Substrate for diamond growth

Abstract

The substrate for diamond growth comprises a splicing unit group, and the splicing unit group comprises a first single crystal diamond which comprises a first bottom surface and a first front surface and serves as a first substrate, and a second single crystal diamond which comprises a second bottom surface and a second front surface and serves as a second substrate; the second single crystal diamond comprises a second bottom surface and a second front surface and serves as a second substrate; the single crystal diamond is characterized by further comprising a connecting piece, in the splicing state, the first front face of the first single crystal diamond and the second front face of the second single crystal diamond are spliced to form a growth surface with a small splicing seam, and an inverted-V-shaped notch is formed between the first bottom face and the second bottom face. Due to the arrangement of the inverted-V-shaped notches of the splicing unit groups, the first front face and the second front face abut against each other to form a growth face, the point effect is not obvious, and meanwhile the smaller splicing seams are, the smaller the influences brought by lattice dislocation can be reduced; due to the arrangement of the inverted-V-shaped notches, the connecting pieces can be conveniently arranged on the first bottom surface and the second bottom surface, and the stability of the splicing unit group structure is kept.

Description

Technical Field

[0001] The utility model relates to the field of joining single crystal or uniform polycrystalline materials with a certain structure, in particular to a substrate for diamond growth. Background Art

[0002] Diamond has become one of the most promising materials in semiconductor materials due to its high thermal conductivity, high breakdown electric field, and high carrier mobility. However, compared with other semiconductor materials (such as Si, SiC, and GaN), the biggest obstacle to the application of diamond is the lack of high-quality single crystals at the inch level.

[0003] The main methods for preparing large-size single-crystal diamond wafers include heteroepitaxial growth, three-dimensional growth, and splicing growth, among which splicing growth is the most commonly used method among all the preparation methods. The splicing method is also called the Mosaic method, which is a method for preparing large-size single crystals by closely arranging multiple small-area conventional single-crystal diamond seed crystals and depositing and growing them on top to form a large-area single-crystal diamond. The splicing method has obvious advantages in preparing large-area single-crystal diamonds and can prepare inch-level single-crystal diamond wafers, but the splicing method also has disadvantages. The splicing joints are enriched with various forms of defects such as dislocations, polycrystalline, interfaces, and microcracks, which affect the mechanical strength, optical transmittance, and electrical properties, making it impossible to obtain high-quality large-size diamonds, which limits the advanced applications of large-size spliced ​​diamonds.

[0004] There are also some patents on the splicing growth method of large-sized single crystal diamond in the prior art, such as the Chinese patent application with publication number CN110184653A, which proposes to splice after grooving the splicing seam of two seed crystals, or the Chinese patent application with publication number CN117779205A, which proposes to preferentially grow and repair the V-shaped groove at the splicing seam for splicing. These splicing methods all achieve the splicing growth of two seed crystals by modifying the structure of the splicing groove at the splicing seam. However, the splicing groove of the existing splicing substrate at the splicing seam is notched upward, and the splicing seam is large, which will make it impossible for the single crystal diamond on the growth surface on both sides of the V-shaped groove to grow continuously, and there are problems of different crystal orientations and tip effects. The crystal quality at the splicing seam of the grown epitaxial layer is still poor.

[0005] Therefore, it is necessary to design a new growth substrate to prepare large-size, high-quality single-crystal diamond. Utility Model Content

[0006] The technical problem to be solved by the utility model is to provide a substrate for diamond growth with good crystal quality at the joint seam in view of the above-mentioned existing technical status.

[0007] The technical solution adopted by the utility model to solve the above technical problems is: the substrate for diamond growth includes a splicing unit group, and the splicing unit group includes:

[0008] A first single crystal diamond, including a first bottom surface attached to the growth base and a first front surface directly used for diamond growth, as a first substrate;

[0009] A second single crystal diamond, including a second bottom surface in contact with the growth base and a second front surface directly used for diamond growth, serving as a second substrate;

[0010] Features:

[0011] The first front surface of the first single crystal diamond is cut to a first deviation angle of β degrees to be spliced, facing the first bottom surface; similarly,

[0012] The second front surface of the second single crystal diamond is cut to face the second bottom surface so that the second deviation angle to be assembled is γ degrees;

[0013] It also includes a connecting piece connecting the first single crystal diamond and the second single crystal diamond. In the assembled state, the first front side of the first single crystal diamond is assembled with the second front side of the second single crystal diamond to form a growth surface with a small joint, and a notch in an inverted V shape of α degrees is formed between the first bottom surface of the first single crystal diamond and the second bottom surface of the second single crystal diamond, and α=β+γ.

[0014] In order to ensure a stable connection between the first single crystal diamond and the second single crystal diamond, further, the first single crystal diamond and the second single crystal diamond are provided with an embedding opening for embedding the connecting piece in the area between the front and bottom surfaces of each. The user completes the splicing of the first substrate and the second substrate by embedding the connecting piece in the embedding opening, thereby preventing the problem of repeated startup and splicing alignment caused by the airflow blowing off the splicing piece when the splicing unit group is sent into the microwave plasma growth system for growth.

[0015] In order to reduce the temperature difference on both sides of the assembled unit group, the insertion opening is further parallel to the front or bottom surface of each single crystal diamond, and the connecting piece is a strip of diamond. The connecting piece plays an auxiliary heat transfer function for the diamond, so that the temperature distribution of the first single crystal diamond and the second single crystal diamond is uniform.

[0016] In order to make the growth surface of the spliced ​​unit group flush, further, the first deviation angle is β degrees, and 0°<β<1.5°, the second deviation angle is γ degrees, and 0°<γ<1.5°, the splicing seam width is 1-60μm, and the thickness difference between the first single crystal diamond and the second single crystal diamond is 0-40μm. The width of the splicing seam is much smaller than that of the prior art, which makes the quality of the large-sized diamond grown by the spliced ​​unit group at the splicing seam better than that of the existing spliced ​​growth substrate.

[0017] Compared with the prior art, the advantages of the utility model are:

[0018] 1. The inverted V-shaped notch direction of the splicing unit group is set so that the first front side and the second front side are against each other to form a growth surface. The width of the splicing seam on the growth surface is only 1-60 μm. The smaller the seam width, the closer the distance between the splicing pieces, and the less obvious the tip effect. At the same time, the smaller the splicing seam, the less the impact of lattice dislocation.

[0019] 2. The setting of the inverted V-shaped notch also facilitates the setting of the connectors on the first bottom surface and the second bottom surface. Users do not need to fill the notch for growth but for the setting of the connectors, thus maintaining the stability of the splicing unit group structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of a splicing unit group according to an embodiment of the utility model;

[0021] Figure 2 It is a partial enlarged view of the longitudinal section of the splicing unit group at the notch of the embodiment of the utility model;

[0022] Figure 3 It is a structural schematic diagram of the embedding opening of the splicing unit group according to an embodiment of the utility model. DETAILED DESCRIPTION

[0023] The present invention will be described in further detail below in conjunction with the accompanying drawings.

[0024] like Figures 1 to 3 The figure shows the best embodiment of the utility model. The substrate for diamond growth of the present embodiment is mainly used for the growth of diamond. When the diamond to be grown is large in size, multiple growth substrates are often spliced ​​into a large growth substrate to grow larger diamonds. However, the quality of the existing large-sized diamonds grown by this method at the splicing seam is not ideal. It does not take into account the crystal orientation problem and the tip effect at the seed crystal splicing. The interface position defect density is high, which leads to poor crystal quality at the splicing seam of the grown epitaxial layer. Therefore, it is beneficial to provide a substrate for diamond growth with good crystal quality at the splicing seam. The structure of the substrate for diamond growth will be described below:

[0025] See also Figure 1 and Figure 2 The substrate for diamond growth includes a splicing unit group 1, which includes a first single crystal diamond 11 and a second single crystal diamond 12, wherein the first single crystal diamond 11 includes a first bottom surface 111 attached to a growth base 3 and a first front surface 112 directly used for diamond growth, and serves as a first substrate; the second single crystal diamond 12 includes a second bottom surface 121 attached to the growth base 3 and a second front surface 122 directly used for diamond growth, and serves as a second substrate; the first front surface 112 of the first single crystal diamond 11 is cut to the first bottom surface 111 into a first deviation angle of β degrees to be spliced ; Similarly, the second front side 122 of the second single crystal diamond 12 is cut to the second bottom side 121 to form a second deviation angle of γ degrees to be spliced; the splicing unit group 1 also includes a connector 13 connecting the first single crystal diamond 11 and the second single crystal diamond 12. In the spliced ​​state, the first front side 112 of the first single crystal diamond 11 is spliced ​​with the second front side 122 of the second single crystal diamond 12 to form a growth surface with a small splicing seam 14, and a notch 10 with a splicing inverted V shape of α degrees is formed between the first bottom side 111 of the first single crystal diamond 11 and the second bottom side 121 of the second single crystal diamond 12, and α=β+γ. The closer the distance that the diamond epitaxial layer needs to cover the splicing seam 14, the less time is required for covering. In the long-term growth process, the lattice may be dislocated, resulting in polycrystalline phenomenon. The smaller the splicing seam 14, the less the impact of lattice dislocation can be reduced.

[0026] See also Figure 3 The first single crystal diamond 11 and the second single crystal diamond 12 are provided with an embedding opening 15 for embedding the connecting piece 13 in the area between the front and bottom surfaces thereof. The user completes the splicing of the first substrate and the second substrate by embedding the connecting piece 13 in the embedding opening 15, thereby preventing the problem of repeated startup and splicing alignment caused by the airflow blowing off the splicing piece when the splicing unit group 1 is sent into the microwave plasma growth system for growth, so that the first single crystal diamond 11 and the second single crystal diamond 12 are firmly connected.

[0027] The insertion opening 15 is parallel to the front or bottom surface of each single crystal diamond, and the connecting member 13 is a strip of diamond. The connecting member 13 assists the heat transfer of the diamond, so that the temperature distribution of the first single crystal diamond 11 and the second single crystal diamond 12 is uniform, and the temperature difference on both sides of the spliced ​​unit group 1 is reduced.

[0028] See also Figure 2, the first deviation angle is β degrees, and 0.5°<β<1°, β is preferably 0.75°, the second deviation angle is γ degrees, and 0.5°<γ<1°, γ is preferably 0.75°; the width of the joint 14 is 1 to 60 μm, and the thickness difference between the first single crystal diamond 11 and the second single crystal diamond 12 is 0 to 40 μm. The width of the joint 14 is much smaller than that of the prior art, which makes the quality of the large-sized diamond grown by the joint unit group 1 better than that of the existing joint growth substrate at the joint, and also makes the growth surface of the joint upper surface of the joint unit group 1 flush.

[0029] The advantage of the substrate for diamond growth in this embodiment is that the first front side 112 of the cut first single crystal diamond 11 and the second front side 122 of the second single crystal diamond 12 are spliced ​​to form a growth surface with a small joint, so that the crystal orientation at the joint is the same, and at the same time, the width of the joint 14 is only 1 to 60 μm, the tip effect is small, and the probability of cracks and polycrystalline phenomena in the single crystal diamond grown at the joint is reduced.

Claims

1. A substrate for diamond growth, comprising a spliced ​​unit group (1), wherein the spliced ​​unit group (1) comprises: A first single crystal diamond (11), comprising a first bottom surface (111) in contact with a growth base and a first front surface (112) directly used for diamond growth, serving as a first substrate; A second single crystal diamond (12) includes a second bottom surface (121) that fits the growth base and a second front surface (122) that is directly used for diamond growth, serving as a second substrate; Features: The first front surface (112) of the first single crystal diamond (11) is cut to a first deviation angle of β degrees toward the first bottom surface (111) to be spliced; similarly, The second front surface (122) of the second single crystal diamond (12) is cut toward the second bottom surface (121) to be assembled so that the second deviation angle is γ degrees; The invention also comprises a connecting member (13) for connecting the first single crystal diamond (11) and the second single crystal diamond (12); in a spliced ​​state, the first front surface (112) of the first single crystal diamond (11) and the second front surface (122) of the second single crystal diamond (12) are spliced ​​to form a growth surface with a small splicing seam (14); and a notch (10) in an inverted V shape with an angle of α is formed between the first bottom surface (111) of the first single crystal diamond (11) and the second bottom surface (121) of the second single crystal diamond (12), and α=β+γ.

2. The substrate for diamond growth according to claim 1, characterized in that: The first single crystal diamond (11) and the second single crystal diamond (12) are provided with an embedding opening (15) for embedding the connecting member (13) in the area between the front surface and the bottom surface of each.

3. The substrate for diamond growth according to claim 2, characterized in that: The embedding opening (15) is parallel to the front surface or the bottom surface of each single crystal diamond, and the connecting piece (13) is a diamond in the form of a strip.

4. The substrate for diamond growth according to any one of claims 1 to 3, characterized in that: The first deviation angle is β degrees, and 0°<β<1.5°, the second deviation angle is γ degrees, and 0°<γ<1.5°, the width of the joint seam (14) is 1 to 60 μm, and the thickness difference between the first single crystal diamond (11) and the second single crystal diamond (12) is 0 to 40 μm.

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