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CN-121992493-A - Preparation method of large-size single crystal diamond and growth base thereof

CN121992493ACN 121992493 ACN121992493 ACN 121992493ACN-121992493-A

Abstract

The invention discloses a growth base for preparing large-size monocrystalline diamond and a preparation method thereof. The growth base comprises a base, a main groove and an auxiliary groove positioned at the bottom of the main groove, wherein the depth relation of the auxiliary groove is that the depth of the auxiliary groove is less than or equal to the thickness of the seed crystal and less than or equal to the depth of the auxiliary groove and the depth of the main groove. The preparation method comprises the steps of S1 screening seed crystals, S2 cloning, separating and processing the seed crystals to obtain prepared seed crystals with the surface roughness Ra less than or equal to 10nm and the thickness difference less than or equal to 5 mu m, S3 trimming the growth surface and the side surface of the prepared seed crystals and determining the step flow direction, S4 loading the seed crystals into the auxiliary grooves of the base table according to the step flow direction for fixation, carrying out first epitaxial growth under negative bias, and S5 carrying out vacuum annealing, cutting polishing and second epitaxial growth on a growing body. The stable and closed growth environment is provided for the seed crystal through the base station structure, and the crystal quality at the splicing joint is effectively improved by combining the process, so that the preparation of the high-quality large-size single crystal diamond is realized.

Inventors

  • Request for anonymity
  • Request for anonymity
  • WANG LINXI
  • JIANG YICHEN
  • CHEN CHENG
  • ZHOU ZEHUA

Assignees

  • 浙江先导微电子科技有限公司

Dates

Publication Date
20260508
Application Date
20251231

Claims (10)

  1. 1. A growth substrate for use in the preparation of large-size single crystal diamond, comprising: A base (1); A main groove (5) arranged at the top of the base (1); the auxiliary groove (6) is arranged at the bottom of the main groove (5); the depth of the auxiliary groove (6) is D1, the depth of the main groove (5) is D2, and the requirements that D1 is less than or equal to H and less than or equal to (D1+D2) are met, and H is the thickness of the monocrystalline diamond seed crystal to be placed in the auxiliary groove (6).
  2. 2. A growth abutment as claimed in claim 1, further comprising a clamping block (2) and a clamping block recess, the clamping block recess being disposed within the primary recess (5) and being in communication with the secondary recess (6), the clamping block (2) being disposed within the clamping block recess for laterally compressing seed crystals disposed in the secondary recess (6); preferably, the depth D1 of the auxiliary groove (6) is 0.8 mm-1.1 mm; Preferably, the height of the clamping block (2) is equal to or smaller than the depth of the clamping block groove.
  3. 3. A method for producing a large-size single crystal diamond, characterized by using the growth stage according to claim 1 or 2, and comprising the steps of: S1, seed crystal screening, namely screening square single crystal diamond seed crystals with growth surfaces and side surfaces being (100) crystal faces, crystal orientation deflection angles being less than or equal to 2 degrees, raman half-height widths being less than or equal to 3cm -1 , X-ray rocking curves being less than or equal to 100 angular seconds and thicknesses being more than or equal to 1mm; S2, seed crystal cloning and processing, namely carrying out homoepitaxial growth on the screened seed crystal to obtain an epitaxial layer, separating the epitaxial layer from the seed crystal, and carrying out slicing and polishing on the separated epitaxial layer material to obtain at least two prepared seed crystals with the surface roughness Ra less than or equal to 10nm and the thickness difference less than or equal to 5 mu m; S3, seed crystal finishing, namely processing the side surface of the prepared seed crystal to ensure that the included angle between the side surface and the horizontal plane is 90 degrees plus or minus 0.1 degree, the height difference is less than or equal to 5 mu m, and determining the step flow growth direction; S4, clamping and splicing growth, namely aligning the trimmed prepared seed crystals according to the step flow direction, and placing the prepared seed crystals into a secondary groove (6) of the growth base to fix the seed crystals so that the splicing gaps among the seed crystals are less than or equal to 5 mu m and the height difference is less than or equal to 5 mu m; And S5, annealing, cutting polishing and regrowing, namely performing first vacuum annealing on the diamond subjected to the first epitaxial growth, performing cutting polishing treatment after the first vacuum annealing, and performing second epitaxial growth.
  4. 4. The method according to claim 3, wherein in the step S2, the process conditions of the homoepitaxial growth include 500-1000 sccm of hydrogen gas flow, 6-8% of methane concentration, 1-2% of oxygen concentration, 1-3% of nitrogen gas concentration, 850-940 ℃ of pressure, 23-25 kPa of pressure, and 120-140 hours of growth time.
  5. 5. The preparation method according to claim 3 or 4, further comprising a step of pre-growing the prepared seed crystal before the step S3, wherein the pre-growing process condition is the same as that of the step S2, the pre-growing time is 5-10 h, and the temperature difference of the seed crystal is less than or equal to 10 ℃.
  6. 6. The method according to claim 3, wherein in the step S4, the first epitaxial growth process conditions include a hydrogen flow of 500-1000 sccm, a methane concentration of 6-8%, an oxygen concentration of 1-3%, a nitrogen concentration of 2-5%o, a temperature of 840-920 ℃ and a pressure of 23-25 kPa, and a growth time of at least 140h, wherein 24h before growth, the nitrogen concentration is greater than 2%o, and the nitrogen concentration gradually decreases to 2%o after full growth for 24 h.
  7. 7. The method according to claim 3, wherein in step S5, the temperature of the first vacuum annealing is 1400 ℃ to 1700 ℃ for 2 to 5 hours.
  8. 8. The method according to claim 3, wherein in the step S5, the process conditions of the second epitaxial growth include a hydrogen flow of 500-1000 sccm, a methane concentration of 6-8%, an oxygen concentration of 1-2%, a nitrogen concentration of 1-3%o, a temperature of 870-920 ℃, a pressure of 23-25 kPa, and a growth time of at least 140h.
  9. 9. The method according to claim 3, wherein in step S5, the diamond edge obtained after the first vacuum annealing is trimmed and cut and polished until the surface roughness Ra is less than or equal to 10nm.
  10. 10. The preparation method of the vacuum annealing device according to claim 4, wherein the process of performing the second vacuum annealing after the cutting and polishing in the step S5 is characterized in that the temperature rising rate is 2-5 ℃ per minute, the annealing temperature is 1200-1400 ℃, the heat preservation is performed for 14-24 h, and the cooling rate is 5-10 ℃ per minute.

Description

Preparation method of large-size single crystal diamond and growth base thereof Technical Field The invention relates to the technical field of semiconductor material preparation, in particular to a base structure for growing diamond and a method for preparing large-size monocrystalline diamond by adopting the base. Background Monocrystalline diamond is widely used in high-end science and technology fields due to its extreme physicochemical properties. However, it is difficult to prepare single crystal diamond of a size of more than an inch class by conventional methods. The mosaic splicing method is the most promising solution at present, but has the core difficulty that defects such as high-density dislocation, polycrystal, microcrack and the like are extremely easy to generate at the splicing seam (interface between seed crystals), so that the performance of the area is seriously deteriorated, and the overall reliability of the product is influenced. The prior art, such as the patent publication CN110184653a, proposes to score grooves at the splice joint to guide growth, while the patent CN117779205A proposes to repair V-grooves by preferential growth. The methods improve the splicing growth to a certain extent, but still have the problems of complex process, high defect density at the splicing seam, unstable growth process and the like. Accordingly, there is a need in the art for a solution that enables systematic optimization of the control of the para-to-growth environment from seed preparation, precision, to simply and stably produce large-sized diamond. Disclosure of Invention The invention aims to provide a large-size single crystal diamond preparation method capable of effectively improving splicing quality and simple and convenient to operate and a growth base thereof, so as to solve at least one technical problem in the background art. In order to achieve the above purpose, the technical scheme adopted by the invention is as follows: in one aspect, the present invention provides a growth substrate for large-size single crystal diamond preparation, comprising: A base; The main groove is arranged at the top of the base; The auxiliary groove is arranged at the bottom of the main groove; the depth of the auxiliary groove is D1, the depth of the main groove is D2, and the requirements that D1 is less than or equal to H (D1+D2) and H is the thickness of the monocrystalline diamond seed crystal to be placed in the auxiliary groove are met. In another aspect, the present invention provides a method for preparing a large-sized single crystal diamond, using the growth substrate, comprising the steps of: S1, seed crystal screening, namely screening square single crystal diamond seed crystals with growth surfaces and side surfaces being (100) crystal faces, crystal orientation deflection angles being less than or equal to 2 degrees, raman half-height widths being less than or equal to 3cm -1, X-ray rocking curves being less than or equal to 100 angular seconds and thicknesses being more than or equal to 1mm; S2, seed crystal cloning and processing, namely carrying out homoepitaxial growth on the screened seed crystal to obtain an epitaxial layer, separating the epitaxial layer from the seed crystal, and carrying out slicing and polishing on the separated epitaxial layer material to obtain at least two prepared seed crystals with the surface roughness Ra less than or equal to 10nm and the thickness difference less than or equal to 5 mu m; S3, seed crystal finishing, namely processing the side surface of the prepared seed crystal to ensure that the included angle between the side surface and the horizontal plane is 90 degrees plus or minus 0.1 degree, the height difference is less than or equal to 5 mu m, and determining the step flow growth direction; S4, clamping and splicing growth, namely aligning the trimmed prepared seed crystals according to the step flow direction, and placing the prepared seed crystals into a secondary groove of the growth base to fix the seed crystals so that the splicing gaps among the seed crystals are less than or equal to 5 mu m and the height difference is less than or equal to 5 mu m; And S5, annealing, cutting polishing and regrowing, namely performing first vacuum annealing on the diamond subjected to the first epitaxial growth, performing cutting polishing treatment after the first vacuum annealing, and performing second epitaxial growth. Compared with the prior art, the invention has the beneficial effects that: The invention provides a plasma field growth environment with excellent uniformity for seed crystals by using the growth base with double-layer grooves, combines seed crystal pretreatment, bias splicing process and post-growth cutting polishing treatment, effectively ensures the flatness and crystal orientation consistency of a splicing interface, reduces the defect density at a splicing joint, and realizes the controllable preparation of high-quality large-size si