A method for testing the orientation of a main reference surface of a silicon carbide crystal
By using an X-ray orientation system on the top surface of a silicon carbide crystal and selecting the (11-28) crystal plane as the reference plane, the Bragg diffraction angle θ was calculated, which solved the problem of accuracy and efficiency in the orientation detection of the main reference plane of silicon carbide substrate, and realized efficient and accurate industrial testing of silicon carbide crystals.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SICC CO LTD
- Filing Date
- 2023-08-23
- Publication Date
- 2026-07-14
AI Technical Summary
Existing technologies struggle to accurately test the orientation of the main reference plane of silicon carbide substrates, particularly the orientation deviation of the NOTCH edge, resulting in low detection accuracy and efficiency. This makes them unsuitable for thinner silicon carbide substrates, and traditional methods require special tooling and equipment modifications.
Using an X-ray orientation system, the (11-28) crystal plane of silicon carbide was selected as the reference plane. The Bragg diffraction angle θ was calculated, and the test was performed on the top surface of the silicon carbide crystal. By adjusting the angle and position of the incident and reflected rays, the deviation value of the orientation of the main reference plane of the silicon carbide crystal was determined.
It expands the detection range, improves testing accuracy, simplifies the operation process, and increases detection efficiency. It is suitable for silicon carbide crystals of different thicknesses, especially sheet substrates, and is suitable for industrial testing.
Smart Images
Figure CN117110337B_ABST
Abstract
Description
Technical Field
[0001] This application relates to a method for testing the orientation of the main reference plane of a silicon carbide crystal, belonging to the field of semiconductor crystal performance testing technology. Background Technology
[0002] In the processing of silicon carbide substrates, the deviation of the orientation of the main reference plane, especially the deviation of the NOTCH edge, is an important control point. This parameter is related to the positioning of the silicon carbide crystal. If the deviation is too large, it will lead to problems such as the silicon carbide crystal position being skewed, surface crystal orientation deviation, and excessive deviation of orthogonal orientation. Therefore, the deviation of the orientation of the main reference plane is a necessary test in the processing of silicon carbide substrates.
[0003] Currently, the testing of deviation values of the main reference plane orientation is generally concentrated in the silicon carbide ingot stage of processing. An X-ray orientation analyzer is used to directly inspect the side of the ingot, i.e., at the location of the main reference plane, or to inspect the side opposite the NOTCH edge or at a 90° angle. The limitation of this method is that it can only be applied to silicon carbide ingots of a certain length. Testing on silicon carbide substrates is a blank area because the thickness of the silicon carbide substrate (equivalent to the length of the silicon carbide ingot) is relatively thin, making it impossible to inspect the side surfaces.
[0004] X-ray testing requires focusing on a specific plane. The main reference plane is vertically perpendicular to the top and bottom surfaces of the crystal rod, i.e., the side surface of the crystal rod. Testing can only be performed directly from the side. For thinner substrates, the side surface is extremely thin, only 350-500 μm thick, making it impossible to test. Furthermore, testing the notch edge requires measurement from the opposite side of the notch edge or from the side at a 90° angle, and it can only be performed on the notch edge of silicon carbide crystal rods. Traditional methods, however, rely on... Figure 1 Because side measurements are required, accuracy is difficult to guarantee. Testing the main reference surface necessitates measuring two values to determine the deviation in orientation. This is particularly true for measuring the notch edge, which can only be tested using the opposite surface or a 90° arc, further exacerbating inaccuracies and reducing efficiency. Ordinary X-ray orientation analyzers generally lack suitable testing platforms, making operation inconvenient and requiring handheld operation or custom-made fixtures. This incompatibility with normal surface orientation testing necessitates frequent fixture switching, leading to poor equipment compatibility, increased time, and reduced efficiency.
[0005] In addition, the laboratory uses the method of testing stacking fault angles to test the orientation of the main reference plane of silicon carbide crystals. However, this testing method is only suitable for testing the orientation of silicon carbide crystal rods and is not entirely applicable to silicon carbide substrates. This is because silicon carbide substrates are relatively thin and may not always have stacking faults, which may lead to deviations that make it impossible to retest. Summary of the Invention
[0006] To address at least one of the aforementioned problems, a method for testing the orientation of the main reference plane of silicon carbide crystals is provided. This method eliminates the need to select a side surface of the silicon carbide crystal as the test surface, making it applicable to silicon carbide crystals of varying thicknesses. It particularly fills the gap in testing sheet-like silicon carbide substrates, significantly expanding the detection range. Because the test surface is a plane rather than a curved surface, the test point is easily located, greatly improving test accuracy and saving testing time. This method requires no special tooling, greatly simplifying operation and eliminating the need for special modifications to ordinary testing instruments, thus increasing detection efficiency and versatility. It can be performed on any silicon carbide crystal, making it suitable for industrial testing of silicon carbide crystals.
[0007] The technical solution provided in this application is as follows:
[0008] A method for testing the orientation of the principal reference plane of a silicon carbide crystal includes the following steps:
[0009] 1) Place the silicon carbide crystal to be tested horizontally on the test stage, select the (11-28) crystal plane of the silicon carbide crystal as the reference plane, and calculate the Bragg diffraction angle θ of the (11-28) crystal plane.
[0010] 2) Adjust the X-ray orientation system and select a straight line that passes through the center point of the top surface of the silicon carbide crystal and is perpendicular to the (11-28) crystal plane as the normal, so that the intersection of the incident ray emitted by the X-ray orientation system and the reflected ray is focused on the center point of the top surface of the silicon carbide crystal.
[0011] The angle between the incident ray and the (11-28) crystal plane and the angle between the reflected ray and the (11-28) crystal plane are both θ. The plane containing the incident ray and the reflected ray is parallel to the (1-100) crystal plane of the silicon carbide crystal. At this time, the X-ray orientation system displays the first signal intensity value.
[0012] 3) Then rotate the test stage horizontally in a clockwise and / or counterclockwise direction. When the signal intensity value displayed by the X-ray orientation system is the largest relative to the first signal intensity value, the angle of rotation of the test stage is the deviation value of the orientation of the silicon carbide crystal's main reference plane.
[0013] Optionally, in step 1), the Bragg diffraction angle θ of the (11-28) crystal plane is calculated as follows:
[0014] 2dsin(θ)=nλ
[0015] Wherein, λ is the wavelength of the X-rays, and the material used to emit X-rays in the X-ray directional system is a copper target structure, so it is a constant value;
[0016] n is a positive natural number; d is the interplanar spacing of the (11-28) crystal planes.
[0017] Calculations show that the Bragg diffraction angle θ of the (11-28) crystal plane is 52.5° ± 0.5°.
[0018] Optionally, in step 2), the angle between the incident ray and the test stage is 9°±1°;
[0019] The angle between the reflected line and the test stage is 96°±1°.
[0020] Optionally, the X-ray orientation system includes an X-ray emitting unit for emitting incident rays, an X-ray receiving unit for receiving reflected rays, and a signal intensity monitoring unit;
[0021] Step 2) also includes a first arc scan: with the center point of the top surface of the silicon carbide crystal as the center and the distance from the X-ray emitting unit to the center point as the radius, and with the top surface of the silicon carbide crystal as the 0° reference plane, the X-ray emitting unit performs a first arc scan on the plane where the incident ray and the reflected ray are located. The range of the first arc scan is 9°±1°. During the first arc scan, when the signal intensity monitoring unit displays the highest signal peak, the X-ray emitting unit is adjusted to this position.
[0022] Optionally, step 2) further includes a second arc scan: with the center point of the top surface of the silicon carbide crystal as the center and the distance from the X-ray receiving unit to the center point as the radius, and with the top surface of the silicon carbide crystal as the 0° reference plane, the X-ray receiving unit performs a second arc scan on the plane where the incident ray and the reflected ray are located. The range of the second arc scan is 96°±1°. When the signal intensity monitoring unit displays the highest signal peak, the X-ray receiving unit is adjusted to this position.
[0023] Optionally, in step 2), the angle between the incident ray and the test stage is 96°±1°;
[0024] The angle between the reflected line and the test stage is 9°±1°.
[0025] Optionally, the X-ray orientation system includes an X-ray emitting unit for emitting incident rays, an X-ray receiving unit for receiving reflected rays, and a signal intensity monitoring unit;
[0026] Step 2) also includes a first arc scan: with the center point of the top surface of the silicon carbide crystal as the center and the distance from the X-ray emitting unit to the center point as the radius, and with the top surface of the silicon carbide crystal as the 0° reference plane, the X-ray emitting unit performs a first arc scan on the plane where the incident ray and the reflected ray are located. The range of the first arc scan is 96°±1°. During the first arc scan, when the signal intensity monitoring unit displays the highest signal peak, the X-ray emitting unit is adjusted to this position.
[0027] Optionally, step 2) further includes a second arc scan: with the center point of the top surface of the silicon carbide crystal as the center and the distance from the X-ray receiving unit to the center point as the radius, and with the top surface of the silicon carbide crystal as the 0° reference plane, the X-ray receiving unit performs a second arc scan on the plane where the incident ray and the reflected ray are located. The range of the second arc scan is 9°±1°. When the signal intensity monitoring unit displays the highest signal peak, the X-ray receiving unit is adjusted to this position.
[0028] Optionally, the height of the test platform can be adjusted, and when the first signal strength value is displayed at its maximum, the test platform can be fixed at that height.
[0029] Then, the test stage is rotated horizontally in a clockwise and / or counterclockwise direction, with an angle range of ±3°. Within this angle range, when the signal intensity value displayed by the X-ray orientation system is the largest relative to the first signal intensity value, the angle of rotation of the test stage is the deviation value of the orientation of the silicon carbide crystal's main reference plane.
[0030] Optionally, the first arc scan, the second arc scan, the adjustment of the height of the test stage, and the horizontal rotation of the test stage in a clockwise and / or counterclockwise direction are repeated multiple times, and the angle of the final rotation of the test stage is the deviation value of the final silicon carbide crystal master reference plane orientation value.
[0031] Optionally, the silicon carbide crystal itself has a tilt angle of 0°–4°;
[0032] The angle between the (11-28) crystal plane and the (0001) crystal plane of the silicon carbide crystal is 39.5°±0.5°.
[0033] Optionally, the silicon carbide crystal is a silicon carbide substrate, a silicon carbide crystal rod, a silicon carbide grinding disc, or a silicon carbide polished disc.
[0034] Optionally, the X-ray orientation system is an X-ray diffractometer or an X-ray orientation instrument.
[0035] The beneficial effects of this application include, but are not limited to:
[0036] According to the method for testing the orientation of the main reference plane of silicon carbide crystals in this application, by selecting the (11-28) crystal plane as the reference plane, calculating the Bragg diffraction angle θ of the crystal plane, and selecting the top surface of the silicon carbide crystal as the test plane, it can be applied to silicon carbide crystals of different thicknesses, especially filling the gap that sheet-like silicon carbide substrates cannot be tested, and greatly expanding the detection range.
[0037] Because the test surface is a flat plane rather than a curved side surface, the test points are easy to locate, which greatly improves the accuracy of the test and saves test time.
[0038] This testing method does not require special tooling, greatly simplifying the operation. It does not require special modifications to ordinary testing instruments, increasing detection efficiency and universality. It can be performed on silicon carbide crystals and is suitable for industrial testing of silicon carbide crystals. Attached Figure Description
[0039] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:
[0040] Figure 1 This is a schematic diagram illustrating the conventional method used in the background art of this application to test the orientation of the master reference plane of a silicon carbide crystal.
[0041] Figure 2 This is a schematic diagram of the orientation of the main reference plane of a silicon carbide crystal used in an embodiment of this application.
[0042] Figure 3 for Figure 2 A schematic diagram of the test angle for the orientation of the main reference plane of the silicon carbide crystal.
[0043] Figure 4 This is a schematic diagram of another test angle for testing the orientation of the main reference plane of a silicon carbide crystal, as described in an embodiment of this application.
[0044] 11. Main reference plane (side surface of silicon carbide crystal), 12. Top surface of silicon carbide crystal, 13. X-ray emitting unit, 14. X-ray receiving unit, 15. Incident ray, 16. Reflected ray.
[0045] 21. (0001) crystal plane, 22. (11-20) crystal plane, 23. (1-100) crystal plane, 24. (11-28) crystal plane, 25. [1-100] crystal orientation, 26. [11-20] crystal orientation,
[0046] 31. Silicon carbide crystal, 32. Normal, 33. Inclination angle of the silicon carbide substrate itself, 34. Angle between the (11-28) crystal plane and the (0001) crystal plane. Detailed Implementation
[0047] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.
[0048] This embodiment provides a method for testing the orientation of the main reference plane of a silicon carbide crystal, the method comprising the following steps:
[0049] 1) Place the silicon carbide crystal to be tested horizontally on the test stage, so that the main reference plane 11 of the silicon carbide crystal is perpendicular to the test stage. Here, the main reference plane 11 of the silicon carbide crystal is also the side surface of the silicon carbide crystal. Select the (11-28) crystal plane 24 of the silicon carbide crystal as the reference plane and calculate the Bragg diffraction angle θ of the (11-28) crystal plane 24.
[0050] The method for calculating the Bragg diffraction angle θ of the (11-28) crystal plane of silicon carbide is as follows:
[0051] 2dsin(θ)=nλ
[0052] Wherein, λ is the wavelength value of the X-ray copper target, and the material used to emit X-rays in the X-ray directional system is a copper target structure, which is a fixed value of 1.54056 angstroms;
[0053] n is a positive natural number, 1; d is the interplanar spacing of the (11-28) crystal planes, approximately 0.97 angstroms.
[0054] After calculation, the Bragg diffraction angle θ of the (11-28) crystal plane is equal to 52.5°±0.5°, that is, 2θ is equal to 105°±1°. Since the calculated 2θ is not an integer, a range value is taken here; preferably, 2θ is about 104°—105°.
[0055] 2) Adjust the X-ray orientation system, referring to... Figure 2 and Figure 3 A straight line passing through the center point of the top surface of the silicon carbide crystal and perpendicular to the (11-28) crystal plane 24 is selected as the normal line 32, so that the intersection of the incident ray 15 emitted by the X-ray orientation system and the reflected ray 16 is focused on the center point of the top surface of the silicon carbide crystal.
[0056] The angle between incident ray 15 and (11-28) crystal plane 24 and the angle between reflected ray 16 and (11-28) crystal plane 24 are both angles θ. The plane containing incident ray 15 and reflected ray 16 is parallel to the (1-100) crystal plane 23 of silicon carbide crystal, and at this time the X-ray orientation system displays the first signal intensity value.
[0057] 3) Then rotate the test stage horizontally in a clockwise and / or counterclockwise direction. When the signal intensity value displayed by the X-ray orientation system is the largest relative to the first signal intensity value, the angle of rotation of the test stage is the deviation value of the orientation of the silicon carbide crystal's main reference plane.
[0058] If the main reference plane of the silicon carbide crystal is not tilted during processing, the plane formed by the incident ray 15 emitted by the X-ray orientation system and the received reflected ray 16 is perpendicular to the (11-28) crystal plane 24. At this time, the signal strength value is the maximum, that is, the angle of rotation of the test stage is 0°, and the signal strength value is the first signal strength value.
[0059] If the silicon carbide crystal master reference plane is skewed during processing, it will cause the (11-28) crystal plane 24 to also be skewed. At this time, the test signal strength will definitely not be at its maximum value. Rotate the test stage horizontally in the clockwise and / or counterclockwise direction to find the point where the signal strength value is strongest. At this time, the plane formed by the incident ray 15 emitted by the X-ray orientation system and the received reflected ray 16 is perpendicular to the (11-28) crystal plane 24. That is, the angle by which the test stage is rotated is the skew angle of the (11-28) crystal plane. Since the (11-28) crystal plane is perpendicular to the (1-100) crystal plane, this angle is the skew angle between the silicon carbide crystal master reference plane 11 and the (1-100) crystal plane 23, which is the deviation value of the orientation of the silicon carbide crystal master reference plane 11.
[0060] The angle 34 between the (11-28) crystal plane 24 and the (0001) crystal plane 21 of the silicon carbide crystal is 39.5°±0.5°. In actual operation, it is not easy to accurately find the reference plane (11-28) crystal plane 24 of the silicon carbide crystal using the above method for testing the orientation of the main reference plane of the silicon carbide crystal, and there may be some operational errors.
[0061] Therefore, in one embodiment, the reference plane (11-28) crystal plane 24 is transformed into a horizontal plane as the reference plane. Specifically, as follows:
[0062] In step 2), the angle between the incident beam 15 and the test stage is 9°±1°;
[0063] The angle between the reflective line 16 and the test stage is 96°±1°. The test stage is parallel to the horizontal plane, and the (0001) crystal plane is also parallel to the horizontal plane.
[0064] refer to Figure 3 Let ∠1 be the angle between the incident ray and the test stage, which is also the angle between the incident ray and the (0001) crystal plane. Let ∠2 be the angle between the reflected ray and the test stage, which is also the angle between the reflected ray and the (0001) crystal plane. The calculation methods for ∠1 and ∠2 are as follows:
[0065] ∠1=∠θ-(39.5°±0.5°)-4°=9°±1°
[0066] ∠2=∠θ+(39.5°±0.5°)+4°=96°±1°
[0067] Where 4° is the tilt angle 33 of the silicon carbide crystal itself. Usually, the tilt angle 33 of the silicon carbide crystal itself is 0° to 4°. Here, we take 4° as an example for calculation.
[0068] The reference plane (11-28) crystal plane 25 is transformed into a horizontal plane as the reference plane. The testing method is as follows:
[0069] In one embodiment, reference Figure 2 and Figure 3 :
[0070] The X-ray orientation system includes an X-ray emitting unit 13 for emitting incident rays, an X-ray receiving unit 14 for receiving reflected rays, and a signal intensity monitoring unit (not shown in the figure);
[0071] After placing the silicon carbide crystal to be tested horizontally on the test stage, perform the following steps ①-④:
[0072] Step ①: Adjust the X-ray emitting unit 13 to perform the first arc scan: Using the center point of the top surface of the silicon carbide crystal 31 as the center and the distance from the X-ray emitting unit 13 to the center point as the radius, and the top surface of the silicon carbide crystal as the 0° reference plane (the top surface of the silicon carbide crystal is parallel to the test stage and is a horizontal plane), the X-ray emitting unit 13 performs the first arc scan in the plane where the incident ray 15 and the reflected ray 16 are located. The range of the first arc scan is 9°±1°. During the first arc scan, when the signal intensity monitoring unit displays the highest signal peak, adjust the X-ray emitting unit 13 to this position.
[0073] Step ②: Adjust the X-ray receiving unit 14 to perform a second arc scan: Using the center point of the top surface of the silicon carbide crystal 31 as the center and the distance from the X-ray receiving unit to the center point as the radius, and using the top surface of the silicon carbide crystal as the 0° reference plane (the top surface of the silicon carbide crystal is parallel to the test stage and is a horizontal plane), the X-ray receiving unit 14 performs a second arc scan on the plane where the incident ray 15 and the reflected ray 16 are located. The range of the second arc scan is 96°±1°. When the signal intensity monitoring unit displays the highest signal peak, adjust the X-ray receiving unit 14 to this position.
[0074] Step 3: Adjust the height of the test platform. When the first signal strength value is displayed at its maximum, fix the test platform at that height.
[0075] Step 4: Then rotate the test stage horizontally in a clockwise and / or counterclockwise direction. The rotation angle range is ±3°. Within this angle range, when the signal intensity value displayed by the X-ray orientation system is the largest relative to the first signal intensity value, the rotation angle of the test stage is the deviation value of the orientation of the silicon carbide crystal principal reference plane 11.
[0076] During the rotation of the test stage, when the maximum signal intensity value displayed by the X-ray orientation system is the first signal intensity value, it indicates that the main reference surface 11 of the silicon carbide crystal was not tilted during processing, and the deviation value of the orientation of the main reference surface 11 of the silicon carbide crystal is 0°.
[0077] Repeat steps ①-④ above, adjusting each parameter again. The resulting deviation value will be more accurate. For even higher precision testing, simply repeat steps ①-④ several times, adjusting the parameter range each time, to obtain a more accurate deviation value.
[0078] In another implementation, Figure 2 and Figure 3 The positions of the X-ray emitting unit 13 and the X-ray receiving unit 14 are swapped, for reference. Figure 4 Similarly, it can also perform the testing of the orientation of the main reference plane 11 of silicon carbide crystal, as detailed below:
[0079] In step 2), the angle between the incident beam 15 and the test stage is 96°±1°;
[0080] The angle between the reflected line 16 and the test stage is 9°±1°.
[0081] Define the angle between the incident ray and the test stage as ∠1, and the angle between the reflected ray and the test stage as ∠2. The calculation methods for ∠1 and ∠2 are as follows:
[0082] ∠1=∠θ+(39.5°±0.5°)+4°=96°±1°
[0083] ∠2=∠θ-(39.5°±0.5°)-4°=9°±1°
[0084] Where 4° is the tilt angle 33 of the silicon carbide crystal itself. Usually, the tilt angle 33 of the silicon carbide crystal itself is 0° to 4°. Here, we take 4° as an example for calculation.
[0085] The reference plane (11-28) crystal plane 24 is transformed into a horizontal plane as the reference plane, and the testing method is as follows:
[0086] After placing the silicon carbide crystal to be tested horizontally on the test stage, perform the following steps ①-④:
[0087] Step ①: Adjust the X-ray emitting unit 13 to perform the first arc scan: Using the center point of the top surface of the silicon carbide crystal 31 as the center and the distance from the X-ray emitting unit 13 to the center point as the radius, and using the top surface of the silicon carbide crystal as the 0° reference plane (the top surface of the silicon carbide crystal is parallel to the test stage and is a horizontal plane), the X-ray emitting unit 13 performs the first arc scan in the plane where the incident ray 15 and the reflected ray 16 are located. The range of the first arc scan is 96°±1°. During the first arc scan, when the signal intensity monitoring unit displays the highest signal peak, adjust the X-ray emitting unit 13 to this position.
[0088] Step ②: Adjust the X-ray receiving unit 14 to perform a second arc scan: Using the center point of the top surface of the silicon carbide crystal 31 as the center and the distance from the X-ray receiving unit 14 to the center point as the radius, and using the top surface of the silicon carbide crystal 31 as the 0° reference plane (the top surface of the silicon carbide crystal is parallel to the test stage and is a horizontal plane), the X-ray receiving unit 14 performs a second arc scan in the plane where the incident ray 15 and the reflected ray 16 are located. The range of the second arc scan is 9°±1°. When the signal intensity monitoring unit displays the highest signal peak, adjust the X-ray receiving unit 14 to this position.
[0089] Step 3: Adjust the height of the test platform. When the first signal strength value is displayed at its maximum, fix the test platform at that height.
[0090] Step 4: Then rotate the test stage horizontally in a clockwise and / or counterclockwise direction, with an angle range of ±3°. Within this angle range, when the signal intensity value displayed by the X-ray orientation system is the largest relative to the first signal intensity value, the angle of rotation of the test stage is the deviation value of the orientation of the silicon carbide crystal's main reference plane.
[0091] During the rotation of the test stage, when the maximum signal intensity value displayed by the X-ray orientation system is the first signal intensity value, it indicates that the main reference surface 11 of the silicon carbide crystal was not tilted during processing, and the deviation value of the orientation of the main reference surface 11 of the silicon carbide crystal is 0°.
[0092] Repeat steps ①-④ above, adjusting each parameter again. The resulting deviation value will be more accurate. For even higher precision testing, simply repeat steps ①-④ several times, adjusting the parameter range each time, to obtain a more accurate deviation value.
[0093] The X-ray orientation system can be either an X-ray diffractometer or an X-ray orientation instrument. Both X-ray diffractometers and X-ray orientation instruments are existing equipment and will not be described in detail here. The X-ray emitting unit is the emitter of the X-ray emitting unit, and the X-ray receiving unit is the receiver of the X-ray emitting unit.
[0094] The silicon carbide crystals in this application can be silicon carbide substrates, silicon carbide crystal rods, silicon carbide grinding discs, or silicon carbide polished discs, etc., with different thicknesses.
[0095] This application selects the (11-28) crystal plane 24 as a reference plane or transforms the (11-28) crystal plane 24 into a horizontal reference plane, such as the test stage and the (0001) crystal plane 21 of the silicon carbide crystal. It calculates the Bragg diffraction angle θ of the (11-28) crystal plane 24 and selects the top surface of the silicon carbide crystal 31 as the test plane, replacing the selection of the side surface 11 of the silicon carbide crystal as the test plane in the prior art. This fills the gap that sheet-like silicon carbide substrates cannot be tested and greatly expands the detection range.
[0096] Because the test surface is a flat plane rather than a curved side surface, the test points are easy to locate, which greatly improves the accuracy of the test and saves test time.
[0097] This testing method requires no special tooling, greatly simplifying the operation. It does not require special modifications to ordinary testing instruments, increasing detection efficiency and versatility. It can be applied to XRD, X-ray orientation instruments, etc., and has high testing accuracy. It can be performed on silicon carbide crystals, making it suitable for industrial testing of silicon carbide crystals.
[0098] The above description is merely an embodiment of this application, and the scope of protection of this application is not limited to these specific embodiments, but is determined by the claims of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the technical concept and principles of this application should be included within the scope of protection of this application.
Claims
1. A method for testing the orientation of the principal reference plane of a silicon carbide crystal, characterized in that, Includes the following steps: 1) Place the silicon carbide crystal to be tested horizontally on the test stage, select the (11-28) crystal plane of the silicon carbide crystal as the reference plane, and calculate the Bragg diffraction angle θ of the (11-28) crystal plane. 2) Adjust the X-ray orientation system and select a straight line that passes through the center point of the top surface of the silicon carbide crystal and is perpendicular to the (11-28) crystal plane as the normal, so that the intersection of the incident ray emitted by the X-ray orientation system and the reflected ray is focused on the center point of the top surface of the silicon carbide crystal. The angle between the incident ray and the (11-28) crystal plane and the angle between the reflected ray and the (11-28) crystal plane are both θ. The plane containing the incident ray and the reflected ray is parallel to the (1-100) crystal plane of the silicon carbide crystal. At this time, the X-ray orientation system displays the first signal intensity value. 3) Then rotate the test stage horizontally in a clockwise and / or counterclockwise direction. When the signal intensity value displayed by the X-ray orientation system is the largest relative to the first signal intensity value, the angle of rotation of the test stage is the deviation value of the orientation of the silicon carbide crystal's main reference plane.
2. The method for testing the orientation of the principal reference plane of a silicon carbide crystal according to claim 1, characterized in that, In step 1), the Bragg diffraction angle θ of the (11-28) crystal plane is calculated as follows: 2dsin(θ)=nλ Wherein, λ is the wavelength of the X-rays, and the material used to emit X-rays in the X-ray directional system is a copper target structure, so it is a constant value; n is a positive natural number; d is the interplanar spacing of the (11-28) crystal planes. Calculations show that the Bragg diffraction angle θ of the (11-28) crystal plane is 52.5° ± 0.5°.
3. The method for testing the orientation of the principal reference plane of a silicon carbide crystal according to claim 1, characterized in that, In step 2), the angle between the incident ray and the test stage is 9°±1°; The angle between the reflected line and the test stage is 96°±1°.
4. The method for testing the orientation of the principal reference plane of a silicon carbide crystal according to claim 3, characterized in that, The X-ray orientation system includes an X-ray emitting unit for emitting incident rays, an X-ray receiving unit for receiving reflected rays, and a signal intensity monitoring unit; Step 2) also includes a first arc scan: with the center point of the top surface of the silicon carbide crystal as the center and the distance from the X-ray emitting unit to the center point as the radius, and with the top surface of the silicon carbide crystal as the 0° reference plane, the X-ray emitting unit performs a first arc scan on the plane where the incident ray and the reflected ray are located. The range of the first arc scan is 9°±1°. During the first arc scan, when the signal intensity monitoring unit displays the highest signal peak, the X-ray emitting unit is adjusted to this position.
5. The method for testing the orientation of the principal reference plane of a silicon carbide crystal according to claim 4, characterized in that, Step 2) also includes a second arc scan: with the center point of the top surface of the silicon carbide crystal as the center and the distance from the X-ray receiving unit to the center point as the radius, and with the top surface of the silicon carbide crystal as the 0° reference plane, the X-ray receiving unit performs a second arc scan on the plane where the incident ray and the reflected ray are located. The range of the second arc scan is 96°±1°. When the signal intensity monitoring unit displays the highest signal peak, the X-ray receiving unit is adjusted to this position.
6. The method for testing the orientation of the principal reference plane of a silicon carbide crystal according to claim 1, characterized in that, In step 2), the angle between the incident beam and the test stage is 96°±1°; The angle between the reflected line and the test stage is 9°±1°.
7. The method for testing the orientation of the principal reference plane of a silicon carbide crystal according to claim 6, characterized in that, The X-ray orientation system includes an X-ray emitting unit for emitting incident rays, an X-ray receiving unit for receiving reflected rays, and a signal intensity monitoring unit; Step 2) also includes a first arc scan: with the center point of the top surface of the silicon carbide crystal as the center and the distance from the X-ray emitting unit to the center point as the radius, and with the top surface of the silicon carbide crystal as the 0° reference plane, the X-ray emitting unit performs a first arc scan on the plane where the incident ray and the reflected ray are located. The range of the first arc scan is 96°±1°. During the first arc scan, when the signal intensity monitoring unit displays the highest signal peak, the X-ray emitting unit is adjusted to this position.
8. The method for testing the orientation of the principal reference plane of a silicon carbide crystal according to claim 7, characterized in that, Step 2) also includes a second arc scan: with the center point of the top surface of the silicon carbide crystal as the center and the distance from the X-ray receiving unit to the center point as the radius, and with the top surface of the silicon carbide crystal as the 0° reference plane, the X-ray receiving unit performs a second arc scan on the plane where the incident ray and the reflected ray are located. The range of the second arc scan is 9°±1°. When the signal intensity monitoring unit displays the highest signal peak, the X-ray receiving unit is adjusted to this position.
9. The method for testing the orientation of the principal reference plane of a silicon carbide crystal according to claim 5 or 8, characterized in that, Adjust the height of the test platform, and fix the test platform at that height when the first signal strength value is displayed at its maximum. Then, the test stage is rotated horizontally in a clockwise and / or counterclockwise direction, with an angle range of ±3°. Within this angle range, when the signal intensity value displayed by the X-ray orientation system is the largest relative to the first signal intensity value, the angle of rotation of the test stage is the deviation value of the orientation of the silicon carbide crystal's main reference plane.
10. The method for testing the orientation of the principal reference plane of a silicon carbide crystal according to claim 9, characterized in that, Repeat the first arc scan, the second arc scan, adjust the height of the test stage, and rotate the test stage horizontally in a clockwise and / or counterclockwise direction multiple times. The angle of the final rotation of the test stage is the deviation value of the final silicon carbide crystal master reference plane orientation value.
11. The method for testing the orientation of the principal reference plane of a silicon carbide crystal according to claim 1, characterized in that, The silicon carbide crystal itself has a tilt angle of 0°–4°; The angle between the (11-28) crystal plane and the (0001) crystal plane of the silicon carbide crystal is 39.5°±0.5°.
12. The method for testing the orientation of the principal reference plane of a silicon carbide crystal according to claim 1, characterized in that, The silicon carbide crystal is a silicon carbide substrate, a silicon carbide crystal rod, a silicon carbide grinding disc, or a silicon carbide polishing disc.