of the surface scratches of the test sample does not exceed 0.1 μm, and the number of scratches with a length exceeding 10 mm does not exceed 2.

5. The method for obtaining the BPD Burgers vector of a hexagonal material according to claim 1, wherein in S2, if the BPD is a screw-type BPD, the extinction principle of the screw-type BPD is in, δ is the extinction effect, is the diffraction vector, is the Burgers vector; The diffraction vectors that do not satisfy the extinction principle are selected from the diffraction vectors perpendicular to the crystal plane family {hhil}, and the diffraction vectors that satisfy the extinction principle are selected from the diffraction vectors perpendicular to the crystal plane family The diffraction vector.

6. The method for obtaining the BPD Burgers vector of hexagonal crystal material according to claim 1, wherein, in S2, if the BPD is an edge-shaped BPD, the extinction principle of the edge-shaped BPD is and in, δ is the extinction effect, is the diffraction vector, is the Burgers vector, is the dislocation line direction; The diffraction vectors that do not satisfy the extinction principle are selected from the diffraction vectors perpendicular to the crystal plane family {000l}, and the diffraction vectors that satisfy the extinction principle are selected from the diffraction vectors perpendicular to the crystal plane family {000l}. The diffraction vector.

7. The method for obtaining the BPD Burgers vector of hexagonal material according to claim 1, characterized in that: In S3, the Bragg diffraction and Laue diffraction principles are used to calculate the detection parameters based on the diffraction vector; Optionally, in S3, the detection parameters include: an X-ray incident angle, an X-ray exit angle and a sample stage rotation angle of an X-ray topography detection system; Optionally, in S3, during the X-ray morphology detection process, the X-ray incident angle is -90° to 70°, the X-ray exit angle is 20° to 150°, and the sample stage rotation angle is -180° to 180°.

8. The method for obtaining the BPD Burgers vector of hexagonal material according to claim 1, characterized in that: In S3, after obtaining the detection parameters, continue to optimize the test parameters, including: cyclically optimizing the rocking curve (RC) and the rotation angle of the sample stage for 3-7 times; preferably, performing a base plane correction omega scan on the detection sample crystal, and performing small area snap defect morphology imaging, and judging whether to continue to optimize the current detection parameters according to the imaging quality; after the optimization is completed, performing a curvature correction scan on the detection sample, and then imaging the crystal defect morphology of the detection sample to obtain a defect morphology diagram of the detection sample; 9. The method for obtaining the BPD Burgers vector of hexagonal material according to claim 1, characterized in that: In S3, the imaging range is 2 to 20 mm, and the scanning speed is 1 to 200 mm / min.

10. The method for obtaining the BPD Burgers vector of hexagonal material according to claim 1, characterized in that: In S4, if a certain BPD is not extinguished in the imaging of the first diffraction vector but is extinguished in the imaging of the second diffraction vector, the Burgers vector of the BPD is obtained according to the second diffraction vector; If a BPD is not extinguished in the imaging of the third diffraction vector, is extinguished in the imaging of the fourth diffraction vector and is extinguished in the imaging of the fifth diffraction vector, and the fourth diffraction vector and the fifth diffraction vector are not parallel, then the Burgers vector of the BPD is obtained according to the cross product of the fourth diffraction vector and the fifth diffraction vector.

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