High-quality graphene manufacturing method and Hall sensor manufactured by using same
By growing graphene crystal arrays on copper foil and transferring them to a silicon substrate, and removing polymer residues combined with acetone, isopropanol, gel remover and deionized water, the problem of polymer residue affecting quality in graphene preparation is solved, and the quality of graphene and the sensitivity of Hall sensors are significantly improved.
Patent Information
- Application Number
- CN202311759771.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-19
- Publication Date
- 2025-06-20
AI Technical Summary
During the graphene preparation process, polymer residues affect the quality of graphene, resulting in poor quality of the graphene, which in turn affects the sensitivity of the Hall sensor.
The graphene crystal array was grown on copper foil using chemical vapor deposition technology and transferred to the silicon substrate by electrochemical peeling. Then, the micro and nanoscale polymer residues were removed by a cleaning process of acetone, isopropanol, gel decoction agent and deionized water, followed by Raman spectroscopy to evaluate the number of layers, crystallinity and doping amount of graphene.
The cleaning process effectively removes polymer residues, reduces its impact on the next process, avoids the multi-layered areas and potential grain boundaries near the crystal nucleation point, significantly improving the quality of graphene, thereby improving the sensitivity of Hall sensors.
Smart Images
Figure CN120176736A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of semiconductor devices, and particularly to a method for manufacturing high-quality graphene and a Hall sensor manufactured by using the method. Background Art
[0002] Graphene has high carrier mobility and mechanical strength, which has attracted extensive attention from researchers all over the world. The preparation of graphene films, especially on metal substrates, has made great progress in recent years. However, in order to facilitate the application of graphene in electronic devices, bypassing the transfer process and directly synthesizing high-quality graphene films on dielectric substrates has become an important trend.
[0003] Currently, the preparation of graphene on non-metallic substrates has also been widely studied. For example, there are already mature processes for preparing graphene on the surfaces of silicon carbide, hexagonal boron nitride, silicon dioxide, and sapphire substrates. During the process of preparing graphene on the substrate, polymer residues will be generated in multiple processes. If the polymer residues from the previous process cannot be effectively removed, it will affect the output effect of the next process. After the superposition of multiple processes, the quality of the finally prepared graphene is poor. Such low-quality graphene has a great impact on the sensitivity of the Hall sensor when applied to the Hall sensor. Summary of the Invention
[0004] One of the purposes of the present invention is to provide a method for manufacturing high-quality graphene, aiming to solve the problem that polymer residues affect the quality of the prepared graphene.
[0005] The present invention provides a method for manufacturing high-quality graphene, including the following steps:
[0006] Step 1: Graphene crystal arrays are grown on copper foil by chemical vapor deposition;
[0007] Step 2: Electrochemically strip the graphene crystal arrays from the copper foil and transfer them to a silicon substrate;
[0008] Step 3: Perform a cleaning process on the silicon substrate with attached graphene crystals: first soak in acetone to remove micron-sized polymer residues, take it out and rinse with isopropanol to remove acetone residues, then use a degreaser to remove nano-sized polymer residues, and finally rinse with deionized water;
[0009] Step 4: Fabricate Hall electrodes on the graphene crystals and the silicon substrate;
[0010] Step 5: Perform the above cleaning process on the silicon substrate with attached graphene crystals and Hall electrodes;
[0011] Step 6: Perform Raman spectroscopy analysis on the graphene crystals near the Hall electrodes;
[0012] Step 7: Spin-coat and cure polymethyl methacrylate on the silicon substrate, graphene, and Hall electrodes;
[0013] Step 8: Perform the cleaning process on the silicon substrate with graphene crystals, Hall electrodes, and polymethyl methacrylate attached;
[0014] Step 9: Conduct Raman spectroscopy analysis on the graphene crystals deposited with polymethyl methacrylate;
[0015] Step 10: Evaluate the number of layers, crystallinity, and doping amount of the graphene crystals before and after the deposition of polymethyl methacrylate based on the comparison of the results of two Raman spectroscopy analyses. If the evaluation results reach the expected level, the manufacturing of graphene is completed. If the results do not reach the expected level, restart from Step 2.
[0016] Optionally, the acetone cleaning time is at least 2 hours.
[0017] Optionally, the treatment time with the degreaser is 3 - 5 minutes.
[0018] Optionally, the degreaser is AR 600 - 71.
[0019] Optionally, in Step 1, the growth conditions of the graphene crystals are: at 1000°C - 1100°C; in a mixed atmosphere of argon, hydrogen, and methane.
[0020] Optionally, the volume flow rate of argon is 800 - 1100 sccm, the volume flow rate of hydrogen is 80 - 110 sccm, and the volume flow rate of methane is 1 - 3 sccm.
[0021] Optionally, the graphene crystals are hexagonal.
[0022] Optionally, the lateral size of the graphene crystals is 145 - 150 microns.
[0023] Optionally, the silicon substrate includes silicon and silicon dioxide.
[0024] The technical effects achieved by the present invention using the above technical solutions:
[0025] After sequential cleaning with acetone, isopropyl alcohol, degreaser, and deionized water, nano-scale polymer residues and micro-scale polymer residues can be removed, and the influence of polymer residues from the previous process on the next process during the preparation of graphene can be significantly reduced. Especially after the graphene crystals are transferred to the silicon substrate and cleaned, small multi-layer regions near the crystal nucleation points and potential grain boundaries caused by the merger of adjacent crystals can be avoided. This effect is particularly important for obtaining high-quality graphene.
[0026] A second object of the present invention is to provide a Hall sensor manufactured by using the above high-quality graphene manufacturing method, aiming to improve the sensitivity of the Hall sensor. BRIEF DESCRIPTION OF THE DRAWINGS
[0027] Figure 1 It is a flowchart of the high-quality graphene manufacturing method in the embodiment. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0028] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.
[0029] It should be noted that in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations.
[0030] Embodiment 1
[0031] The embodiment of the present application provides a high-quality graphene manufacturing method. Referring to Figure 1 , the specific steps are as follows:
[0032] Step 1: A hexagonal graphene crystal array is grown on a copper foil by chemical vapor deposition technology; the growth conditions of the graphene crystal: using argon nucleation seeds to generate single crystals around each nucleation point, and the lateral size of the single crystal (the distance between a pair of parallel sides of the hexagon) is 150 microns; at a temperature of 1050 °C, in a mixed atmosphere of argon (900 sccm), hydrogen (100 sccm) and methane (1 sccm), growth is carried out in a chemical vapor deposition device.
[0033] Step 2: Select a silicon substrate containing silicon and / or silicon dioxide as the target substrate, make marks on the target substrate, electrochemically strip the graphene crystal array from the copper foil, and transfer it to the silicon substrate by aligning with the marks.
[0034] Step 3: Perform a cleaning process on the silicon substrate with attached graphene crystals: soak in acetone for at least 2 hours to remove micron-level polymer residues; after taking out, rinse with isopropyl alcohol, and use the property of mutual solubility of isopropyl alcohol and acetone to remove acetone; then treat with a degreaser for 3 minutes to remove nano-level polymer residues, and the degreaser is preferably AR 600-71; finally, rinse with deionized water.
[0035] Step 4: Use electron beam lithography technology and reactive ion etching technology to fabricate Hall electrodes on the graphene crystal and the silicon substrate.
[0036] Step 5: Perform the above cleaning process on the silicon substrate with the attached graphene crystal and Hall electrodes.
[0037] Step 6: Use the 530nm laser and 100x objective lens of the Renishaw laser Raman spectrometer to perform Raman spectroscopy analysis on the graphene crystal near the Hall electrode. The laser power is set to 1 megawatt to avoid overheating.
[0038] Step 7: Spin-coat and cure polymethyl methacrylate on the silicon substrate, graphene, and Hall electrodes. Polymethyl methacrylate is used for lithography and encapsulation. For the lithography step, polymethyl methacrylate is baked on a hot plate at 120°C for 5 minutes, while for encapsulation, the baking temperature and time are increased to 160°C and 15 minutes respectively to ensure complete evaporation of the solvent. The thickness of the polymethyl methacrylate layer is measured using a Bruker probe surface profiler.
[0039] Step 12: Perform the above cleaning process on the silicon substrate with the attached graphene crystal, Hall electrodes, and polymethyl methacrylate.
[0040] Step 15: Perform Raman spectroscopy analysis on the graphene crystal deposited with polymethyl methacrylate.
[0041] Step 18: According to the comparison of the results of the two Raman spectroscopy analyses in Step 6 and Step 9, evaluate the number of graphene crystal layers, crystallinity, and doping amount before and after the deposition of polymethyl methacrylate; if the evaluation results reach the expected level, the manufacturing of graphene is completed, and if the evaluation results do not reach the expected level, restart from Step 2 to remanufacture graphene.
[0042] Example 2
[0043] The embodiment of the present application provides a method for manufacturing high-quality graphene, referring to Figure 1 , and the specific steps are as follows:
[0044] Step 1: A hexagonal graphene crystal array is grown on a copper foil by chemical vapor deposition technology; the growth conditions of the graphene crystal: use argon nucleation seeds to generate single crystals around each nucleation point, and the lateral size of the single crystal (the distance between a pair of parallel sides of the hexagon) is 145 micrometers; at a temperature of 1100°C, in a mixed atmosphere of argon (800 sccm), hydrogen (80 sccm), and methane (3 sccm), growth is carried out in a chemical vapor deposition device.
[0045] Step 2: Select a silicon substrate containing silicon and / or silicon dioxide as the target substrate, make marks on the target substrate, electrochemically exfoliate the graphene crystal array from the copper foil, and transfer it to the silicon substrate by aligning with the marks.
[0046] Step 3: Perform a cleaning process on the silicon substrate with attached graphene crystals: soak it in acetone for at least 2 hours to remove micron-scale polymer residues; after taking it out, rinse it with isopropanol, and utilize the property of isopropanol and acetone being miscible to remove acetone; then treat it with a degumming agent for 5 minutes to remove nano-scale polymer residues, and the degumming agent is preferably AR 600-71; finally, rinse it with deionized water.
[0047] Step 4: Fabricate Hall electrodes on the graphene crystals and the silicon substrate using electron beam lithography technology and reactive ion etching technology.
[0048] Step 5: Perform the above cleaning process on the silicon substrate with attached graphene crystals and Hall electrodes.
[0049] Step 6: Use the 530nm laser and 100x objective lens of the Renishaw laser Raman spectrometer to perform Raman spectroscopy analysis on the graphene crystals near the Hall electrodes. The laser power is set to 1 megawatt to avoid overheating.
[0050] Step 7: Spin-coat and cure polymethyl methacrylate on the silicon substrate, graphene, and Hall electrodes. Polymethyl methacrylate is used for lithography and encapsulation. For the lithography step, polymethyl methacrylate is baked on a hot plate at 120°C for 5 minutes, while for encapsulation, the baking temperature and time are increased to 160°C and 15 minutes respectively to ensure complete evaporation of the solvent. The thickness of the polymethyl methacrylate layer is measured using a Bruker probe-type surface profiler.
[0051] Step 8: Perform the above cleaning process on the silicon substrate with attached graphene crystals, Hall electrodes, and polymethyl methacrylate.
[0052] Step 9: Perform Raman spectroscopy analysis on the graphene crystals deposited with polymethyl methacrylate.
[0053] Step 10: According to the comparison of the results of the two Raman spectroscopy analyses in Step 6 and Step 9, evaluate the number of graphene crystal layers, crystallinity, and doping amount before and after the deposition of polymethyl methacrylate; if the evaluation results reach the expected level, the manufacturing of graphene is completed, and if the evaluation results do not reach the expected level, start from Step 2 to remanufacture graphene.
[0054] Example 3
[0055] The embodiment of the present application provides a method for manufacturing high-quality graphene. Referring to Figure 1 , the specific steps are as follows:
[0056] Step 1: A hexagonal graphene crystal array is grown on a copper foil by chemical vapor deposition. Growth conditions of the graphene crystals: Argon nucleation seeds are used to generate single crystals around each nucleation point. The lateral size of the single crystal (the distance between a pair of parallel sides of the hexagon) is 150 microns. Growth is carried out in a chemical vapor deposition apparatus at a temperature of 1000 °C in a mixed atmosphere of argon (1100 sccm), hydrogen (110 sccm), and methane (2 sccm).
[0057] Step 2: A silicon substrate containing silicon and / or silicon dioxide is selected as the target substrate. Marks are made on the target substrate. The graphene crystal array is electrochemically peeled off from the copper foil and transferred to the silicon substrate while aligning with the marks.
[0058] Step 3: The silicon substrate with the attached graphene crystals is subjected to a cleaning process: Soak in acetone for at least 2 hours to remove micron-scale polymer residues; after taking out, rinse with isopropyl alcohol, and utilize the property of mutual solubility of isopropyl alcohol and acetone to remove acetone; then treat with a degreaser for 3 minutes to remove nano-scale polymer residues. The degreaser is preferably AR 600-71; finally, rinse with deionized water.
[0059] Step 4: Hall electrodes are fabricated on the graphene crystals and the silicon substrate using electron beam lithography and reactive ion etching techniques.
[0060] Step 5: The silicon substrate with the attached graphene crystals and Hall electrodes is subjected to the above cleaning process.
[0061] Step 6: Raman spectroscopy analysis is performed on the graphene crystals near the Hall electrodes using a 530 nm laser and a 100x objective lens of a Renishaw laser Raman spectrometer. The laser power is set to 1 megawatt to avoid overheating.
[0062] Step 7: Poly(methyl methacrylate) is spin-coated and cured on the silicon substrate, graphene, and Hall electrodes. Poly(methyl methacrylate) is used for lithography and encapsulation. For the lithography step, poly(methyl methacrylate) is baked on a hot plate at 120 °C for 5 minutes, while for encapsulation, the baking temperature and time are increased to 160 °C and 15 minutes respectively to ensure complete evaporation of the solvent. The thickness of the poly(methyl methacrylate) layer is measured using a Bruker probe-type surface profiler.
[0063] Step 8: The silicon substrate with the attached graphene crystals, Hall electrodes, and poly(methyl methacrylate) is subjected to the above cleaning process.
[0064] Step 9: Raman spectroscopy analysis is performed on the graphene crystals deposited with poly(methyl methacrylate).
[0065] Step Ten: Evaluate the number of graphene crystal layers, crystallinity, and doping amount before and after poly(methyl methacrylate) deposition based on the comparison of the two Raman spectroscopy analysis results in Step Six and Step Nine; if the evaluation results reach the expected level, the manufacturing of graphene is completed; if the evaluation results do not reach the expected level, restart from Step Two to remanufacture graphene.
[0066] As described in Comprehensive Examples 1, 2, and 3, the high-quality graphene manufacturing method provided by the embodiments of the present application can remove nanoscale polymer residues and microscale polymer residues after sequential cleaning with acetone, isopropyl alcohol, a degumming agent, and deionized water, and can greatly reduce the influence of polymer residues in the previous process on the next process during the preparation of graphene. In particular, after the graphene crystal is transferred to the silicon substrate and cleaned, small multi-layer regions near the crystal nucleation points and potential grain boundaries caused by the merger of adjacent crystals can be avoided. This effect is particularly important for obtaining high-quality graphene. The embodiments of the present application also provide a Hall sensor prepared by applying the above high-quality graphene manufacturing method, which has the effect of improving the sensitivity of the Hall sensor.
[0067] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.
Claims
1. A method for manufacturing high-quality graphene, characterized in that, It includes the following steps: Step 1, grow a graphene crystal array on a copper foil by chemical vapor deposition; Step 2, electrochemically exfoliate the graphene crystal array from the copper foil and transfer it to a silicon substrate; Step 3, perform a cleaning process on the silicon substrate with attached graphene crystals: first soak it in acetone to remove micron-scale polymer residues, take it out and rinse with isopropyl alcohol to remove acetone residues, then use a degreaser to remove nano-scale polymer residues, and finally rinse with deionized water; Step 4, fabricate Hall electrodes on the graphene crystals and the silicon substrate; Step 5, perform the said cleaning process on the silicon substrate with attached graphene crystals and Hall electrodes; Step 6, perform Raman spectroscopy analysis on the graphene crystals near the Hall electrodes; Step 7, spin-coat and cure polymethyl methacrylate on the silicon substrate, graphene, and Hall electrodes; Step 8, perform the said cleaning process on the silicon substrate with attached graphene crystals, Hall electrodes, and polymethyl methacrylate; Step 9, perform Raman spectroscopy analysis on the graphene crystals deposited with polymethyl methacrylate; Step 10, evaluate the number of graphene crystal layers, crystallinity, and doping amount before and after the deposition of polymethyl methacrylate according to the comparison of the two Raman spectroscopy analysis results. If the evaluation result reaches the expected level, the manufacturing of graphene is completed. If the evaluation result does not reach the expected level, restart from Step 2.
2. The method for manufacturing high-quality graphene according to claim 1, characterized in that, The acetone cleaning time is at least 2 hours.
3. The method for manufacturing high-quality graphene according to claim 1, characterized in that, The degreaser treatment time is 3 - 5 minutes.
4. The method for manufacturing high-quality graphene according to claim 1, characterized in that, The degreaser is AR 600 - 71.
5. The method for manufacturing high-quality graphene according to claim 1, characterized in that, In Step 1, the growth conditions of the graphene crystals are: at 1000°C - 1100°C; in a mixed atmosphere of argon, hydrogen, and methane.
6. The method for manufacturing high-quality graphene according to claim 5, characterized in that, The volume flow rate of the argon is 800 - 1100 sccm, the volume flow rate of the hydrogen is 80 - 110 sccm, and the volume flow rate of the methane is 1 - 3 sccm.
7. The method for manufacturing high-quality graphene according to claim 1, characterized in that, The graphene crystals are hexagonal.
8. The method for manufacturing high-quality graphene according to claim 1, characterized in that, The lateral size of the graphene crystals is 145 - 150 microns.
9. The method for manufacturing high-quality graphene according to claim 1, characterized in that, The silicon substrate includes silicon and silicon dioxide.
10. A Hall sensor, characterized in that, Prepared by using the high-quality graphene manufacturing method described in any one of claims 1 to 9.