CN110468449B

CN110468449B - Microwave plasma reactor for manufacturing single crystal diamond and diffusion device thereof

Info

Publication number: CN110468449B
Application number: CN201910866487.4A
Authority: CN
Inventors: 马付根; 江南; 宋茜茜
Original assignee: Anhui Chenxinwei Industrial Technology Co ltd; Ningbo Chenxin Vac Industrial Technology Co ltd
Current assignee: Anhui Chenxinwei Industrial Technology Co ltd; Ningbo Chenxin Vac Industrial Technology Co ltd
Priority date: 2019-09-12
Filing date: 2019-09-12
Publication date: 2021-09-07
Anticipated expiration: 2039-09-12
Also published as: CN110468449A

Abstract

The invention discloses a microwave plasma reactor for manufacturing single crystal diamond and a diffusion device thereof.A diffusion base is provided with a conical wall body, the upper edge of the wall body is provided with a first flange plate, and the lower edge of the wall body is provided with a second flange plate parallel to the first flange plate; the wall body is enclosed to form a diffusion opening in the wall body, and the cross section area of the diffusion opening is gradually increased from the first flange plate to the second flange plate; the air inlet pipe group comprises at least two air inlet pipes which are uniformly distributed in the circumferential direction around the axis of the diffusion base; the dielectric glass is clamped in the first flange plate and seals the upper part of the diffusion opening; wherein, still set up a plurality of gas pockets along axis circumference equipartition on the wall body, the gas that the intake pipe was brought passes through the gas pocket and introduces in the diffusion mouth, through setting up the diffusion base that is the taper, and the guide microwave keeps distributing around the seed crystal with even and stable ellipsoid equipotential, provides better environment for the growth of seed crystal, improves the growth quality of seed crystal.

Description

Microwave plasma reactor for manufacturing single crystal diamond and diffusion device thereof

Technical Field

The invention relates to the technical field of microwave plasma chemical vapor deposition equipment, in particular to a microwave plasma reactor for manufacturing single-crystal diamond and a diffusion device thereof.

Background

Natural diamond is valued because it is obtained from millions of years of high temperature and pressure and pushed to the surface. With the continuous innovation of equipment and technology, the quality of artificial diamond is continuously close to that of natural diamond and the cost is gradually controlled. The development of artificial masonry, i.e., single crystal diamond, has therefore always received widespread attention worldwide.

The synthesis method of the single crystal diamond mainly comprises a high temperature high pressure method (HPHT) and a chemical vapor deposition method (CVD). The HPHT method is relatively mature but has certain limitations: the process is difficult to control, the period is long, the cost is high, the obtained material has extremely high hardness, and the processing is difficult. The CVD method, especially the Microwave Plasma Chemical Vapor Deposition (MPCVD), is a well-established method for preparing high-grade large-particle diamond and large-area diamond, and has the advantages of controllable process conditions, low requirements on equipment materials, short period and the like.

The MPCVD method is a method in which microwaves generated by a microwave generator are transmitted to a reactor by a waveguide tube and CH is introduced into the reactor₄And H₂The high-intensity microwave energy excites and decomposes the carbon-containing gas above the substrate to form active carbon-containing groups and atomic hydrogen, and plasma is formed, thereby depositing the diamond film on the substrate. Different types of MPCVD devices differ in the form of microwave plasma reactors, for example, patent publication No. CN108588820A discloses a microwave plasma CVD device and diamond synthesis method, wherein the reactor is in the form of a metal chamber with a microwave window, and when the device is in operation, the resonant chamber is first evacuated, a mixed gas of methane and hydrogen is introduced into the resonant chamber, and then microwaves are generated by a microwave source, the microwaves generated by the microwave source are TE-converted in a first waveguide₁₀The mode is transmitted, after being converted by the coupling antenna, the mode is transmitted in a TEM mode in the second waveguide tube, and after entering the coupling conversion cavity, the mode is converted into a TM mode again by the coupling antenna₀₁And in the mode, the mixture enters a resonant cavity through a medium window, methane above a deposition table forms active carbon-containing groups and atomic hydrogen and forms spherical plasma, and thus, a diamond film is deposited on the upper surface of the seed crystal.

TM₀₁The equipotential surface distribution of the microwave electric field in the mode is ellipsoidal, the intensity of the electric field is gradually reduced from the central area to the outside, after the microwave enters the resonant cavity through the medium window, the mixed gas enters the resonant cavity to destroy the distribution of the equipotential surface of the electric field, influence the growth environment of seed crystals and be not beneficial to manufacturing high-quality single crystalsAnd (4) crystal diamond.

Disclosure of Invention

The first purpose of the invention is to provide a diffusion device, when microwave is introduced into a resonant cavity, the distribution of the original electric field is not easily influenced, the equipotential surface of a concentric ellipsoid can be well kept to be distributed around a seed crystal base station, a good environment is provided for the growth of the seed crystal, and the manufacture of high-quality single crystal diamond is facilitated.

The above object of the present invention is achieved by the following technical solutions:

a diffusion device, comprising:

the diffusion base is provided with a conical wall body, a first flange plate is arranged on the upper edge of the wall body, and a second flange plate parallel to the first flange plate is arranged on the lower edge of the wall body; the wall body is enclosed to form a diffusion opening, and the cross section area of the diffusion opening is gradually increased from the first flange plate to the second flange plate;

the air inlet pipe group comprises at least two air inlet pipes which are uniformly distributed in the circumferential direction around the axis of the diffusion base; and the number of the first and second groups,

the dielectric glass is clamped in the first flange plate and seals the upper part of the diffusion opening;

the wall body is further provided with a plurality of air holes which are uniformly distributed along the circumferential direction of the axis, and air brought in by the air inlet pipe is introduced into the diffusion hole through the air holes.

By adopting the technical scheme, converted microwaves enter the diffusion port of the diffusion base through the dielectric glass, the cross section area of the diffusion port is gradually increased from the microwave inlet end to the outlet end, so that when the microwaves are propagated in the diffusion port, the boundary of an electric field equipotential surface is gradually enlarged, and a radiation area favorable for a seed crystal growth environment is finally developed; secondly, due to the arrangement of a plurality of air holes, the mixed gas can form an air film on the inner surface of the wall body when entering the diffusion port, so that the pollution of the formed plasma on the inner surface of the wall body is reduced, the uniform stability of the microwave in the transmission process is better ensured, and the quality of the manufactured diamond is improved; and due to the conical arrangement of the wall body, the mixed gas has a downward flow component when entering the diffuser, and further can flow downwards along the inner wall of the resonant cavity, so that the forming range of a gas film is expanded, the service life of the whole equipment is prolonged, a better growth environment is provided for single crystals, and the manufacture of high-quality and large-size single crystal diamonds is facilitated.

Preferably, the method further comprises the following steps:

the clamping sleeve is connected with the diffusion base and comprises an inner interlayer attached to the outer peripheral surface of the first flange plate, an air cavity is formed between the inner interlayer and the outer surface of the wall body and communicated with the diffusion port through an air hole, and the air inlet pipe is connected with the air cavity.

Through adopting above-mentioned technical scheme, the gas mixture that is introduced by many intake pipes can enter into the air cavity in advance, and the air cavity can be filled gradually and finally enters into the diffusion mouth from all gas pockets on the wall body by gas mixture, reaches better air inlet mode, and whole air inlet process air current has centripetal homogeneity, keeps the microwave stable in the radiation process, better for providing the environment of single crystal growth.

Preferably, the jacket further comprises an outer interlayer positioned at the outer edge of the inner interlayer, a cooling channel is formed between the inner interlayer and the outer interlayer, and a liquid inlet pipe and a liquid outlet pipe which are communicated with the cooling channel are arranged on the outer interlayer.

By adopting the technical scheme, for producing and manufacturing the monocrystal diamond with larger size, the power of microwave must be increased, and when the power of microwave is increased, the temperature is also increased, particularly in a medium glass area, and the arrangement of the inner interlayer and the outer interlayer ensures that a cooling channel is formed between the inner interlayer and the outer interlayer, cooling liquid is introduced into the whole diffusion base through the liquid inlet pipe and the liquid outlet pipe in the cooling channel, and after the temperature of the diffusion base is reduced, the medium glass is cooled along with the cooling liquid through heat transfer, so that the use upper limit of the power of microwave is increased, and the monocrystal diamond with large size can be conveniently manufactured; secondly, the air cavity is also wrapped by outside cooling channel, at first promotes the leakproofness of whole air cavity, when letting in the coolant liquid in cooling channel simultaneously, also cools down whole air cavity, through the velocity of flow of control coolant liquid in cooling channel, reaches the regulation of air cavity internal temperature, and indirect control the reaction temperature of mist, realization control by temperature change provides better growing environment for the single crystal.

Preferably, the lower end of the jacket is connected to the second flange, and an opening communicating with the cooling passage is provided at the lower end.

Through adopting above-mentioned technical scheme, open-ended setting makes when dashing into the coolant liquid in to cooling channel, the coolant liquid can the direct contact to the second ring flange, improve the heat exchange rate of second ring flange, the surface temperature of second ring flange has been reduced, first ring flange utilizes the interlining to realize the heat exchange, and the wall body through with first, the heat exchange of second ring flange realizes the cooling, better reaching the cooling to whole diffusion base, further can promote the use upper limit of microwave power, provide growing environment for making the more oversized single crystal diamond.

Preferably, the diffuser opening has a taper of 130 ° -140 °.

By adopting the technical scheme, the taper of the diffusion opening is arranged to be matched with an ellipsoid equipotential surface formed by microwaves, so that the microwaves can be gradually expanded in boundary, and when the taper is too large, the electric field intensity of the central area of the equipotential surface is reduced when the microwaves are transmitted to the position of the seed crystal due to the overlarge boundary of an electric field after the microwaves exit from the diffusion opening, and the seed crystal is not beneficial to growth; the taper is too small, so that the intensity of the central area of the equipotential surface of the electric field can be ensured, the temperature is too high, the growth of the seed crystal is not facilitated, the electric field intensity of the central area of the equipotential surface can be ensured within the taper range, the surface temperature of the seed crystal is not too high, and a better environment is provided for the growth of the seed crystal.

Preferably, 12-24 air holes are uniformly distributed in the circumferential direction.

By adopting the technical scheme, the uniformity of the mixed gas entering the diffusion port can be ensured by the arrangement of the number of the air holes, a surrounding type gas inlet mode is realized, the quantity of gas entering the diffusion port at one time is small due to the small number of the air holes, the reaction efficiency is influenced, meanwhile, the uniformity of the gas entering the diffusion port is low, the electric field distribution of microwaves is easily influenced by multiple air flows, the growth environment of the seed crystals is further influenced, and the uniform formation of a gas film on the inner surface of a wall body is not facilitated; and the number of the air holes is too large, the air flow rate converged into the diffusion port at one time is increased, the reaction of mixed gas is easily uneven, when the number of the air holes is 12-24, the air can enter the diffusion port by proper air inflow when the uniformity in the air inlet process is ensured, the reaction efficiency is improved, and the environment for growing the single crystal diamond is better provided.

Preferably, the diameter of the air hole is 0.05-0.1 of the height of the diffusion opening.

By adopting the technical scheme, the ratio of the diameter of the air hole to the height of the diffusion opening is set, the total reaction amount of the mixed gas in the diffusion opening is controlled, the larger the ratio is, the larger the gas amount of the mixed gas accounts for the diffusion opening, the more the relative gas reaction amount is, and the less the gas reaction amount is, otherwise, the mixed gas can react more fully in the ratio range, and a better environment is provided for the growth of the single crystal.

Preferably, the axis of the air hole is perpendicular to the wall.

By adopting the technical scheme, the wall body is conical, and after the axis of the air hole is vertical to the wall body, an airflow component along the inner surface of the wall body is formed through force decomposition, so that the formed air film is better attached to the inner surface, and the pollution of microwaves to the inner surface of the wall body is reduced; and secondly, the other gas flow component of the mixed gas is in the horizontal direction and can be coated on the periphery of the microwave equipotential surface, so that the uniformity of the microwave in gradual diffusion is improved.

Preferably, the first flange plate is provided with a limiting groove, the medium glass is clamped in the limiting groove, a sealing ring groove is formed in the groove bottom of the limiting groove, and a silver wire sealing ring is embedded in the sealing ring groove.

By adopting the technical scheme, the silver wire sealing ring processed by silver wires is not easy to oxidize in a high-temperature environment, and has high chemical stability; secondly, the microwave diffusion ring has better cleanliness, and after being embedded in the sealing ring groove, the cleanliness of the upper end face of the diffusion port after the microwave passes through the dielectric glass is ensured; moreover, the silver wire sealing ring is used as a metal sealing ring, when the dielectric glass is clamped in the limiting groove and extrudes the silver wire sealing ring, the silver wire sealing ring deforms, fills the first sealing ring groove and the uneven part of the surface of the dielectric glass, realizes vacuum sealing, and enables microwaves to be well transmitted.

The second purpose of the invention is to provide a microwave plasma reactor for manufacturing single crystal diamond, when microwave is introduced into a resonant cavity, the distribution of the original electric field is not easily influenced, the equipotential surface of a concentric ellipsoid can be well kept to be distributed around a seed crystal base station, a good environment is provided for the growth of the seed crystal, and the manufacture of high-quality single crystal diamond is facilitated.

a microwave plasma reactor for manufacturing single crystal diamond comprises a plasma chamber and a diffusion device, wherein the plasma chamber is provided with a resonant cavity, the diffusion device is connected above the plasma chamber, and a diffusion opening is communicated with the resonant cavity.

By adopting the technical scheme, the microwave uniformly enters the resonant cavity under the action of the diffusion device, and the seed crystal is positioned at the center of the equipotential surface, so that the uniformity and stability of microwave radiation in the growth process of the seed crystal are ensured, and the manufacture of finished diamond is improved.

In conclusion, the beneficial technical effects of the invention are as follows:

1. the conical diffusion base is arranged to guide microwaves to be distributed around the seed crystal in a uniform and stable ellipsoid equipotential surface, so that a better environment is provided for the growth of the seed crystal, and meanwhile, the gas holes formed in the wall body are combined to ensure that the input mixed gas can be uniformly distributed in space, so that the sufficiency in reaction is improved, and the growth quality of the seed crystal is improved;

2. by designing the number, the diameter and the angle of the air holes, the reasonable air flow is ensured to be input into the diffusion hole, the reaction sufficiency of the mixed gas is better improved, and meanwhile, an air film is formed on the wall body and the inner surface of the resonant cavity, so that the pollution to the inner wall of the whole equipment is reduced, a better reaction environment is created in the resonant cavity, and the growth quality of the seed crystal is improved;

3. an air cavity is formed between the inner interlayer and the outer surface of the wall body by arranging the jacket, so that the uniformity of mixed gas entering the diffusion port is improved, the uniform distribution of the mixed gas in space is better realized, and the reaction effect is improved;

4. through the contact of interior intermediate layer and first ring flange to and set up the lower extreme opening with cooling channel and realize that the coolant liquid is direct to contact with the second ring flange, reach better heat transfer effect, let in the coolant liquid simultaneously in cooling channel, realize the heat exchange of interior, outer intermediate layer, and the velocity of flow through the control coolant liquid can reach the purpose of accuse temperature, and then to the better cooling of diffusion base, improve microwave power's use upper limit, be convenient for make produce the diamond that the quality is high, the size is big.

Drawings

FIG. 1 is a schematic view of a diffusion device according to an embodiment;

FIG. 2 is a top view of a diffusion device according to one embodiment;

FIG. 3 is an enlarged view of portion A of FIG. 1;

FIG. 4 is a schematic structural diagram of a microwave plasma reactor according to a second embodiment.

In the figure, 10, a diffusion base; 11. a wall body; 111. air holes; 12. a first flange plate; 121. sealing the ring groove; 13. a second flange plate; 14. a diffusion port; 15. an air cavity; 20. an air inlet pipe; 30. dielectric glass; 40. a jacket; 41. an inner interlayer; 42. an outer interlayer; 43. a cooling channel; 44. an opening; 45. a liquid inlet pipe; 46. a liquid outlet pipe; 50. a silver wire seal ring; 60. a plasma chamber; 61. a resonant cavity; 62. a base station; 63. and an air outlet pipe.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "left," "right," and the like as used herein are for illustrative purposes only and do not represent the only embodiments.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

Example one

Referring to fig. 1, there is shown a structure of a diffusion device comprising a diffusion base 10, a dielectric glass 30 mounted on the diffusion base 10, and a jacket 40. The diffusion base 10 includes a tapered wall 11, a first flange 12 connected to an upper edge of the wall 11, and a second flange 13 connected to a lower edge of the wall 11, wherein the first flange 12 and the second flange 13 are disposed in parallel, and a diameter of the first flange 12 is smaller than a diameter of the second flange 13, so that the two form a step distribution.

The wall 11 encloses internally a diffuser 14, the cross-section of the diffuser 14 increasing uniformly from the side of the first flange 12 towards the second flange 13, the entire diffuser 14 having a taper a between 130 ° and 140 °, preferably 135 °.

The wall body 11 is further provided with a plurality of air holes 111, one end of each air hole 111 is communicated with the diffusion port 14, the number of the air holes 111 is 12-24, the number of the air holes 111 is preferably 24, and the interval angle between every two adjacent air holes 111 is 15 degrees. The height of the whole diffusion opening 14 is defined as H, the diameter of the air hole 111 is phi, phi/H is between 0.05-0.1, and phi/H is preferably 0.05. Meanwhile, the axis of each air hole 111 has an angle β with the wall 11, the angle β being 90 °, that is, the axis of the air hole 111 is disposed perpendicular to the wall 11.

Table 1 shows the mass analysis of the produced seed crystals for different diffusion opening tapers, the number of the air holes and the height ratio of the diameter of the air holes.

TABLE 1 seed Crystal quality analysis Table

	Diffusion opening taper	Number of air holes (number)	Air hole diameter height ratio (phi/H)	Quality of seed crystal
					Sample 1	130°	18	0.1	Height of
Sample 2	135°	12	0.08	Height of
					Sample 3	140°	24	0.05	Height of
Sample No. 4	125°	24	0.1	Excessive stress and cracking
					Sample No. 5	145°	18	0.1	Small size
Sample No. 6	135°	12	0.2	Low purity
					Sample 7	135°	6	0.1	Low purity and anisotropy
Sample 8	135°	30	0.1	Has anisotropic and high stress

As can be seen from Table 1, in order to produce a seed crystal with high quality and large size, the number of air holes needs to be kept between 12 and 24, the diffusion taper is between 130 and 140 degrees, and the diameter-height ratio of the air holes is between 0.05 and 0.1.

The clamping sleeve 40 is connected with the diffusion base 10 by welding, and specifically comprises an inner interlayer 41 and an outer interlayer 42, the inner interlayer 42 and the outer interlayer 42 are arranged in concentric circles, and the inner interlayer 41 is embraced on the outer peripheral surface of the first flange 12, so that the surface parts of the inner interlayer and the outer interlayer are attached. The inner interlayer 41 also forms an annular air cavity 15 with the outer surface of the wall body 11, and the other end of the air hole 111 is communicated with the air cavity 15, so that the air cavity 15 is communicated with the diffusion port 14 through a plurality of air holes 111. The surface of the inner interlayer 41 is welded with the outer peripheral surface of the first flange 12, the lower end surface of the inner interlayer 41 is welded at the upper end surface of the second flange 13, and a sealing surface is formed at the welding position, so that the air cavity 15 forms a closed environment, and the leakage of the mixed gas from the gap between the jacket 40 and the diffusion base 10 is effectively avoided.

The outer sandwich 42 is arranged at the outer edge of the inner sandwich 41, a cooling channel 43 is formed between the outer sandwich and the inner sandwich, the upper end of the inner sandwich 42 and the lower end of the outer sandwich are closed, the lower end of the inner sandwich is provided with an opening 44, and the opening 44 is closed by the upper end surface of the second flange 13.

Referring to fig. 1 and 2, a liquid inlet pipe 45 and a liquid outlet pipe 46 are further disposed on the outer circumferential surface of the outer interlayer 42, the liquid inlet pipe 45 and the liquid outlet pipe 46 are spaced at 180 ° and are both connected to the cooling channel 43, the liquid inlet pipe 45 is used to introduce cooling liquid into the cooling channel 43, and the liquid outlet pipe 46 outputs the cooling liquid after heat exchange, so as to achieve the effect of cooling circulation. Simultaneously, the inner diameters of the liquid inlet pipe 46 and the liquid outlet pipe 46 are uniform and equal, the flow speed of the cooling liquid is controlled by controlling the input flow of the cooling liquid, the temperature control is realized, and the flow of the cooling liquid can be realized by arranging a variable pump. In particular, the diffusion base 10 and the jacket 40 are made of a metal material such as stainless steel, which improves the efficiency of heat transfer.

Still be provided with intake pipe 20 group on the cover 40, intake pipe 20 group includes a plurality of intake pipes 20 along the equipartition of wall body 11 axis circumference, and in this embodiment, intake pipe 20 has two, and both interval is 180. The gas source conveys mixed gas to the 20 groups of gas inlet pipes and divides the mixed gas into each gas inlet pipe 20, so that synchronous and multi-directional gas inlet is realized.

Each air inlet pipe 20 passes through the inner interlayer 41 and the outer interlayer 42 of the jacket 40 and is connected with the air cavity 15, so that the mixed gas is brought into the air cavity 15 in advance and then enters the diffusion port 14 through the plurality of air holes 111.

Referring to fig. 1 and fig. 3 together, the upper end surface of the first flange 12 is further provided with a limiting groove, and the dielectric glass 30 is clamped in the limiting groove. The groove bottom of the limiting groove is provided with a sealing ring groove 121, the sealing ring groove 121 is embedded with a silver wire sealing ring 50, the sealing ring deforms under the extrusion of the medium glass 30, and then vacuum sealing is formed between the sealing ring and the medium glass, and the upper end of the diffusion opening 14 is sealed.

Example two

Referring to fig. 4, a microwave plasma reactor for manufacturing single crystal diamond includes a diffusion device of the first embodiment and a plasma chamber 60 connected to the diffusion device. The diffuser is connected to the plasma chamber 60 by a second flange 13 and the entire diffuser is located above the plasma chamber 60.

The plasma chamber 60 has a resonator 61 therein, the diffusion port 14 communicates with the resonator 61, a base 62 is provided at the bottom of the resonator 61, and the seed crystal is placed on the base 62. The resonator 61 is cylindrical, and the base 62 is located at the center of the resonator 61 and at the axial position of the diffuser 14. The bottom of the resonant cavity 61 is also communicated with a plurality of gas outlet pipes 63 for circulating exhaust of the mixed gas.

When the gas filling device works, mixed gas is filled into the gas cavity 15 through the gas inlet pipe 20 in advance, after the gas filling device is filled for a period of time, all the gas holes 111 are enabled to synchronously gas into the diffusion opening 14, at the moment, the microwave generator is started, microwaves enter the diffusion opening 14 through the medium glass 30 after conversion, particularly, the gas holes 111 are vertically formed in the wall body 11, and when the mixed gas enters the diffusion opening 14 through the gas holes 111, the mixed gas has horizontal and gas flow components along the inner surface of the wall body 11, so that a gas film is formed on the inner surface of the arm body and the inner wall of the resonant cavity 61, and a better reaction environment is created; meanwhile, the microwave passes through the diffusion port 14 to reach the center of the base 62 in the ellipsoid equipotential surface of the microwave, so that the good growth environment of the seed crystal is ensured, and the manufacture of high-quality and large-size single crystal diamond is facilitated.

The present embodiment is only for explaining the present invention, and it is not limited to the present invention, and those skilled in the art can make modifications of the present embodiment without inventive contribution as needed after reading the present specification, but all of them are protected by patent law within the scope of the claims of the present invention.

Claims

1. A diffusion device, comprising:

the diffusion base (10) is provided with a conical wall body (11), a first flange (12) is arranged on the upper edge of the wall body (11), and a second flange (13) parallel to the first flange (12) is arranged on the lower edge of the wall body (11); the wall body (11) is enclosed to form a diffusion opening (14), and the cross section area of the diffusion opening (14) is gradually increased from the first flange plate (12) to the second flange plate (13);

the air inlet pipe (20) group comprises at least two air inlet pipes (20) which are uniformly distributed in the circumferential direction around the axis of the diffusion base (10); and the number of the first and second groups,

the dielectric glass (30) is clamped in the first flange plate (12) and seals the upper part of the diffusion opening (14);

the wall body (11) is further provided with a plurality of air holes (111) which are uniformly distributed along the circumferential direction of the axis, and air brought in by the air inlet pipe (20) is introduced into the diffusion port (14) through the air holes (111);

the diffusion openings (14) have a taper angle of 130-140 degrees, 12-24 air holes (111) are uniformly distributed in the circumferential direction, and the diameter of each air hole (111) is 0.05-0.1 of the height of each diffusion opening (14).

2. The diffusing device of claim 1, further comprising:

the jacket (40) is connected with the diffusion base (10) and comprises an inner interlayer (41) which is attached to the outer peripheral surface of the first flange plate (12), an air cavity (15) is formed between the inner interlayer (41) and the outer surface of the wall body (11), the air cavity (15) is communicated with the diffusion port (14) through an air hole (111), and the air inlet pipe (20) is connected with the air cavity (15).

3. A diffusing device according to claim 2, characterized in that the jacket (40) further comprises an outer layer (42) at the outer edge of the inner layer (41), a cooling channel (43) being formed between the inner and outer layers (42), wherein the outer layer (42) is provided with a liquid inlet pipe (45) and a liquid outlet pipe (46) communicating with the cooling channel (43).

4. A diffusing device according to claim 3, characterized in that the jacket (40) is connected at its lower end to the second flange (13) and is provided at the lower end with an opening (44) communicating with the cooling channel (43).

5. A diffusing device according to claim 1, characterized in that the axis of the air hole (111) is perpendicular to the wall (11).

6. The diffusion device according to claim 1, wherein the first flange plate (12) is provided with a limiting groove, the dielectric glass (30) is clamped in the limiting groove, a sealing ring groove (121) is formed in the groove bottom of the limiting groove, and a silver wire sealing ring (50) is embedded in the sealing ring groove (121).

7. A microwave plasma reactor for manufacturing single crystal diamond, comprising a plasma chamber (60) and a diffuser device according to any one of claims 1 to 6, the plasma chamber (60) having a resonant cavity (61), the diffuser device being connected above the plasma chamber (60), wherein the diffuser port (14) communicates with the resonant cavity (61).