Spliced single crystal diamond, preparation method thereof and single crystal diamond

Abstract

The embodiment of the invention provides a spliced single crystal diamond, a preparation method thereof and a single crystal diamond, a plurality of first Ti / Au mask strips which are arranged at intervals are adopted in a defect area of an epitaxial layer of the spliced diamond to serve as a blocking structure, and when the first spliced single crystal diamond is grown in an epitaxial mode, the first Ti / Au mask strips are separated from the blocking structure. According to the invention, the longitudinal extension of the splicing diamond epitaxial layer corresponding to the dislocation at the splicing seam can be hindered, and the defect area AA is prevented from being shielded by a whole mask, so that the purpose of improving the quality of the first splicing single crystal diamond in epitaxial growth is achieved; and moreover, the Ti / Au layer is used as a mask layer, the Ti layer can ensure adhesiveness, and the Au layer has relatively good ductility, so that the epitaxially grown first spliced single crystal diamond has a stress release space, the fracture risk of the first spliced single crystal diamond is reduced, and the crystal quality is further improved.

Description

Technical Field

[0001] The present disclosure relates to the field of semiconductor technology, and particularly to a spliced single-crystal diamond, a preparation method thereof, and a single-crystal diamond. Background Art

[0002] Diamond has extremely excellent comprehensive properties and has very broad application prospects in the fields of electronics, heat sinks, optical windows, and machining. The size of natural diamond is limited, making it difficult to meet the requirements of large-size application fields. Therefore, artificial diamond preparation has developed. There are two main synthesis methods: the high-pressure high-temperature method (HPHT) and the chemical vapor deposition method (CVD). Among them, microwave plasma chemical vapor deposition (MPCVD) in the chemical vapor deposition method has gradually become the mainstream preparation method due to its good stability and large deposition area. The preparation of diamond by the MPCVD method is divided into two methods: heteroepitaxy and homoepitaxy. The heteroepitaxy method can obtain larger-size diamonds, but the quality is poor and the dislocation density is high. The homoepitaxy method is limited by the size of the seed crystal and cannot obtain large-size diamonds, but the quality is high and the dislocation density is small. Therefore, to prepare large-size high-quality single-crystal diamonds, a Mosaic splicing method based on homoepitaxy has been proposed.

[0003] The Mosaic splicing method refers to a technique in which multiple small-size seed crystals are tiled and spliced together in an MPCVD chamber for deposition growth. This technique uses lateral epitaxy during the growth process to connect the independent diamond seed crystals together. Compared with the traditional homoepitaxy method, this technique can obtain larger-area single-crystal diamonds. Compared with the diamonds prepared by the heteroepitaxy method, the crystals prepared by this technique have high quality and low dislocation density. Therefore, the Mosaic splicing method provides a possibility for the preparation of large-size high-quality single-crystal diamonds. However, affected by stress and dislocation density, the problem of deterioration of the crystal quality at the splicing seam connection is serious, affecting the overall performance of the crystal. Moreover, the wider the original splicing seam, the greater the crystal orientation difference on both sides of the splicing seam, the greater the stress during the growth process, and the worse the crystal connection quality.

[0004] Therefore, a new preparation method for spliced single-crystal diamonds is needed to obtain large-size spliced single-crystal diamonds with more uniform crystal quality, smaller dislocation density, and smaller area of the quality deterioration region. Summary of the Invention

[0005] In view of this, the embodiments of the present disclosure provide a spliced single-crystal diamond, a preparation method thereof, and a single-crystal diamond to improve the crystal quality of large-size spliced single-crystal diamonds.

[0006] The specific solutions of a spliced single-crystal diamond, a preparation method thereof, and a single-crystal diamond provided by the embodiments of the present disclosure are as follows: On the one hand, a spliced single-crystal diamond provided by an embodiment of the present disclosure includes: A spliced diamond substrate including a plurality of spliced diamond seeds, and there is a splicing seam between the plurality of diamond seeds; A spliced diamond epitaxial layer covering the surface of the spliced diamond substrate, and the spliced diamond epitaxial layer has a defect region covering the splicing seam; A first Ti / Au mask layer located on a side of the spliced diamond epitaxial layer away from the spliced diamond substrate and covering the defect region; the first Ti / Au mask layer includes a plurality of first Ti / Au mask strips extending along the extending direction of the splicing seam and arranged at intervals; A first spliced single-crystal diamond filling the gaps of the first Ti / Au mask layer and covering the surfaces of the first Ti / Au mask strips and the spliced diamond epitaxial layer away from the spliced diamond substrate.

[0007] In some embodiments, in the above-mentioned spliced single-crystal diamond provided by the embodiment of the present disclosure, the first Ti / Au mask layer includes: a Ti layer close to the spliced diamond epitaxial layer, and an Au layer located on a side of the Ti layer away from the spliced diamond epitaxial layer; the thickness of the Ti layer is less than the thickness of the Au layer.

[0008] In some embodiments, in the above-mentioned spliced single-crystal diamond provided by the embodiment of the present disclosure, the splicing seam includes a first splicing seam between adjacent rows of the diamond seeds and a second splicing seam between adjacent columns of the diamond seeds, the defect region includes a first defect region covering the first splicing seam and a second defect region covering the second splicing seam, and the first defect region and the second defect region have an intersection region; The plurality of first Ti / Au mask strips include: a plurality of first sub-mask strips extending along the extending direction of the first defect region and arranged at intervals, and a plurality of second sub-mask strips extending along the extending direction of the second defect region and arranged at intervals; the first sub-mask strips and the second sub-mask strips intersect in the intersection region to form a grid structure.

[0009] In some embodiments, in the above-mentioned spliced single-crystal diamond provided by the embodiment of the present disclosure, the widths of the first sub-mask strips and the second sub-mask strips are 1-10 μm, the gap widths between adjacent first sub-mask strips and the gap widths between adjacent second sub-mask strips are 5-20 μm, and the thicknesses of the first sub-mask strips and the second sub-mask strips are 50-1000 nm.

[0010] In some embodiments, in the above-mentioned spliced single-crystal diamond provided by the embodiment of the present disclosure, it further includes: A second Ti / Au mask layer is located on a side of the first spliced single-crystal diamond away from the spliced diamond substrate and covers the defect area; the second Ti / Au mask layer includes a plurality of second Ti / Au mask strips extending along the extension direction of the splicing seam and arranged at intervals, and a positive projection of the second Ti / Au mask strip on the spliced diamond substrate overlaps a positive projection of a gap between adjacent first Ti / Au mask strips on the spliced diamond substrate; A second spliced single-crystal diamond fills the gap of the second Ti / Au mask layer and covers each of the second Ti / Au mask strips and a surface of the first spliced single-crystal diamond away from the spliced diamond substrate.

[0011] In some embodiments, in the above-mentioned spliced single-crystal diamond provided by the embodiments of the present disclosure, the plurality of second Ti / Au mask strips include: a plurality of third sub-mask strips extending along the extension direction of the first defect area and arranged at intervals, and a plurality of fourth sub-mask strips extending along the extension direction of the second defect area and arranged at intervals; the third sub-mask strips and the fourth sub-mask strips cross in the cross area to form a grid structure.

[0012] In some embodiments, in the above-mentioned spliced single-crystal diamond provided by the embodiments of the present disclosure, a positive projection of the third sub-mask strip on the spliced diamond substrate overlaps a positive projection of a gap between adjacent first sub-mask strips on the spliced diamond substrate, and a positive projection of the fourth sub-mask strip on the spliced diamond substrate overlaps a positive projection of a gap between adjacent second sub-mask strips on the spliced diamond substrate.

[0013] On the other hand, the embodiments of the present disclosure also provide a method for preparing a spliced single-crystal diamond, including: S1. Seed crystal splicing: splicing a plurality of diamond seeds to obtain a spliced diamond substrate; S2. Spliced growth: performing epitaxial growth on the surface of the spliced diamond substrate to form a whole-surface spliced diamond epitaxial layer; S3. Surface treatment: grinding and polishing the surface of the spliced diamond epitaxial layer and then placing it in a hydrogen plasma atmosphere to expose the defect area of the spliced diamond epitaxial layer, and the defect area covers the splicing seam between the plurality of diamond seeds; S4. Patterned mask: forming a first Ti / Au mask layer in the defect area, and the first Ti / Au mask layer includes a plurality of first Ti / Au mask strips extending along the extension direction of the splicing seam and arranged at intervals; S5. Epitaxial growth: performing epitaxial growth on the surface of the spliced diamond epitaxial layer formed with the first Ti / Au mask layer to form a first spliced single-crystal diamond.

[0014] In some embodiments, in the above-mentioned preparation method provided by the embodiments of the present disclosure, it further includes: repeatedly executing steps S3 - S5.

[0015] In some embodiments, in the above-mentioned preparation method provided by the embodiments of the present disclosure, when repeatedly executing step S4, the orthographic projection of the currently formed Ti / Au mask strip on the spliced diamond substrate overlaps with the orthographic projection of the gap between the adjacent Ti / Au mask strips formed in the previous time on the spliced diamond substrate.

[0016] In some embodiments, in the above-mentioned preparation method provided by the embodiments of the present disclosure, step S4 for patterning the mask specifically includes: Forming a spin-on resist layer on the surface of the spliced diamond epitaxial layer; Spin-coating a photoresist layer on the side of the resist layer away from the spliced diamond epitaxial layer; Exposing and developing the photoresist layer to form a plurality of windows extending along the extension direction of the splicing seam and arranged at intervals in the defect area, and the windows expose the spliced diamond epitaxial layer; Forming a Ti / Au layer on the side of the remaining photoresist layer away from the spliced diamond epitaxial layer; Removing the remaining resist layer and the photoresist layer to obtain the first Ti / Au mask layer located in the windows.

[0017] On the other hand, the embodiments of the present disclosure also provide a single-crystal diamond, including: A spliced diamond epitaxial layer having a defect area; A first Ti / Au mask layer located on one side of the spliced diamond epitaxial layer and covering the defect area; the first Ti / Au mask layer includes a plurality of first Ti / Au mask strips extending along at least one direction and arranged at intervals; A first spliced single-crystal diamond located on the side of the first Ti / Au mask layer away from the spliced diamond epitaxial layer, and the first spliced single-crystal diamond fills the gaps of the first Ti / Au mask layer and covers the surfaces of each of the first Ti / Au mask strips and the spliced diamond epitaxial layer.

[0018] In some embodiments, in the above-mentioned single-crystal diamond provided by the embodiments of the present disclosure, it further includes: The second Ti / Au mask layer is located on the side of the first spliced single-crystal diamond away from the spliced diamond epitaxial layer and covers the defect area; the second Ti / Au mask layer includes a plurality of second Ti / Au mask strips arranged at intervals and having the same extending direction as that of the first Ti / Au mask strip, and the orthographic projection of the second Ti / Au mask strip on the spliced diamond epitaxial layer overlaps with the orthographic projection of the gap between adjacent first Ti / Au mask strips on the spliced diamond epitaxial layer; The second spliced single-crystal diamond is located on the side of the second Ti / Au mask layer away from the spliced diamond epitaxial layer, and the second spliced single-crystal diamond fills the gaps of the second Ti / Au mask layer and covers each of the second Ti / Au mask strips and the surface of the first spliced single-crystal diamond away from the spliced diamond epitaxial layer.

[0019] The beneficial effects of the present disclosure are as follows: A spliced single-crystal diamond, a preparation method thereof, and a single-crystal diamond provided by an embodiment of the present disclosure, by using a plurality of first Ti / Au mask strips arranged at intervals as a blocking structure in the defect area of the spliced diamond epitaxial layer, when epitaxially growing the first spliced single-crystal diamond, it can hinder the longitudinal extension of the dislocations corresponding to the splicing seam of the spliced diamond epitaxial layer, and avoid the defect area AA being blocked by a whole piece of mask, so as to achieve the purpose of improving the quality of the epitaxially grown first spliced single-crystal diamond; moreover, the Ti / Au layer is used as the mask layer, the Ti layer can ensure the adhesion, and the Au layer has good ductility, so that the epitaxially grown first spliced single-crystal diamond has a space for stress release, reducing its fracture risk and further improving the crystal quality. Description of the Drawings

[0020] Figure 1 is a schematic plan view of a spliced single-crystal diamond provided by an embodiment of the present disclosure; Figure 2 is Figure 1 a schematic cross-sectional view along the CC' direction in Figure 3 is another schematic plan view of a spliced single-crystal diamond provided by an embodiment of the present disclosure; Figure 4 is Figure 3 a schematic cross-sectional view along the CC' direction in Figure 5 is a schematic flow chart of a preparation method of a spliced single-crystal diamond provided by an embodiment of the present disclosure; Figure 6 is another schematic flow chart of a preparation method of a spliced single-crystal diamond provided by an embodiment of the present disclosure; Figure 7Schematic flow chart of another preparation method of the spliced single-crystal diamond provided by the embodiments of the present disclosure; Figure 8 Schematic three-dimensional structure diagram of the spliced single-crystal diamond in the preparation process provided by the embodiments of the present disclosure; Figure 9 Another schematic three-dimensional structure diagram of the spliced single-crystal diamond in the preparation process provided by the embodiments of the present disclosure; Figure 10 Another schematic three-dimensional structure diagram of the spliced single-crystal diamond in the preparation process provided by the embodiments of the present disclosure; Figure 11 Another schematic three-dimensional structure diagram of the spliced single-crystal diamond in the preparation process provided by the embodiments of the present disclosure; Figure 12 Another schematic three-dimensional structure diagram of the spliced single-crystal diamond in the preparation process provided by the embodiments of the present disclosure; Figure 13 Another schematic three-dimensional structure diagram of the spliced single-crystal diamond in the preparation process provided by the embodiments of the present disclosure; Figure 14 Another schematic three-dimensional structure diagram of the spliced single-crystal diamond in the preparation process provided by the embodiments of the present disclosure; Figure 15 Another schematic three-dimensional structure diagram of the spliced single-crystal diamond in the preparation process provided by the embodiments of the present disclosure; Figure 16 Another schematic three-dimensional structure diagram of the spliced single-crystal diamond in the preparation process provided by the embodiments of the present disclosure; Figure 17 Another schematic three-dimensional structure diagram of the spliced single-crystal diamond in the preparation process provided by the embodiments of the present disclosure; Figure 18 Another schematic three-dimensional structure diagram of the spliced single-crystal diamond in the preparation process provided by the embodiments of the present disclosure; Figure 19 Schematic cross-sectional structure diagram of the spliced single-crystal diamond in the preparation process provided by the embodiments of the present disclosure; Figure 20 Another schematic cross-sectional structure diagram of the spliced single-crystal diamond in the preparation process provided by the embodiments of the present disclosure; Figure 21 Another schematic cross-sectional structure diagram of the spliced single-crystal diamond in the preparation process provided by the embodiments of the present disclosure; Figure 22 Another schematic cross-sectional structure diagram of the spliced single-crystal diamond in the preparation process provided by the embodiments of the present disclosure; Figure 23Another cross-sectional structure diagram of the spliced single-crystal diamond during the preparation process provided by the embodiments of the present disclosure; Figure 24 Another cross-sectional structure diagram of the spliced single-crystal diamond during the preparation process provided by the embodiments of the present disclosure; Figure 25 Another cross-sectional structure diagram of the spliced single-crystal diamond during the preparation process provided by the embodiments of the present disclosure; Figure 26 Another cross-sectional structure diagram of the spliced single-crystal diamond during the preparation process provided by the embodiments of the present disclosure; Figure 27 A structure diagram of a single-crystal diamond provided by the embodiments of the present disclosure; Figure 28 Another structure diagram of a single-crystal diamond provided by the embodiments of the present disclosure. Detailed implementation manners

[0021] To make the objectives, technical solutions and advantages of the embodiments of the present disclosure clearer, the technical solutions of the embodiments of the present disclosure will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present disclosure. It should be noted that in the drawings, the thicknesses of layers, films, panels, regions, etc. are enlarged for clarity. In the present disclosure, exemplary embodiments are described with reference to cross-sectional views that are schematic diagrams of idealized embodiments. Thus, deviations from the shapes of the figures as a result of, for example, manufacturing techniques and / or tolerances are to be expected. Accordingly, the embodiments described in the present disclosure should not be construed as limited to the specific shapes of the regions shown in the present disclosure, but include deviations in shape resulting from, for example, manufacturing. For example, regions illustrated or described as flat may typically have rough and / or non-linear features; sharp corners illustrated may be rounded, etc. Thus, the regions shown in the figures are schematic in nature, and their dimensions and shapes do not represent the exact shapes of the illustrated regions, do not reflect true proportions, and are intended only to schematically illustrate the content of the present disclosure. And the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. To keep the following description of the embodiments of the present disclosure clear and concise, detailed descriptions of known functions and known components are omitted in the present disclosure.

[0022] Unless otherwise defined, technical or scientific terms used herein shall have the ordinary meaning as understood by those of ordinary skill in the art to which this disclosure pertains. The terms "first", "second", and similar terms used in the description and claims of this disclosure do not denote any order, quantity, or importance, but are merely used to distinguish different components. Words such as "comprising" or "including" mean that the elements or items appearing before the word cover the elements or items listed after the word and their equivalents, without excluding other elements or items. Words such as "connected" or "coupled" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. Words such as "inner", "outer", "upper", "lower", etc. are only used to indicate relative positional relationships, and when the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0023] In the following description, when an element or layer is referred to as being "on" or "connected to" another element or layer, the element or layer may be directly on the other element or layer, directly connected to the other element or layer, or there may be intermediate elements or intermediate layers. When an element or layer is referred to as being "disposed on one side of" another element or layer, the element or layer may be directly on one side of the other element or layer, directly connected to the other element or layer, or there may be intermediate elements or intermediate layers. However, when an element or layer is referred to as being "directly on" or "directly connected to" another element or layer, there are no intermediate elements or intermediate layers. The term "and / or" includes any and all combinations of one or more of the associated listed items.

[0024] Embodiments of the present disclosure provide a spliced single-crystal diamond, as Figure 1 and Figure 2 shown, Figure 1 is a schematic plan view of a spliced single-crystal diamond, Figure 2 is Figure 1 a schematic cross-sectional view along the CC' direction in The spliced single-crystal diamond includes: A spliced diamond substrate 1, including a plurality of spliced diamond seeds 11, and there is a splicing seam G between the plurality of diamond seeds 11; specifically, the plurality of diamond seeds 11 may be closely arranged in the row direction (horizontal direction), may be closely arranged in the column direction (vertical direction), or may be arranged in an array in the row direction and the column direction. The width of the splicing seam G is less than 500 μm. In the embodiments of the present disclosure, the case where the plurality of diamond seeds 11 are arranged in an array is taken as an example; The spliced diamond epitaxial layer 2 covers the surface of the spliced diamond substrate 1, and the spliced diamond epitaxial layer 2 has a defective area AA covering the splice seam G; specifically, the spliced diamond epitaxial layer 2 is a film layer grown by splicing on the surface of the spliced diamond substrate 1, and the defective area AA is a region where the quality deteriorates due to stress concentration, dislocations, etc. at the position corresponding to the splice seam G in the spliced diamond epitaxial layer 2; The first Ti / Au mask layer 3 is located on the side of the spliced diamond epitaxial layer 2 away from the spliced diamond substrate 1 and covers the defective area AA; the first Ti / Au mask layer 3 includes a plurality of first Ti / Au mask strips 31 extending along the extending direction of the splice seam G and arranged at intervals; specifically, each first Ti / Au mask strip 31 covers the defective area AA. When growing a new spliced single-crystal diamond by epitaxy subsequently, on the one hand, it hinders the longitudinal (i.e., the direction perpendicular to the spliced diamond substrate 1) extension of crystal dislocations in the defective area AA during the lateral epitaxial growth process, reduces the dislocation density of the new epitaxial layer, and achieves the purpose of improving the quality of the diamond crystal; on the other hand, the plurality of first Ti / Au mask strips 31 arranged at intervals can prevent the defective area AA from being blocked by a whole mask, which affects the epitaxial quality of the crystal; The first spliced single-crystal diamond 4 fills the gaps of the first Ti / Au mask layer 3, and covers each first Ti / Au mask strip 31 and the surface of the spliced diamond epitaxial layer 2 away from the spliced diamond substrate 1; specifically, the first spliced single-crystal diamond 4 is a film layer grown by epitaxy on the surface of the spliced diamond epitaxial layer 2 away from the spliced diamond substrate 1. Since each first Ti / Au mask strip 31 hinders the longitudinal extension of crystal dislocations in the defective area AA, the crystal quality of the first spliced single-crystal diamond 4 corresponding to the splice seam G area is greatly improved, that is, the stress concentration and crystal dislocation density in the splice seam G area are reduced.

[0025] For the above-mentioned spliced single-crystal diamond provided by the embodiment of the present disclosure, by using a plurality of first Ti / Au mask strips arranged at intervals as a blocking structure in the defective area of the spliced diamond epitaxial layer, when growing the first spliced single-crystal diamond by epitaxy, it can hinder the longitudinal extension of dislocations at the position corresponding to the splice seam in the spliced diamond epitaxial layer, and avoid the defective area AA from being blocked by a whole mask, so as to achieve the purpose of improving the quality of the first spliced single-crystal diamond grown by epitaxy; moreover, as a mask layer, the Ti layer can ensure the adhesion, and the Au layer has good ductility, enabling the first spliced single-crystal diamond grown by epitaxy to have a space for stress release, reducing its fracture risk, and further improving the crystal quality.

[0026] In some embodiments, in the above-mentioned spliced single-crystal diamond provided by the embodiment of the present disclosure, such as Figure 1 and Figure 2As shown, the first Ti / Au mask layer 3 includes: a Ti layer close to the spliced diamond epitaxial layer 2, and an Au layer located on the side of the Ti layer away from the spliced diamond epitaxial layer 2. That is, in the defect region AA, the entire surface Ti layer is first evaporated, and then the entire surface Au layer is evaporated. The first Ti / Au mask layer 3 can be formed by a photolithography process; among them, the thickness of the Ti layer is less than the thickness of the Au layer. Specifically, because the Au layer has good ductility, the first spliced single-crystal diamond 4 has space for stress release, reducing its fracture risk, and the Ti layer is to improve the adhesion of the Au layer. Therefore, the thickness of the Ti layer can be less than the thickness of the Au layer.

[0027] In some embodiments, the thickness of the Ti layer can be 10 nm, and the thickness of the Au layer can be 90 nm, but this is not limited thereto.

[0028] In some embodiments, in the above-mentioned spliced single-crystal diamond provided by the embodiments of the present disclosure, as Figure 1 and Figure 2 shown, the splicing seam G includes a first splicing seam located between adjacent two rows of diamond seeds 11 and a second splicing seam located between adjacent two columns of diamond seeds 11. The defect region AA includes a first defect region A1 covering the first splicing seam and a second defect region A2 covering the second splicing seam. The first defect region A1 and the second defect region A2 have an intersection region BB; The plurality of first Ti / Au mask strips 31 include: a plurality of first sub-mask strips 311 extending along the extending direction of the first defect region A1 and arranged at intervals, and a plurality of second sub-mask strips 312 extending along the extending direction of the second defect region A2 and arranged at intervals; the first sub-mask strips 311 and the second sub-mask strips 312 intersect in the intersection region BB to form a grid structure.

[0029] It should be noted that the extending direction of the first defect region A1 can be the row direction, and the extending direction of the second defect region A2 can be the column direction. The attached Figure 1 drawing of the present disclosure is a three-dimensional schematic diagram, and the column direction has a certain inclination angle. In fact, the row direction and the column direction can be perpendicular.

[0030] In some embodiments, in the above-mentioned spliced single-crystal diamond provided by the embodiments of the present disclosure, as Figure 1 and Figure 2As shown, the widths of the first sub-mask strip 311 and the second sub-mask strip 312 can be 1 - 10 μm, such as 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, etc.; the gap widths between adjacent first sub-mask strips 311 and the gap widths between adjacent second sub-mask strips 312 can be 5 - 20 μm, such as 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, etc.; the thicknesses of the first sub-mask strip 311 and the second sub-mask strip 312 can be 50 - 1000 nm, such as 50 nm, 100 nm, 150 nm, 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, 1000 nm, etc.

[0031] In this way, the patterned first Ti / Au mask layer 3 adopted in the present disclosure is composed of strip-shaped first Ti / Au mask strips 31 arrayed in the row direction and the column direction. Its thickness and width are much smaller than the width of the original splicing seam, and the mask strips are narrow while the gaps between the mask strips are wide. During the growth process, the diamonds in the gaps between adjacent first sub-mask strips 311 and the gaps between adjacent second sub-mask strips 312 are more likely to be connected, with less accumulated growth stress and fewer defects introduced after epitaxial growth, resulting in a significant improvement in the quality of the epitaxially grown first spliced single-crystal diamond 4.

[0032] It should be noted that Figure 1 in the present disclosure, taking the splicing of 4 diamond seeds 11 as an example, of course, it is only for illustrative purposes, and the number of spliced diamond seeds 11 can be selected according to needs.

[0033] In some embodiments, in the above-mentioned spliced single-crystal diamond provided by the embodiments of the present disclosure, as Figure 3 and Figure 4 shown, Figure 3 is another schematic plan view of the spliced single-crystal diamond, Figure 4 is Figure 3 the schematic cross-sectional structure along the CC' direction in Figure 1 This spliced single-crystal diamond may further include on the basis of the The second Ti / Au mask layer 5 is located on the side of the first spliced single-crystal diamond 4 away from the spliced diamond substrate 1 and covers the defect region AA; the second Ti / Au mask layer 5 includes a plurality of second Ti / Au mask strips 51 that extend along the extension direction of the splicing seam G and are arranged at intervals, and the orthographic projection of the second Ti / Au mask strip 51 on the spliced diamond substrate 1 overlaps with the gap between adjacent first Ti / Au mask strips 31 in the orthographic projection on the spliced diamond substrate 1; specifically, each second Ti / Au mask strip 51 covers the defect region AA. When subsequently growing the second spliced single-crystal diamond 6 by epitaxy, on the one hand, during the lateral epitaxial growth process, it hinders the longitudinal extension of the dislocations in the defect region AA that are not blocked by the first Ti / Au mask strip 31. In this way, the second spliced single-crystal diamond 6 formed under the double blockage of the first Ti / Au mask strip 31 and the second Ti / Au mask strip 51 has a lower dislocation density and less stress concentration compared to the first spliced single-crystal diamond 4, and a diamond with better crystal quality can be obtained; on the other hand, the plurality of second Ti / Au mask strips 51 arranged at intervals can also prevent the defect region AA from being blocked by a whole piece of mask, which affects the epitaxial quality of the crystal. The second spliced single-crystal diamond 6 fills the gap of the second Ti / Au mask layer 5, and covers the surfaces of each second Ti / Au mask strip 51 and the first spliced single-crystal diamond 4 away from the spliced diamond substrate 1; specifically, the second spliced single-crystal diamond 6 is a film layer grown by epitaxy on the surface of the first spliced single-crystal diamond 4 away from the spliced diamond substrate 1. Since each second Ti / Au mask strip 51 hinders the longitudinal extension of the dislocations in the defect region AA that are not blocked by the first Ti / Au mask strip 31, the crystal quality of the second spliced single-crystal diamond 6 corresponding to the splicing seam G region is greatly improved, that is, the stress concentration and crystal dislocation density in the splicing seam G region are further reduced.

[0034] In some embodiments, in the above-mentioned spliced single-crystal diamond provided by the embodiments of the present disclosure, as Figure 3 and Figure 4 shown, the plurality of second Ti / Au mask strips 51 include: a plurality of third sub-mask strips 511 that extend along the extension direction of the first defect region A1 and are arranged at intervals, and a plurality of fourth sub-mask strips 512 that extend along the extension direction of the second defect region A2 and are arranged at intervals; the third sub-mask strips 511 and the fourth sub-mask strips 512 cross in the cross region BB to form a grid structure.

[0035] In some embodiments, in the above-mentioned spliced single-crystal diamond provided by the embodiments of the present disclosure, as Figure 3 and Figure 4As shown, the positive projection of the third sub-mask strip 511 on the spliced diamond substrate 1 overlaps with the positive projection of the gap between the adjacent first sub-mask strip 311 on the spliced diamond substrate 1, and the positive projection of the fourth sub-mask strip 512 on the spliced diamond substrate 1 overlaps with the positive projection of the gap between the adjacent second sub-mask strip 312 on the spliced diamond substrate 1. In this way, a dislocation design of the second Ti / Au mask layer 5 and the first Ti / Au mask layer 3 can be realized to ensure that all positions of the defect area AA are blocked by the mask strips, so as to obtain high-quality spliced diamond.

[0036] Specifically, as Figure 3 and Figure 4 shown, the second Ti / Au mask layer 5 can be laterally moved 5-10 μm relative to the first Ti / Au mask layer 3, that is, the second Ti / Au mask layer 5 and the first Ti / Au mask layer 3 form a stacked mask structure to improve the crystal quality of the uppermost spliced diamond.

[0037] It should be noted that the embodiments of the present disclosure can also continue to fabricate the mask layer and epitaxially grow the spliced single-crystal diamond on the basis of Figure 3 and Figure 4 to continuously improve the crystal quality of the uppermost epitaxially grown spliced diamond at the splicing seam until a large-size spliced single-crystal diamond with uniform overall quality is obtained. The number of times of continuously fabricating the mask layer and epitaxially growing the spliced single-crystal diamond is not limited, as long as it is ensured that the positive projection of the currently formed Ti / Au mask strip on the spliced diamond substrate overlaps with the positive projection of the gap between the adjacent Ti / Au mask strips formed in the previous time on the spliced diamond substrate.

[0038] Based on the same inventive concept, the embodiments of the present disclosure also provide a method for preparing a spliced single-crystal diamond. As Figure 5 shown, it includes: S1. Seed crystal splicing: splicing a plurality of diamond seeds to obtain a spliced diamond substrate; Specifically, a plurality of pre-treated diamond seeds are placed flat on the growth substrate and arranged closely with each other, so that the width of the splicing seam between the plurality of diamond seeds is less than 500 μm. Among them, the plurality of diamond seeds 11 can be arranged closely along the row direction, can be arranged closely along the column direction, or can be arranged in an array along the row direction and the column direction.

[0039] S2. Splicing growth: epitaxially growing on the surface of the spliced diamond substrate to form a whole spliced diamond epitaxial layer; Specifically, the spliced plurality of diamond seeds are placed in a microwave chamber for growth. Through lateral epitaxial growth, the diamond seeds are in contact with and connected to each other, and finally a whole spliced diamond epitaxial layer is obtained.

[0040] S3. Surface treatment: After grinding and polishing the surface of the spliced diamond epitaxial layer, it is placed in a hydrogen plasma atmosphere to expose the defect area of the spliced diamond epitaxial layer, and the defect area covers the splicing seams between multiple diamond seeds; Specifically, the defect area is a deteriorated quality area with defects such as stress concentration and dislocations at the splicing seam of the spliced diamond epitaxial layer. For spliced growth, as the diamond connection coverage process progresses, the stress concentration area will shift, making it difficult to determine the position of its defect area relative to the splicing seam. After polishing, it is even more difficult to define the scope of the defect area. Therefore, the present disclosure adopts surface treatment first, that is, the grown spliced diamond epitaxial layer is flattened by methods such as laser grinding and chemical mechanical polishing, and then the flattened spliced diamond epitaxial layer is placed in a hydrogen plasma atmosphere to expose the defect area of the spliced diamond epitaxial layer, which is convenient for accurately positioning the defect area and facilitating the determination of the preparation position of the subsequent mask layer, and then patterning mask treatment can more effectively improve the crystal quality.

[0041] S4. Patterning mask: A first Ti / Au mask layer is formed in the defect area, and the first Ti / Au mask layer includes a plurality of first Ti / Au mask strips extending along the extension direction of the splicing seam and arranged at intervals; Specifically, the defect area of the spliced diamond epitaxial layer after spliced growth is subjected to patterned mask plating. The mask layer covers the defect area. During the subsequent lateral epitaxial growth process, the mask layer can hinder the longitudinal extension of dislocations in the defect area of the spliced diamond epitaxial layer, reduce the dislocation density of the new epitaxial layer, and achieve the purpose of improving the diamond crystal quality. Moreover, the Ti / Au layer is used as the mask layer. The Ti layer can ensure adhesion, and the Au layer has good ductility, enabling the diamond grown epitaxially subsequently to have a space for stress release, reducing its fracture risk, and further improving the crystal quality.

[0042] Specifically, for the specific structure of the first Ti / Au mask layer and the corresponding beneficial effects, reference can be made to the relevant description in the aforementioned one kind of spliced single crystal diamond, and details will not be elaborated here.

[0043] S5. Epitaxial growth: Epitaxial growth is carried out on the surface of the spliced diamond epitaxial layer formed with the first Ti / Au mask layer to form a first spliced single crystal diamond; Specifically, the spliced diamond epitaxial layer formed with the first Ti / Au mask layer is placed in a microwave plasma chamber for epitaxial deposition growth. The plurality of first Ti / Au mask strips will hinder the longitudinal extension of defects such as dislocations in the defect area to the first spliced single crystal diamond, effectively reducing the dislocation density and improving the quality of the crystal.

[0044] The above preparation method provided by the embodiments of the present disclosure adopts a splicing epitaxial growth technology that is easier to connect, which can improve the crystal quality of the first spliced single-crystal diamond at the splicing seam, reduce the dislocation density of the first spliced single-crystal diamond at the splicing seam, and improve the overall performance of the first spliced single-crystal diamond, so as to achieve the purpose of expanding the diamond size while improving its growth quality. Compared with the traditional splicing growth method, through the above preparation method of the present disclosure, large-size spliced single-crystal diamonds with more uniform quality, smaller dislocation density, and smaller defect area can be obtained.

[0045] In some embodiments, in the above preparation method provided by the embodiments of the present disclosure, as Figure 6 shown, before step S1, it further includes: S10. Seed crystal pretreatment: Polishing and cleaning multiple diamond seed crystals with the same size specification.

[0046] Specifically, select multiple diamond seed crystals with similar crystal plane orientations, similar surface states, and almost the same height for pretreatment, including processes such as grinding, polishing, and cleaning, and finally obtain multiple diamond seed crystals with low surface roughness and small height difference.

[0047] In some embodiments, in the above preparation method provided by the embodiments of the present disclosure, in order to continuously improve the crystal quality of the finally obtained spliced single-crystal diamond at the splicing seam until a large-size spliced single-crystal diamond with uniform overall quality is obtained, after the above step S5, it may further include: repeating steps S3 - S5.

[0048] Specifically, as steps S3 - S5 are repeatedly executed, the dislocation density brought by the defect area will be reduced to the lowest, and a large-size spliced single-crystal diamond with the most improved quality will be obtained; the number of times of repeating steps S3 - S5 can be determined according to the crystal quality of the finally obtained spliced single-crystal diamond at the splicing seam, such as 2 times, 3 times, or even more times.

[0049] In some embodiments, in the above preparation method provided by the embodiments of the present disclosure, when repeating step S4, it is necessary to ensure that the positive projection of the currently formed Ti / Au mask strip on the spliced diamond substrate overlaps with the positive projection of the gap between the adjacent Ti / Au mask strips formed in the previous time on the spliced diamond substrate, so that the currently formed Ti / Au mask strip can hinder the longitudinal extension of the dislocations not blocked by the Ti / Au mask strip formed in the previous time, to continuously improve the crystal quality of the top-layer epitaxially grown spliced diamond at the splicing seam until a large-size spliced single-crystal diamond with uniform overall quality is obtained.

[0050] Specifically, the currently formed Ti / Au mask strip can be the result of a 5-10 μm lateral movement relative to the previously formed Ti / Au mask strip, so as to completely cover the dislocation extension in the initial defect area.

[0051] In some embodiments, in the above preparation method provided by the embodiments of the present disclosure, as Figure 7 shown, the above step S4 for patterning the mask specifically may include: S701. Form a spin-on resist layer on the surface of the spliced diamond epitaxial layer; Specifically, a 300-nm-thick lift-off resist layer can be spin-coated on the surface of the spliced diamond epitaxial layer and then baked.

[0052] S702. Spin-coat a photoresist layer on the side of the lift-off resist layer away from the spliced diamond epitaxial layer; Specifically, the photoresist layer can be a positive photoresist or a negative photoresist.

[0053] S703. Expose and develop the photoresist layer to form a plurality of windows extending along the splicing seam direction and arranged at intervals in the defect area, and the windows expose the spliced diamond epitaxial layer; Specifically, for example, the positive photoresist is exposed to UV light in a mask aligner through a photomask, and the exposed positive photoresist is developed and then rinsed in flowing deionized water and then dried in a nitrogen atmosphere.

[0054] S704. Form a Ti / Au layer on the side of the remaining photoresist layer away from the spliced diamond epitaxial layer; Specifically, a 100-nm-thick Ti / Au layer can be deposited on the side of the remaining positive photoresist away from the spliced diamond epitaxial layer by evaporation or magnetron sputtering, where the thickness of the Ti layer is 10 nm and the thickness of the Au layer is 90 nm.

[0055] S705. Remove the remaining lift-off resist layer and photoresist layer to obtain a first Ti / Au mask layer located in the window; Specifically, the remaining positive photoresist and the Ti / Au layer thereon are lifted off, and after cleaning, a first Ti / Au mask layer located in the window is finally obtained. For example, the width of the first Ti / Au mask strip is 5 μm, the gap width between adjacent first Ti / Au mask strips is 10 μm, and the thickness is 100 nm.

[0056] Next, taking specific embodiments as examples, the preparation method of the spliced single-crystal diamond provided by the present disclosure will be introduced in detail.

[0057] (1) Seed crystal pretreatment: Select a seed crystal with a crystal plane index of (100) and a length, width, and height of 10 mm 10mm Ten identical diamond single seeds were replicated from a 0.5 mm diamond seed crystal. The crystal plane index (100) indicates that the shape of the diamond seed crystal is a cubic face. Then, mechanical grinding and polishing were performed on multiple diamond seed crystals respectively to preliminarily reduce the roughness. Subsequently, chemical mechanical polishing was used for fine polishing to further reduce the roughness to <5 nm, making the heights of the ten diamond single seeds approximately the same, with the height difference controlled within ±50 μm. The processed diamond seed crystals were cleaned, and the cleaning process included boiling mixed acid pickling (using HNO 3 and H 2 SO 4 , and the volume ratio of the two was 1:3), ultrasonic cleaning with deionized water, and ultrasonic cleaning with acetone and ethanol. The cleaned diamond seed crystals were dried.

[0058] (2) Seed crystal splicing: As shown in Figure 8 and Figure 19 , Figure 8 is a three-dimensional schematic structure diagram, Figure 19 is Figure 8 the corresponding cross-sectional structure diagram. The processed diamond seed crystals 11 were placed flat on the growth molybdenum holder. The diamond seed crystals 11 were arranged in an array and closely packed with each other, with a gap of less than 500 μm, forming a spliced diamond substrate 1 on the molybdenum holder. Then, the molybdenum holder was placed on the growth base in the MPCVD chamber.

[0059] (3) Spliced growth: As shown in Figure 9 and Figure 20 , in the MPCVD chamber, spliced growth based on homoepitaxy was carried out. The hydrogen content was 95%, the methane content was 5%, the growth temperature was 950 ± 50 , the chamber pressure was 110 torr, and the growth time was 120 h. An integral spliced diamond epitaxial layer 2 was obtained on the surface of the spliced diamond substrate 1.

[0060] (4) Surface treatment: As shown in Figure 10 and Figure 21 , the spliced diamond epitaxial layer 2 after spliced growth was taken out, and methods such as grinding and chemical mechanical polishing were used to planarize the grown spliced diamond epitaxial layer 2, reducing the roughness to <5 nm. The planarized spliced diamond epitaxial layer 2 was placed in a hydrogen plasma atmosphere to expose the defect area AA.

[0061] (5) Patterning mask: As shown in Figure 11 and Figure 22 , a 300 nm thick lift-off resist layer was spin-coated on the defect area AA of the spliced diamond epitaxial layer 2 at a rotation speed of 4000 rpm, at 180 Bake for 20 min, and then spin coat a 1-μm-thick photoresist layer (such as a positive photoresist) on the peeled resist layer at a rotation speed of 5000 rpm. At 90 Bake for 30 min. After baking, expose the positive photoresist to UV light in a mask aligner through a photomask. After the exposed positive photoresist is developed, rinse it in flowing deionized water, dry it in a nitrogen atmosphere, and obtain a plurality of strip-shaped windows arranged at intervals, located in the defect area AA and extending along the extension direction of the splicing seam G. Then, etch for 5 min at low power to remove the PR residue in the windows. After that, use the magnetron sputtering method to deposit a 100-nm-thick Ti / Au layer on the surface of the spliced diamond epitaxial layer 2, with a 10-nm-thick Ti layer and a 90-nm-thick Au layer. After the deposition is completed, soak the diamond in the stripping solution for 1-2 h, strip the remaining positive photoresist and the Ti / Au layer thereon, and obtain a patterned first Ti / Au mask layer 3 on the surface of the spliced diamond epitaxial layer 2 after cleaning.

[0062] (6) Epitaxial growth: As Figure 12 and Figure 23 shown, place the spliced diamond with the patterned first Ti / Au mask layer 3 in the MPCVD chamber, etch for 5 min under low-power conditions, remove the surface residue, and then perform epitaxial deposition growth. The hydrogen content is 93%, the methane content is 7%, the growth temperature is 1000 ± 50 , the chamber pressure is 140 torr, and the growth time is 60 h. Perform epitaxial deposition growth to form the first spliced single-crystal diamond 4. The patterned first Ti / Au mask layer 3 will prevent dislocations and other defects in the defect area AA from extending longitudinally to the first spliced single-crystal diamond 4, effectively reducing the dislocation density and improving the crystal quality.

[0063] (7) Surface treatment: As Figure 13 and Figure 24 shown, repeat the above step (4) to expose the defect area of the first spliced single-crystal diamond 4, denoted as DD. The dislocation density in this defect area is lower than that in the defect area AA.

[0064] (8) Patterned mask: As Figure 14 and Figure 25 shown, repeat the above step (5) to obtain a patterned second Ti / Au mask layer 5 in the defect area of the first spliced single-crystal diamond 4.

[0065] (9) Epitaxial growth: As Figure 15 and Figure 26 shown, repeat the above step (6) to obtain a second spliced single-crystal diamond 6 with large size, high quality, and uniform overall quality.

[0066] (10) As Figures 16 - 18As shown, the above steps (4)-(6) can also be continued. Figure 16 The defective area of the second spliced single-crystal diamond 6 is exposed, denoted by EE, and the dislocation density of this defective area is lower than that of the BB area. Figure 17 A patterned third Ti / Au mask layer 7 is obtained in the defective area of the second spliced single-crystal diamond 6. The third Ti / Au mask layer 7 includes a plurality of fifth sub-mask strips 711 extending along the extending direction of the first defective area A1 and arranged at intervals, and a plurality of sixth sub-mask strips 712 extending along the extending direction of the second defective area A2 and arranged at intervals. Figure 18 A third spliced single-crystal diamond 8 with large size, high quality and more uniform overall quality is obtained by epitaxial growth.

[0067] It should be noted that, in the above preparation method provided by the embodiments of the present disclosure, the lithography process involved in forming each layer structure may not only include some or all of the process steps such as deposition, photoresist coating, mask template masking, exposure, development, etching, photoresist stripping, etc., but may also include other process steps, which are specifically subject to the pattern required in the actual production process and are not limited herein. For example, a post-baking process may be included after development and before etching. Among them, the deposition process may be chemical vapor deposition, plasma-enhanced chemical vapor deposition or physical vapor deposition, which is not limited herein; the mask plate used in the masking process may be a half-tone mask plate (Half Tone Mask), a single-slit diffraction mask plate (Single Slit Mask) or a gray-tone mask plate (Gray Tone Mask), which is not limited herein; the etching may be dry etching or wet etching, which is not limited herein.

[0068] Based on the same inventive concept, an embodiment of the present invention also provides a single-crystal diamond, as Figure 27 shown, including: A spliced diamond epitaxial layer 2, and the spliced diamond epitaxial layer 2 has a defective area AA. A first Ti / Au mask layer 3, located on one side of the spliced diamond epitaxial layer 2 and covering the defective area AA; the first Ti / Au mask layer 3 includes a plurality of first Ti / Au mask strips 31 extending along at least one direction and arranged at intervals. A first spliced single-crystal diamond 4, located on the side of the first Ti / Au mask layer 3 away from the spliced diamond epitaxial layer 2. The first spliced single-crystal diamond 4 fills the gaps of the first Ti / Au mask layer 3 and covers the surfaces of each first Ti / Au mask strip 31 and the spliced diamond epitaxial layer 2.

[0069] It should be noted that Figure 27 the single-crystal diamond shown is the structure obtained after peeling off the spliced diamond substrate 1 in Figure 2 ​Figure 27 For the specific structures, regions, materials, thicknesses, and beneficial effects of each film layer, reference can be made to Figure 1 and Figure 2 the relevant descriptions in , and details will not be elaborated here.

[0070] In some embodiments, in the above-mentioned single-crystal diamond provided by the embodiments of the present disclosure, as Figure 28 shown, it further includes: A second Ti / Au mask layer 5, located on the side of the first spliced single-crystal diamond 4 away from the spliced diamond epitaxial layer 2, and covering the defect region AA; the second Ti / Au mask layer 5 includes a plurality of second Ti / Au mask strips 51 arranged at intervals and having the same extending direction as the first Ti / Au mask strip 31, and the positive projection of the second Ti / Au mask strip 51 on the spliced diamond epitaxial layer 2 overlaps with the positive projection of the gap between adjacent first Ti / Au mask strips 31 on the spliced diamond epitaxial layer 2; A second spliced single-crystal diamond 6, located on the side of the second Ti / Au mask layer 5 away from the spliced diamond epitaxial layer 2, the second spliced single-crystal diamond 6 fills the gaps of the second Ti / Au mask layer 5, and covers the surfaces of each second Ti / Au mask strip 51 and the first spliced single-crystal diamond 4 away from the spliced diamond epitaxial layer 2.

[0071] It should be noted that Figure 28 the single-crystal diamond shown is a structure obtained after peeling off the spliced diamond substrate 1 in Figure 4 , and for the specific structures, regions, materials, thicknesses, and beneficial effects of each film layer in Figure 28 reference can be made to Figure 3 and Figure 4 the relevant descriptions in , and details will not be elaborated here.

[0072] The above-mentioned single-crystal diamond provided by the embodiments of the present disclosure can be applied to fields such as electronics, heat sinks, optical windows, and machining.

[0073] In a spliced single-crystal diamond, its preparation method, and a single-crystal diamond provided by the embodiments of the present disclosure, by using a plurality of first Ti / Au mask strips arranged at intervals as a blocking structure in the defect region of the spliced diamond epitaxial layer, when epitaxially growing the first spliced single-crystal diamond, it can hinder the longitudinal extension of the dislocations corresponding to the splicing seam of the spliced diamond epitaxial layer, and avoid the defect region AA being blocked by a whole piece of mask, thereby achieving the purpose of improving the quality of the epitaxially grown first spliced single-crystal diamond; moreover, the Ti / Au layer is used as a mask layer, the Ti layer can ensure adhesion, and the Au layer has good ductility, enabling the epitaxially grown first spliced single-crystal diamond to have a space for stress release, reducing its fracture risk, and further improving the crystal quality.

[0074] Although the preferred embodiments of the present disclosure have been described, additional changes and modifications can be made to these embodiments by those skilled in the art once they learn of the basic creative concept. Therefore, the appended claims are intended to be construed to include the preferred embodiments as well as all changes and modifications that fall within the scope of the present disclosure.

[0075] Obviously, those skilled in the art can make various changes and modifications to the present disclosure without departing from the spirit and scope of the present disclosure. Thus, if these modifications and variations of the present disclosure fall within the scope of the claims of the present disclosure and their equivalent technologies, the present disclosure is also intended to include these modifications and variations.

Claims

1. A spliced ​​single crystal diamond, characterized in that: include: A spliced ​​diamond substrate includes a plurality of spliced ​​diamond seed crystals, wherein there are splicing seams between the plurality of diamond seed crystals; A spliced ​​diamond epitaxial layer covers the surface of the spliced ​​diamond substrate, wherein the spliced ​​diamond epitaxial layer has a defective area covering the spliced ​​seam; A first Ti / Au mask layer is located on a side of the spliced ​​diamond epitaxial layer away from the spliced ​​diamond substrate and covers the defective area; the first Ti / Au mask layer comprises a plurality of first Ti / Au mask strips extending along an extension direction of the splicing seam and arranged at intervals; The first spliced ​​single crystal diamond fills the gaps in the first Ti / Au mask layer and covers the surfaces of each of the first Ti / Au mask strips and the spliced ​​diamond epitaxial layer away from the spliced ​​diamond substrate.

2. The spliced ​​single crystal diamond according to claim 1, characterized in that: The first Ti / Au mask layer includes: a Ti layer close to the spliced ​​diamond epitaxial layer, and an Au layer located on a side of the Ti layer away from the spliced ​​diamond epitaxial layer; the thickness of the Ti layer is smaller than the thickness of the Au layer.

3. The spliced ​​single crystal diamond according to claim 1, characterized in that: The joint seam includes a first joint seam between two adjacent rows of diamond seed crystals and a second joint seam between two adjacent columns of diamond seed crystals, the defect area includes a first defect area covering the first joint seam and a second defect area covering the second joint seam, and the first defect area and the second defect area have an intersection area; The first plurality of Ti / Au mask strips include: a plurality of first sub-mask strips extending along the extension direction of the first defect region and arranged at intervals, and a plurality of second sub-mask strips extending along the extension direction of the second defect region and arranged at intervals; the first sub-mask strips and the second sub-mask strips intersect in the intersection region to form a grid structure.

4. The spliced ​​single crystal diamond according to claim 3, characterized in that: The width of the first sub-mask strips and the second sub-mask strips is 1-10 μm, the gap width between adjacent first sub-mask strips and the gap width between adjacent second sub-mask strips is 5-20 μm, and the thickness of the first sub-mask strips and the second sub-mask strips is 50-1000 nm.

5. The spliced ​​single crystal diamond according to claim 3, characterized in that: Also includes: A second Ti / Au mask layer is located on a side of the first spliced ​​single crystal diamond away from the spliced ​​diamond substrate and covers the defective area; the second Ti / Au mask layer comprises a plurality of second Ti / Au mask strips extending along the splicing seam extension direction and arranged at intervals, and the orthographic projection of the second Ti / Au mask strips on the spliced ​​diamond substrate overlaps with the orthographic projection of the gap between adjacent first Ti / Au mask strips on the spliced ​​diamond substrate; The second spliced ​​single crystal diamond fills the gaps in the second Ti / Au mask layer and covers the second Ti / Au mask strips and the surface of the first spliced ​​single crystal diamond away from the spliced ​​diamond substrate.

6. The spliced ​​single crystal diamond according to claim 5, characterized in that: The plurality of second Ti / Au mask strips include: a plurality of third sub-mask strips extending along the extension direction of the first defect region and arranged at intervals, and a plurality of fourth sub-mask strips extending along the extension direction of the second defect region and arranged at intervals; the third sub-mask strips and the fourth sub-mask strips intersect in the intersection region to form a grid structure.

7. The spliced ​​single crystal diamond according to claim 6, characterized in that: The orthographic projection of the third sub-mask strip on the spliced ​​diamond substrate overlaps with the orthographic projection of the gap between the adjacent first sub-mask strips on the spliced ​​diamond substrate, and the orthographic projection of the fourth sub-mask strip on the spliced ​​diamond substrate overlaps with the orthographic projection of the gap between the adjacent second sub-mask strips on the spliced ​​diamond substrate.

8. A method for preparing spliced ​​single crystal diamond, characterized in that: include: S1. Seed crystal splicing: splicing multiple diamond seed crystals to obtain a spliced ​​diamond substrate; S2, splicing growth: performing epitaxial growth on the surface of the spliced ​​diamond substrate to form a whole surface of the spliced ​​diamond epitaxial layer; S3, surface treatment: grinding and polishing the surface of the spliced ​​diamond epitaxial layer and placing it in a hydrogen plasma atmosphere to expose defective areas of the spliced ​​diamond epitaxial layer, wherein the defective areas cover the splicing seams between the plurality of diamond seed crystals; S4, patterning mask: forming a first Ti / Au mask layer in the defect area, wherein the first Ti / Au mask layer includes a plurality of first Ti / Au mask strips extending along the extension direction of the joint seam and arranged at intervals; S5. Epitaxial growth: performing epitaxial growth on the surface of the spliced ​​diamond epitaxial layer formed with the first Ti / Au mask layer to form a first spliced ​​single crystal diamond.

9. The preparation method according to claim 8, characterized in that: Also includes: Repeat steps S3-S5.

10. The preparation method according to claim 9, characterized in that: When step S4 is repeatedly performed, the orthographic projection of the currently formed Ti / Au mask strip on the spliced ​​diamond substrate overlaps with the orthographic projection of the gap between the adjacent Ti / Au mask strips formed previously on the spliced ​​diamond substrate.

11. The preparation method according to any one of claims 8 to 10, characterized in that: Step S4 is to perform patterning of the mask, which specifically includes: forming a spin-on stripping resist layer on the surface of the spliced ​​diamond epitaxial layer; Spin coating a photoresist layer on a side of the stripping resist layer away from the spliced ​​diamond epitaxial layer; Exposing and developing the photoresist layer to form a plurality of windows extending along the extension direction of the splicing seam and arranged at intervals in the defective region, wherein the windows expose the spliced ​​diamond epitaxial layer; forming a Ti / Au layer on a side of the remaining photoresist layer away from the spliced ​​diamond epitaxial layer; The remaining stripping resist layer and the photoresist layer are removed to obtain the first Ti / Au mask layer located in the window.

12. A single crystal diamond, characterized in that: include: splicing diamond epitaxial layers, the spliced ​​diamond epitaxial layers having defective regions; A first Ti / Au mask layer is located on one side of the spliced ​​diamond epitaxial layer and covers the defective area; the first Ti / Au mask layer includes a plurality of first Ti / Au mask strips extending in at least one direction and arranged at intervals; The first spliced ​​single crystal diamond is located on a side of the first Ti / Au mask layer away from the spliced ​​diamond epitaxial layer. The first spliced ​​single crystal diamond fills the gaps in the first Ti / Au mask layer and covers the surfaces of each of the first Ti / Au mask strips and the spliced ​​diamond epitaxial layer.

13. The single crystal diamond according to claim 12, characterized in that Also includes: A second Ti / Au mask layer is located on a side of the first spliced ​​single crystal diamond away from the spliced ​​diamond epitaxial layer and covers the defective area; the second Ti / Au mask layer comprises a plurality of second Ti / Au mask strips extending in the same direction as the first Ti / Au mask strips and arranged at intervals, and the orthographic projection of the second Ti / Au mask strips on the spliced ​​diamond epitaxial layer overlaps the orthographic projection of the gap between adjacent first Ti / Au mask strips on the spliced ​​diamond epitaxial layer; The second spliced ​​single crystal diamond is located on a side of the second Ti / Au mask layer away from the spliced ​​diamond epitaxial layer. The second spliced ​​single crystal diamond fills the gaps in the second Ti / Au mask layer and covers the surfaces of each of the second Ti / Au mask strips and the first spliced ​​single crystal diamond away from the spliced ​​diamond epitaxial layer.

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