CN113652746B - Method for improving quality of single crystal diamond - Google Patents
Method for improving quality of single crystal diamond Download PDFInfo
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- CN113652746B CN113652746B CN202111224634.1A CN202111224634A CN113652746B CN 113652746 B CN113652746 B CN 113652746B CN 202111224634 A CN202111224634 A CN 202111224634A CN 113652746 B CN113652746 B CN 113652746B
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- 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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- 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
Abstract
A method of improving the quality of single crystal diamond comprising the steps of: before growth, obtaining the gas leakage rate in the growth furnace, and judging whether the measured value of the gas leakage rate is in a standard set interval or not so as to determine whether to introduce nitrogen-hydrogen mixed gas or not in the growth process; when the measured value of the gas leakage rate is larger than the maximum standard value, the nitrogen-hydrogen mixed gas is not introduced until the growth is finished; when the measured value of the gas leakage rate is smaller than the maximum standard value, introducing nitrogen-hydrogen mixed gas into the growth furnace when the growth starts until the growth is finished; and the content of the introduced nitrogen-hydrogen mixed gas is gradually increased along with the reduction of the measured value of the gas leakage rate in the range of the interval smaller than the maximum standard value of the gas leakage rate. The invention can match the corresponding introduction amount of the nitrogen-hydrogen mixed gas according to different gas leakage rates, and can obtain the diamond with a stepped single crystal growth mechanism, and the diamond has few polycrystalline points, smooth surface, no hillock and no defect.
Description
Technical Field
The invention belongs to the technical field of diamond preparation by adopting a chemical vapor deposition method, and particularly relates to a method for improving the quality of single crystal diamond based on the vacuum performance of a growth furnace.
Background
The MPCVD method is a mainstream method for growing single crystal diamond at present and is also a preferred method for growing high-quality single crystal diamond. The vacuum performance of the MPCVD device is different due to different methods of equipment manufacture, material selection, structure design and assembly of accessories of various MPCVD equipment manufacturers, so that the phenomena of yellowing and browning of the color of the single crystal diamond, generation of polycrystalline points on the surface, cracking inside the single crystal wafer and the like can occur in the process of growing the single crystal diamond by corresponding technologists. These phenomena are related to the vacuum performance of the MPCVD apparatus, and the concentration of nitrogen in the reaction gas is controlled according to the vacuum performance of the apparatus, thereby avoiding the above phenomena. Therefore, the invention is important to judge the vacuum performance of the growth furnace to improve the quality of the single crystal diamond.
Disclosure of Invention
The invention provides a method for improving the quality of single crystal diamond, which matches the corresponding introduction amount of nitrogen-hydrogen mixed gas according to the measured gas leakage rate in a growth furnace so as to obtain better defect-free high-quality single crystal diamond.
In order to solve the technical problems, the invention adopts the technical scheme that:
a method of improving the quality of single crystal diamond comprising the steps of:
before growth, obtaining the gas leakage rate in a growth furnace, and judging whether the measured value of the gas leakage rate is in a standard set interval or not so as to determine whether to introduce nitrogen-hydrogen mixed gas or not in the growth process;
when the measured value of the gas leakage rate is larger than the maximum standard value, the nitrogen-hydrogen mixed gas is not introduced until the growth is finished;
when the measured value of the gas leakage rate is smaller than the maximum standard value, introducing the nitrogen-hydrogen mixed gas into the growth furnace when the growth starts until the growth is finished;
and the content of the introduced nitrogen-hydrogen mixed gas is gradually increased along with the reduction of the measured value of the gas leakage rate in the range of the interval smaller than the maximum standard value of the gas leakage rate.
Further, when the gas leakage rate is less than the minimum standard value, the introduction amount of the nitrogen-hydrogen mixed gas is unchanged, and the volume ratio is 0.1-0.2%.
Further, the maximum standard value of the air leakage rate is 1 × 10-8Pa·m3/s；
And the minimum standard value of the air leakage rate is 1 multiplied by 10-10Pa·m3/s。
Furthermore, at least two groups of intervals are arranged between the maximum standard value and the minimum standard value of the air leakage rate, and the intervals are respectively 1 multiplied by 10-9-1×10-8Pa·m3S and 1X 10-10-1×10-9Pa·m3/s；
When the air leakage rate is 1 × 10-9-1×10-8Pa·m3When the volume ratio is within the/s, the volume ratio of the nitrogen-hydrogen mixed gas is 0-0.05%;
when the air leakage rate is 1 × 10-10-1×10-9Pa·m3The volume ratio of the nitrogen-hydrogen mixed gas is 0.05-0.1% within the volume/s.
Further, the gas leakage rate is obtained by helium mass spectrometer detection.
Further, the volume ratio of hydrogen to nitrogen in the nitrogen-hydrogen mixed gas is 99: 1; and the purity thereof is not less than 5N.
Further, when the growth starts, methane gas is always introduced into the growth furnace until the growth is finished; wherein the volume ratio of the methane gas is 5-10%, and the purity of the methane gas is not less than 5N.
Further, before the growing, the method further comprises:
selecting a plurality of single crystal diamond seed crystals with the same size;
pretreating the diamond seed crystal;
and placing the pretreated diamond seed crystal in the growth furnace to prepare for deposition.
Further, the diamond seed crystal is pretreated, specifically including:
placing the diamond seed crystals in a mixed solution of concentrated sulfuric acid and concentrated nitric acid with a volume ratio of 3:1 for acid washing, and carrying out acid washing for 1-4h at a constant temperature when the acid washing temperature is 250 ℃;
respectively ultrasonically cleaning the diamond seed crystals in alcohol and acetone for 15 min;
and finally, drying the diamond seed crystals in a dryer.
Further, the step of placing the pretreated diamond seed crystal in the growth furnace for deposition specifically comprises:
placing the diamond seed crystal on a deposition table in the growth furnace;
closing the growing furnace door, vacuumizing, and controlling the air pressure in the growing furnace to be 1 x 10-2Below torr;
introducing hydrogen and adjusting the gas pressure to be 6-20 torr;
starting a microwave power supply, adjusting the microwave input power to 800-;
adjusting the microwave power and the reaction pressure, and enabling the temperature of the diamond seed crystal to be in the range of 800-1100 ℃ for preparing growth.
The method for improving the quality of the single crystal diamond designed by the invention is adopted to match the corresponding introduction amount of the nitrogen-hydrogen mixed gas required to be introduced during the growth according to different gas leakage rates, and under the condition that other conditions are not changed, the gas leakage rate is 1 multiplied by 10 under the condition that other conditions are not changed-10-1×10-8Pa·m3When the volume ratio of nitrogen-hydrogen mixed gas is 0-0.2% in the range of/s, the obtained diamond with a single crystal growth mechanism of stepped growth has few polycrystalline points, smooth surface, no hillock and no defect. And a small amount of nitrogen is doped, so that the growth of lattice defects through internal and external stress can be prevented, the generation of polycrystalline points is reduced, and the growth of diamond crystals is facilitated.
Drawings
FIG. 1 shows an embodiment of the present invention when the air leakage rate is greater than 1 × 10-8Pa·m3A real object diagram of the single crystal diamond obtained at/s;
FIG. 2 shows the leakage rate of 1 × 10 in one embodiment of the present invention-10-1×10-8Pa·m3A physical diagram of the single crystal diamond obtained at a time between/s;
FIG. 3 shows an embodiment of the present invention when the air leakage rate is less than 1 × 10-10A physical map of the single crystal diamond obtained.
Detailed Description
The invention is described in detail below with reference to the figures and specific embodiments.
Before deposition growth, the gas leakage rate in the growth furnace needs to be monitored to determine the content of air permeating into the furnace outside the growth furnace, so that the content of nitrogen-hydrogen mixed gas introduced into the growth furnace can be accurately judged, and the high-quality single crystal diamond can be prepared only by the method. Therefore, how to divide the gas leakage rate interval and determine the content of the corresponding nitrogen-hydrogen mixed gas discharged into the growth furnace in the interval range of the corresponding gas leakage rate is the key point of the invention.
The embodiment provides a method for improving the quality of single crystal diamond, which comprises the following steps:
before growth, obtaining the gas leakage rate in the growth furnace, and judging whether the measured value of the gas leakage rate is in a standard set interval or not so as to determine whether to introduce nitrogen-hydrogen mixed gas or not in the growth process; when the measured value of the gas leakage rate is larger than the maximum standard value, the nitrogen-hydrogen mixed gas is not introduced until the growth is finished; when the measured value of the gas leakage rate is smaller than the maximum standard value, introducing mixed gas containing nitrogen into the growth furnace when the growth starts until the growth is finished; and the content of the introduced nitrogen-hydrogen mixed gas is gradually increased along with the reduction of the measured value of the gas leakage rate in the range of the interval smaller than the maximum standard value of the gas leakage rate. The purpose is to judge whether excess air enters the growth furnace or not by testing the air leakage rate in the growth furnace to reflect the vacuum performance in the growth furnace; this is because the nitrogen gas contained in the air requires the content of the nitrogen-hydrogen mixed gas to gradually increase as the vacuum performance in the growth furnace decreases, that is, as the measured value of the gas leakage rate decreases. In this embodiment, it is only necessary to monitor the gas leakage rate in the growth furnace once before the growth, so as to accurately know how much nitrogen-hydrogen mixed gas is introduced into the growth furnace during the growth process.
When the air leakage rate is less than the minimum standard value, the introduction amount of the nitrogen-hydrogen mixed gas is unchanged, the volume ratio is 0.1-0.2% all the time until the growth is finished, and then the introduction is stopped. At this time, the air entering the growth furnace is less, so that nitrogen-hydrogen mixed gas with more volume ratio can be introduced into the growth furnace.
The maximum standard value of the air leakage rate is 1X 10-8Pa·m3S, when the measured value of the air leakage rate is more than 1 x 10-8Pa·m3When the concentration is in the second range, nitrogen-hydrogen mixed gas does not need to be introduced into the growth furnace in the growth process. At this time, the vacuum performance in the growth furnace is poor, and more air is introduced, so that nitrogen-hydrogen mixed gas does not need to be introduced into the growth furnace.
The minimum standard value of the air leakage rate is 1 × 10-10Pa·m3S, when the value of the measured air leakage rate is less than 1 x 10-10Pa·m3And when the nitrogen and hydrogen mixed gas is in the second time, continuously introducing the nitrogen and hydrogen mixed gas with the volume ratio of 0.1-0.2% into the growth furnace in the growth process, and stopping introducing until the growth is finished.
At least two groups of intervals are arranged between the maximum standard value and the minimum standard value of the air leakage rate, and the intervals are respectively 1 multiplied by 10-9-1×10-8Pa·m3S and 1X 10-10-1×10-9Pa·m3/s。
When the air leakage rate is 1 × 10-9-1×10-8Pa·m3And when the concentration is within/s, continuously introducing the nitrogen-hydrogen mixed gas with the volume ratio of 0-0.05% in the growth process until the growth is finished.
When the air leakage rate is 1 × 10-10-1×10-9Pa·m3And in the/s range, continuously introducing the nitrogen-hydrogen mixed gas with the volume ratio of 0.05-0.1% in the growth process, and stopping introducing until the growth is finished.
In this embodiment, the gas leakage rate is obtained by helium mass spectrometer detection, and the nitrogen-hydrogen mixed gas is a nitrogen-hydrogen mixed gas, that is, a mixture of 99% by volume of hydrogen and 1% by volume of nitrogen is included, that is, the volume ratio of hydrogen to nitrogen in the nitrogen-hydrogen mixed gas is 99: 1; and the purity of the nitrogen-hydrogen mixed gas is not less than 5N.
Further, before the growth, the method also comprises the step of continuously introducing methane gas into the growth furnace until the growth is finished. Wherein the volume ratio of the methane gas is 5-10%, and the purity of the methane gas is not less than 5N. Namely, no matter what the air leakage rate is, the methane gas is always introduced into the growth furnace, and the volume ratio of the introduced methane gas is always between 5 and 10 percent, so that the quality of diamond nucleation and nucleation in the growth process can be ensured.
Further, before the growing, the method further comprises the following steps:
firstly, selecting a plurality of single crystal diamond seed crystals with the same size.
And then, pretreating the diamond seed crystal, specifically:
placing the diamond seed crystals in a mixed solution of concentrated sulfuric acid and concentrated nitric acid for acid washing, wherein the volume ratio of the concentrated sulfuric acid to the concentrated nitric acid is 3: 1; pickling for 1-4h at a constant temperature when the pickling temperature is 250 ℃;
respectively ultrasonically cleaning diamond seed crystals in alcohol and acetone for 15 min;
and finally, drying the diamond seed crystals in a dryer.
Placing the pretreated diamond seed crystal in a growth furnace for deposition, and specifically comprising the following steps:
placing diamond seed crystals on a deposition table in a growth furnace;
closing the furnace door and vacuumizing, and controlling the air pressure in the growth furnace at 1 × 10-2Below torr;
introducing hydrogen and adjusting the pressure in the furnace to 6-20 torr;
starting a microwave power supply, adjusting the microwave input power to 800-;
adjusting the microwave power and the reaction pressure, and enabling the temperature of the diamond seed crystal to be in the range of 800-1100 ℃ for preparation of deposition.
In this embodiment, the volume ratio of all gases is relative to the volume of hydrogen in the reaction chamber, because the main gas in the actual deposition process is hydrogen, which can form a plasma to form the deposition environment required for diamond grain growth. Meanwhile, the hydrogen atoms of the plasma can etch the graphite phase generated in the growth process of the diamond grains, and the growth of the diamond is facilitated.
In order to make the method of the present invention more comprehensible to those skilled in the art, the technical solutions of the present invention will be explained in detail with reference to specific embodiments, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments.
Example 1:
a method for improving the quality of single crystal diamond comprises the following steps:
(1) detecting the vacuum performance gas leakage rate of the growth furnace by using a helium mass spectrometer to obtain the gas leakage rate of the growth furnace of 1 multiplied by 10-7Pa·m3S, greater than 1X 10-8Pa·m3S; the nitrogen-hydrogen mixed gas does not need to be introduced during the growth.
(2) Selecting a plurality of monocrystal diamond seed crystals with consistent grain size.
(3) Placing the diamond seed crystals in a mixed solution of concentrated sulfuric acid and concentrated nitric acid with a volume ratio of 3:1 for pickling, heating the pickling temperature to 250 ℃, and pickling for 1-4h at a constant temperature;
respectively ultrasonically cleaning diamond seed crystals in alcohol and acetone tanks for 15 min;
and finally, drying the diamond seed crystals in a dryer.
(4) Placing the diamond seed crystal after pretreatment on a molybdenum support in a growth furnace, and then placing the diamond seed crystal on a deposition table in a reaction chamber;
closing the growth furnace cavity door, vacuumizing and controlling the reaction pressure in the growth furnace to be 1 x 10-2Below torr; introducing hydrogen and adjusting the reaction pressure in the growth furnace to 6-20 torr;
starting a microwave power supply, adjusting the microwave input power to 800-;
adjusting the microwave power and enabling the temperature of the diamond seed crystal to be within the range of 800-1100 ℃; the diamond growth deposition was prepared by passing 8% methane through and the aeration was stopped until the growth was complete.
As shown in FIG. 1, it is a diagram of a diamond material obtained by the method of example 1, and it can be seen from the diagram that the growth furnace is usedAir leakage rate greater than 1 × 10-8Pa·m3And at the time of s, the vacuum performance in the growth furnace is poor, at the time, nitrogen in the air outside the growth furnace permeates into the reaction cavity to participate in the reaction, and the grown diamond shows yellowing and browning in color, has nitrogen-based defects, and also has the problems of microcracks, micro-inclusions and the like.
Example 2:
a method for improving the quality of single crystal diamond comprises the following steps:
(1) detecting the vacuum performance gas leakage rate of the growth furnace by using a helium mass spectrometer to obtain the gas leakage rate of the growth furnace of 0.8 multiplied by 10-8Pa·m3S at 1X 10-9 -1×10-8Pa·m3The interval/s; then nitrogen-hydrogen mixed gas with volume ratio of 0-0.05% is needed to be introduced during growth.
(2) Selecting a plurality of monocrystal diamond seed crystals with consistent grain size.
(3) Placing the diamond seed crystals in a mixed solution of concentrated sulfuric acid and concentrated nitric acid with a volume ratio of 3:1 for pickling, heating the pickling temperature to 250 ℃, and pickling for 1-4h at a constant temperature;
respectively ultrasonically cleaning diamond seed crystals in alcohol and acetone tanks for 15 min;
and finally, drying the diamond seed crystals in a dryer.
(4) Placing the diamond seed crystal after pretreatment on a molybdenum support in a growth furnace, and then placing the diamond seed crystal on a deposition table in a reaction chamber;
closing the growth furnace cavity door, vacuumizing and controlling the reaction pressure in the growth furnace to be 1 x 10-2Below torr; introducing hydrogen and adjusting the reaction pressure in the growth furnace to 6-20 torr;
starting a microwave power supply, adjusting the microwave input power to 800-;
adjusting the microwave power and enabling the temperature of the diamond seed crystal to be within the range of 800-1100 ℃;
and introducing 5% by volume of methane and 0.02% by volume of nitrogen-hydrogen mixed gas to prepare for diamond growth deposition, and stopping introducing gas until the growth is finished.
Example 3:
a method for improving the quality of single crystal diamond comprises the following steps:
(1) detecting the vacuum performance gas leakage rate of the growth furnace by using a helium mass spectrometer to obtain the gas leakage rate of the growth furnace of 0.5 multiplied by 10-9Pa·m3S at 1X 10-10-1×10-9Pa·m3The interval/s; then nitrogen-hydrogen mixed gas with volume ratio of 0.05-0.1% is needed to be introduced during growth.
(2) Selecting a plurality of monocrystal diamond seed crystals with consistent grain size.
(3) Placing the diamond seed crystals in a mixed solution of concentrated sulfuric acid and concentrated nitric acid with a volume ratio of 3:1 for pickling, heating the pickling temperature to 250 ℃, and pickling for 1-4h at a constant temperature;
respectively ultrasonically cleaning diamond seed crystals in alcohol and acetone tanks for 15 min;
and finally, drying the diamond seed crystals in a dryer.
(4) Placing the diamond seed crystal after pretreatment on a molybdenum support in a growth furnace, and then placing the diamond seed crystal on a deposition table in a reaction chamber;
closing the growth furnace cavity door, vacuumizing and controlling the reaction pressure in the growth furnace to be 1 x 10-2Below torr; introducing hydrogen and adjusting the reaction pressure in the growth furnace to 6-20 torr;
starting a microwave power supply, adjusting the microwave input power to 800-;
adjusting the microwave power and enabling the temperature of the diamond seed crystal to be within the range of 800-1100 ℃;
and introducing 9% by volume of methane and 0.08% by volume of nitrogen-hydrogen mixed gas to prepare diamond growth deposition, and stopping introducing gas until the growth is finished.
As shown in FIG. 2, the graph of the diamond obtained by the method of example 2 and example 3 shows that the air leakage rate of the growth furnace is 1X 10-10-1×10-8Pa·m3When the temperature is within the/s interval, the vacuum performance of the growth furnace is better, the air leakage rate is lower, and at the moment, a small amount of nitrogen in the air outside the growth furnace can permeate into the reaction chamber to participate in the reaction to grow outThe diamond of (2) has high purity, few polycrystalline points, smooth surface, no hillock and no defects.
Example 4:
a method for improving the quality of single crystal diamond comprises the following steps:
(1) the helium mass spectrometer is used for detecting the vacuum performance gas leakage rate of the growth furnace, and the gas leakage rate of the growth furnace is 0.7 multiplied by 10-10Pa·m3S is less than 1 × 10-10Pa·m3S; then nitrogen-hydrogen mixed gas with volume ratio of 0.1-0.2% is needed to be introduced during growth.
(2) Selecting a plurality of monocrystal diamond seed crystals with consistent grain size.
(3) Placing the diamond seed crystals in a mixed solution of concentrated sulfuric acid and concentrated nitric acid with a volume ratio of 3:1 for pickling, heating the pickling temperature to 250 ℃, and pickling for 1-4h at a constant temperature;
respectively ultrasonically cleaning diamond seed crystals in alcohol and acetone tanks for 15 min;
and finally, drying the diamond seed crystals in a dryer.
(4) Placing the diamond seed crystal after pretreatment on a molybdenum support in a growth furnace, and then placing the diamond seed crystal on a deposition table in a reaction chamber;
closing the growth furnace cavity door, vacuumizing and controlling the reaction pressure in the growth furnace to be 1 x 10-2Below torr; introducing hydrogen and adjusting the reaction pressure in the growth furnace to 6-20 torr;
starting a microwave power supply, adjusting the microwave input power to 800-;
adjusting the microwave power and enabling the temperature of the diamond seed crystal to be within the range of 800-1100 ℃;
and introducing 7% by volume of methane and 0.15% by volume of nitrogen-hydrogen mixed gas to prepare for diamond growth deposition, and stopping introducing gas until the growth is finished.
Is a graph of a diamond material obtained by the method of example 4, as shown in FIG. 2, it can be seen from the graph that when the air leakage rate of the growth furnace is less than 1X 10-10Pa·m3At the time of/s, the vacuum performance of the growth furnace is very good, the air leakage rate is low, and at the time, the growth furnace is arranged in the air outside the growth furnaceThe nitrogen only permeates into the reaction chamber to participate in the reaction, a certain amount of nitrogen-hydrogen mixed gas needs to be introduced, the growth mechanism of the diamond can be represented as step-type growth, and macroscopically, the diamond is represented as smooth without hillocks, so that the growth of diamond crystals is facilitated. And a small amount of nitrogen is doped, so that the growth of lattice defects through internal and external stress can be prevented, and the generation of polycrystalline points is reduced.
Example 5:
a method for improving the quality of single crystal diamond comprises the following steps:
(1) the helium mass spectrometer is used for detecting the vacuum performance gas leakage rate of the growth furnace, and the gas leakage rate of the growth furnace is 0.7 multiplied by 10-10Pa·m3S is less than 1 × 10-10Pa·m3S; the nitrogen-hydrogen mixed gas is not introduced.
(2) Selecting a plurality of monocrystal diamond seed crystals with consistent grain size.
(3) Placing the diamond seed crystals in a mixed solution of concentrated sulfuric acid and concentrated nitric acid with a volume ratio of 3:1 for pickling, heating the pickling temperature to 250 ℃, and pickling for 1-4h at a constant temperature;
respectively ultrasonically cleaning diamond seed crystals in alcohol and acetone tanks for 15 min;
and finally, drying the diamond seed crystals in a dryer.
(4) Placing the diamond seed crystal after pretreatment on a molybdenum support in a growth furnace, and then placing the diamond seed crystal on a deposition table in a reaction chamber;
closing the growth furnace cavity door, vacuumizing and controlling the reaction pressure in the growth furnace to be 1 x 10-2Below torr; introducing hydrogen and adjusting the reaction pressure in the growth furnace to 6-20 torr;
starting a microwave power supply, adjusting the microwave input power to 800-;
adjusting the microwave power and enabling the temperature of the diamond seed crystal to be within the range of 800-1100 ℃;
methane was added at 7% volume in preparation for diamond growth deposition, and aeration was stopped until growth was complete.
As shown in FIG. 3, the diamond compact obtained by the method of example 5 was usedAs can be seen from the figure, when the gas leakage rate of the growth furnace is less than 1X 10-10Pa·m3At the time of the second generation, the vacuum performance of the growth furnace is very good, the air leakage rate is extremely low, only a small amount of nitrogen in the air outside the growth furnace can permeate into the reaction chamber to participate in the reaction, and the mixed gas of nitrogen and hydrogen is not introduced into the growth furnace, so that the purity of the grown diamond is high, the lattice defects can grow through internal and external stress, but polycrystalline points are easily formed on the surface of the single crystal diamond, and the quality is better than that of the single crystal diamond shown in the figure 1 but is not as good as that of the single crystal diamond shown in the figure 2.
The method for improving the quality of the single crystal diamond designed by the invention is adopted to match the corresponding introduction amount of the nitrogen-hydrogen mixed gas required to be introduced during the growth according to different gas leakage rates, and under the condition that other conditions are not changed, the gas leakage rate is 1 multiplied by 10-10-1×10-8Pa·m3When the volume ratio of nitrogen-hydrogen mixed gas is 0-0.2% in the range of/s, the obtained diamond with a single crystal growth mechanism of stepped growth has few polycrystalline points, smooth surface, no hillock and no defect. And a small amount of nitrogen is doped, so that the growth of lattice defects through internal and external stress can be prevented, the generation of polycrystalline points is reduced, and the growth of diamond crystals is facilitated.
The embodiments of the present invention have been described in detail, and the description is only for the preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. All equivalent changes and modifications made within the scope of the present invention shall fall within the scope of the present invention.
Claims (4)
1. A method of improving the quality of single crystal diamond, comprising the steps of:
before growth, obtaining the gas leakage rate in a growth furnace, and judging whether the measured value of the gas leakage rate is in a standard set interval or not so as to determine whether to introduce nitrogen-hydrogen mixed gas or not in the growth process;
when the measured value of the gas leakage rate is larger than the maximum standard value, the nitrogen-hydrogen mixed gas is not introduced until the growth is finished;
when the measured value of the gas leakage rate is smaller than the maximum standard value, introducing the nitrogen-hydrogen mixed gas into the growth furnace when the growth starts until the growth is finished;
and the content of the introduced nitrogen-hydrogen mixed gas is gradually increased along with the reduction of the measured value of the gas leakage rate in the range of the interval smaller than the maximum standard value of the gas leakage rate;
when the gas leakage rate is less than the minimum standard value, the introduction amount of the nitrogen-hydrogen mixed gas is unchanged, and the volume ratio is 0.1-0.2%;
the maximum standard value of the air leakage rate is 1 multiplied by 10-8Pa·m3/s；
And the minimum standard value of the air leakage rate is 1 multiplied by 10-10Pa·m3/s；
Two groups of intervals are arranged between the maximum standard value and the minimum standard value of the air leakage rate, and the intervals are respectively 1 multiplied by 10-9-1×10- 8Pa·m3S and 1X 10-10-1×10-9Pa·m3/s；
When the air leakage rate is 1 × 10-9-1×10-8Pa·m3When the volume ratio is within the/s, the volume ratio of the nitrogen-hydrogen mixed gas is 0-0.05%;
when the air leakage rate is 1 × 10-10-1×10-9Pa·m3When the volume ratio is within the range of/s, the volume ratio of the nitrogen-hydrogen mixed gas is 0.05-0.1%;
the gas leakage rate is obtained by detecting through a helium mass spectrometer;
the volume ratio of hydrogen to nitrogen in the nitrogen-hydrogen mixed gas is 99: 1; and the purity is not less than 5N;
placing the pretreated diamond seed crystal in the growth furnace for deposition, and specifically comprising the following steps:
placing the diamond seed crystal on a deposition table in the growth furnace;
closing the furnace door of the growing furnace, vacuumizing, and controlling the air pressure in the growing furnace to be 1 x 10-2Below torr;
introducing hydrogen and adjusting the gas pressure to be 6-20 torr;
starting a microwave power supply, adjusting the microwave input power to 800-;
adjusting the microwave power and the reaction pressure, and enabling the temperature of the diamond seed crystal to be in the range of 800-1100 ℃ for preparing growth.
2. A method of improving the quality of single crystal diamond as claimed in claim 1 further comprising, at the start of growth, passing methane gas through the growth furnace until growth is complete; wherein the volume ratio of the methane gas is 5-10%, and the purity of the methane gas is not less than 5N.
3. A method of improving the quality of single crystal diamond according to claim 1 or 2, further comprising, prior to said growing:
selecting a plurality of single crystal diamond seed crystals with the same size;
pretreating the diamond seed crystal;
and placing the pretreated diamond seed crystal in the growth furnace to prepare for deposition.
4. A method of improving the quality of a single crystal diamond as recited in claim 3 wherein the pre-treating of the diamond seed comprises:
placing the diamond seed crystals in a volume ratio of 3:1, pickling in a mixed solution of concentrated sulfuric acid and concentrated nitric acid, and pickling for 1-4 hours at a constant temperature when the pickling temperature is 250 ℃;
respectively ultrasonically cleaning the diamond seed crystals in alcohol and acetone for 15 min;
and finally, drying the diamond seed crystals in a dryer.
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| CN114112249B (en) * | 2021-11-24 | 2023-10-27 | 航天科工(长沙)新材料研究院有限公司 | Method, device and medium for testing vacuum leak rate of MPCVD equipment |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5391409A (en) * | 1991-04-01 | 1995-02-21 | Sumitomo Electric Industries, Ltd. | Low temperature method for synthesizing diamond with high quality by vapor phase deposition |
| WO2016144256A1 (en) * | 2015-03-09 | 2016-09-15 | Iia Technologies Pte. Ltd. | Monocrystalline diamonds and methods of growing the same |
| CN107740184A (en) * | 2017-09-30 | 2018-02-27 | 湖北碳六科技有限公司 | A kind of gradient single-crystal diamond and preparation method thereof |
| CN110820044A (en) * | 2019-12-02 | 2020-02-21 | 长沙新材料产业研究院有限公司 | High-quality diamond growth method and system |
| CN112877773A (en) * | 2021-01-13 | 2021-06-01 | 哈尔滨工业大学 | Non-air-flow MPCVD single crystal diamond growth method using solid carbon source |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9487858B2 (en) * | 2008-03-13 | 2016-11-08 | Board Of Trustees Of Michigan State University | Process and apparatus for diamond synthesis |
| WO2010068419A2 (en) * | 2008-11-25 | 2010-06-17 | Carnegie Institution Of Washington | Production of single crystal cvd diamond rapid growth rate |
| SG179318A1 (en) * | 2010-09-27 | 2012-04-27 | Gemesis Company S Pte Ltd | Method for growing white color diamonds by using diborane and nitrogen in combination in a microwave plasma chemical vapor deposition system |
| GB201320304D0 (en) * | 2013-11-18 | 2014-01-01 | Element Six Ltd | Methods of fabricating synthetic diamond materials using microwave plasma actived chemical vapour deposition techniques and products obtained using said |
-
2021
- 2021-10-21 CN CN202111224634.1A patent/CN113652746B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5391409A (en) * | 1991-04-01 | 1995-02-21 | Sumitomo Electric Industries, Ltd. | Low temperature method for synthesizing diamond with high quality by vapor phase deposition |
| WO2016144256A1 (en) * | 2015-03-09 | 2016-09-15 | Iia Technologies Pte. Ltd. | Monocrystalline diamonds and methods of growing the same |
| CN107407005A (en) * | 2015-03-09 | 2017-11-28 | 二A 科技有限公司 | Single-crystal diamond and its growing method |
| CN107740184A (en) * | 2017-09-30 | 2018-02-27 | 湖北碳六科技有限公司 | A kind of gradient single-crystal diamond and preparation method thereof |
| CN110820044A (en) * | 2019-12-02 | 2020-02-21 | 长沙新材料产业研究院有限公司 | High-quality diamond growth method and system |
| CN112877773A (en) * | 2021-01-13 | 2021-06-01 | 哈尔滨工业大学 | Non-air-flow MPCVD single crystal diamond growth method using solid carbon source |
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