Method for preparing low-dielectric-loss monocrystal diamond based on periodic defects

Abstract

The invention discloses a periodic defect-based low-dielectric-loss monocrystal diamond preparation method, which belongs to the field of semiconductors, and comprises the following steps: providing a diamond substrate; the diamond substrate is subjected to photoetching treatment, so that a dot matrix pattern is formed on the upper surface of the diamond substrate through photoetching, and the distance between every two adjacent dots in the dot matrix pattern is equal to the wavelength corresponding to the frequency of the external electric field; an etching process or an ion implantation process is adopted, the area where each point in the dot matrix pattern is located is damaged, a diamond damaged substrate is obtained, and the upper surface of the diamond damaged substrate is provided with a periodic defect dot matrix structure; growing a single crystal diamond layer with periodic defects on the upper surface of the diamond damaged substrate, and adjusting a growth process to enable the defects on the single crystal diamond layer to be line defects penetrating through the single crystal diamond layer; and carrying out fragmentation treatment on the damaged diamond substrate and the monocrystal diamond layer to obtain a monocrystal diamond finished product with periodic defects.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor technology, specifically relating to a method for preparing low dielectric loss single-crystal diamond based on periodic defects. Background Technology

[0002] Diamond is a wide-bandgap semiconductor material with excellent dielectric properties, which originate from its unique spline properties. 3 Hybrid cubic crystal structures have irreplaceable advantages in extreme electronic device scenarios such as high frequency, high voltage, and high temperature.

[0003] Diamond has a dielectric loss (tanδ) as low as 10 Ω·cm in the 1–100 GHz and even terahertz frequency bands. -4 ~10 -5 It has a dielectric constant (εr≈5.5) that is almost constant with frequency, and also possesses excellent thermal conductivity (thermal conductivity ~2000W / (m²)). Diamond (K) is an ideal dielectric substrate for high-frequency communication systems. Its low-loss characteristics make it suitable for 5G / 6G high-frequency substrates and terahertz devices; its high breakdown field strength supports high-voltage power devices and pulse energy storage media; its wide-temperature stability meets the requirements of extreme environments in aerospace and nuclear industries; and it can also serve as a quantum bit isolation layer to ensure the accuracy of quantum computing, making it a key dielectric material in the field of special electronics. However, due to limitations in growth and processing techniques, it is difficult to achieve the theoretical dielectric properties of single-crystal diamond, and its dielectric loss increases rapidly above the terahertz frequency band.

[0004] Due to the strong covalent bonds between carbon atoms, the contributions of electronic polarization, ionic polarization, and electric dipole polarization to dielectric loss in single-crystal diamond are negligible. The dielectric loss of existing single-crystal diamond is mainly constrained by two key factors, becoming the core bottleneck limiting its large-scale application in high-end electronic devices. The first is space charge polarization loss, which specifically includes interface polarization loss and defect polarization loss. Charge accumulation at the interface and charge relaxation caused by lattice defects significantly increase dielectric loss. The second is phonon polarization loss. Even with a dense diamond lattice structure and high bonding strength, the vibration of lattice atoms under an external electric field can still induce phonon polarization, thus adversely affecting the dielectric loss of single-crystal diamond. While space charge polarization loss can be significantly reduced by optimizing the diamond growth process and improving the quality of the diamond material, phonon polarization loss is related to the external electric field and is difficult to optimize by improving the quality of the diamond material.

[0005] Therefore, how to effectively suppress the phonon polarization loss of diamond, achieve precise control of the dielectric loss of single-crystal diamond, and reduce the dielectric loss of diamond in the terahertz and above frequency bands are key technical problems that urgently need to be solved in this field. Summary of the Invention

[0006] To address the aforementioned problems in the prior art, this invention provides a method for preparing low-dielectric-loss single-crystal diamond based on periodic defects. The technical problem to be solved by this invention is achieved through the following technical solution: This invention provides a method for preparing low-dielectric-loss single-crystal diamond based on periodic defects, comprising: Step 1: Provide a diamond substrate; Step 2: Perform photolithography on the diamond substrate to form a dot matrix pattern on the upper surface of the diamond substrate. The diamond substrate is surrounded by an external electric field, and the distance between two adjacent dots in the dot matrix pattern is equal to the wavelength corresponding to the frequency of the external electric field. Step 3: Using etching or ion implantation, damage treatment is performed on the area where each dot in the dot pattern is located to obtain a diamond damaged substrate. The upper surface of the diamond damaged substrate has a periodic defect dot structure. Step 4: Grow a single-crystal diamond layer with periodic defects on the upper surface of the diamond-damaged substrate. By adjusting the growth process, the defects on the single-crystal diamond layer are made to be line defects that penetrate the single-crystal diamond layer. Step 5: The diamond damaged substrate and the single-crystal diamond layer are sliced ​​to obtain a single-crystal diamond product with periodic defects.

[0007] In one embodiment of the present invention, step four specifically includes: The diamond-damaged substrate is placed on a molybdenum metal support and then placed into the chamber of the MPCVD equipment; Reduce the air pressure inside the chamber of the MPCVD equipment to ensure that the air pressure inside the chamber does not exceed 0.001 mbar; H2 is introduced into the MPCVD equipment at a flow rate of 100 sccm to 800 sccm; When the air pressure in the chamber reaches 15 Torr~20 Torr, turn on the microwave source to raise the air pressure in the chamber to 120 Torr~200 Torr. The power of the microwave source is 3000W~5000W, and the temperature of the diamond-damaged substrate surface is 800℃~1000℃. CH4, N2, O2 and Ar are introduced into the MPCVD equipment to begin the growth process of a single-crystal diamond layer with periodic defects.

[0008] In one embodiment of the present invention, when CH4, N2, O2 and Ar are introduced into the MPCVD equipment, the flow rate of CH4 is 8 sccm to 40 sccm, the flow rate of N2 is 0.001 sccm to 0.05 sccm, the flow rate of O2 is 0 sccm to 5 sccm, and the flow rate of Ar is 0.2 sccm to 2 sccm. When starting the growth process of a single-crystal diamond layer with periodic defects, maintain the growth rate at 4-20 μm / h and grow for 50-200 h to ensure that the thickness of the single-crystal diamond layer is ≥700 μm.

[0009] In one embodiment of the present invention, after the single crystal diamond layer is grown, the flow of CH4, N2, O2 and Ar is stopped, and the cavity pressure and power are gradually reduced. Pump the air pressure inside the cavity to 20 Torr, and after the temperature inside the cavity stabilizes, turn off the microwave source. Stop the H2 supply, pump the air pressure in the chamber down to 0.001 mbar, and turn off the pump; Air is introduced into the cavity to break the vacuum, and the grown diamond damage substrate and single-crystal diamond layer are removed from the cavity.

[0010] In one embodiment of the present invention, step five specifically includes: Laser cutting is used to slice the diamond damaged substrate and the single-crystal diamond layer to obtain a single-crystal diamond product with periodic defects.

[0011] In one embodiment of the present invention, after the step of slicing the diamond-damaged substrate and the single-crystal diamond layer using a laser cutting process, the method further includes: The cut surface of the sliced ​​single-crystal diamond layer is placed upwards in an MPCVD device and etched for 10 to 20 minutes at a temperature of 200℃ to 400℃ in a hydrogen plasma atmosphere to remove the amorphous carbon and graphite phases caused by the laser on the cut surface of the single-crystal diamond layer.

[0012] In one embodiment of the present invention, step one specifically includes: A diamond substrate is provided, and the diamond substrate is cleaned using acetone, ethanol and alcohol. The roughness Ra of the diamond substrate is ≤5nm and the thickness is 1mm~7mm.

[0013] In one embodiment of the present invention, step three specifically includes: The area containing each dot in the dot matrix pattern is damaged by etching or ion implantation. After the damage treatment is completed, the diamond substrate is cleaned with acetone to remove the photoresist on the surface of the diamond substrate, thus obtaining a damaged diamond substrate.

[0014] In one embodiment of the present invention, the distance between two adjacent dots in the dot matrix pattern is 3μm to 30000μm.

[0015] In one embodiment of the present invention, when the region containing each dot in the dot matrix pattern is damaged by ion implantation, the implanted ion elements include at least one or more of carbon, silicon, and nitrogen.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: In the above-mentioned scheme of this application, firstly, by introducing periodic defects into the diamond material, the crystal lattice structure of diamond is altered, and scattering centers are generated, achieving phonon localization. Localized phonons cannot effectively propagate energy, thus reducing the propagation loss of phonon vibrations within the material, thereby reducing phonon polarization loss and improving the dielectric properties of the diamond material. Secondly, by changing the distance between defects within the diamond material, low-dielectric-loss single-crystal diamond materials at different frequencies are specifically prepared to address future applications of diamond in various extreme environments. Furthermore, by introducing periodic defects into single-crystal diamond, the dielectric loss of single-crystal diamond materials operating in terahertz and above frequency environments can be reduced, expanding the application scope of diamond's excellent dielectric properties and laying the technological foundation for single-crystal diamond in the fields of terahertz imaging and terahertz communication.

[0017] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the method for preparing single-crystal diamond in an embodiment of the present invention; Figure 2 This is a schematic diagram of the diamond substrate in an embodiment of the present invention; Figure 3 This is a schematic diagram of photolithography on a diamond substrate in an embodiment of the present invention; Figure 4 This is a schematic diagram of a diamond-damaged substrate in an embodiment of the present invention; Figure 5 This is a schematic diagram of growing a single-crystal diamond layer on a diamond-damaged substrate in an embodiment of the present invention; Figure 6 This is a schematic diagram of the finished single-crystal diamond product in an embodiment of the present invention.

[0019] Figure labels: 1-Diamond substrate, 2-Photoresist, 3-Single crystal diamond layer, 4-Single crystal diamond finished product. Detailed Implementation

[0020] The present invention will be further described in detail below with reference to specific embodiments, but the implementation of the present invention is not limited thereto.

[0021] Please see Figures 1 to 6This invention provides a method for preparing low-dielectric-loss single-crystal diamond based on periodic defects, comprising: S1: Provides a diamond substrate 1; S2: Photolithography is performed on the diamond substrate 1 to form a dot matrix pattern on the upper surface of the diamond substrate 1. The diamond substrate 1 is surrounded by an external electric field, and the distance between two adjacent dots in the dot matrix pattern is equal to the wavelength corresponding to the frequency of the external electric field. S3: Using etching or ion implantation, damage is applied to the area containing each dot in the dot pattern to obtain a diamond damaged substrate. The upper surface of the diamond damaged substrate has a periodic defect dot structure. S4: A single-crystal diamond layer 3 with periodic defects is grown on the upper surface of the diamond damaged substrate, wherein the defects on the single-crystal diamond layer are made into line defects that penetrate the single-crystal diamond layer by adjusting the growth process. S5: The diamond damaged substrate and the single-crystal diamond layer 3 are sliced ​​to obtain the single-crystal diamond product 4 with periodic defects.

[0022] In some embodiments of this application, the diamond substrate 1 is subjected to photolithography, and photoresist 2 is left on the surface of the diamond substrate.

[0023] In the above-mentioned scheme of this application, firstly, by introducing periodic defects into the diamond material, the crystal lattice structure of diamond is altered, and scattering centers are generated, achieving phonon localization. Localized phonons cannot effectively propagate energy, thus reducing the propagation loss of phonon vibrations within the material, thereby reducing phonon polarization loss and improving the dielectric properties of the diamond material. Secondly, by changing the distance between defects within the diamond material, low-dielectric-loss single-crystal diamond materials at different frequencies are specifically prepared to address future applications of diamond in various extreme environments. Furthermore, by introducing periodic defects into single-crystal diamond, the dielectric loss of single-crystal diamond materials operating in terahertz and above frequency environments can be reduced, expanding the application scope of diamond's excellent dielectric properties and laying the technological foundation for single-crystal diamond in the fields of terahertz imaging and terahertz communication.

[0024] This application proposes for the first time to utilize periodic defects to specifically reduce the phonon polarization loss of diamond at different frequencies. By changing the defect spacing to adapt to different external electric field frequency scenarios, it can effectively reduce the dielectric loss in the terahertz and above frequency bands, laying the technological foundation for its application in terahertz imaging, communication and other fields.

[0025] In some embodiments of this application, step four specifically includes: The diamond-damaged substrate is placed on a molybdenum metal support and then placed into the chamber of the MPCVD equipment; Reduce the air pressure inside the chamber of the MPCVD equipment to ensure that the air pressure inside the chamber does not exceed 0.001 mbar; H2 is introduced into the MPCVD equipment at a flow rate of 100 sccm to 800 sccm; When the air pressure in the chamber reaches 15 Torr~20 Torr, turn on the microwave source to raise the air pressure in the chamber to 120 Torr~200 Torr. The power of the microwave source is 3000W~5000W, and the temperature of the diamond-damaged substrate surface is 800℃~1000℃. CH4, N2, O2, and Ar are introduced into the MPCVD equipment to begin the growth process of a single-crystal diamond layer with periodic defects. Using this method, placing the damaged diamond substrate on a molybdenum metal support and then into the MPCVD chamber helps maintain substrate stability and temperature uniformity during the high-temperature process. First, the chamber pressure is reduced to below extremely high vacuum, effectively reducing impurity residue and providing a clean environment for subsequent growth. Hydrogen gas is introduced and the pressure is gradually built up to create a stable gas atmosphere before the microwave source is turned on. When the pressure reaches 15-20 Torr, the microwave is turned on, raising the pressure to 120-200 Torr while maintaining the substrate surface temperature at 800-1000°C. This step excites and maintains a stable hydrogen plasma, activating the surface for diamond growth. Finally, a mixture of methane, nitrogen, oxygen, and argon is introduced, and epitaxial growth begins in the established plasma environment. This facilitates the continuation and controlled growth of defect structures, providing the necessary process conditions for forming line defects that penetrate the single-crystal diamond layer.

[0026] In some embodiments of this application, when CH4, N2, O2 and Ar are introduced into the MPCVD equipment, the flow rate of CH4 is 8 sccm to 40 sccm, the flow rate of N2 is 0.001 sccm to 0.05 sccm, the flow rate of O2 is 0 sccm to 5 sccm, and the flow rate of Ar is 0.2 sccm to 2 sccm. When initiating the growth process of single-crystal diamond layers with periodic defects, the growth rate is maintained at 4-20 μm / h, with a growth time of 50-200 h, ensuring a single-crystal diamond layer thickness ≥700 μm. Using this method, a methane flow rate of 8-40 sccm provides a stable carbon source for diamond growth. Simultaneously, the nitrogen flow rate is controlled at an extremely low range of 0.001-0.05 sccm, introducing trace amounts of nitrogen to regulate the crystal growth pattern and influence defect formation without introducing excessive impurities that could degrade electrical performance. The oxygen flow rate is adjustable between 0 and 5 sccm, allowing the etching effect of oxygen to suppress the formation of non-diamond carbon phases and improve crystal purity when needed. The argon flow rate is controlled at 0.2-2 sccm, helping to maintain plasma stability. With this gas composition, maintaining a growth rate of 4-20 μm / h and a long growth time of 50-200 h allows for a cumulative single-crystal diamond layer thickness exceeding 700 μm. In this way, continuous and stable epitaxy of high-quality single-crystal diamond can be achieved, ensuring the controllable preparation of thick-layer diamond materials with periodic through-line defects, laying the foundation for obtaining materials with low dielectric loss in the future.

[0027] In some embodiments of this application, after the single-crystal diamond layer has been grown, the flow of CH4, N2, O2 and Ar is stopped, and the cavity pressure and power are gradually reduced. Pump the air pressure inside the cavity to 20 Torr, and after the temperature inside the cavity stabilizes, turn off the microwave source. Stop the H2 supply, pump the air pressure in the chamber down to 0.001 mbar, and turn off the pump; Air is introduced into the cavity to break the vacuum, allowing the grown diamond-damaged substrate and single-crystal diamond layer to be removed from the cavity. This method, by stopping the supply of reactive gas and gradually reducing the cavity pressure and power after growth, avoids thermal stress shocks to the high-temperature diamond material caused by sudden changes in process parameters. The pressure is then evacuated to 20 Torr and the temperature is allowed to stabilize, enabling the substrate and newly grown diamond layer to cool uniformly in a controlled environment. After the microwave source is turned off, the thermal environment of the material becomes more stable. Next, the hydrogen supply is stopped, and the cavity pressure is further evacuated to an extremely high vacuum, helping to remove residual reactive gases and potential contaminants from the cavity. Finally, air is introduced to break the vacuum, balancing the pressure inside and outside the cavity, facilitating the safe and stable removal of the grown diamond sample.

[0028] In some embodiments of this application, step five specifically includes: Laser cutting is used to separate a damaged diamond substrate and a single-crystal diamond layer into slabs, resulting in a finished single-crystal diamond product with periodic defects. This method utilizes laser cutting for slab separation; the high energy density of the laser beam allows for precise application to ultrahard materials like diamond, achieving highly efficient cutting and separation.

[0029] In some embodiments of this application, after the step of slicing the diamond-damaged substrate and the single-crystal diamond layer using a laser cutting process, the method further includes: The cut face of the slab-processed single-crystal diamond layer is placed upwards in an MPCVD (Multi-Plasma Chromatography) device and etched for 10-20 minutes at 200℃~400℃ in a hydrogen plasma atmosphere to remove the amorphous carbon and graphite phases induced by the laser on the cut surface of the single-crystal diamond layer. Using this method, after laser cutting and slab preparation, the cut face is placed upwards in an MPCVD device for hydrogen plasma etching. Under the high temperature of the laser, non-diamond carbon phases such as amorphous carbon or graphite phases are locally generated on the cut surface. The presence of these phases can affect the surface uniformity and electrical properties of the material. At a relatively low temperature of 200℃ to 400℃, the activity of hydrogen plasma can selectively react with these non-diamond carbon phases, removing them as gaseous hydrocarbons. This step directly targets the surface damage layer introduced by laser processing. Through 10 to 20 minutes of etching, the cut surface can be effectively cleaned and repaired, restoring its diamond phase surface properties, thereby ensuring the material quality and structural integrity of the cut surface area of ​​the finished single-crystal diamond product.

[0030] In some embodiments of this application, step one specifically includes: A diamond substrate is provided and cleaned using acetone, ethanol, and alcohol. The roughness Ra of the diamond substrate is ≤5 nm, and the thickness is 1 mm to 7 mm. This method, using solvents such as acetone and ethanol to clean the diamond substrate, effectively removes surface-adhered organic contaminants, grease, and particulate impurities, providing a clean starting surface for subsequent photolithography and growth steps. Selecting a substrate with a surface roughness Ra value not exceeding 5 nm ensures high surface flatness, which facilitates precise transfer of photolithographic patterns and uniform epitaxial growth of high-quality single-crystal diamond layers. Simultaneously, controlling the substrate thickness between 1 mm and 7 mm provides sufficient mechanical strength and thermal stability for subsequent processes, enabling it to withstand the physical and thermal stresses during photolithography, etching, ion implantation, and high-temperature MPCVD growth. This avoids deformation or cracking caused by an excessively thin substrate, providing reliable substrate support for the entire fabrication process.

[0031] In some embodiments of this application, step three specifically includes: The area containing each dot in the dot matrix pattern is damaged by etching or ion implantation. After damage treatment, the diamond substrate is cleaned with acetone to remove the photoresist, resulting in a damaged diamond substrate. This method, using etching or ion implantation to damage the photolithographically defined lattice regions, allows for the precise formation of the desired periodic damage lattice on the diamond substrate surface, forming the basis for subsequent periodic defect structures. Etching directly removes material through physical or chemical processes to create pits, while ion implantation introduces atomic-level damage at specific locations in the crystal lattice through high-energy ion bombardment. Both methods effectively disrupt the crystal integrity of localized areas. After damage treatment, acetone cleaning removes the surface photoresist, removing the photoresist layer that acts as a mask and fully exposing the underlying diamond surface with its established periodic damage pattern. This yields a clean diamond damaged substrate with a clearly defined damage lattice, preparing it for the subsequent epitaxial growth of a single-crystal diamond layer with through-line defects.

[0032] In some embodiments of this application, the distance between two adjacent points in the lattice pattern is 3 μm to 30,000 μm (corresponding to 100 THz to 10 GHz). Using this method, the distance between two adjacent points in the photolithographic lattice pattern is set between 3 micrometers and 30,000 micrometers, covering a scale from micrometers to centimeters. Shorter spacing can handle high-frequency external electric field environments, while longer spacing is suitable for low-frequency or quasi-static field applications. This broad spacing selection allows the fabrication process to flexibly adapt to electric fields of different target frequencies, controlling the arrangement period of periodic defects within the diamond material by matching the wavelength corresponding to the frequency of the external electric field. In this way, low-dielectric-loss single-crystal diamond materials suitable for various specific frequency scenarios can be fabricated, expanding the applicability of this method in practical applications.

[0033] In some embodiments of this application, when ion implantation is used to damage the region containing each point in the lattice pattern, the implanted ions include at least one or more of carbon, silicon, and nitrogen. Using this method, selecting carbon, silicon, or nitrogen during ion implantation damage treatment achieves good compatibility with the carbon matrix of the diamond substrate. The implantation of these elements can directly cause atomic-level arrangement disturbances and local structural damage in the diamond lattice, thereby forming the desired damage centers at precise locations defined by photolithography. The implantation of carbon ions can introduce additional carbon atoms, potentially causing localized stress or amorphization; silicon and nitrogen, as heteroatoms, can directly alter the chemical bonding and local charge distribution of the lattice. This diverse element selection provides a flexible and controllable approach to the precise formation of periodic damage lattices, helping to establish a clear defect template in the substrate and laying the foundation for the continued growth of through-line defects in the subsequent single-crystal diamond layer.

[0034] Example 1: like Figure 2 , Figure 3 , Figure 4 , Figure 5 and Figure 6 As shown, the method for preparing low-dielectric-loss single-crystal diamond based on periodic defects in this application specifically includes: S01: Prepare a single-crystal diamond substrate and clean it using acetone, ethanol, and alcohol. The single-crystal diamond substrate has a roughness Ra=2nm, a thickness of 2mm, and dimensions of 10×10 mm. 2 .

[0035] S02: A dot matrix pattern is etched on the single-crystal diamond substrate in S01 using photolithography. The distance between the dots is the wavelength corresponding to the frequency of the external electric field. Specifically, the required dot matrix pattern is photolithographically etched on the surface of a diamond substrate. In this embodiment, the distance between the dots is 300 μm (corresponding to 100THz-10GHz) for a 1THz application scenario.

[0036] S03: Using etching or ion implantation techniques, artificial damage is performed on the diamond substrate in the dot matrix area. After the damage process is completed, the photoresist is cleaned off to obtain a diamond substrate with a periodic defect matrix on the surface. Specifically, in S02, the diamond substrate surface with photolithographic patterns is etched to obtain the required periodic lattice defects using an etching process. The etching machine is an inductively coupled plasma etching machine, and acetone is used to wash away the photoresist used as a mask on the diamond surface. S04: Growing single-crystal diamond with periodic defects on a diamond substrate with a periodic defect lattice on the surface, adjusting the growth process to make the bottom surface defects become line defects, and making the single-crystal diamond that runs through the entire epitaxial layer. Specifically, a diamond substrate with a periodic defect lattice on its surface, prepared by SO3, is placed on a molybdenum metal support, placed in an MPCVD device, and the chamber pressure is evacuated to 0.001 mbar or below. H2 is introduced into the MPCVD equipment at a flow rate of 400 sccm; When the cavity pressure reaches 15 Torr, the microwave source is turned on. The cavity pressure is increased to 160 Torr, the power is 4000W, and the surface temperature of the diamond substrate is 920℃. CH4, N2, O2, and Ar were introduced into the MPCVD equipment to begin the growth process of single-crystal diamond material with periodic defects. The flow rates were 28 sccm for CH4, 0.005 sccm for N2, 2 sccm for O2, and 0.2 sccm for Ar. The growth rate was maintained at 10 μm / h for 100 h to ensure that the single-crystal diamond layer thickness was ≥1000 μm, thus guaranteeing that the single-crystal diamond material with periodic defects could be self-supporting after lamination.

[0037] After growth is complete, stop the supply of CH4, N2, O2, and Ar, and slowly reduce the cavity pressure and power. Pump the cavity pressure to 20 Torr, wait for the cavity temperature to stabilize, and then turn off the microwave source. Stop the supply of H2, pump the cavity pressure to 0.001 mbar, and turn off the pump. Introduce air into the cavity to break the vacuum, and remove the grown single-crystal diamond material from the cavity.

[0038] S05: Perform a slicing process on the epitaxially grown single-crystal diamond to obtain single-crystal diamond with periodic defects.

[0039] Specifically, the grown diamond material is first sliced ​​using a laser cutting process, and the epitaxial single-crystal diamond material with periodic defects is separated from the original diamond substrate. Then, the cut surface of the single-crystal diamond material with periodic defects is placed upwards in the MPCVD equipment and etched at 400°C in a hydrogen plasma atmosphere for 20 minutes to remove the amorphous carbon and graphite phases caused by the laser from the grown single-crystal diamond material with periodic defects.

[0040] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0041] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0042] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0043] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A method for preparing low-dielectric-loss single-crystal diamond based on periodic defects, characterized in that, include: Step 1: Provide a diamond substrate; Step 2: Perform photolithography on the diamond substrate to form a dot matrix pattern on the upper surface of the diamond substrate, wherein the diamond substrate has an external electric field, and the distance between two adjacent dots in the dot matrix pattern is equal to the wavelength corresponding to the frequency of the external electric field. Step 3: Using etching or ion implantation, damage treatment is performed on the area where each dot in the dot pattern is located to obtain a diamond damaged substrate. The upper surface of the diamond damaged substrate has a periodic defect dot structure. Step 4: A single-crystal diamond layer with periodic defects is grown on the upper surface of the diamond damaged substrate, wherein the defects on the single-crystal diamond layer are made into line defects that penetrate the single-crystal diamond layer by adjusting the growth process. Step 5: The diamond damaged substrate and the single crystal diamond layer are sliced ​​to obtain a single crystal diamond product with periodic defects.

2. The method for preparing low-dielectric-loss single-crystal diamond based on periodic defects according to claim 1, characterized in that, Step four specifically includes: The diamond-damaged substrate is placed on a molybdenum metal support and then placed into the chamber of the MPCVD equipment; Reduce the air pressure inside the chamber of the MPCVD equipment so that the air pressure inside the chamber does not exceed 0.001 mbar; H2 is introduced into the MPCVD equipment at a flow rate of 100 sccm to 800 sccm; When the air pressure in the chamber reaches 15 Torr~20 Torr, the microwave source is turned on to raise the air pressure in the chamber to 120 Torr~200 Torr. The power of the microwave source is 3000W~5000W, and the temperature of the diamond damaged substrate surface is 800℃~1000℃. CH4, N2, O2 and Ar are introduced into the MPCVD equipment to begin the growth process of a single-crystal diamond layer with periodic defects.

3. The method for preparing low-dielectric-loss single-crystal diamond based on periodic defects according to claim 2, characterized in that, When CH4, N2, O2 and Ar are introduced into the MPCVD equipment, the flow rate of CH4 is 8 sccm to 40 sccm, the flow rate of N2 is 0.001 sccm to 0.05 sccm, the flow rate of O2 is 0 sccm to 5 sccm, and the flow rate of Ar is 0.2 sccm to 2 sccm. When starting the growth process of a single-crystal diamond layer with periodic defects, maintain the growth rate at 4-20 μm / h and grow for 50-200 h to ensure that the thickness of the single-crystal diamond layer is ≥700 μm.

4. The method for preparing low-dielectric-loss single-crystal diamond based on periodic defects according to claim 3, characterized in that, After the single-crystal diamond layer has grown, the flow of CH4, N2, O2 and Ar is stopped, and the cavity pressure and power are gradually reduced. Pump the air pressure inside the cavity to 20 Torr, and after the temperature inside the cavity stabilizes, turn off the microwave source. Stop the H2 supply, pump the air pressure in the chamber down to 0.001 mbar, and turn off the pump; Air is introduced into the cavity to break the vacuum, and the grown diamond damage substrate and single-crystal diamond layer are removed from the cavity.

5. The method for preparing low-dielectric-loss single-crystal diamond based on periodic defects according to claim 1, characterized in that, Step five specifically includes: The diamond damaged substrate and the single-crystal diamond layer are sliced ​​using a laser cutting process to obtain a finished single-crystal diamond product with periodic defects.

6. The method for preparing low-dielectric-loss single-crystal diamond based on periodic defects according to claim 5, characterized in that, After the step of slicing the diamond damaged substrate and the single-crystal diamond layer using laser cutting technology, the method further includes: The cut surface of the single-crystal diamond layer after slicing is placed upwards in an MPCVD device and etched for 10 to 20 minutes at a temperature of 200℃ to 400℃ in a hydrogen plasma atmosphere to remove the amorphous carbon and graphite phases caused by the laser on the cut surface of the single-crystal diamond layer.

7. The method for preparing low-dielectric-loss single-crystal diamond based on periodic defects according to claim 1, characterized in that, Step one specifically includes: A diamond substrate is provided, and the diamond substrate is cleaned using acetone, ethanol and alcohol, wherein the roughness Ra of the diamond substrate is ≤5nm and the thickness is 1mm~7mm.

8. The method for preparing low-dielectric-loss single-crystal diamond based on periodic defects according to claim 1, characterized in that, Step three specifically includes: The area containing each dot in the dot matrix pattern is damaged by etching or ion implantation. After the damage treatment is completed, the diamond substrate is cleaned with acetone to remove the photoresist on the surface of the diamond substrate, thus obtaining a damaged diamond substrate.

9. The method for preparing low-dielectric-loss single-crystal diamond based on periodic defects according to claim 1, characterized in that, The distance between two adjacent dots in the dot matrix pattern is 3μm to 30000μm.

10. The method for preparing low-dielectric-loss single-crystal diamond based on periodic defects according to claim 1, characterized in that, When ion implantation is used to damage the area containing each dot in the lattice pattern, the implanted ion elements include at least one or more of carbon, silicon, and nitrogen.

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