CN117448950A - Method for reducing mutual interference of diamond crystal growth based on edge laser etching treatment - Google Patents
Method for reducing mutual interference of diamond crystal growth based on edge laser etching treatment Download PDFInfo
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- CN117448950A CN117448950A CN202311430505.7A CN202311430505A CN117448950A CN 117448950 A CN117448950 A CN 117448950A CN 202311430505 A CN202311430505 A CN 202311430505A CN 117448950 A CN117448950 A CN 117448950A
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- 239000013078 crystal Substances 0.000 title claims abstract description 110
- 229910003460 diamond Inorganic materials 0.000 title claims abstract description 74
- 239000010432 diamond Substances 0.000 title claims abstract description 74
- 238000000034 method Methods 0.000 title claims abstract description 38
- 238000010329 laser etching Methods 0.000 title claims abstract description 23
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 45
- 229910002804 graphite Inorganic materials 0.000 claims abstract description 40
- 239000010439 graphite Substances 0.000 claims abstract description 40
- 238000004140 cleaning Methods 0.000 claims abstract description 17
- 238000000259 microwave plasma-assisted chemical vapour deposition Methods 0.000 claims abstract description 10
- 239000007789 gas Substances 0.000 claims description 12
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 8
- 229910052799 carbon Inorganic materials 0.000 claims description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 5
- 239000002253 acid Substances 0.000 claims description 4
- 239000012159 carrier gas Substances 0.000 claims description 4
- 238000004040 coloring Methods 0.000 claims description 4
- 239000008367 deionised water Substances 0.000 claims description 4
- 229910021641 deionized water Inorganic materials 0.000 claims description 4
- 229910052757 nitrogen Inorganic materials 0.000 claims description 4
- 239000003960 organic solvent Substances 0.000 claims description 4
- 238000005406 washing Methods 0.000 claims description 4
- 230000000903 blocking effect Effects 0.000 abstract description 4
- 230000009286 beneficial effect Effects 0.000 abstract description 2
- 238000005520 cutting process Methods 0.000 description 6
- 238000010586 diagram Methods 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 238000005498 polishing Methods 0.000 description 3
- 241000201976 Polycarpon Species 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 230000004888 barrier function Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000005229 chemical vapour deposition Methods 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 238000005488 sandblasting Methods 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C30—CRYSTAL GROWTH
- C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
- C30B25/00—Single-crystal growth by chemical reaction of reactive gases, e.g. chemical vapour-deposition growth
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/36—Removing material
- B23K26/362—Laser etching
-
- C—CHEMISTRY; METALLURGY
- C30—CRYSTAL GROWTH
- C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
- C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
- C30B29/02—Elements
- C30B29/04—Diamond
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Metallurgy (AREA)
- Crystallography & Structural Chemistry (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- General Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Plasma & Fusion (AREA)
- Mechanical Engineering (AREA)
- Crystals, And After-Treatments Of Crystals (AREA)
Abstract
The invention provides a method for reducing mutual interference of diamond crystal growth based on edge laser etching treatment, and belongs to the field of diamond growth. The method comprises the following steps: s1: selecting a proper diamond seed crystal, and cleaning the diamond seed crystal; s2: carrying out laser etching on four sides of the diamond to enable the edge of the seed crystal to form a graphite area in which graphite is easy to grow; s3: placing the seed crystal into an MPCVD cavity for diamond blank growth; s4: and (3) processing the blank after the growth, and removing polycrystal and graphite at the edge to obtain the diamond monocrystal. The invention has the beneficial effects that compared with the prior art: according to the invention, the laser etching is performed on the four sides of the seed crystal, so that the edge of the seed crystal is changed into a graphite area easy to grow graphite, a blocking area is formed, the seed crystal is prevented from horizontally growing along the edge, the seed crystal is further prevented from horizontally expanding, and the mutual interference of diamond crystal growth is reduced.
Description
Technical Field
The invention belongs to the field of diamond growth, and relates to a method for reducing the mutual interference of diamond crystal growth based on edge laser etching treatment.
Background
Diamond is a crystal body composed of carbon elements and having a cubic crystal structure. Diamond has the highest hardness among all known materials, as well as excellent optical and thermal properties, and is widely used in various industrial processes and semiconductor industries.
There are two technical paths for crystal growth of diamond. One is high temperature and pressure, which simulates diamond formation under natural geological conditions, typically using high pressures of 4-7GPa and high temperatures of 1000-1500 ℃. Another method is a CVD method in which atoms of diamond form diamond crystals by means of layered growth on a diamond seed under vacuum conditions. Among various diamond growth CVD growth methods, MPCVD growth is a currently mainstream growth method due to advantages such as high purity and high crystal quality.
In MPCVD growth, seed selection and treatment are central factors for improving the production yield, and seed selection is generally controlled by parameters such as the size, crystal orientation, crystal face and the like of the seed. In the current MPCVD growth, based on factors such as cost, process and the like, diamond crystal seeds with (001) crystal faces are generally selected, the side length of each crystal seed is generally between 7 and 40mm, and the thickness of each crystal seed is generally between 0.3 and 1.5 mm; for the crystal orientation of the crystal seed four sides, two types are generally adopted in MPCVD growth, one four sides are in a <100> crystal orientation, the other four sides are in a <110> crystal orientation, and the two crystal orientations are relatively easy to control the growth direction, so that the yield of diamond growth can be ensured.
In the MPCVD diamond growth process, if a microwave frequency of 2.45GHz is used, the current growth table diameter is between 50mm and 100 mm; if a microwave frequency of 915MHz is used, the diameter of the growth stage is between 100 and 300 mm. Since the seed crystal size is much smaller than the growth stage, it is conventional practice to place as many seed crystals as possible on the growth stage, thereby improving the batch yield and reducing the production cost. Common placement modes include:
1) Placing in a zero gap, wherein the seed crystals are all close together, and the growth of the seed crystals can be mutually influenced;
2) Gap placement, see fig. 1, the gap between the seeds is controlled between 0.3 and 1.5mm, and the gap is selected to be matched with the process parameters. In this growth mode, both seeds are used in the growth. Interactions between seeds fall into two cases due to the anisotropy of diamond growth rate;
for the seed crystal with <100> side, the seed crystal generally grows outwards in the direction of the plane of the seed crystal, and eventually two adjacent seed crystals are contacted with each other, the surface of the last seed crystal extends to the surface of the other seed crystal, and finally, a part of the surface of the covered seed crystal does not grow in the vertical direction, and the seed crystal with the extended crystal face is generally difficult to use, and finally, the yield is reduced;
for the seed crystal of <110> edge, during crystal growth, the <110> edge will shrink inward, resulting in a reduced growth surface, eventually forming a cone, and eventually resulting in a reduced overall yield.
In sum, both of these approaches result in reduced yields and reduced yields. Based on this, how to reduce the mutual interference in the diamond crystal growth process is a problem to be solved in the prior art.
Disclosure of Invention
In order to solve the problems, the invention aims to provide a method for reducing the mutual interference of diamond crystal growth based on edge laser etching treatment, which can avoid the mutual interference and extrusion of diamond crystals in the growth process and ensure that all crystal seeds on a growth table can grow in a balanced and stable way.
In order to achieve the above object, the present invention has the following technical scheme.
The invention provides a method for reducing the mutual interference of diamond crystal growth based on edge laser etching treatment, which comprises the following steps:
s1: selecting a proper diamond seed crystal, and cleaning the diamond seed crystal;
s2: carrying out laser etching on four sides of the diamond to enable the edge of the seed crystal to form a graphite area in which graphite is easy to grow;
s3: placing the seed crystal into an MPCVD cavity for diamond blank growth;
s4: cutting and polishing the grown blank, and removing the polycrystal and graphite at the edge to obtain the diamond monocrystal.
Further, in step S1, the side length of the diamond seed crystal is 7-50mm, and the directions of four sides are parallel to the <100> crystal phase.
Further, in step S1, the cleaning process of the diamond seed crystal is as follows: acid washing, organic solvent cleaning and deionized water cleaning, and removing attachments on the surface of the seed crystal.
Further, in step S2, since the diamond monocrystal cannot be grown on the graphite, only graphite can be grown, and after the graphite region is formed by laser etching, a blocking region is formed, so that the crystal seed is prevented from horizontally growing along the edge, the crystal seed is prevented from horizontally expanding, and the mutual interference of the diamond crystal growth is reduced.
Further, in step S2, the thickness of the graphite region exceeds 0.05mm, and the smoothness of the graphite region and the edge line reaches 5umRa or more.
In step S2, the shape of the graphite region is one of a sawtooth shape and a rectangle shape, and if the graphite region is a sawtooth shape, the direction of the sawtooth is parallel to the <110> direction, and the width of the sawtooth is not more than 1mm; in the case of a rectangle, the four sides of the rectangle are parallel to the <100> direction, and the width of the rectangle is not more than 1mm.
Further, in step S3, the growth conditions are:
process gas: the carrier gas is H2, and the flow rate ranges from 500sccm to 10slm; the carbon source is CH4, and the flow is 6-14% of H2; the coloring gas is N2, N2 is added by pure nitrogen or mixed gas, and the content of N2 is 10ppm to 8000ppm of CH 4;
growth pressure: 80-250Torr;
growth power: microwave power 5kW to 70kW;
growth temperature: 900-1300 ℃;
growth rate: 6-500um/hr.
The invention has the beneficial effects that compared with the prior art: according to the invention, the laser etching is performed on the four sides of the seed crystal, so that the edge of the seed crystal is changed into a graphite area easy to grow graphite, a blocking area is formed, the seed crystal is prevented from horizontally growing along the edge, the seed crystal is further prevented from horizontally expanding, and the mutual interference of diamond crystal growth is reduced.
Drawings
Fig. 1 is a photomicrograph of a prior art gap-setting diamond seed after growth.
Fig. 2 is a photomicrograph of a saw-edged diamond seed crystal after growth in example 1.
Fig. 3 is a schematic diagram of diamond seeds forming graphite regions after side treatment in example 1.
Fig. 4 is a second schematic diagram of diamond seeds forming graphite regions after side treatment in example 1.
Fig. 5 is a schematic diagram III of a diamond seed crystal forming graphite regions after the side treatment in example 1.
Detailed Description
The present invention will be described in further detail with reference to the following examples in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.
In order to achieve the above object, the technical scheme of the present invention is as follows.
With reference to figures 2-5 of the drawings,
example 1:
the embodiment provides a method for reducing the mutual interference of diamond crystal growth based on edge laser etching treatment, which comprises the following steps:
s11: selecting a proper diamond seed crystal, and cleaning the diamond seed crystal;
s12: carrying out laser etching on four sides of the diamond to enable the edge of the seed crystal to form a graphite area in which graphite is easy to grow;
s13: placing the seed crystal into an MPCVD cavity for diamond blank growth;
s14: cutting and polishing the grown blank, and removing the polycrystal and graphite at the edge to obtain the diamond monocrystal.
Further, in step S11, the diamond seed crystal has a side length of 7-50mm, and the directions of four sides are parallel to the <100> crystal phase.
Further, in step S11, the cleaning process of the diamond seed crystal is as follows: acid washing, organic solvent cleaning and deionized water cleaning, and removing attachments on the surface of the seed crystal.
Further, in step S12, since the diamond monocrystal cannot be grown on the graphite, only graphite can be grown, and after the graphite region is formed by laser etching, a blocking region is formed, so that the crystal seed is prevented from horizontally growing along the edge, the crystal seed is prevented from horizontally expanding, and the mutual interference of the diamond crystal growth is reduced.
Further, in step S12, the thickness of the graphite region exceeds 0.05mm, and the smoothness of the graphite region and the edge line reaches 5umRa or more.
Further, in step S12, the shape of the graphite region is one of a sawtooth shape and a rectangle shape, and if the graphite region is a sawtooth shape, the direction of the sawtooth is parallel to the <110> direction, and the width of the sawtooth is not more than 1mm; in the case of a rectangle, the four sides of the rectangle are parallel to the <100> direction, and the width of the rectangle is not more than 1mm.
Further, in step S13, the growth conditions are:
process gas: the carrier gas is H2, and the flow is 500sccm; the carbon source is CH4, and the flow is H2 6; the coloring gas is N2, N2 is added by a pure nitrogen mode or a mixed gas mode, and the N2 content is 10ppm of CH 4;
growth pressure: 80Torr;
growth power: microwave power 5kW;
growth temperature: 900 degrees celsius;
growth rate: 6um/hr.
As can be seen from a comparison of fig. 2 and fig. 1, after the edge of the seed crystal is treated by a laser etching process to form a graphite region, the growth of the seed crystal along the horizontal direction can be reduced, and the mutual interference of the growth of the seed crystal can be avoided.
Example 2:
the embodiment provides a method for reducing the mutual interference of diamond crystal growth based on edge laser etching treatment, which comprises the following steps:
s21: selecting a proper diamond seed crystal, and cleaning the diamond seed crystal;
s22: mechanically cutting four sides of the seed crystal to form a sawtooth-shaped edge, wherein the sawtooth direction is parallel to the <110> direction, so that the edge of the seed crystal becomes a region easy to grow polycrystal or graphite;
s23: placing the seed crystal into an MPCVD cavity for diamond blank growth;
s24: cutting and polishing the grown blank, and removing the polycrystal and graphite at the edge to obtain the diamond monocrystal.
Further, in step S21, the diamond seed crystal has a side length of between 50mm, and the directions of four sides are parallel to the <100> crystal phase.
Further, in step S21, the cleaning process of the diamond seed crystal is as follows: acid washing, organic solvent cleaning and deionized water cleaning, and removing attachments on the surface of the seed crystal.
Further, in step S22, the edge of the seed crystal is mechanically cut, so that the two sides of the saw tooth are in the <110> direction, the growth in the <110> direction will not expand, the edge of the seed crystal becomes a region where polycrystalline or graphite is easy to grow, a barrier region is formed, the seed crystal is prevented from horizontally growing along the edge, further, the horizontal expansion of the seed crystal is prevented, and the mutual interference of diamond crystal growth is reduced.
Further, in step S22, the mechanical cutting method includes laser, water jet, and sand blasting; during mechanical cutting, part or all of the seed thickness may be cut.
Further, in step S22, the width of the saw tooth is not more than 1mm, the depth of the saw tooth is more than 0.1mm, the smoothness of the upper edge line of the saw tooth is more than 3umRa, and the smoothness of the side surface of the saw tooth is more than 5 umRa.
Further, in step S23, the growth conditions are:
process gas: the carrier gas is H2, and the flow is 10slm; the carbon source is CH4, and the flow is 14% of H2; the coloring gas is N2, N2 is added by a pure nitrogen mode or a mixed gas mode, and the N2 content is 8000ppm of CH 4;
growth pressure: 250Torr;
growth power: microwave power 70kW;
growth temperature: 1300 degrees celsius;
growth rate: 500um/hr.
The above embodiments are merely illustrative of the present invention, and the protective scope of the present invention is not limited to the above embodiments only. The object of the present invention can be achieved by those skilled in the art based on the above disclosure of the present invention and the ranges taken by the parameters.
Claims (6)
1. The method for reducing the mutual interference of diamond crystal growth based on the edge laser etching treatment comprises the following steps:
s1: selecting a proper diamond seed crystal, and cleaning the diamond seed crystal;
s2: carrying out laser etching on four sides of the diamond to enable the edge of the seed crystal to form a graphite area in which graphite is easy to grow;
s3: placing the seed crystal into an MPCVD cavity for diamond blank growth;
s4: and (3) processing the blank after the growth, and removing polycrystal and graphite at the edge to obtain the diamond monocrystal.
2. The method for reducing mutual interference of diamond crystal growth based on an edge laser etching process according to claim 1, wherein in step S1, the diamond seed has a side length of 7-50mm, and the directions of four sides are parallel to <100> crystal phase.
3. The method for reducing mutual interference of diamond crystal growth based on an edge laser etching process according to claim 1, wherein in step S1, the cleaning process of the diamond seed crystal is: acid washing, organic solvent cleaning and deionized water cleaning, and removing attachments on the surface of the seed crystal.
4. The method for reducing mutual interference of diamond crystal growth based on an edge laser etching process according to claim 1, wherein in step S2, the thickness of the graphite region exceeds 0.05mm, and the smoothness of the graphite region and the edge line reaches 5umRa or more.
5. The method for reducing mutual interference of diamond crystal growth based on edge laser etching process according to claim 1, wherein in step S2, the shape of the graphite region is one of saw teeth and rectangular, and if saw teeth are formed, the saw teeth are parallel to the <110> direction, and the width of the saw teeth is not more than 1mm; in the case of a rectangle, the four sides of the rectangle are parallel to the <100> direction, and the width of the rectangle is not more than 1mm.
6. The method for reducing mutual interference of diamond crystal growth based on an edge laser etching process according to claim 1, wherein in step S3, the growth conditions are:
process gas: the carrier gas is H2, and the flow rate ranges from 500sccm to 10slm; the carbon source is CH4, and the flow is 6-14% of H2; the coloring gas is N2, N2 is added by pure nitrogen or mixed gas, and the content of N2 is 10ppm to 8000ppm of CH 4;
growth pressure: 80-250Torr;
growth power: microwave power 5kW to 70kW;
growth temperature: 900-1300 ℃;
growth rate: 6-500um/hr.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202311430505.7A CN117448950A (en) | 2023-10-31 | 2023-10-31 | Method for reducing mutual interference of diamond crystal growth based on edge laser etching treatment |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202311430505.7A CN117448950A (en) | 2023-10-31 | 2023-10-31 | Method for reducing mutual interference of diamond crystal growth based on edge laser etching treatment |
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