Gas inlet top tray and gas mixing device of MOCVD (metal organic chemical vapor deposition) equipment

Abstract

The invention relates to a gas inlet top tray and a gas mixing device of MOCVD (Metal Organic Chemical Vapor Deposition) equipment, and belongs to the technical field of vapor deposition equipment. Comprising a top tray body; two first gas channel upper cover plates and two second gas channel upper cover plates are mounted on the top surface of the top tray body; a first gas inlet and a second gas inlet are respectively formed in the first gas channel upper cover plates and the second gas channel upper cover plates; four groups of gas distribution plates are mounted on the bottom surface of the top tray body and are uniformly distributed along the circumferential direction, each group of gas distribution plates comprises a first gas distribution plate and a second gas distribution plate, a plurality of first gas nozzles and second gas nozzles are respectively formed in the bottoms of the first gas distribution plate and the second gas distribution plate, and the first gas nozzles and the second gas nozzles in each group are distributed in a staggered manner; and the first gas nozzle and the second gas nozzle are respectively communicated with the first gas inlet and the second gas inlet. According to the invention, gas subsequently entering the cavity body of the mixing cavity can be uniformly distributed, so that stable laminar flow of the gas is formed in the mixing cavity.

Description

Technical Field

[0001] The present invention relates to the technical field of vapor deposition equipment, and particularly to an intake top plate and a gas mixing device of an MOCVD equipment. Background Art

[0002] During the preparation of ultraviolet LED chips, due to the influence of factors such as material quality and doping during epitaxy, as well as the difficulties existing in chip and packaging processes, the high aluminum nitride technology lags far behind the development of indium gallium nitride blue-green light technology. The most prominent is that commercial blue-green light MOCVD equipment cannot well inhibit pre-reaction, which will lead to a decline in material quality and high consumption of sources. Therefore, the special MOCVD equipment for manufacturing ultraviolet LEDs has become an important link restricting the development of the ultraviolet LED chip industry.

[0003] When manufacturing a special MOCVD equipment for ultraviolet LEDs, a thorny problem encountered is how to better make the AlN thin film substrate grow evenly enough to provide a basis for subsequent material growth. In the MOCVD reaction vessel, complex transport processes are taking place. The source gas TMAl and group III gas NH3 are transported into the reactor under the carrier of the carrier gas H2, and the fluidity of the gas determines the flow field distribution in the reaction vessel. The flow field distribution directly affects the spatial distribution of the reactants and ultimately affects the chemical reaction in the reaction vessel and the uniformity of the growth of the AlN thin film. In order to make the reactants grow as evenly as possible on the substrate surface, the ideal situation should be that the reaction source gas is evenly distributed near the substrate surface. However, current various MOCVD equipments cannot well mix the reaction source gas.

[0004] During the growth of the AlN thin film, it is mainly affected by three main factors: flow field, temperature field, and chemical reaction. In existing MOCVD equipments, the mixing uniformity of the source gas is crucial for the growth of the AlN thin film. In order to improve the growth uniformity of the AlN thin film, the mixing uniformity of the source gas should be improved as much as possible. Therefore, how to better control the uniformity of the reactants in the reaction chamber is an important path to improve the growth uniformity of the AlN thin film.

[0005] Existing MOCVD equipments have problems of insufficient mixing of the source gas in the reaction chamber and uneven distribution of the reactants in the reaction vessel. Summary of the Invention

[0006] To solve the above technical problems, the present invention provides an intake top plate and a gas mixing device of an MOCVD equipment. The technical solution of the present invention is as follows:

[0007] The present invention provides an intake top plate of an MOCVD equipment, which includes a top plate body;

[0008] On the top surface of the top plate body, two first gas channel upper covers and two second gas channel upper covers are installed. The first gas channel upper cover and the second gas channel upper cover are respectively provided with a penetrating first gas inlet and a second gas inlet.

[0009] On the bottom surface of the top plate body, a four-component gas distribution plate is installed. The four-component gas distribution plates are all arranged along the direction parallel to the diameter of the bottom surface and are evenly distributed in the circumferential direction. Each component gas distribution plate includes a first gas distribution plate and a second gas distribution plate. The bottoms of the first gas distribution plate and the second gas distribution plate are respectively provided with a plurality of uniformly distributed first gas nozzles and second gas nozzles. The first gas nozzles and the second gas nozzles in each component gas distribution plate are staggered. The first gas nozzles and the second gas nozzles are respectively communicated with the first gas inlet and the second gas inlet.

[0010] The first gas enters the first gas distribution plate through the first gas inlet and is ejected from a plurality of first gas nozzles; the second gas enters the second gas distribution plate through the second gas inlet and is ejected from a plurality of second gas nozzles.

[0011] Optionally, two first gas upper channel grooves and two second gas upper channel grooves are formed on the top surface of the top plate body. The first gas channel upper cover is installed on the top of the first gas upper channel groove, and the second gas channel upper cover is installed on the top of the second gas upper channel groove.

[0012] Four first gas lower channel grooves and four second gas lower channel grooves are formed on the bottom surface of the top plate body. One first gas lower channel groove and one second gas lower channel groove form a set of gas distribution lower channels. The first gas distribution plate and the second gas distribution plate are respectively installed at the bottoms of the first gas lower channel groove and the second gas lower channel groove. A first gas distribution nozzle and a second gas distribution nozzle are respectively installed in the middle of the tops of the first gas distribution plate and the second gas distribution plate. The first gas inlet, the bottom of the first gas upper channel groove, the top of the first gas lower channel groove, the first gas distribution nozzle and the first gas nozzle are communicated; the second gas inlet, the bottom of the second gas upper channel groove, the top of the second gas lower channel groove, the second gas distribution nozzle and the second gas nozzle are communicated.

[0013] Optionally, the two first gas upper channel grooves are symmetrical to each other, and the two second gas upper channel grooves are symmetrical to each other. The first gas inlet and the second gas inlet are respectively located in the middle of the first gas channel upper cover plate and the second gas channel upper cover plate. Two first gas channel groove connection holes perpendicular to the top surface and penetrating through the top plate body are provided at both ends of the first gas channel groove, and two second gas channel groove connection holes perpendicular to the top surface and penetrating through the top plate body are provided at both ends of the second gas channel groove. The first gas channel upper cover plate and the bottom of the first gas upper channel groove form a first gas upper channel, and the second gas channel upper cover plate and the bottom of the second gas upper channel groove form a second gas upper channel. The four first gas distribution nozzles and the four second gas distribution nozzles are respectively communicated with the four first gas channel groove connection holes and the four second gas channel groove connection holes.

[0014] Optionally, both the first gas upper channel groove and the second gas upper channel groove are double-layer groove structures. The width of the first lower-layer groove of the first gas upper channel groove is smaller than the width of its first upper-layer groove. The shape and size of the first gas channel upper cover plate are adapted to the first upper-layer groove, and the first gas channel upper cover plate and the first lower-layer groove form a first gas upper channel; the width of the second lower-layer groove of the second gas upper channel groove is smaller than the width of its second upper-layer groove. The shape and size of the second gas channel upper cover plate are adapted to the second upper-layer groove, and the second gas channel upper cover plate and the second lower-layer groove form a second gas upper channel; the width of the lower-layer groove of the first gas lower channel groove and the second gas lower channel groove is larger than the width of the upper-layer groove.

[0015] Optionally, the first gas distribution plate includes a first gas channel lower cover plate. A plurality of first ventilation openings with the same shape and size are uniformly arranged through the first gas channel lower cover plate. A plurality of uniformly distributed first ventilation shells are installed on the bottom surface of the first gas channel lower cover plate. The first ventilation shells correspond to the first ventilation openings one by one. A first gas nozzle is opened at the cylindrical arc surface on one side of the first ventilation shell. The shape and size of the first gas channel lower cover plate are adapted to the lower-layer groove of the first gas lower channel groove, and the first gas channel lower cover plate and the upper-layer groove of the first gas lower channel groove form a first gas lower channel.

[0016] Optionally, the shape of the first gas distribution nozzle is a cylindrical ring structure. Two symmetrical square through holes are opened on both sides of the first gas distribution nozzle, and the top of the gas distribution nozzle extends to the first gas upper channel groove.

[0017] Optionally, the first gas distribution plate and the second gas distribution plate in each group of gas distribution plates are arranged on both sides of the center line and are at equal distances from the center line. The center line is the perpendicular diameter line on the top plate body; the first gas nozzles and the second gas nozzles of the four groups of gas distribution plates are all distributed in the counterclockwise or clockwise direction, and the arrangement positions of the first gas distribution plate and the second gas distribution plate in each group of gas distribution plates are the same.

[0018] Optionally, the distance between the first gas distribution plate and the second gas distribution plate is 10 mm;

[0019] The distances between the first gas distribution plate and the second gas distribution plate and the center of the top plate body are different. The offset distance between the first gas distribution plate and the second gas distribution plate is half of the hole pitch between adjacent first gas nozzles or adjacent second gas nozzles.

[0020] The present invention also provides a gas mixing device for an MOCVD apparatus, which includes the above-mentioned intake top plate and a mixing chamber annular wall. The mixing chamber annular wall is a cylindrical annular structure, which is adapted to the top plate body and extends away from the top surface with the bottom surface as a reference. An air distribution plate is installed inside the mixing chamber annular wall, and a number of uniformly distributed spray nozzles are arranged in the middle of the air distribution plate. The top plate body, the mixing chamber annular wall and the air distribution plate form the mixing chamber cavity of the gas mixing device, and a nickel plate is installed on the bottom surface of the air distribution plate.

[0021] Optionally, the height of the mixing chamber cavity is 25 mm.

[0022] All the above optional technical solutions can be arbitrarily combined, and the present invention does not elaborate on the structures after the combinations one by one.

[0023] By means of the above solution, the beneficial effects of the present invention are as follows:

[0024] By arranging the four gas distribution plates of the intake top plate to be evenly distributed, and the first gas nozzles and the second gas nozzles are arranged at equal intervals on the first gas distribution plate and the second gas distribution plate in each group of gas distribution plates respectively, it can ensure that the gas entering the mixing chamber cavity subsequently can be evenly distributed, so that a stable laminar flow is formed therein. By arranging the first gas nozzles and the second gas nozzles in each group of gas distribution plates to be staggered, the gases ejected by them respectively will not cause obstruction and turbulence, which is beneficial to the sufficient and uniform mixing of the reaction gases. Therefore, the present invention solves the problems of uneven mixing of the source gas in the reaction chamber and uneven distribution of the reactants in the reaction vessel, and can significantly improve the uniformity of the growth thickness of the AlN thin film.

[0025] The above description is only an overview of the technical solution of the present invention. In order to be able to understand the technical means of the present invention more clearly and implement it in accordance with the content of the specification, the following takes the preferred embodiments of the present invention and combines with the drawings to describe in detail as follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a schematic structural view of the intake top plate provided by the embodiment of the present invention from one perspective;

[0027] Figure 2 is a schematic structural view of the intake top plate provided by the embodiment of the present invention from another perspective;

[0028] Figure 3It is a schematic structural diagram of the intake top plate provided by the embodiment of the present invention after removing the upper cover plate of the first gas channel and the upper cover plate of the second gas channel;

[0029] Figure 4 It is a schematic structural diagram of the intake top plate provided by the embodiment of the present invention after removing the first gas distribution plate and the second gas distribution plate;

[0030] Figure 5 It is a schematic structural diagram of the first gas distribution plate in one perspective in the embodiment of the present invention;

[0031] Figure 6 It is a schematic structural diagram of the first gas distribution plate in another perspective in the embodiment of the present invention;

[0032] Figure 7 It is a schematic structural diagram of the second gas distribution plate in the embodiment of the present invention;

[0033] Figure 8 It is a schematic structural diagram of the first gas distribution nozzle in the embodiment of the present invention;

[0034] Figure 9 It is a schematic diagram of the intake principle of the intake top plate provided by the embodiment of the present invention;

[0035] Figure 10 It is a perspective view of a partial structure of the gas mixing device provided by the embodiment of the present invention;

[0036] Figure 11 It is a schematic sectional view of the gas mixing device provided by the embodiment of the present invention;

[0037] Figure 12 It is a simulation diagram of the thickness distribution of the AlN thin film at different heights of the mixing cavity in the embodiment of the present invention;

[0038] Figure 13 It is a schematic diagram of gas mixing in the prior art (Patent CN / ZL201697239.0) of the present invention;

[0039] Figure 14 It is a simulation diagram of the thickness distribution of the AlN thin film formed in the prior art (Patent CN / ZL201697239.0) of the present invention;

[0040] Figure 15 It is a simulation diagram of the thickness distribution of the AlN thin film formed in the embodiment of the present invention. Detailed implementation manners

[0041] Next, with reference to the drawings and embodiments, the detailed implementation manners of the present invention will be further described in detail. The following embodiments are used to illustrate the present invention, but are not used to limit the scope of the present invention.

[0042] As Figures 1 to 4As shown, the intake top plate of the MOCVD device provided by the embodiment of the present invention includes a top plate body 1;

[0043] Two first gas channel upper covers 2 and two second gas channel upper covers 3 are installed on the top surface 101 of the top plate body 1. Through first gas inlets 201 and second gas inlets 301 are respectively provided on the first gas channel upper cover 2 and the second gas channel upper cover 3;

[0044] Four gas distribution plates are installed on the bottom surface 106 of the top plate body 1. The four gas distribution plates are all arranged along the direction parallel to the diameter of the bottom surface 106 and are evenly arranged in the circumferential direction. Each gas distribution plate includes a first gas distribution plate 4 and a second gas distribution plate 5. A number of evenly distributed first gas nozzles 404 and second gas nozzles 504 are respectively provided at the bottoms of the first gas distribution plate 4 and the second gas distribution plate 5. The first gas nozzles 404 and the second gas nozzles 504 in each gas distribution plate are staggered. The first gas nozzles 404 and the second gas nozzles 504 are respectively communicated with the first gas inlet 201 and the second gas inlet 301;

[0045] The first gas enters the first gas distribution plate 4 through the first gas inlet 201 and is ejected by a number of first gas nozzles 404; the second gas enters the second gas distribution plate 5 through the second gas inlet 301 and is ejected by a number of second gas nozzles 504.

[0046] Specifically, the top plate body 1 is disc-shaped and is made of a metal material. At least one observation hole can also be provided on the top surface 101 of the top plate body 1.

[0047] For the intake top plate provided by the embodiment of the present invention, the four gas distribution plates are evenly distributed. The first gas nozzles 404 and the second gas nozzles 504 are respectively arranged at equal intervals on the first gas distribution plate 4 and the second gas distribution plate 5 in each gas distribution plate to ensure that the gas entering the mixing chamber cavity 9 subsequently can be evenly distributed, so that a stable laminar flow is formed therein. Further, the first gas nozzles 404 and the second gas nozzles 504 in each gas distribution plate are staggered, so that the gases ejected by them will not generate obstruction and turbulence, which is beneficial to the full and uniform mixing of the reaction gases.

[0048] In a specific embodiment, two first gas upper channel grooves 102 and two second gas upper channel grooves 103 are formed on the top surface 101 of the top plate body 1. The first gas channel upper cover plate 2 is installed on the top of the first gas upper channel groove 102, and the second gas channel upper cover plate 3 is installed on the top of the second gas upper channel groove 103. Four first gas lower channel grooves 107 and four second gas lower channel grooves 108 are formed on the bottom surface 106 of the top plate body 1. One first gas lower channel groove 107 and one second gas lower channel groove 108 form a set of gas distribution lower channel grooves. The four sets of gas distribution lower channel grooves are all arranged in a direction parallel to the diameter of the bottom surface 106 and are evenly distributed in the circumferential direction. The first gas distribution plate 4 and the second gas distribution plate 5 are respectively installed at the bottoms of the first gas lower channel groove 107 and the second gas lower channel groove 108. The first gas distribution nozzle 6 and the second gas distribution nozzle are respectively installed in the middle of the tops of the first gas distribution plate 4 and the second gas distribution plate 5. The first gas inlet 201, the bottom of the first gas upper channel groove 102, the top of the first gas lower channel groove 107, the first gas distribution nozzle 6 and the first gas nozzle 404 are communicated; the second gas inlet 301, the bottom of the second gas upper channel groove 103, the top of the second gas lower channel groove 108, the second gas distribution nozzle and the second gas nozzle 504 are communicated. The tops of the first gas lower channel groove 107 and the second gas lower channel groove 108 are located on the same parallel cross-section extending from the bottom surface 106 to the top surface 101.

[0049] Exemplarily, the shapes of the first gas upper channel groove 102 and the second gas upper channel groove 103 are both parts of a toroid, and the shapes of the first gas lower channel groove 107 and the second gas lower channel groove 108 are both rounded cuboids. A rounded cuboid means that the cylinder diameters at both ends of the cuboid are the same as the width of the cuboid.

[0050] During specific implementation, after the first gas enters the first gas distribution plate 4 through the first gas inlet 201, the bottom of the first gas upper channel groove 102, the top of the first gas lower channel groove 107, and the first gas distribution nozzle 6, it is ejected by a plurality of first gas nozzles 404; after the second gas enters the second gas distribution plate 5 through the second gas inlet 301, the bottom of the second gas upper channel groove 103, the top of the second gas lower channel groove 108, and the second gas distribution nozzle, it is ejected by a plurality of second gas nozzles 504.

[0051] Furthermore, the two first gas upper channel grooves 102 are symmetric to each other, and the two second gas upper channel grooves 103 are symmetric to each other. The first gas inlet 201 and the second gas inlet 301 are respectively located in the middle of the first gas channel upper cover plate 2 and the second gas channel upper cover plate 3. Two first gas channel groove connection holes 104 perpendicular to the top surface 101 and penetrating through the top plate body 1 are provided at both ends of the first gas channel groove 102, and two second gas channel groove connection holes 105 perpendicular to the top surface 101 and penetrating through the top plate body 1 are provided at both ends of the second gas channel groove 103. The first gas channel upper cover plate 2 and the bottom of the first gas upper channel groove 102 form a first gas upper channel, and the second gas channel upper cover plate 3 and the bottom of the second gas upper channel groove 103 form a second gas upper channel. The four first gas distribution nozzles 6 and the four second gas distribution nozzles are respectively communicated with the four first gas channel groove connection holes 104 and the four second gas channel groove connection holes 105.

[0052] During specific implementation, after the first gas enters the first gas distribution plate 4 through the first gas inlet 201, the first gas upper channel, the first gas channel groove connection hole 104, and the first gas distribution nozzle 6, it is ejected from a number of first gas nozzles 404; the second gas enters the second gas distribution plate 5 through the second gas inlet 301, the second gas upper channel, the second gas channel groove connection hole 105, and the gas distribution nozzle 6.

[0053] In a specific embodiment, both the first gas upper channel groove 102 and the second gas upper channel groove 103 are double-layer groove structures. The width of the first lower-layer groove of the first gas upper channel groove 102 is smaller than the width of its first upper-layer groove. The shape and size of the first gas channel upper cover plate 2 are adapted to the first upper-layer groove, so that the top surface of the combination of the two is located within the top surface 101, and the first gas channel upper cover plate 2 and the first lower-layer groove form a first gas upper channel; the width of the second lower-layer groove of the second gas upper channel groove 103 is smaller than the width of its second upper-layer groove. The shape and size of the second gas channel upper cover plate 3 are adapted to the second upper-layer groove, so that the top surface of the combination of the two is located within the top surface 101, and the second gas channel upper cover plate 3 and the second lower-layer groove form a second gas upper channel; the width of the lower-layer groove of the first gas lower channel groove 107 and the second gas lower channel groove 108 is larger than the width of the upper-layer groove.

[0054] In a specific embodiment, as Figure 5 and Figure 6As shown, the first gas distribution plate 4 includes a first gas channel lower cover plate 401. A number of first ventilation openings 402 with the same shape and size are evenly distributed through the first gas channel lower cover plate 401. A number of evenly distributed first ventilation shells 403 are installed on the bottom surface of the first gas channel lower cover plate 401. The first ventilation shells 403 correspond to the first ventilation openings 402 one by one. A first gas spray opening 404 is formed at the cylindrical arc surface on one side of the first ventilation shell 403. The shape and size of the first gas channel lower cover plate 401 are adapted to the lower groove of the first gas lower channel groove 107, and the bottom surface of the combination of the two is located within the bottom surface 106. The first gas channel lower cover plate 401 and the upper groove of the first gas lower channel groove 107 form a first gas lower channel.

[0055] Specifically, the shapes of the first gas channel lower cover plate 401 and the first ventilation openings 402 are both rounded cuboids. The size of the first ventilation openings 402 can be equal to or slightly larger than the inner shell size of the first ventilation shells 403.

[0056] In a specific embodiment, as Figure 7 shown, the structure of the second gas distribution plate 5 is the same as that of the first gas distribution plate 4, including a second gas channel lower cover plate 501. A number of second ventilation openings 502 with the same shape and size are evenly distributed through the second gas channel lower cover plate 501. A number of evenly distributed second ventilation shells 503 are installed on the bottom surface of the second gas channel lower cover plate 501. The second ventilation shells 503 correspond to the second ventilation openings 502 one by one. A second gas spray opening 504 is formed at the cylindrical arc surface on one side of the second ventilation shell 503. The shape and size of the second gas channel lower cover plate 501 are adapted to the lower groove of the second gas lower channel groove 108, and the bottom surface of the combination of the two is located within the bottom surface 106. The second gas channel lower cover plate 501 and the upper groove of the second gas lower channel groove 108 form a second gas lower channel.

[0057] In a specific embodiment, as Figure 8 shown, the first gas distribution spray opening 6 is in the shape of a cylindrical ring structure. Two symmetrically arranged square through holes 601 are formed on both sides of the gas distribution spray opening 6. The top of the first gas distribution spray opening 6 extends to the first gas upper channel groove 102; specifically, the top of the first gas distribution spray opening 6 is inserted into the first gas channel groove connection hole 104. The structure of the second gas distribution spray opening is the same as that of the first gas distribution spray opening 6. The second gas distribution spray opening extends to the second gas upper channel groove 103 and is specifically inserted into the second gas channel groove connection hole 105.

[0058] Specifically, after the first gas and the second gas enter the first gas distribution spray opening 6 and the second gas distribution spray opening respectively, they can pass through the two square through holes 601 and reach a number of first gas spray openings 404 and a number of second gas spray openings 504.

[0059] Figure 13 Shown is a schematic diagram of gas mixing in the prior art (patent CN / ZL201697239.0) before the present invention. It can be seen that each first nozzle for the first gas and each second nozzle for the second gas in the existing design are single, and the jet directions are towards all around instead of being unidirectional. This will lead to uneven gas diffusion. At the same time, when the two gases are ejected, they will collide with each other and generate obstacles, resulting in insufficient and uneven gas mixing. This is an important reason for the poor thickness uniformity of the AlN thin film. Figure 14 Shown is a simulation diagram of the thickness distribution of the AlN thin film formed by the prior art (patent CN / ZL201697239.0), and its uniformity is only Cv≤9.827%, which fully proves this problem.

[0060] In view of the problems existing in the existing intake top plate, the embodiments of the present invention specifically point out that, as Figure 2 , Figure 4 , Figures 5 to 7 , first gas nozzles 404 arranged at the same spacing are provided on the first gas distribution plate 4, and second gas nozzles 504 arranged at the same spacing are provided on the second gas distribution plate 5; all the first gas nozzles 404 are open on one side and have the same direction; all the second gas nozzles 504 are open on one side and have the same direction; the opening directions of all the second gas nozzles 504 are consistent with the corresponding first gas nozzles 404. In this way, after the first gas and the second gas are ejected from the spray nozzles, they flow in the same direction with a spacing, forming multiple fluid beams. Due to the diffusion of the gas, flexible mixing is achieved while flowing, avoiding the excessive local pressure generated by the impact during counterflush mixing, resulting in poor mixing degree, and improving the mixing uniformity.

[0061] Particularly, the first gas nozzles 404 on each group of first gas distribution plates 4 and the second gas nozzles 504 on the second gas distribution plates 5 are arranged staggeredly, and then the first gas and the second gas are ejected staggeredly through the first gas nozzles 404 and the second gas nozzles 504. In the embodiments of the present invention, the specific implementation situation is that four groups of gas distribution plates are fixed on the disk surface of the top plate body 1 by bolts, so that the subsequent four groups of gas distribution plates are evenly distributed in the mixing cavity 9; the first gas nozzles 404 on each first gas distribution plate 4 and the second gas nozzles 504 on the second gas distribution plates 5 have the same direction, and then the first gas and the second gas ejected from the first gas nozzles 404 and the second gas nozzles 504 are all ejected along the same direction trend, as Figure 9 shown. The direction of the arrow d in the figure is the jet direction of the first gas and the second gas. It can be seen from Figure 9 that the first gas and the second gas are all ejected along the same direction trend. In the embodiments of the present invention, the specific implementation is that the first gas and the second gas are both ejected along the counterclockwise direction; it can be seen from Figure 9It can be seen that the first gas distributor plate 4 and the second gas distributor plate 5 in each group of gas distributor plates are arranged on both sides of the center line a and b, respectively, and are equidistant from the center line. The center lines a and b are mutually perpendicular diameter lines on the disk surface of the mixing chamber body 1. The design principle of the distance between the first gas distributor plate 4 and the second gas distributor plate 5 in each group of gas distributor plates is that, firstly, four groups of gas distributor plates must be arranged in the top disk body 1, and secondly, the distance between the first gas distributor plate 4 and the second gas distributor plate 5 must meet the installation space requirements for bolt fixing. In accordance with these two principles, the example of the present invention designs the distance c between the first gas distributor plate 4 and the second gas distributor plate 5 to be 10 mm while meeting the minimum space requirements for bolt installation. Figure 9 The first gas distribution plate 4 and the second gas distribution plate 5 in each group of gas distribution plates are arranged in the same position, so Figure 9 For example, along the direction of gas injection, that is, counterclockwise, the arrangement position of each second gas distribution plate 5 is set in front of the first gas distribution plate 4. In order to prevent the first gas from being blocked by the second gas nozzle 504 on the second gas distribution plate 5 after being ejected from the first gas nozzle 404 on the first gas distribution plate 4, or colliding with the second gas ejected from the second gas nozzle 504, thereby generating turbulence, resulting in insufficient and uneven gas mixing, so in an embodiment of the present invention, the first gas distribution plate 4 and its first gas nozzle 404 and the second gas distribution plate 5 and its second gas nozzle 504 are at different distances from the center of the disk surface of the top disk body 1. The first gas distribution plate 4 and its first gas nozzle 404 are closer to the center of the disk surface of the mixing chamber body 1, and the staggered distance is half of the hole distance between each adjacent first gas nozzle 404, and also half of the hole distance between each adjacent second gas nozzle 504; combined with Figure 9 , along the direction from the center of the top plate body 1 to the outside, that is, the direction of the mixing chamber annular wall 7, that is, the direction of the arrow e, from the inside to the outside, the first gas nozzles 404 and the second gas nozzles 504 are arranged alternately in sequence, the innermost nozzle is the first gas nozzle 404, and the outermost nozzle is the second gas nozzle 504; moreover, viewed from the direction of the arrow e, the hole spacing between each first gas nozzle 404 and its adjacent second gas nozzle 504 is the same, which is half of the hole spacing between adjacent first gas nozzles 404 on each first gas dividing plate 4, and also half of the hole spacing between adjacent second gas nozzles 504 on each second gas dividing plate 5; in this way, the first gas nozzles 404 on each group of the first gas dividing plates 4 and the second gas nozzles 504 on the second gas dividing plates 5 form a staggered arrangement, so that the first gas and the second gas are ejected at the same time in time, and each gas jet ejected through the first gas nozzle 404 and the second gas nozzle 504 in space forms a spaced flow from the inside to the outside. Therefore, this is more conducive to avoiding obstruction and turbulence of the first gas and the second gas ejected therefrom, and is conducive to sufficient and uniform mixing of the reaction gases, thereby improving the uniformity of the thickness of the AlN film.

[0062] Further, as shown in Figure 10 and Figure 11 , the embodiment of the present invention also provides a gas mixing device for an MOCVD device, which includes the intake top plate and the mixing chamber annular wall 7 of the MOCVD device provided in the above embodiment. The mixing chamber annular wall 7 is a cylindrical ring structure, and the mixing chamber annular wall 7 is adapted to the top plate body 1 and extends away from the top surface 101 with the bottom surface 106 as a reference. An air distribution plate 8 is installed inside the mixing chamber annular wall 7. The air distribution plate 8 is a thin cylindrical structure, and a number of spray ports 801 arranged at equal intervals are distributed in the middle of the air distribution plate 8. The top plate body 1, the mixing chamber annular wall 7 and the air distribution plate 8 form a mixing chamber cavity 9 of the gas mixing device. A nickel plate 10 is installed on the bottom surface of the air distribution plate 8.

[0063] As shown in Figure 11 , the dimension design of the height A of the mixing chamber cavity 9 has a crucial impact on the full and uniform mixing of reaction gases, and thus has a significant impact on the uniformity of the growth thickness of the AlN thin film. Generally, the larger the dimension of the height A of the mixing chamber cavity 9, the more conducive to the full and uniform mixing of reaction gases; but the larger the dimension, the lower the ejection speed of the reaction gases from the spray ports 801 of the air distribution plate 8. The reduction of the ejection speed will lead to the reduction of the growth rate and crystal quality of the AlN thin film. Therefore, it is necessary to reasonably design the dimension of the height A of the mixing chamber cavity 9 so that the reaction gases can be fully and uniformly mixed and at the same time ensure a suitable ejection speed to ensure the qualified growth rate, crystal quality and thickness uniformity of the AlN thin film.

[0064] As shown in Figure 12 , it simulates the thickness distribution of the AlN thin film at different heights of the mixing chamber cavity 9 in the embodiment of the present invention. When the dimension of the height A of the mixing chamber cavity 9 is A < 20 mm and A > 30 mm, the uniformity of the thickness of the AlN thin film is very poor and will not be shown in detail; when 20 ≤ A ≤ 30, Figure 12 , the thickness distributions of the AlN thin film at the heights A of 20 mm, 25 mm, and 30 mm of the mixing chamber cavity 9 are respectively shown. Their thickness non-uniformities are Cv20 ≤ 3.839%, Cv25 ≤ 0.358%, and Cv30 ≤ 1.145%. Therefore, in the embodiment of the present invention, it is preferably set that the dimension of the height A of the mixing chamber cavity 9 is 25 mm.

[0065] When the gas mixing device provided by the embodiment of the present invention is installed, first, place the two upper covers 2 of the first gas channels into the first upper grooves and seal-weld them by argon arc welding; place the two upper covers 3 of the second gas channels into the second upper grooves and seal-weld them by argon arc welding; place the first gas distribution nozzle 6 and the second gas distribution nozzle with the opening directions of the two square through holes 601 being the same as the extending directions of the first air vent 402 and the second air vent 403 respectively. Then, place the four first gas distribution plates 4 into the lower grooves of the first gas lower channel groove 107 and fix them with bolts; place the four second gas distribution plates 5 into the lower grooves of the second gas lower channel groove 108 and fix them with bolts. Finally, fix the gas homogenizing plate 8 on the top plate body 1 with bolts, and fix the nickel plate 10 on the gas homogenizing plate 8 with bolts.

[0066] In the embodiment of the present invention, the nickel plate 10 is fixed on the gas homogenizing plate 8 by bolts. Since nickel has a higher thermal conductivity than stainless steel, heat can quickly diffuse from the center to the edge, which improves the stability and uniformity of the thermal field, and further improves the uniformity of the growth of the AlN thin film; at the same time, in the embodiment of the present invention, the nickel plate 10 can also be polished. The smooth surface of the nickel plate 10 can reduce the turbulence of the gas flow when flowing on the bottom surface of the gas homogenizing plate 8, making the gas flow pass over the bottom surface more smoothly. The smooth surface of the nickel plate 10 can evenly take away heat, avoiding uneven heat exchange caused by local turbulence, and further improving the thickness uniformity; in addition, the nickel plate 10 can greatly reduce the adhesion of reaction products, minimizing the influence of the adherends on the temperature field and the flow field, and further improving the uniformity of the growth of the AlN thin film; finally, the nickel plate 10 adopts a detachable structure, which greatly facilitates its cleaning, and effectively avoids frequent disassembly and cleaning of components such as the top plate body 1 and the gas homogenizing plate 8.

[0067] When the gas mixing device provided by this embodiment is in use, the first gas enters the first gas upper channel through the first gas inlet 201, sequentially passes through the first gas channel groove connection hole 104 and the first gas distribution nozzle 6, reaches the first gas lower channel, and is distributed to the first jet nozzle 404, so as to be injected into the mixing chamber cavity 9. The second gas enters the second gas upper channel through the second gas inlet 301, sequentially passes through the second gas channel groove connection hole 105 and the second gas distribution nozzle, reaches the second gas lower channel, and is distributed to the second jet nozzle 504, so as to be injected into the mixing chamber cavity 9. The gas mixed in the mixing chamber cavity 9 is evenly sprayed onto the high-speed rotating graphite tray 11 through the spray holes 801 of the gas homogenizing plate 8, completing the mixing, homogenization, and reaction of the gas, and thus completing the entire process of AlN thin film epitaxial growth.

[0068] The embodiment of the present invention has been verified through simulation, such as Figure 14 and Figure 15The thickness distributions of the AlN thin films before and after the implementation of the embodiments of the present invention are respectively simulated. It can be seen therefrom that the non-uniformity of the AlN thin film thickness is improved from the original Cv≤9.827% to Cv≤0.358%, and the improvement is significant. Therefore, the uniformity of the growth thickness of the AlN thin film deposited by the embodiments of the present invention is greatly improved.

[0069] In summary, the intake top plate and the gas mixing device provided by the embodiments of the present invention have the following characteristics:

[0070] (1) The jet ports of the first gas and the second gas are arranged in the same direction. After the first gas and the second gas are ejected from the spray ports, they flow in the same direction with a spacing, forming multiple fluid beams. Due to the diffusion effect of the gas, flexible mixing is achieved while flowing, avoiding the excessive local pressure generated by the impact during counter-jet mixing, which leads to poor mixing degree, and improving the mixing uniformity.

[0071] (2) The first gas distribution plate and the second gas distribution plate are evenly installed in the mixing cavity. It is more flexible in structure, convenient for disassembly and replacement; the jet ports of different gases are staggered, so that the gases ejected by them will not generate obstruction and turbulence, which is conducive to the full and uniform mixing of the reaction gases.

[0072] (3) With a reasonable design of the height of the mixing cavity, while the reaction gases are fully and evenly mixed, a suitable jet speed can be ensured, ensuring a qualified growth rate, crystal quality and thickness uniformity of the AlN thin film.

[0073] (4) By setting a polished nickel plate, the adhesion of the reaction products can be greatly reduced, and the turbulence generated when the air flow flows at the bottom surface of the gas distribution plate can be effectively reduced, making the air flow more stable, quickly and evenly taking away heat, avoiding the uneven heat exchange caused by local turbulence, improving the thickness uniformity, and the detachable structure facilitates its cleaning, effectively avoiding the frequent disassembly and cleaning of components such as the top plate body and the gas distribution plate.

[0074] The above is only the preferred embodiment of the present invention and is not intended to limit the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. An air intake top plate of a MOCVD device, characterized in that: It comprises a top plate body (1); Two first gas channel upper cover plates (2) and two second gas channel upper cover plates (3) are installed on the top surface (101) of the top plate body (1), and the first gas channel upper cover plates (2) and the second gas channel upper cover plates (3) are respectively provided with a first gas inlet (201) and a second gas inlet (301) penetrating therethrough; Four groups of gas plates are installed on the bottom surface (106) of the top plate body (1). The four groups of gas plates are arranged in a direction parallel to the diameter of the bottom surface (106) and are evenly arranged in a circumferential direction. Each group of gas plates comprises a first gas distribution plate (4) and a second gas distribution plate (5). The bottoms of the first gas distribution plate (4) and the second gas distribution plate (5) are respectively provided with a plurality of evenly distributed first gas nozzles (404) and second gas nozzles (504). The first gas nozzles (404) and the second gas nozzles (504) in each group of gas distribution plates are arranged in a staggered manner. The first gas nozzles (404) and the second gas nozzles (504) are respectively connected to the first gas inlet (201) and the second gas inlet (301). The first gas enters the first gas distribution plate (4) through the first gas inlet (201) and is then ejected from a plurality of first gas ejection ports (404); the second gas enters the second gas distribution plate (5) through the second gas inlet (301) and is then ejected from a plurality of second gas ejection ports (504).

2. The gas inlet top plate of the MOCVD equipment according to claim 1, characterized in that: Two first gas upper channel grooves (102) and two second gas upper channel grooves (103) are provided on the top surface (101) of the top plate body (1); the first gas channel upper cover plate (2) is installed on the top of the first gas upper channel groove (102), and the second gas channel upper cover plate (3) is installed on the top of the second gas upper channel groove (103); The bottom surface (106) of the top plate body (1) is provided with four first gas lower passage grooves (107) and four second gas lower passage grooves (108), one first gas lower passage groove (107) and one second gas lower passage groove (108) forming a group of gas lower passage grooves, a first gas distributor plate (4) and a second gas distributor plate (5) are respectively mounted at the bottom of the first gas lower passage groove (107) and the second gas lower passage groove (108), and the first gas distributor plate (4) and the second gas distributor plate (5) are respectively mounted at the bottom of the first gas lower passage groove (107) and the second gas lower passage groove (108). 5) A first gas separation nozzle (6) and a second gas separation nozzle are respectively installed in the middle of the top; the first gas inlet (201), the bottom of the first gas upper channel groove (102), the top of the first gas lower channel groove (107), the first gas separation nozzle (6) and the first gas nozzle (404) are connected; the second gas inlet (301), the bottom of the second gas upper channel groove (103), the top of the second gas lower channel groove (108), the second gas separation nozzle and the second gas nozzle (504) are connected.

3. The gas inlet top plate of the MOCVD equipment according to claim 2, characterized in that: The two first gas upper channel grooves (102) are symmetrical to each other, and the two second gas upper channel grooves (103) are symmetrical to each other. The first gas inlet (201) and the second gas inlet (301) are respectively located between the first gas channel upper cover plate (2) and the second gas channel upper cover plate (3). Two first gas channel groove connecting holes (104) perpendicular to the top surface (101) and penetrating the top plate body (1) are provided at both ends of the first gas channel groove (102). Two first gas channel groove connecting holes (104) perpendicular to the top surface (101) and penetrating the top plate body (1) are provided at both ends of the second gas channel groove (103). A second gas channel groove connecting hole (105) is formed on the top surface (101) and passes through the top plate body (1); the first gas channel upper cover plate (2) and the bottom of the first gas channel groove (102) form a first gas upper channel; the second gas channel upper cover plate (3) and the bottom of the second gas channel groove (103) form a second gas upper channel; four first gas distribution nozzles (6) and four second gas distribution nozzles are respectively connected to the four first gas channel groove connecting holes (104) and the four second gas channel groove connecting holes (105).

4. The gas inlet top plate of the MOCVD equipment according to claim 2 or 3, characterized in that: The first gas upper channel groove (102) and the second gas upper channel groove (103) are both double-layer groove structures; the width of the first lower layer groove of the first gas upper channel groove (102) is smaller than the width of the first upper layer groove; the shape and size of the first gas channel upper cover plate (2) are adapted to the first upper layer groove; the first gas channel upper cover plate (2) and the first lower layer groove form a first gas upper channel; the width of the second lower layer groove of the second gas upper channel groove (103) is smaller than the width of the second upper layer groove; the shape and size of the second gas channel upper cover plate (3) are adapted to the second upper layer groove; the second gas channel upper cover plate (3) and the second lower layer groove form a second gas upper channel; the width of the lower layer groove of the first gas lower channel groove (107) and the second gas lower channel groove (108) is greater than the width of the upper layer groove.

5. The gas inlet top plate of the MOCVD equipment according to claim 2 or 3, characterized in that: The first gas distribution plate (4) comprises a first gas channel lower cover plate (401), a plurality of first vents (402) of the same shape and size are evenly distributed through the first gas channel lower cover plate (401), a plurality of evenly distributed first vent shells (403) are installed on the bottom surface of the first gas channel lower cover plate (401), the first vent shells (403) correspond to the first vents (402) one by one, a first gas nozzle (404) is provided on a cylindrical arc surface on one side of the first vent shell (403), the shape and size of the first gas channel lower cover plate (401) are adapted to the lower groove of the first gas channel groove (107), and the first gas channel lower cover plate (401) and the upper groove of the first gas channel groove (107) form a first gas channel.

6. The gas inlet top plate of the MOCVD equipment according to claim 2 or 3, characterized in that: The first gas separation nozzle (6) is in the shape of a cylindrical ring structure, and two mutually symmetrical square through holes (601) are provided on both sides of the first gas separation nozzle (6), and the top of the gas separation nozzle (6) extends to the first gas upper channel groove (102).

7. The gas inlet top plate of the MOCVD equipment according to claim 1, 2 or 3, characterized in that: The first gas distribution plate (4) and the second gas distribution plate (5) in each group of gas distribution plates are arranged on both sides of the center line and are equidistant from the center line, and the center line is a mutually perpendicular diameter line on the top plate body (1); the first gas nozzles (404) and the second gas nozzles (504) of the four groups of gas distribution plates are distributed in a counterclockwise or clockwise direction, and the first gas distribution plates (4) and the second gas distribution plates (5) in each group of gas distribution plates are arranged in the same position.

8. The gas inlet top plate of the MOCVD equipment according to claim 1, 2 or 3, characterized in that: The distance between the first gas distribution plate (4) and the second gas distribution plate (5) is 10 mm; The first gas distribution plate (4) and the second gas distribution plate (5) are at different distances from the center of the top plate body (1), and the offset distance between the first gas distribution plate (4) and the second gas distribution plate (5) is half of the hole distance between adjacent first gas nozzles (404) or adjacent second gas nozzles (504).

9. A gas mixing device for MOCVD equipment, characterized in that: The invention comprises an air inlet top plate and a mixing chamber ring wall (7) of an MOCVD device as claimed in any one of claims 1 to 8, wherein the mixing chamber ring wall (7) is a cylindrical ring structure, the mixing chamber ring wall (7) is adapted to the top plate body (1) and extends in a direction away from the top surface (101) with the bottom surface (106) as a reference, an air homogenizing plate (8) is installed inside the mixing chamber ring wall (7), a plurality of evenly distributed spray ports (801) are arranged in the middle of the air homogenizing plate (8), the top plate body (1), the mixing chamber ring wall (7) and the air homogenizing plate (8) constitute a mixing chamber body (9) of the mixing device, and a nickel plate (10) is installed on the bottom surface of the air homogenizing plate (8).

10. The gas mixing device of the MOCVD equipment according to claim 9, characterized in that: The height of the mixing chamber body (9) is 25 mm.

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