An optimization method for silicon carbide ion beam polishing based on light metal ion doped quantum dots

Abstract

The present invention discloses a method for optimizing silicon carbide ion beam polishing based on light metal ion-doped quantum dots, belonging to the technical field of sacrificial layer materials. The method of the present invention for in-situ growing a CsPbBr3 quantum dot sacrificial layer on the surface of a SiC material comprises the following steps: mixing a lead source, a cesium source, and a solvent to obtain a CsPbBr3 precursor solution; doping the CsPbBr3 precursor solution with light metal ions to obtain a light metal ion-doped CsPbBr3 precursor solution; and dripping the light metal ion-doped CsPbBr3 precursor solution onto 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 CsPbBr3 quantum dot sacrificial layer. The present invention uses the CsPbBr3 quantum dot layer as a sacrificial layer for a SiC wafer, improves the luminescence performance of its quantum dots by light metal ion doping, and simultaneously enhances the interfacial bonding between the quantum dot layer and the SiC wafer.

Description

Technical Field

[0001] The present invention relates to the technical field of sacrificial layer materials, and in particular to a method for optimizing silicon carbide ion beam polishing based on light metal ion-doped quantum dots. Background Art

[0002] Silicon carbide (SiC), as an advanced material with outstanding performance, has been widely used in many fields due to its excellent mechanical strength, high-temperature stability, chemical inertness and wide-bandgap semiconductor properties. Especially in semiconductor and optoelectronic devices, SiC has become an important basic material for the next generation of electronic and optoelectronic technologies because it can maintain stable performance under high pressure, high temperature and extreme environments. However, it is precisely because of the high hardness and extremely strong chemical inertness of SiC materials that traditional chemical polishing processes are difficult to meet the requirements of high-precision processing. Existing SiC materials often have problems such as low processing efficiency, long processing time, and poor surface quality during the chemical polishing process, which can easily lead to surface microscopic defects, scratches or damage, thereby affecting the overall performance and reliability of the device. With the continuous improvement of the surface quality requirements of SiC materials, the limitations of traditional polishing technology in high-precision processing have become increasingly prominent.

[0003] Ion beam polishing utilizes the physical and chemical properties of a high-energy ion beam to remove and modify the microstructure of SiC surfaces, achieving highly precise surface processing. Unlike traditional mechanical polishing, ion beam polishing does not require direct contact with the material surface, thus avoiding damage caused by mechanical stress and improving polishing uniformity and surface finish. Furthermore, ion beam polishing exhibits exceptional uniformity when processing high-hardness materials, significantly improving surface finish and overall processing quality.

[0004] Although ion beam polishing technology has extremely high processing potential, there are still some technical challenges in practical application. A key issue is that during the polishing process, due to the different ion beam polishing rates, there are also differences in the material removal rate, which can easily lead to changes in the roughness of the SiC surface material layer. Different ion beam parameters (such as energy, angle, etc.) may lead to inconsistent removal rates of the surface atomic layer, thereby affecting the final flatness and smoothness of the surface. In some cases, excessive erosion or uneven action of the ion beam can also cause the formation of surface irregularities or microscopic defects, weakening the processing effect, and still needs further improvement. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for optimizing ion beam polishing of silicon carbide based on light metal ion doped quantum dots, so as to solve the above-mentioned problems in the background technology. The present invention selects CsPbBr3 quantum dot composite film as the sacrificial layer of SiC material, mainly because the unique advantages of the prepared CsPbBr3 quantum dot sacrificial layer in terms of size, fluorescence efficiency and coupling with the substrate have been discovered. The present invention first uses the quantum dot layer as the sacrificial layer of the SiC wafer, improves the luminescence performance of its quantum dots by doping with light metal ions, and at the same time enhances the interface bonding force between the quantum dot layer and the SiC wafer, thereby ensuring that it obtains a silicon carbide material with higher flatness and smoothness during ion beam polishing, while avoiding the problem of surface irregularities or microscopic defects caused by excessive erosion or uneven action of the ion beam on silicon carbide.

[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 in-situ growing a sacrificial layer of CsPbBr3 quantum dots on a SiC material surface, comprising the following steps:

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

[0009] (2) doping the CsPbBr3 precursor solution with light metal ions to obtain a light metal ion-doped CsPbBr3 precursor solution;

[0010] (3) adding the light metal ion-doped 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 CsPbBr3 quantum dot sacrificial layer.

[0011] 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.

[0012] Preferably, the solvent is polymethyl methacrylate and / or N,N-dimethylformamide.

[0013] Preferably, the type of light metal ion is Na + or K + ; The molar ratio of the lead source to the light metal ion is 64-6400:1.

[0014] Preferably, the temperature of the crystallization is 70-100° C. and the time is 1-2 minutes.

[0015] Preferably, the annealing temperature is 70-110° C., and the annealing time is 1-5 minutes.

[0016] The second technical solution of the present invention is to provide a SiC material prepared according to the above method and having an in-situ grown CsPbBr3 quantum dot sacrificial layer.

[0017] The third technical solution of the present invention is to provide a polishing method for the SiC material having the above-mentioned in-situ grown CsPbBr3 quantum dot sacrificial layer, comprising the following steps:

[0018] In an Ar gas atmosphere, the SiC material having the in-situ grown CsPbBr3 quantum dot sacrificial layer is subjected to pulsed ion beam polishing to obtain a polished SiC material.

[0019] Preferably, the parameters of the pulsed ion beam polishing are: ion beam power 110W, pulse frequency 100Hz, 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.

[0020] Under the pulsed ion beam polishing parameters defined in the present invention, a polishing rate of 0.17 μm / min can be achieved.

[0021] 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.

[0022] The technical principles of the present invention are as follows:

[0023] 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 wafer surface is impacted with a specific energy to remove the material at the atomic level. By adjusting the rate of the plasma beam, the thickness of the material removed can be precisely controlled during each pulse, making the material removal process more uniform. The pulsed ion beam frequency is selected to be 100Hz. When the pulse frequency is lower than 100Hz, the effect of the ions on the material surface is relatively mild, resulting in a longer processing time and a waste of manpower and material resources. When the pulse frequency is higher than 100Hz, the temperature of the material surface will rise faster, resulting in increased local melting and evaporation of the material, thereby causing heat loss on the material surface and increasing the surface roughness. Therefore, the optimized ion beam pulse setting can effectively reduce the impact on the SiC wafer surface, avoid introducing new surface damage, and achieve smooth removal of the sacrificial layer.

[0024] The purpose of the annealing treatment specified in this invention is to promote further crystallization and growth of the CsPbBr3 quantum dots. The annealed CsPbBr3 sacrificial layer can more firmly bond to the silicon carbide substrate. Unannealed products not only have a higher roughness, but also make the sacrificial layer more likely to detach from the substrate. Annealing effectively enhances the coupling strength between the quantum dot sacrificial layer and the substrate.

[0025] The beneficial technical effects of the present invention are as follows:

[0026] This paper proposes a method for optimizing SiC ion beam polishing using light metal ion-doped quantum dots. This method aims to address issues in existing ion beam polishing processes, particularly by improving the smoothness of the polished surface. Specifically, the quantum dot layer is first used as a sacrificial layer for the SiC wafer. Light metal ion doping improves the luminescence performance of the quantum dots, reduces surface defects and traps in the sacrificial layer, and strengthens the interfacial bonding between the quantum dot layer and the SiC wafer, improving subsequent polishing quality.

[0027] During the polishing phase, the present invention utilizes optimized pulsed ion beam technology to achieve efficient planarization of SiC wafers. Under the polishing parameters defined by the present invention, the etch rate of the prepared sacrificial layer approaches that of the SiC substrate material, thereby transferring a smooth surface covered with the sacrificial layer to the SiC substrate surface. Compared to conventional polishing methods, the present invention precisely controls the energy of the ion beam, enabling rapid removal of the sacrificial layer without introducing surface damage, improving the optical quality and mechanical strength of the wafer surface and achieving efficient and precise surface smoothing.

[0028] The present invention uses a CsPbBr3 quantum dot composite film as the sacrificial layer for the SiC material, primarily due to the unique advantages of the prepared CsPbBr3 quantum dot sacrificial layer in terms of size, fluorescence efficiency, and substrate coupling. To further enhance the fluorescent labeling effect of the CsPbBr3 quantum dots, the present invention employs a light metal ion doping strategy. By introducing light metal ions, the luminescence intensity and stability of the quantum dots are significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] 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.

[0030] Figure 1 Schematic diagram of the pulsed ion beam polishing process of Example 1-2.

[0031] Figure 2 Performance characterization of the SiC materials with in-situ CsPbBr3 quantum dot sacrificial layers grown in Examples 1-2 and Comparative Example 1. (a) compares the PL spectra of Example 1 and Comparative Example 1, (b) compares the PL spectra of Example 2 and Comparative Example 1. (c) shows the absorption spectra of Examples 1-2 and Comparative Example 1, and (d) shows the XRD patterns of Examples 1-2 and Comparative Example 1.

[0032] Figure 3 Surface morphology of the wafers of the polished SiC materials in S3 and Comparative Example 1. (a) is the SiC material after polishing in S3, and (b) is the Comparative Example 1.

[0033] Figure 4 This is the surface morphology of the wafer of the polished SiC material of Comparative Example 2.

[0034] Figure 5 This is the surface morphology of the wafer of the polished SiC material of Comparative Example 3.

[0035] Figure 6 This is the curve of ion beam removal thickness and wafer surface roughness change.

[0036] Figure 7 This is the polishing rate and wafer surface roughness change curve.

[0037] Figure 8 The wafer surface morphology before and after polishing. (a) shows the SiC material with an in-situ CsPbBr3 quantum dot sacrificial layer, and (b) shows the SiC material after polishing.

[0038] Figure 9 The wafer surface morphology of the product before and after polishing at a polishing rate of 0.22 μm / min. (a) shows the SiC material with an in-situ growth of a sacrificial layer of CsPbBr3 quantum dots, and (b) shows the SiC material after polishing.

[0039] Figure 10 The wafer surface morphology of the product before and after polishing at a polishing rate of 0.05 μm / min. (a) shows the SiC material with an in-situ growth of a sacrificial layer of CsPbBr3 quantum dots, and (b) shows the SiC material after polishing. DETAILED DESCRIPTION

[0040] 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.

[0041] 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.

[0042] 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.

[0043] The terms “include,” “including,” “have,” “contain,” etc. used in the present invention are open-ended terms, meaning including but not limited to.

[0044] The present invention discloses a method for in-situ growing a CsPbBr3 quantum dot sacrificial layer on a SiC material surface, comprising the following steps:

[0045] (1) mixing a lead source, a cesium source, and a solvent to obtain a CsPbBr3 precursor solution;

[0046] (2) doping the CsPbBr3 precursor solution with light metal ions to obtain a light metal ion-doped CsPbBr3 precursor solution;

[0047] (3) adding the light metal ion-doped 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 CsPbBr3 quantum dot sacrificial layer.

[0048] Preferably, the step (1) is specifically as follows:

[0049] 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.

[0050] 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.

[0051] 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 0.9-1.1, 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.

[0052] Preferably, the step (2) is specifically as follows:

[0053] In a nitrogen environment, weigh 0.102g NaBr (sodium bromide) powder or 0.119g KBr (potassium bromide) powder into a 40mL glass bottle, add 4-6mL DMF, place a magnet, place it on a heating plate, set the heating plate temperature to 50-80°C, adjust the magnetic stirring speed to 1000-1500rpm, stir overnight to obtain an ion-doped liquid; then mix the ion-doped liquid and the CsPbBr3 precursor solution in a volume ratio of 1:1-100 to obtain a light metal ion-doped CsPbBr3 precursor solution.

[0054] Preferably, the step (3) is specifically as follows:

[0055] After preheating the light metal ion-doped CsPbBr3 precursor solution to 70-100°C, it is dropped onto the cleaned SiC wafer substrate and spin-coated at a speed of 1000-2000 rpm for 20-40s using a coater. Then, it is placed on a heating plate at 70-100°C to promote in-situ nucleation and crystallization of CsPbBr3 quantum dots. Then, it is annealed at 70-110°C for 1-5 minutes to obtain a SiC material with an in-situ grown CsPbBr3 quantum dot sacrificial layer (light metal ion-doped CsPbBr3 quantum dot composite film).

[0056] Unless otherwise specified, "overnight" in the present invention is calculated as 12 hours.

[0057] The raw materials used in the following examples and comparative examples of the present invention are all commercially available products.

[0058] Example 1

[0059] A method for in-situ growth of a CsPbBr3 quantum dot sacrificial layer on a SiC material surface and a polishing method thereof, comprising the following steps:

[0060] (1) Preparation of CsPbBr3 precursor solution:

[0061] 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.

[0062] 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.

[0063] In a nitrogen environment glove box, CsBr / DMF solution and PMMA / DMF solution were mixed in a volume ratio of 3:40, and a magnetic stirrer was placed on a hot plate. The hot plate temperature was adjusted to 90°C, the magnetic stirring speed was adjusted to 1600 rpm, and stirring was carried out for 10 hours to obtain an intermediate solution; then PbBr2 / DMF solution was mixed with the intermediate solution (the molar ratio of Pb element in PbBr2 / DMF solution to Cs element in the intermediate solution was 0.9), and heating and stirring were continued at a temperature of 90°C and a speed of 1600 rpm for 10 hours to obtain a CsPbBr3 precursor solution.

[0064] (2) Preparation of light metal ion-doped CsPbBr3 precursor solution:

[0065] In a nitrogen glove box, 0.102 g of NaBr powder was weighed into a 40 mL glass bottle, 4 mL of DMF was added, and a magnet was placed. The bottle was placed on a heating plate, the heating plate temperature was set to 50 ° C, the magnetic stirring speed was adjusted to 1300 rpm, and the solution was stirred overnight to obtain a Na ion-doped solution. The Na ion-doped solution and the CsPbBr3 precursor solution were then mixed in volume ratios of 1:1, 1:2, 1:4, 1:10, 1:50, and 1:100, respectively, and ultrasonicated for 10 minutes to obtain CsPbBr3 precursor solutions doped with light metal ions with different doping ratios.

[0066] (3) Preparation of light metal ion-doped CsPbBr3 quantum dot composite films:

[0067] The above-mentioned light metal ion-doped CsPbBr3 precursor solution was preheated to 80°C and then dropped onto the cleaned SiC wafer substrate. It was spin-coated at 2000 rpm for 30 seconds using a coater, then placed on a heating plate at 100°C for 1 minute, and then annealed at 80°C for 3 minutes to obtain SiC materials with in-situ grown CsPbBr3 quantum dot sacrificial layers (light metal ion-doped CsPbBr3 quantum dot composite films) of different doping ratios.

[0068] (4) The SiC materials with in-situ grown CsPbBr3 quantum dot sacrificial layers of different doping ratios were polished, and the steps were 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 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 rate 0.17 μm / min. Set the polishing scan 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 a normal state to obtain a polished SiC material (the polished SiC material when the volume ratio of the Na ion doping solution to the CsPbBr3 precursor solution is 1:10 is recorded as S1).

[0075] Example 2

[0076] The only difference from Example 1 is that the preparation method of the light metal ion-doped CsPbBr3 precursor solution is modified as follows:

[0077] In a glove box under a nitrogen environment, 0.119 g of KBr powder was weighed into a 40 mL glass bottle, 4 mL of DMF was added, and a magnet was placed, placed on a heating plate, the heating plate temperature was set to 50°C, the speed of the magnetic stirring was adjusted to 1300 rpm, and stirred overnight to obtain a K ion-doped solution; then the K ion-doped solution and the CsPbBr3 precursor solution were mixed in volume ratios of 1:1, 1:2, 1:4, 1:10, 1:50, and 1:100, respectively, and ultrasonicated for 10 minutes to obtain CsPbBr3 precursor solutions doped with light metal ions with different doping ratios (the polished SiC material when the volume ratio of the final K ion-doped solution to the CsPbBr3 precursor solution was 1:50 was recorded as S2, and the SiC material with an in-situ grown CsPbBr3 quantum dot sacrificial layer when the volume ratio of the final K ion-doped solution to the CsPbBr3 precursor solution was 1:100 was recorded as S3).

[0078] Figure 1 Schematic diagram of the pulsed ion beam polishing process of Example 1-2.

[0079] Comparative Example 1

[0080] The only difference from Example 1 is that step (2) is omitted, and the CsPbBr3 precursor solution in step (1) is directly preheated and subsequently treated.

[0081] Comparative Example 2

[0082] The only difference from S3 is that the pulse frequency is changed to 150Hz.

[0083] Comparative Example 3

[0084] The only difference from S3 is that the annealing operation at 80° C. for 3 min is omitted.

[0085] Effect verification

[0086] 1. The photoluminescence performance of the SiC material with in-situ growth of CsPbBr3 quantum dot sacrificial layer in Examples 1-2 and Comparative Example 1 was characterized. The test results are as follows: Figure 2 shown.

[0087] Figure 2 Performance characterization of the SiC materials with in-situ CsPbBr3 quantum dot sacrificial layers grown in Examples 1-2 and Comparative Example 1. (a) compares the PL spectra of Example 1 and Comparative Example 1, (b) compares the PL spectra of Example 2 and Comparative Example 1. (c) shows the absorption spectra of Examples 1-2 and Comparative Example 1, and (d) shows the XRD patterns of Examples 1-2 and Comparative Example 1.

[0088] Figure 2 In (a) and (b), the curve labeled 0 represents comparative example 1, and the curves labeled 1:1, 1:2, 1:4, 1:10, 1:50, and 1:100 respectively represent the SiC materials with in-situ grown CsPbBr3 quantum dot sacrificial layers obtained at the corresponding ion doping liquid concentrations in the corresponding embodiments.

[0089] Figure 2 In (c) and (d), Na doped represents the material data when the volume ratio of Na ion doping solution and CsPbBr3 precursor solution is 1:10, K doped represents the material data when the volume ratio of K ion doping solution and CsPbBr3 precursor solution is 1:50, and W / O and no doped represent the product data of Comparative Example 1.

[0090] Depend on Figure 2 It can be seen that the photoluminescence spectrum (PL) peak of the material is at 519nm. As the concentration of light metal ions increases, the PL of the CsPbBr3 quantum dots in the material will have a slight red shift, indicating a decrease in the band gap. In Example 1, when Na +When the doping ratio is 1:10, the PL peak of CsPbBr3 quantum dots is the highest, which is 2.9 times higher than that of the undoped sample (Comparative Example 1). + When the ion doping ratio is 1:50, the PL peak of CsPbBr3 quantum dots is the highest, which is 2.5 times higher than that of the undoped sample. Therefore, light metal doping has an improving effect on the luminescence intensity of CsPbBr3 quantum dots. This may be because the doping of light metal ions can effectively passivate the defects and traps on the surface of the CsPbBr3 quantum dot film, thereby reducing the defects and traps on the surface of the film. However, when the doping ratio of light metal monovalent cations increases, it will cause fluorescence quenching of CsPbBr3 quantum dots; when the doping concentration is 1:1, the fluorescence effect of CsPbBr3 quantum dots is completely quenched. This may be because the increase in the doping ion concentration will lead to an increase in non-radiative recombination centers in CsPbBr3 quantum dots or the generation of deep energy level defects, thereby reducing the luminescence brightness of CsPbBr3 quantum dots. By Figure 2 From (c) in the figure, we can see that the doping of light metal ions has no significant effect on the absorption spectrum, and the absorption band is at 525nm. Figure 2 As shown in (d), the main crystal planes (100), (110), (200), (210), (220), and (300) of CsPbBr3 quantum dots were detected in all materials, proving that light metal doping did not change the crystal structure of CsPbBr3 quantum dots. + The XRD characteristic peaks of doped CsPbBr3 are sharper, indicating that it has higher crystallinity after doping.

[0091] 2. 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 Examples 1-2 and Comparative Example 1 to evaluate the polishing effect. The characterization method is as follows:

[0092] (1) Clean the polished SiC material surface to prevent oil, fingerprints or other contaminants from affecting the measurement results.

[0093] (2) A Zygo NewView 700s white light interferometer was used to perform micrometer-scale medium and high frequency detection on the wafer surface. A magnification of 50 times was selected, the detection range was 468μm×351μm, and the maximum resolution was 1024×1024 pixels.

[0094] (3) Place the SiC wafer on the interferometer measurement table and adjust the optical focal length until the workpiece surface is clearly visible.

[0095] (4) Randomly test two points on the SiC wafer, calculate the surface roughness parameters and reconstruct the three-dimensional surface shape.

[0096] By controlling the ion beam pulse frequency, the thickness of the sacrificial layer removed by the ion beam in S3 is controlled (0-300nm), and the corresponding wafer surface roughness is calculated. The test results are as follows Figure 6 shown.

[0097] By controlling the polishing rate, the effect on the surface roughness of the wafer is statistically analyzed. The test results are as follows: Figure 7 shown.

[0098] Figure 6 The thickness of the sacrificial layer removed by ion beam is correlated with the surface roughness of the wafer, and the surface topography of the wafer is shown. (a) is the surface roughness curve, and (b) and (c) are the surface topography images of the wafer at different removal thicknesses.

[0099] Figure 7 This is the polishing rate and wafer surface roughness change curve of S3.

[0100] Figure 8 Figure 3 shows the surface morphology of the wafer S3 before and after polishing. (a) shows S3, and (b) shows the SiC material after polishing.

[0101] The polishing rate of S3 is controlled by controlling the ion beam power (at 200W, the polishing rate is 0.22μm / min; at 50W, the polishing rate is 0.05μm / min), and the corresponding wafer surface roughness is calculated. The test results are as follows: Figure 9-10 shown.

[0102] Figure 9 The wafer surface morphology of the product of S3 at a polishing rate of 0.22 μm / min before and after polishing.

[0103] Among them, (a) is S3, and (b) is the polished SiC material.

[0104] Figure 10 The wafer surface morphology of the product of S3 at a polishing rate of 0.05μm / min before and after polishing. Among them, (a) is S3, and (b) is the SiC material after polishing.

[0105] Figure 6 The roughness variation of the wafer surface at different removal thicknesses is shown. The surface roughness variation is divided into two parts. In the first part, the roughness increases rapidly because the ion beam deposits more energy at the indentation when removing the sacrificial material layer. In the second part, as the ion beam polishing thickness increases, the indentation depth gradually decreases, and the roughness decreases. Therefore, the thickness of the sacrificial material layer cannot be too thin, otherwise it will lead to incomplete defect filling, which will increase the surface roughness. Excessively thick sacrificial material layers will increase polishing time and waste financial and material resources. By optimizing the thickness of the quantum dot sacrificial layer, the thickness was determined to be 200nm.

[0106] Depend on Figure 7 It can be seen that at a polishing rate of 0.17 μm / min, the wafer roughness is the lowest, which is 1.568 nm ( Figure 8 ), the roughness of the SiC wafer is effectively reduced by nearly half compared to before polishing. When the polishing rate is greater than 0.17μm / min (0.22μm / min), the ion beam bombards the wafer surface unevenly, and the surface defects of the wafer are not effectively removed, and the roughness increases ( Figure 9 When the polishing rate is less than 0.17μm / min (0.05μm / min), the material removal rate will be significantly reduced ( Figure 10 ), resulting in the entire polishing process taking longer, which is particularly disadvantageous in mass production and will increase production cycle and operating costs; long-term slow processing will also cause the surface temperature to gradually increase. Although the energy input of the pulsed ion beam itself is low, continuous processing may still cause temperature accumulation and cause thermal stress, thereby affecting the temperature flatness of the surface and increasing its surface roughness.

[0107] Figure 3 Surface morphology of the wafers of the polished SiC materials in S3 and Comparative Example 1. (a) is the SiC material after polishing in S3, and (b) is the Comparative Example 1.

[0108] like Figure 3 As shown, the surface roughness of the silicon carbide coated with a sacrificial layer doped with light metal ions after polishing is 1.568nm (S3), and the surface roughness of the silicon carbide coated with a sacrificial layer not doped with light metal ions after polishing is 2.947nm (Comparative Example 1), and the surface roughness is increased by nearly 2 times.

[0109] Figure 4 This is the surface morphology of the wafer of the polished SiC material of Comparative Example 2.

[0110] like Figure 4 As shown, Figure 3 As shown, the roughness of the product of Comparative Example 2 is 9.649 nm, which is 9 times higher than that of the product (S3) prepared at 100 Hz.

[0111] Figure 5 This is the surface morphology of the wafer of the polished SiC material of Comparative Example 3.

[0112] like Figure 5 As shown, the product without annealing treatment (Comparative Example 3) has a higher roughness, which is increased by about 2700%.

[0113] 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 an in-situ grown CsPbBr3 quantum dot sacrificial layer, characterized in that: The following steps are involved: In an Ar gas atmosphere, a SiC material having an in-situ grown sacrificial layer of CsPbBr3 quantum dots is subjected to pulsed ion beam polishing to obtain a polished SiC material; The parameters of the pulsed ion beam polishing are: ion beam power 110 W, pulse frequency 100 Hz, 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 having an in-situ grown CsPbBr3 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) doping the CsPbBr3 precursor solution with light metal ions to obtain a light metal ion-doped CsPbBr3 precursor solution; (3) adding the light metal ion-doped 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 CsPbBr3 quantum dot sacrificial layer; The lead source is PbBr2; the cesium source is CsBr; the molar ratio of the lead source to the cesium source is 0.9-1.1; The type of light metal ion is Na + or K + ; The molar ratio of the lead source to the light metal ion is 64-6400:1; The thickness of the CsPbBr3 quantum dot sacrificial layer is 200 nm.

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 70-110° C. and the annealing time is 1-5 minutes.

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