An ion beam polishing method based on quantum dot coupled silicon carbide in-situ growth

Abstract

The present invention discloses an ion beam polishing method based on the in-situ growth of coupled silicon carbide with quantum dots, belonging to the technical field of SiC surface polishing. The preparation method of the SiC material with an in-situ growth quantum dot sacrificial layer of the present invention comprises the following steps: mixing a lead source, a cesium source and a solvent to obtain a CsPbBr3 precursor solution; dropping the CsPbBr3 precursor solution onto the surface of the SiC material, leveling it, heating and crystallizing it, and annealing it to obtain a SiC material with an in-situ growth quantum dot sacrificial layer. The present invention proposes an ion beam polishing method based on the in-situ growth of coupled silicon carbide with quantum dots, using the quantum dot layer as the sacrificial layer of the SiC wafer, which can not only effectively reduce the thickness of the sacrificial layer and significantly improve the flatness of the SiC surface, but also achieve a good fluorescent labeling effect. The CsPbBr3 quantum dots prepared by the present invention have extremely small nanometer sizes and can deeply fill the microcracks and micro-nano scratches on the surface of the SiC wafer, completely coupling with the microcracks on the surface of the SiC wafer, and realizing precise filling of defects.

Description

Technical Field

[0001] The present invention relates to the technical field of SiC surface polishing, and in particular to an ion beam polishing method based on quantum dot-coupled silicon carbide in-situ growth. Background Art

[0002] Single-crystal silicon carbide (SiC) has become a major research focus in third-generation semiconductor materials due to its remarkable physical and mechanical properties, such as wide band gap, high thermal conductivity, excellent stiffness, low thermal expansion coefficient, and outstanding wear resistance. However, due to SiC's high brittleness, high hardness, and low fracture toughness, it is difficult to maintain a high-quality smooth surface during processing. These problems can easily lead to increased surface roughness and the generation of microcracks in SiC materials, which in turn have a negative impact on the final application performance. Therefore, in the processing of SiC, ultra-smooth surface polishing technology is crucial.

[0003] Traditional surface polishing processes are primarily based on chemical mechanical polishing (CMP). CMP technology primarily involves mechanical grinding, using small-particle hard abrasives to ductilely remove the wafer surface, removing residual stress layers and mechanical damage layers from the grinding process, thereby improving surface flatness and quality. The polishing slurry primarily consists of abrasives such as aluminum oxide (Al2O3), silicon dioxide (SiO2), and cerium dioxide (CeO2), along with oxidants such as potassium permanganate (KMnO4) and hydrogen peroxide (H2O2). The oxidation reaction and mechanical removal simultaneously remove surface defects and flatten the surface. However, due to the mechanical grinding action, the CMP process is prone to introducing new damage layers, resulting in defects such as scratches, pits, subsurface microcracks, and abrasive residue. The presence of these defects directly affects the final product yield and optoelectronic performance. Moreover, on the one hand, the CMP process requires strict control of material loss during the processing, which usually needs to be kept within 10% of the thickness of the entire device. This means that CMP must not only effectively remove excess material, but also precisely control the removal rate and the final surface effect, which places extremely high demands on the accuracy of the CMP process. On the other hand, the CMP process involves consumables such as polishing heads, polishing pads, polishing discs and polishing tools, which further increases production costs.

[0004] Pulsed ion beam technology utilizes the physical sputtering effect, bombarding the surface of optical components with high-energy ion beams to remove material at the atomic level. Compared to traditional polishing methods, pulsed ion beam processes are less affected by the chemical properties and hardness of the material, enabling efficient polishing of complex free-form surfaces without causing surface damage. In traditional pulsed ion beam polishing, a sacrificial layer material is typically applied to the wafer surface through coating or sputtering. This sacrificial layer is used to fill surface defects and provide a smooth base before polishing. However, due to their physical properties, existing sacrificial layer materials often have difficulty completely filling and coupling into microcracks and micro-nano scratches on the SiC wafer surface. During pulsed ion beam polishing, incomplete filling of the sacrificial layer material can lead to further expansion of the defect area and even cause new surface damage during material removal, making it difficult to effectively ensure wafer flatness and surface quality after polishing. Furthermore, the typical thickness of the sacrificial layer exceeds 1μm, significantly increasing material removal time and production costs during pulsed ion beam polishing. In summary, traditional sacrificial layer materials have many shortcomings, and improving polishing efficiency and reducing material loss are urgent issues that need to be addressed. Summary of the Invention

[0005] The purpose of the present invention is to provide an ion beam polishing method based on quantum dot coupled silicon carbide in situ growth to solve the above-mentioned problems in the background technology. The present invention proposes an ion beam polishing method based on quantum dot coupled silicon carbide in situ growth, using the quantum dot layer as a sacrificial layer of the SiC wafer, which can not only effectively reduce the thickness of the sacrificial layer and significantly improve the flatness of the SiC surface, but also achieve a good fluorescent labeling effect. The CsPbBr3 quantum dots prepared by the present invention have extremely small nanometer sizes and can deeply fill the microcracks and micro-nano scratches on the surface of the SiC wafer, and are completely coupled with the microcracks on the surface of the SiC wafer to achieve precise filling of defects.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] One of the technical solutions of the present invention is to provide a method for preparing a SiC material having an in-situ grown quantum dot sacrificial layer, comprising the following steps:

[0008] (1) mixing a lead source, a cesium source, and a solvent to obtain a CsPbBr3 precursor solution;

[0009] (2) adding the CsPbBr3 precursor solution dropwise to the surface of the SiC material, coating it flat, heating it for crystallization, and annealing it to obtain a SiC material with an in-situ grown quantum dot sacrificial layer.

[0010] Preferably, the lead source is PbBr2; the cesium source is CsBr; and the molar ratio of the lead source to the cesium source is 0.9-1.1.

[0011] Preferably, the solvent is polymethyl methacrylate and / or N,N-dimethylformamide.

[0012] Preferably, the temperature of the crystallization is 70-100° C. and the time is 1-2 minutes.

[0013] Preferably, the annealing temperature is 40-110° C., and the annealing time is 1-5 min.

[0014] The second technical solution of the present invention is to provide a SiC material with an in-situ grown quantum dot sacrificial layer obtained according to the above preparation method.

[0015] The third technical solution of the present invention is to provide a polishing method for the SiC material of the above-mentioned in-situ grown quantum dot sacrificial layer, comprising the following steps:

[0016] In an Ar gas atmosphere, the SiC material having the quantum dot sacrificial layer grown in situ is subjected to pulsed ion beam polishing to obtain a polished SiC material.

[0017] Preferably, the parameters of the pulsed ion beam polishing are: ion beam rate power 110W, screen grid voltage 800V, acceleration grid voltage 110V, screen grid current 18mA, neutralizer current 158mA, Ar gas flow rate 20SCCM, and polishing time 1-2min.

[0018] Under the pulsed ion beam polishing parameters defined in the present invention, a polishing rate of 0.17 μm / min can be achieved.

[0019] The fourth technical solution of the present invention: provides an optimization method for silicon carbide ion beam polishing, in which a CsPbBr3 quantum dot sacrificial layer is grown in situ on the silicon carbide surface, and then pulsed ion beam polishing is performed.

[0020] The fifth technical solution of the present invention: provides an application of CsPbBr3 quantum dots as a sacrificial layer for polishing SiC materials.

[0021] The technical principles of the present invention are as follows:

[0022] In the pulsed ion beam polishing stage, the present invention places the SiC material with the in-situ grown CsPbBr3 quantum dot sacrificial layer on the ion beam etcher. First, argon (Ar) is introduced into the etching chamber and ionized by the ion source to generate argon ions, forming a high-density plasma. The ion beam is then accelerated and focused by the three-grid ion optical system so that the ion beam can act accurately on the wafer surface. The ion beam is then excited by the accelerating electric field to remove the sacrificial layer material on the wafer surface. In each pulse cycle, the Ar in the plasma +Under the action of the accelerating electric field, the Ar impacts the wafer surface with a specific energy, removing the material at the atomic level. + The bombardment not only removes excess material from the surface but also repairs microscopic defects, making the wafer surface smoother at the atomic scale. Ultimately, after multiple pulsed plasma beams, the SiC wafer surface achieves an ultra-smooth finish with low surface roughness, meeting the surface quality requirements of high-precision optical components. Compared to traditional polishing methods, pulsed plasma beam technology achieves efficient and precise surface smoothing without introducing surface damage.

[0023] The purpose of the annealing treatment defined in the present invention is to promote further crystallization and growth of CsPbBr3 quantum dots, while further enhancing the coupling strength between the quantum dots and the substrate and improving the polishing quality.

[0024] The beneficial technical effects of the present invention are as follows:

[0025] The present invention proposes an ion beam polishing method based on quantum dot-coupled silicon carbide in-situ growth. The quantum dot layer is used as a sacrificial layer of the SiC wafer, which can not only effectively reduce the thickness of the sacrificial layer and significantly improve the flatness of the SiC surface, but also achieve a good fluorescent marking effect.

[0026] The present invention selects a CsPbBr3 quantum dot composite film as a sacrificial layer for SiC materials, primarily due to the unique advantages of the prepared CsPbBr3 quantum dot sacrificial layer in terms of size, fluorescence efficiency, and substrate coupling. The CsPbBr3 quantum dots prepared in the present invention have extremely small nanometer dimensions, enabling them to deeply fill microcracks and micro-nano scratches on the surface of the SiC wafer, fully coupling with the microcracks on the SiC wafer surface, and precisely filling defects. Furthermore, the high fluorescence efficiency of these quantum dots ensures the generation of a clear, bright fluorescence signal during the detection process, effectively marking defects. Under the polishing parameters specified in the present invention, the etch rate of the prepared sacrificial layer approaches that of the SiC substrate material, allowing the smooth surface covered by the sacrificial layer to be transferred to the SiC substrate surface. Furthermore, the in-situ growth of the CsPbBr3 quantum dots enables uniform nanometer-scale distribution on the wafer surface. Furthermore, due to their small size, the quantum dot layer can achieve a nanometer-level thickness. Compared to traditional sacrificial layers (1μm), the use of quantum dots as a sacrificial layer effectively reduces the thickness of the sacrificial layer, achieving wafer flattening. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0028] Figure 1 Schematic diagram of the pulsed ion beam polishing process of Example 1. (a) shows a SiC surface with defects, (b) shows a SiC surface after in-situ growth of a quantum dot sacrificial layer, (c) shows the ion beam polishing process, and (d) shows the ultra-smooth SiC surface after polishing.

[0029] Figure 2 The film thickness curve and fluorescence effect diagram of the SiC material with the in-situ growth of the CsPbBr3 quantum dot sacrificial layer in Example 1. Among them, (a) is the film thickness curve, and (b) is the fluorescence effect diagram.

[0030] Figure 3 The film thickness curve and fluorescence effect diagram of the SiC material to be polished in Comparative Example 2. Among them, (a) is the film thickness curve, (b) is the actual image under natural light, and (c) is the actual image under ultraviolet light.

[0031] Figure 4 The following are the surface defect detection results of the SiC material with the in-situ growth of the CsPbBr3 quantum dot sacrificial layer before and after ultraviolet light excitation in Example 1. (a) is before excitation, and (b) is after excitation.

[0032] Figure 5 The surface morphology of the wafer before and after polishing of Comparative Example 3. (a) is the SiC wafer substrate, and (b) is the SiC material after polishing.

[0033] Figure 6 The wafer surface morphology before and after polishing in Example 1. (a) is the SiC material with an in-situ grown CsPbBr3 quantum dot sacrificial layer, and (b) is the SiC material after polishing.

[0034] Figure 7 The wafer surface topography before and after polishing of Comparative Example 4. (a) is the wafer surface topography before polishing, (b) is the wafer surface topography after polishing, (c) is the 3D topography before polishing, and (d) is the 3D topography after polishing.

[0035] Figure 8 The wafer surface topography before and after polishing of Comparative Example 2. (a) is the wafer surface topography before polishing, (b) is the wafer surface topography after polishing, and (c) is the three-dimensional topography after polishing. DETAILED DESCRIPTION

[0036] Various exemplary embodiments of the present invention are now described in detail. This detailed description should not be considered as a limitation of the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention. It should be understood that the terms used in the present invention are only for describing specific embodiments and are not intended to limit the present invention.

[0037] In addition, for numerical ranges in the present invention, it is understood that each intervening value between the upper and lower limits of the range is also specifically disclosed. Each smaller range between any stated value or stated range, and any other stated value or intervening value in the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges may independently be included or excluded in the range.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention pertains. Although preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present invention.

[0039] The terms “include,” “including,” “have,” “contain,” etc. used in the present invention are open-ended terms, meaning including but not limited to.

[0040] The present invention discloses a method for preparing a SiC material with an in-situ grown quantum dot sacrificial layer, comprising the following steps:

[0041] (1) mixing a lead source, a cesium source, and a solvent to obtain a CsPbBr3 precursor solution;

[0042] (2) adding the CsPbBr3 precursor solution dropwise to the surface of the SiC material, coating it flat, heating it for crystallization, and annealing it to obtain a SiC material with an in-situ grown quantum dot sacrificial layer.

[0043] Preferably, the step (1) is specifically as follows:

[0044] In a nitrogen environment, 1 g of polymethyl methacrylate (PMMA) and 2-4 mL of N,N-dimethylformamide (DMF) were mixed, and a magnetic stirrer was placed on a hot plate. The hot plate temperature was set to 100-130°C, and the speed of the magnetic stirrer was adjusted to 1500-1800 rpm. The mixture was stirred for 1-3 hours until a transparent solution was formed, thereby obtaining a PMMA / DMF solution.

[0045] In a nitrogen environment, 1.267 g of PbBr2 (lead bromide) and 0.514 g of CsBr (cesium bromide) powder were respectively placed in 40 mL glass bottles, 4-6 mL of DMF was added, and a magnetic stirrer was placed. The mixture was placed on a hot plate, the hot plate temperature was set to 50-80°C, and the magnetic stirring speed was adjusted to 1000-1500 rpm. The mixture was stirred overnight and then filtered through a 0.22 μm syringe filter to obtain CsBr / DMF solution and PbBr2 / DMF solution, respectively.

[0046] In a nitrogen environment, the CsBr / DMF solution and the PMMA / DMF solution are mixed, and a magnetic stirrer is placed on a heating plate. The temperature of the heating plate is adjusted to 80-100°C, the speed of the magnetic stirring is adjusted to 1500-1800 rpm, and the mixture is stirred for 10-12 hours to obtain an intermediate solution; then the PbBr2 / DMF solution and the intermediate solution are mixed according to a PbBr2:CsBr molar ratio of 2:3, and heating and stirring are continued at a temperature of 80-100°C and a speed of 1500-1800 rpm for 10-12 hours to obtain the CsPbBr3 precursor solution.

[0047] Preferably, the step (2) is specifically as follows:

[0048] After preheating the CsPbBr3 precursor solution to 70-100°C, it is added dropwise to the cleaned SiC wafer substrate and spin-coated at 1000-2000 rpm for 20-40s using a coater. The substrate is then placed on a heating plate at 70-100°C to promote in-situ nucleation and crystallization of CsPbBr3 quantum dots. The substrate is then annealed at 40-110°C for 1-5 minutes to obtain a SiC material with an in-situ grown quantum dot sacrificial layer (CsPbBr3 quantum dot composite film).

[0049] Unless otherwise specified, "overnight" in the present invention is calculated as 12 hours.

[0050] The raw materials used in the following examples and comparative examples of the present invention are all commercially available products.

[0051] Example 1

[0052] The preparation method and polishing method of SiC material with in-situ growth of quantum dot sacrificial layer are as follows:

[0053] (1) Preparation of CsPbBr3 precursor solution:

[0054] In a nitrogen glove box, 1 g of PMMA and 4 mL of DMF were mixed, placed in a magnetic stirrer, and placed on a hot plate. The hot plate temperature was set to 100°C, and the magnetic stirring speed was adjusted to 1600 rpm. Stirring was continued for 1 h until a transparent solution was formed, thereby obtaining a PMMA / DMF solution.

[0055] In a nitrogen glove box, 1.267 g of PbBr2 and 0.514 g of CsBr powder were placed in 40 mL glass bottles, 5 mL of DMF was added to each, and a magnetic stirrer was placed. The mixture was placed on a hot plate, the hot plate temperature was set to 50°C, and the magnetic stirring speed was adjusted to 1300 rpm. The mixture was stirred overnight and then filtered through a 0.22 μm syringe filter to obtain CsBr / DMF solution and PbBr2 / DMF solution, respectively.

[0056] In a glove box with a nitrogen environment, CsBr / DMF solution and PMMA / DMF solution were mixed in a volume ratio of 3:40, and a magnetic bar was placed on a heating plate. The temperature of the heating plate was adjusted to 90°C, the speed of the magnetic stirring was adjusted to 1600 rpm, and the mixture was stirred for 10 hours to obtain an intermediate solution; then the PbBr2 / DMF solution was mixed with the intermediate solution (the molar ratio of the Pb element in the PbBr2 / DMF solution to the Cs element in the intermediate solution was 0.9), and the mixture was heated and stirred at a temperature of 90°C and a speed of 1600 rpm for 10 hours to obtain a CsPbBr3 precursor solution.

[0057] (2) Preparation of CsPbBr3 quantum dot composite film:

[0058] After preheating the above CsPbBr3 precursor solution to 80°C, add it dropwise to the cleaned SiC wafer substrate ( Figure 1 (a) in the figure, a SiC material with an in-situ quantum dot sacrificial layer (CsPbBr3 quantum dot composite film) was obtained by spin coating at 2000 rpm for 30 seconds using a spin coater, then placed on a hot plate at 100°C for 1 minute, and then annealed at 80°C for 3 minutes. Figure 1 (b) in the figure.

[0059] (3) Polishing the SiC material with the quantum dot sacrificial layer grown in situ, the steps are as follows:

[0060] 1. Clean the finished product with an air gun to ensure that it is free of dust and other contaminants, then install the workpiece on a high-precision processing platform and ensure that its position is fixed.

[0061] 2. Set the ion beam polishing parameters: ion beam rate power 110W, screen grid voltage 800V, accelerating grid voltage 110V, screen grid current 18mA, neutralizer current 158mA, Ar gas flow rate 20sccm, polishing rate 0.17μm / min. Set the polishing process scanning mode to rectangular coordinates.

[0062] 3. Start the vacuum pump to ensure that the polishing process is carried out in a high vacuum environment to avoid collision between the ion beam and air molecules and reduce energy loss.

[0063] 4. Start the ion source to generate an ion beam. The ion beam used is Ar + source.

[0064] 5. Start the polishing process and set the polishing time to 1.2min ( Figure 1 (c) in the figure.

[0065] 6. After polishing is completed, restore the working environment to normal state and obtain the polished SiC material ( Figure 1 (d) in the above figure.

[0066] Figure 1 Schematic diagram of the pulsed ion beam polishing process of Example 1. (a) shows a SiC surface with defects, (b) shows a SiC surface after in-situ growth of a quantum dot sacrificial layer, (c) shows the ion beam polishing process, and (d) shows the ultra-smooth SiC surface after polishing.

[0067] Comparative Example 1

[0068] The only difference from Example 1 is that the polishing process in step (3) is modified as follows:

[0069] 1. Clean the finished product with an air gun to ensure that it is free of dust and other contaminants, then install the workpiece on a high-precision processing platform and ensure that its position is fixed.

[0070] 2. Set the ion beam polishing parameters: ion beam rate power 110W, screen grid voltage 800V, accelerating grid voltage 110V, screen grid current 25mA, neutralizer current 165mA, Ar gas flow rate 30sccm, polishing rate 0.17μm / min. Set the polishing process scanning mode to rectangular coordinates.

[0071] 3. Start the vacuum pump to ensure that the polishing process is carried out in a high vacuum environment to avoid collision between the ion beam and air molecules and reduce energy loss.

[0072] 4. Start the ion source to generate an ion beam. The ion beam used is Ar + source.

[0073] 5. Start the polishing process and set the polishing time to 1.2 minutes.

[0074] 6. After polishing is completed, the working environment is restored to normal to obtain the polished SiC material.

[0075] Comparative Example 2

[0076] The only difference from Example 1 is that step (2) is modified to:

[0077] SU-8 photoresist was dropped onto the cleaned SiC wafer substrate, and spin-coated at 2000 rpm for 30 seconds using a coating machine, and then placed on a hot plate at 80°C for annealing for 1 minute to obtain the SiC material to be polished, and then the polishing treatment of step (3) was carried out.

[0078] Comparative Example 3

[0079] The only difference from Example 1 is that the in-situ growth of the quantum dot sacrificial layer is omitted, and the SiC wafer substrate cleaned in step (2) is directly polished.

[0080] Comparative Example 4

[0081] The only difference from Example 1 is that the SiC wafer substrate in step (2) is modified to a rough-ground SiC wafer substrate. The preparation method of the rough-ground SiC wafer substrate is:

[0082] Boron carbide powder with a particle size of 50 μm is used as an abrasive and mixed with water to form a grinding liquid (boron carbide powder accounts for 30% of the grinding liquid). The SiC wafer substrate is fixed on the grinding disk and the pressure is 3 kg / cm 2 The grinding was performed at a speed of 500 rpm to obtain a rough-ground SiC wafer substrate.

[0083] The purpose of the rough grinding is to verify the polishing effect of the polishing method of the present invention on samples with high roughness (more and larger scratches and defects).

[0084] Effect verification

[0085] 1. The sacrificial layer and photoluminescence effect of the SiC material with in-situ quantum dot sacrificial layer grown in Example 1 and Comparative Example 2 were characterized; the wavelength of the ultraviolet light used in the photoluminescence effect test was 365nm. The test results are as follows Figure 2-3 shown.

[0086] The fluctuation of the film thickness curve can represent the roughness of the film. The greater the fluctuation, the greater the roughness, and the flatter the curve, the smaller the roughness.

[0087] Figure 2 The film thickness curve and fluorescence effect diagram of the SiC material with the in-situ growth of the CsPbBr3 quantum dot sacrificial layer in Example 1. Among them, (a) is the film thickness curve, and (b) is the fluorescence effect diagram.

[0088] Depend on Figure 2 It can be seen that the quantum dot sacrificial layer prepared in Example 1 has a thickness of about 187 nm and has bright fluorescence intensity.

[0089] Figure 3The film thickness curve and fluorescence effect diagram of the SiC material to be polished in Comparative Example 2. Among them, (a) is the film thickness curve, (b) is the actual image under natural light, and (c) is the actual image under ultraviolet light.

[0090] Depend on Figure 3 It can be seen that the thickness of the sacrificial layer in Comparative Example 2 is about 188 nm, which is almost 5 times that of Example 1. Moreover, the SiC material to be polished in Comparative Example 2 has no fluorescence effect and therefore has no defect marking function.

[0091] 2. Surface defect detection of materials after UV light excitation. Test results are as follows Figure 4 shown.

[0092] Figure 4 The following are the surface defect detection results of the SiC material with the in-situ growth of the CsPbBr3 quantum dot sacrificial layer before and after ultraviolet light excitation in Example 1. (a) is before excitation, and (b) is after excitation.

[0093] Figure 4 In the figure, the purple frame indicates a pit defect on the material surface, while the red frame indicates a surface defect invisible under white light. As shown in the figure, the CsPbBr3 quantum dot composite film can effectively fluorescently label defects after being excited by ultraviolet light, thus achieving the purpose of defect detection.

[0094] 3. To characterize the surface roughness of the wafer after ion beam polishing, a white light interferometer was used to characterize the surface roughness of the polished SiC materials in Example 1 and Comparative Examples 1-2 to evaluate the polishing effect. The characterization method is as follows:

[0095] (1) Clean the polished SiC material surface to prevent oil, fingerprints or other contaminants from affecting the measurement results.

[0096] (2) A Zygo NewView 700s white light interferometer was used to perform micron-scale medium and high frequency detection on the wafer surface, with magnifications of 10x and 50x, respectively. The detection range was 468μm×351μm, and the data resolution was 1.5μm and 7.5μm, respectively.

[0097] (3) Place the SiC wafer on the interferometer measurement table and adjust the optical focal length until the workpiece surface is clearly visible.

[0098] (4) Randomly test two points on the SiC wafer, calculate the surface roughness parameters and reconstruct the three-dimensional surface shape.

[0099] Figure 5 The surface morphology of the wafer before and after polishing of Comparative Example 3. (a) is the SiC wafer substrate, and (b) is the SiC material after polishing.

[0100] Figure 6 The wafer surface morphology before and after polishing in Example 1. (a) is the SiC material with an in-situ grown CsPbBr3 quantum dot sacrificial layer, and (b) is the SiC material after polishing.

[0101] Figure 7 The wafer surface topography before and after polishing of Comparative Example 4. (a) is the wafer surface topography before polishing, (b) is the wafer surface topography after polishing, (c) is the 3D topography before polishing, and (d) is the 3D topography after polishing.

[0102] Figure 8 The wafer surface topography before and after polishing of Comparative Example 2. (a) is the wafer surface topography before polishing, (b) is the wafer surface topography after polishing, and (c) is the three-dimensional topography after polishing.

[0103] Figure 5 It can be seen that without in-situ generation of quantum dot sacrificial layer, the surface roughness of SiC wafer substrate before polishing is 2.472nm, while after pulsed ion beam polishing, the surface roughness increases significantly to 8.622nm. In contrast, after adding CsPbBr3 quantum dots as sacrificial layer, the surface roughness of SiC after polishing is reduced to 1.505nm (see Figure 6 ), the surface roughness was reduced by nearly 573%.

[0104] Figure 7 It can be seen that after ion beam polishing, the scratches on the material surface are effectively reduced and the surface roughness is reduced by nearly 1 times. The experimental results show that the quantum dots of the present invention can significantly improve the flatness of the SiC surface as a sacrificial layer.

[0105] Figure 8 As can be seen, the surface roughness of the material before polishing was 2.121 nm, while after polishing, the surface roughness increased to 517.041 nm. This is mainly because the sacrificial layer material in Comparative Example 2 has large differences in thickness and uniformity, which cannot evenly cover and fill the microcracks on the wafer surface, resulting in unsatisfactory polishing results. As a result, after pulsed ion beam treatment, obvious burrs and irregularities appear on the wafer surface. Figure 8 This further demonstrates the superiority of the quantum dot sacrificial layer designed in the present invention in planarization processing.

[0106] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A polishing method for SiC material with in-situ growth of quantum dot sacrificial layer, characterized in that: The following steps are involved: In an Ar gas atmosphere, pulsed ion beam polishing is performed on the SiC material having the quantum dot sacrificial layer grown in situ to obtain a polished SiC material; The parameters of the pulsed ion beam polishing are: ion beam rate power 110 W, screen grid voltage 800 V, accelerating grid voltage 110 V, screen grid current 18 mA, neutralizer current 158 ​​mA, Ar gas flow rate 20 SCCM, and polishing time 1-2 min; The method for preparing a SiC material with an in-situ grown quantum dot sacrificial layer comprises the following steps: (1) Mixing a lead source, a cesium source, and a solvent to obtain a CsPbBr3 precursor solution; (2) adding the CsPbBr3 precursor solution dropwise to the surface of the SiC material, coating it flat, heating it for crystallization, and annealing it to obtain a SiC material with an in-situ grown quantum dot sacrificial layer; The lead source is PbBr2; the cesium source is CsBr; and the molar ratio of the lead source to the cesium source is 0.9-1.

1.

2. The polishing method according to claim 1, wherein The solvent is polymethyl methacrylate and / or N,N-dimethylformamide.

3. The polishing method according to claim 1, wherein The temperature of the temperature-raising crystallization is 70-100° C., and the time is 1-2 minutes.

4. The polishing method according to claim 1, wherein The annealing temperature is 40-110° C. and the annealing time is 1-5 minutes.

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