CN114108078B

CN114108078B - Crucible assembly and single crystal growth apparatus having the same

Info

Publication number: CN114108078B
Application number: CN202111448221.1A
Authority: CN
Inventors: 乔帅帅; 陈俊宏
Original assignee: Jiangsu Jixin Semiconductor Silicon Research Institute Co Ltd
Current assignee: Jiangsu Jixin Advanced Materials Co ltd
Priority date: 2021-11-30
Filing date: 2021-11-30
Publication date: 2023-06-02
Anticipated expiration: 2041-11-30
Also published as: CN114108078A

Abstract

The invention discloses a crucible assembly and a single crystal growth device with the same, wherein the crucible assembly comprises: a crucible; the inner cavity of the crucible is divided into a first cavity and a second cavity by the flow guiding device, the first cavity is suitable for placing seed crystals, an air outlet is formed in the cavity wall of the first cavity, the second cavity is suitable for placing raw materials, an air inlet is formed in the cavity wall of the second cavity, the inner side of the flow guiding device is limited with a flow guiding channel, the flow guiding channel and the seed crystals are opposite in the vertical direction and coaxially arranged, the flow guiding channel comprises a first channel, a second channel and a third channel which are sequentially connected from bottom to top, one side of the first channel, far away from the second channel, is communicated with the second cavity, one end of the third channel, far away from the second channel, is communicated with the first cavity, and the inner diameter of the second channel is not larger than the diameter of the seed crystals. According to the crucible assembly disclosed by the invention, a flat or slightly convex growth interface is formed on the seed crystal, so that the crystal quality is improved.

Description

Crucible assembly and single crystal growth apparatus having the same

Technical Field

The invention relates to the technical field of crystal growth, in particular to a crucible assembly and a single crystal growth device with the same.

Background

Related art indicates that the proportion of silicon carbide (SiC) monocrystalline materials in new energy automobiles, photovoltaic inversion, rail transit, ultra-high voltage power grids and 5G communication adopting silicon carbide power devices is increasing year by year. Silicon carbide single crystal materials are becoming one of the most important electronic materials. However, the existing silicon carbide crystal growth process is still immature, and the produced crystal is easy to have concave growth interfaces, so that the defects of coarse step appearance, stacking fault, inclusion of extraneous polytypes and the like of the crystal are caused.

Disclosure of Invention

The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention is directed to a crucible assembly that can improve a growth interface of crystals, thereby improving crystal quality.

The invention also provides a single crystal growth device with the crucible assembly.

The crucible assembly according to the first aspect of the present invention includes: a crucible; the inner cavity of the crucible is divided into a first cavity positioned at the upper side of the flow guiding device and a second cavity positioned at the lower side of the flow guiding device, the first cavity is suitable for placing seed crystals, an air outlet is formed in the cavity wall of the first cavity, the second cavity is suitable for placing raw materials, an air inlet is formed in the cavity wall of the second cavity, a flow guiding channel is defined at the inner side of the flow guiding device, the flow guiding channel and the seed crystals are oppositely and coaxially arranged along the up-down direction, the flow guiding channel comprises a first channel, a second channel and a third channel which are sequentially connected from bottom to top, one side of the first channel away from the second channel is communicated with the second cavity, one end of the third channel away from the second channel is communicated with the first cavity, the inner diameter of the second channel is not larger than the diameter of the seed crystals, the air inlet is suitable for introducing inert gas to drive the gas generated by heating the raw materials in the second cavity to enter the first cavity through the flow guiding channel and enter the seed crystals, the air outlet is suitable for discharging redundant gas.

According to the crucible assembly, the flow guide channel and the seed crystal are opposite in the up-down direction and coaxially arranged, and the diameter of the second channel is set to be not larger than the diameter of the seed crystal, so that the second channel can guide silicon carbide gas to the surface of the seed crystal in the direction opposite to the seed crystal, when the diameter of the second channel is smaller than the diameter of the seed crystal, the growth interface of the seed crystal can be formed into a slight convex shape, and when the diameter of the second channel is equal to the diameter of the seed crystal, the seed crystal can form a flat growth interface, and therefore the defect that the crystal growth interface in the related art is concave and quality defects caused by the concave shape can be avoided, and the yield is improved.

According to some embodiments of the invention, the flow guiding device comprises: a flow directing body defining the first channel and the second channel; the auxiliary flow guiding piece is arranged at the upper end of the flow guiding main body, the third channel is defined on the inner side of the auxiliary flow guiding piece, and the auxiliary flow guiding piece is detachably connected with the flow guiding main body, or the auxiliary flow guiding piece and the flow guiding main body are integrally formed.

Further, the flow guiding body includes: a constriction defining the first passage, the first passage having a cross-sectional area that gradually decreases in a bottom-to-top direction along an axis of the deflector; and the lower end of the accelerating part is connected with the upper end of the contraction part, the upper end of the accelerating part is connected with the auxiliary flow guide piece, the accelerating part defines the second channel, the sectional area of the second channel is kept unchanged in the direction from bottom to top along the axis of the flow guide device, and the diameter of the second channel is smaller than the diameter of the seed crystal.

Further, the cross-sectional area of the third channel gradually increases or remains constant in a bottom-to-top direction along the axis of the deflector; the diameter of the third channel is greater than the diameter of the second channel when the cross-sectional area of the third channel remains unchanged.

According to some embodiments of the invention, an end of the third channel adjacent to the seed crystal is formed as a flow guiding port, the flow guiding device is provided with a gas permeable portion covering the flow guiding port, a projection of the seed crystal in a reference plane is located in a projection of the gas permeable portion in the reference plane, the gas permeable portion includes a plurality of gas permeable regions arranged radially inward and outward, and a gas flux of the gas permeable region located on an inner side is not smaller than a gas flux of the gas permeable region located on an outer side in a radial and inward-outward direction, the reference plane is perpendicular to a central axis of the seed crystal.

According to some embodiments of the invention, the seed crystal and the ventilation part are coaxial, the diameter of the seed crystal is d1, the diameter of the ventilation part is d2, and the difference between d2 and d1 is in the range of: d2-d1 is more than or equal to 0 and less than or equal to 10mm.

In some embodiments, the plurality of breathable zones comprises at least: the first ventilation zone and the second ventilation zone, the first ventilation zone is circular, the second ventilation zone encircles the periphery side of the first ventilation zone and is coaxial with the first ventilation zone, the value range of the ratio a of the gas flux of the first ventilation zone to the gas flux of the second ventilation zone is: a is more than or equal to 1 and less than or equal to 1.5.

According to some embodiments of the invention, the first air-permeable region is axially opposite the second channel, and a surface area of the first air-permeable region is equal to a cross-sectional area of the second channel.

Further, the diameter of the seed crystal is d1, the diameter of the first ventilation area is d3, and the ratio of d3 to d1 is in the range of: d3/d1 is more than or equal to 0.15 and less than or equal to 0.30.

In some embodiments, the distance between the upper end of the flow guiding device and the seed crystal is L1, the diameter of the seed crystal is d1, and the ratio of L1 to d1 is in the range of: l1/d1 is more than or equal to 0.25 and less than or equal to 0.75.

According to some embodiments of the invention, the crucible comprises: a main body portion; a seed crystal placement part, which is positioned at the upper side of the main body part and at the center of the top wall of the main body part, wherein the projection of the seed crystal placement part on a reference surface is smaller than the projection of the main body part in the reference surface, the seed crystal placement part defines a seed crystal placement space communicated with the inner cavity of the main body part, the seed crystal is arranged in the seed crystal placement space, the reference surface is perpendicular to the central axis of the seed crystal, and the cross section of the crucible is formed into a convex shape; and one part of the flow guiding device is positioned in the inner cavity of the main body part, and the other part of the flow guiding device extends into the seed crystal placement space.

Further, the height of the main body part is H, the distance between the bottom end of the flow guiding device and the bottom wall of the main body part is L2, and the ratio of L2 to H is in the range of: L2/H is more than or equal to 0.3 and less than or equal to 0.55.

In some embodiments, a diversion inlet is formed at one end of the first channel facing away from the second channel, a cross section area of the diversion inlet is S1, a projected area of the main body portion in the reference plane is S2, and a ratio of S1 to S2 is in a range of values: S1/S2 is more than or equal to 0.6 and less than or equal to 1.

The single crystal growth apparatus according to the second aspect of the present invention includes: a crucible assembly according to the first aspect of the present invention; the heating device is arranged on the outer side of the crucible to heat the raw materials; and a purging device adapted to blow an inert gas into the crucible from the gas inlet to drive the partial gas to flow from the second chamber to the first chamber and to be discharged from the gas outlet.

According to the single crystal growth device provided by the embodiment of the invention, the crucible assembly is arranged, so that the crystal has a flat or slightly convex growth interface, the growth quality of the crystal is greatly improved, and the yield is improved.

Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Drawings

FIG. 1 is a schematic view of a single crystal growing apparatus according to an embodiment of the present invention;

FIG. 2 is a schematic view of a crucible according to an embodiment of the present invention;

FIG. 3 is a schematic view of one embodiment of a deflector according to an embodiment of the present invention;

FIG. 4 is a schematic view of another embodiment of a deflector according to an embodiment of the present invention;

FIG. 5 is a schematic view of yet another embodiment of a deflector according to an embodiment of the present invention;

FIG. 6 is a schematic view of yet another embodiment of a deflector according to an embodiment of the present invention;

FIG. 7 is a schematic view of yet another embodiment of a deflector according to an embodiment of the present invention;

fig. 8 is a schematic view of a breathable portion according to an embodiment of the invention.

Reference numerals:

single crystal growing apparatus 100:

the crucible assembly 1 is provided with a plurality of grooves,

the crucible 11 is provided with a plurality of holes,

a main body portion 111, a seed crystal mounting portion 112,

the seed crystal seating space 1121,

a first chamber 113, a second chamber 114, an air outlet 115,

the flow guiding device 12 is arranged in the air guiding device,

the flow guiding body 121, the constriction 1211, the acceleration 1212, the auxiliary flow guiding member 122,

The flow-guiding channel 123 is provided with a flow-guiding channel,

a first passage 1231, a second passage 1232, a third passage 1233, a pilot outlet 1234, a pilot inlet 1235,

the air-permeable portion 124,

the first ventilation zone 1241, the second ventilation zone 1242,

the heating means 2 are arranged such that,

the purge means 3 are provided with a purge device,

seed crystal 200.

Detailed Description

Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative and intended to explain the present invention and should not be construed as limiting the invention.

A crucible assembly 1 according to an embodiment of the first aspect of the present invention is described below with reference to fig. 1 to 8.

Referring to fig. 1 and 8, a crucible assembly 1 according to an embodiment of the present invention can be used for growth preparation of crystals, such as growth preparation of silicon carbide single crystals. Specifically, the crucible assembly 1 may include: a crucible 11 and a deflector 12.

Wherein the deflector 12 is disposed in the crucible 11, for example, the deflector 12 may be detachably connected or fixedly connected to an inner peripheral wall of the crucible 11. The flow guiding device 12 may divide the inner cavity of the crucible 11 into a first chamber 113 and a second chamber 114, the first chamber 113 is located on the upper side of the flow guiding device 12, the second chamber 114 is located on the lower side of the flow guiding device 12, the first chamber 113 is suitable for placing the seed crystal 200, for example, the seed crystal 200 may be fixed on the top wall of the crucible 11 by a fixture or a mounting base, an air outlet 115 is formed on the cavity wall of the first chamber 113, a raw material, for example, a silicon carbide raw material, is suitable for being placed in the second chamber 114, and an air inlet (not shown) is formed on the cavity wall of the second chamber 114.

The guiding device 12 is arranged at the lower side of the seed crystal, the guiding channel 123 is defined at the inner side of the guiding device 12, the guiding channel 123 and the seed crystal are opposite to each other along the up-down direction and coaxially arranged, the guiding device 12 comprises a first channel 1231, a second channel 1232 and a third channel 1233 which are sequentially connected from bottom to top, one side of the first channel 1231, away from the second channel 1232, is communicated with the second chamber 114, one end of the third channel 1233, away from the second channel 1232, is communicated with the first chamber 113, the inner diameter of the second channel 1232 is not larger than the diameter of the seed crystal 200, for example, the diameter of the second channel 1232 can be smaller than or equal to the diameter of the seed crystal 200, the air inlet is suitable for introducing inert gas to drive gas generated by heating raw materials in the second chamber 114 to enter the first chamber 113 through the guiding channel 123 and deposit on the seed crystal 200, and the air outlet 115 is suitable for discharging redundant gas.

Thus, when the raw material in the second chamber 114 is heated to generate silicon carbide gas, the inert gas blown into the second chamber 114 from the gas inlet may drive the silicon carbide gas to flow through the first channel 1231, the second channel 1232 and the third channel 1233 in sequence into the first chamber 113, deposit and grow on the surface of the seed crystal 200, and the surplus silicon carbide gas and inert gas may be discharged from the gas outlet 115.

According to the crucible assembly 1 of the embodiment of the invention, the flow guiding channel 123 and the seed crystal are arranged oppositely and coaxially in the up-down direction, and the diameter of the second channel 1232 is set to be not larger than the diameter of the seed crystal 200, so that the second channel 1232 can guide silicon carbide gas to the surface of the seed crystal 200 in the direction opposite to the seed crystal, and when the diameter of the second channel 1232 is smaller than the diameter of the seed crystal 200, the growth interface of the seed crystal 200 can be formed in a slightly convex shape, and when the diameter of the second channel 1232 is equal to the diameter of the seed crystal 200, the seed crystal 200 can be formed into a flat growth interface, so that the crystal growth interface in the related art is concave and quality defects caused by the concave shape can be avoided, and the yield is improved.

In some embodiments, the flow directing device 12 may include: a deflector body 121 and an auxiliary deflector 122. Wherein the flow directing body 121 defines a first channel 1231 and a second channel 1232; the auxiliary guide member 122 is disposed at an upper end of the guide body 121, and the auxiliary guide member 122 defines a third channel 1233. Alternatively, the guide body 121 and the auxiliary guide 122 may be integrally formed and also connected by a detachable connection, such as a socket connection or a clip connection, so that the guide 12 is simple in structure and convenient to assemble with the crucible 11.

Alternatively, both the flow guiding body 121 and the auxiliary flow guiding member 122 may be heat insulating material members, and preferably, the flow guiding body 121 and the auxiliary flow guiding member 122 are made of graphite material with high density and low gas flux or other similar materials. The breathable portion 124 may be formed as a breathable film having a thickness of 5mm to 11mm,the density of the air-permeable portion 124 was 1.2g/cm ³ ～1.7g/cm ³ The remaining surfaces of the auxiliary flow guide 122 excluding the gas permeable portion 124 are impermeable to silicon carbide gas.

In some embodiments, referring to fig. 3-7, the flow directing body 121 includes: a constriction 1211 and an acceleration. The constriction 1211 defines a first passage 1231, and the cross-sectional area of the first passage 1231 is gradually reduced in a direction along the axis of the flow guiding device 12 and from bottom to top, so that gas is easily collected and the flow rate of the gas is increased, and for example, the inner surface of the constriction 1211 may be formed in a tapered shape or may be formed in an arc-shaped surface. The lower extreme of accelerating part links to each other with the upper end of constriction 1211, and the upper end of accelerating part links to each other with supplementary water conservancy diversion spare, and accelerating part defines second passageway 1232, and along the axis of guiding device 12 and from the bottom-up direction, the sectional area of second passageway 1232 remains unchanged and the diameter of second passageway 1232 is less than the diameter of seed crystal, so, second passageway 1232 constitutes the passageway of falling funnel shape with first passageway 1231, is favorable to accelerating the air current, and simultaneously, second passageway 1232 can ensure that carborundum gas stably accurately transmits to the surface of seed crystal.

Further, the cross-sectional area of the third passage 1233 gradually increases or remains constant in a direction along the axis of the deflector 12 and from bottom to top; while the cross-sectional area of the third passage 1233 remains unchanged, the diameter of the third passage 1233 is larger than the diameter of the second passage 1232. For example, the third channel 1233 may be formed in a cylindrical shape, or may be formed in an inverted cone shape, or may be formed in a bowl shape, since the flow guiding body 121 is in an inverted funnel shape having a cross-sectional area that is reduced first and then is unchanged, the cross-sectional area of the third channel 1233 is set to be constant or increased, and at least a portion of the cross-sectional area of the third channel 1233 is larger than that of the second channel 1232, vapor entering the third channel 1233 from the second channel 1232 may be diffused in the circumferential direction, so as to avoid excessive vapor deposition amount in the middle of the seed crystal due to excessive concentration of the vapor in the middle of the flow guiding channel 123, and excessive protrusion of the crystal interface caused thereby, which may not meet the quality requirement.

For example, as shown in fig. 7, when the cross-sectional area of the third passage 1233 is constant in the axial direction of the flow guiding passage 123 and in the bottom-to-top direction, the area of each of the third passages 1233 is larger than the cross-sectional area of the second passage 1232; as shown in fig. 3 to 6, for example, when the cross-sectional area of the third passage 1233 is gradually increased, the cross-sectional area of the portion of the third passage 1233 other than the portion where it is connected to the second passage 1232 is larger than the cross-sectional area of the second passage 1232.

According to some embodiments of the present invention, an end of the third passage 1233 adjacent to the seed crystal 200 (e.g., an upper end of the third passage 1233 shown in fig. 1) is formed as a flow guide outlet 1234, the flow guide 12 is provided with a gas permeable portion 124 covering the flow guide outlet 1234, a projection of the seed crystal in a reference plane is located in a projection of the gas permeable portion 124 in the reference plane, the gas permeable portion 124 includes a plurality of gas permeable regions arranged radially inward and outward, and a gas flux of the gas permeable region located on an inner side is not smaller than a gas flux of the gas permeable region located on an outer side in a radial and inward-outward direction, and the reference plane is perpendicular to a central axis of the seed crystal.

For example, as shown in fig. 1 and 8, the ventilation part 124 is formed at the upper end of the auxiliary flow guiding member 122, the multiple ventilation areas of the ventilation part 124 are arranged radially inwards and outwards, the outer circumferences of the multiple ventilation areas are formed as concentric circles, in any two adjacent ventilation areas in the multiple ventilation areas in the radial direction and the direction from inside to outside, the gas flux of the ventilation area located at the inner side can be equal to the gas flux of the ventilation area located at the outer side, and the gas deposition amount of each part on the surface of the seed crystal 200 is relatively uniform, at this time, the crystal can have a flat interface; alternatively, the gas flux of the gas permeable region on the inner side may be greater than the gas flux of the gas permeable region on the outer side, so that the gas deposition amount in the middle portion of the seed crystal 200 is greater than that in the peripheral portion, thereby forming a slightly convex growth interface for the crystal. At this time, the reference plane may be a horizontal plane perpendicular to the central axis of the seed crystal 200.

In addition, the ventilation part 124 is disposed at the upper end of the auxiliary flow guiding member 122, so that the distance between the ventilation part 124 and the seed crystal 200 is relatively short, and the gas deposition amount of each area on the surface of the seed crystal 200 is more easily controlled, thereby controlling and improving the growth interface of the crystal, and simultaneously, the natural flow of the high-temperature gas to the first chamber 113 through the flow guiding channel 123 is also facilitated.

Optionally, a protection layer may be disposed on the channel wall of the flow guiding channel 123, where the protection layer may be made of a material with high temperature resistance and no reaction with gas, such as tantalum carbide, niobium carbide, and tungsten carbide, and the protection layer may be coated on the channel wall of the flow guiding channel 123 by CVD (chemical vapor deposition) or the like, so that loss of gas may be avoided, and the utilization rate of raw materials may be improved. Preferably, the thickness of the protective layer may be 50 μm to 80 μm, which is advantageous in simplifying the process.

According to some embodiments of the present invention, the seed crystal 200 may be coaxially disposed with the air permeable portion 124, that is, the central axis of the seed crystal 200 and the central axis of the air permeable portion 124 are the same axis, where the diameter of the seed crystal 200 is d1, the diameter of the air permeable portion 124 is d2, and the difference between d2 and d1 is in the range of: 0.ltoreq.d2-d1.ltoreq.10mm, that is, the diameter of the ventilation portion 124 is greater than or equal to the diameter of the seed crystal 200, for example, the difference between d2 and d1 may be 0mm, 2mm, 4mm, 6mm, 8mm or 10mm, so that it is ensured that the gas in the flow guide channel 123 is deposited on the surface of the seed crystal 200 in a tiled manner after passing through the ventilation portion 124, and that the surface of the seed crystal 200 is deposited with gas everywhere, and the gas adhesion amounts around the circumference corresponding to different radii of the surface of the seed crystal 200 are relatively uniform, so that the crystal is more symmetrical, and the quality is further improved.

In some embodiments, referring to fig. 8, the plurality of ventilation zones may include at least: a first ventilation zone 1241 and a second ventilation zone 1242. The first ventilation area 1241 is circular, the second ventilation area 1242 surrounds the outer peripheral side of the first ventilation area 1241, the second ventilation area 1242 is coaxial with the first ventilation area 1241, that is, the outer edge of the second ventilation area 1242 and the outer edge of the first ventilation area 1241 are formed into concentric circles, so that after the gas passes through the ventilation film with the seed crystal 200 opposite to and coaxial with the ventilation part 124, the gas deposition amount in the area corresponding to the same ventilation area on the surface of the seed crystal 200 is more uniform, and the ratio between the gas deposition amounts in different areas corresponding to different ventilation areas on the surface of the seed crystal 200 and the ratio between the gas deposition amounts in a plurality of ventilation areas are close to or the same as each other, so that the formed crystal is more symmetrical, the quality is better, and the yield is higher.

Further, the ratio a of the gas fluxes of the first ventilation area 1241 and the second ventilation area 1242 is in the range of: 1.ltoreq.a.ltoreq.1.5, for example, the ratio a of the gas fluxes of the first and second gas

permeable regions

1241 and 1242 may be 1, 1.1, 1.2, 1.3, 1.4 or 1.5, wherein when a is 1, the gas fluxes of the first and second gas

permeable regions

1241 and 1242 are the same, and at this time, the crystal interface may be formed as a flat interface, and when a is greater than 1, the crystal interface is formed as a slightly convex interface. Thus, when the ratio a of the gas fluxes of the first and second gas

permeable regions

1241 and 1242 is too small, for example, less than 1, the crystal interface is formed into a concave shape to cause defects in the crystal, and when the ratio a of the gas fluxes of the first and second gas

permeable regions

1241 and 1242 is too large, for example, greater than 1.5, the crystal interface is prevented from being too convex to cause the quality of the crystal to be unsatisfactory. For example, a plurality of ventilation holes may be provided on the ventilation part 124, the diameter of the ventilation holes is 0.1-0.8mm, and the ratio of the densities of the ventilation holes of the first ventilation area 1241 and the second ventilation area 1242 is 1-1.5, so that the value range of the ratio a of the gas fluxes of the first ventilation area 1241 and the second ventilation area 1242 is achieved: a is more than or equal to 1 and less than or equal to 1.5.

According to some embodiments of the present invention, the first ventilation area 1241 is axially opposite to the second channel 1232, and the surface area of the first ventilation area 1241 and the cross-sectional area of the second channel 1232 are equal, so that it is ensured that more silicon carbide gas passes through the first ventilation area 1241 to reach the corresponding position on the surface of the seed crystal 200, so that the growth interface of the seed crystal 200 is formed to be slightly convex, to improve the quality thereof.

Further, the diameter of the seed crystal 200 is d1, the diameter of the first ventilation area 1241 is d3, and the ratio of d3 to d1 is in the range: 0.15.ltoreq.d3/d1.ltoreq.0.30, for example, the ratio of d3 to d1 may be 0.15, 0.2, 0.25 or 0.3, which is advantageous for forming a slightly convex interface with relatively thicker middle and relatively thinner periphery of the crystal, and at the same time, makes the shape of the crystal relatively symmetrical, thereby improving the crystal quality.

According to some embodiments of the present invention, the distance between the flow guiding device 12 and the seed crystal 200 is L1, the diameter of the seed crystal 200 is d1, and the ratio of L1 to d1 is in the range: 0.25.ltoreq.L1/d1.ltoreq.0.75, for example, the ratio of L1 to d1 may be 0.25, 0.4, 0.5, 0.7 or 0.75, so that it is possible to avoid that too close a distance of the deflector 12 from the seed crystal 200 causes a large amount of gas to diffuse around after colliding with the seed crystal 200 at a high flow rate, that too far a distance of the deflector 12 from the seed crystal 200 causes a decrease in the gas flow rate to reduce the growth rate of the crystal, and that when too far a distance of the deflector 12 from the seed crystal 200 causes a too far distance of the gas permeable portion 124 from the seed crystal 200 and thus the gas deposition amount control effect of the gas permeable portion 124 on each region of the surface of the seed crystal 200 becomes poor.

According to some embodiments of the present invention, referring to fig. 1 and 2, a crucible 11 may include: a main body portion 111 and a seed crystal placement portion 112. Wherein the seed crystal placement portion 112 is located at an upper side of the body portion 111 and at a center of a top wall of the body portion 111, a projection of the seed crystal placement portion 112 on the reference plane is smaller than a projection of the body portion 111 in the reference plane, the seed crystal placement portion 112 may define a seed crystal placement space 1121, the seed crystal 200 is disposed in the seed crystal placement space 1121, for example, the seed crystal 200 may be disposed at an inner top wall of the seed crystal placement portion 112, and the seed crystal placement space 1121 communicates with an inner cavity of the body portion 111. In this way, the crucible 11 is formed in a convex shape in the vertical section, so that silicon carbide gas flowing from the second chamber 114 to the first chamber 113 can be more concentrated in the seed crystal installation space 1121, and thus, gas can be sufficiently deposited on the seed crystal 200, thereby improving the utilization rate of raw materials to some extent, and at the same time, further accelerating the growth rate of crystals.

The part of the guiding device 12 is located in the inner cavity of the main body 111 and the other part of the guiding device stretches into the seed crystal placing space 1121, the first chamber 113 is located on the upper side of the guiding device 12, the first chamber 113 comprises the seed crystal placing space 1121 and part of the inner cavity of the main body 111, which is located on the upper side of the guiding device 12, the second chamber 114 is located on the lower side of the guiding device 12, and the guiding channel 123 is located on the inner side of the guiding device 12, so that the guiding device 12 can smoothly guide the air flow in the second chamber 114 to the first chamber 113, and meanwhile, the whole structure is simple, and the manufacturing and the assembly are convenient.

Further, the height of the main body 111 is H, the distance between the bottom end of the guiding device 12 and the bottom wall of the main body 111 is L2, and the ratio of L2 to H is in the range of: L2/H0.3.ltoreq.L2.ltoreq.0.55, for example, the ratio of L2 to H may be 0.3, 0.4, 0.5 or 0.55, so that too small a distance between the deflector 12 and the bottom wall of the main body 111, for example, L2/H less than 0.3, can be avoided, and the space between the deflector 12 and the raw material is too small, so that the gas generated by sublimation of the raw material is easy to accumulate around the gas inlet 1232 and generate vortex, thereby reducing the gas flow speed and affecting the crystal growth rate; and the excessively large distance between the flow guiding device 12 and the bottom wall of the main body 111, such as L2/H greater than 0.55, can be avoided, so that the space between the flow guiding device 12 and the raw materials is excessively large, the gas flow speed is reduced, the flow guiding effect of the flow guiding device 12 on the gas is not obvious, and the growth rate of crystals is influenced.

In some embodiments, a flow guiding inlet 1235 is formed at one end of the first channel 1231 facing away from the second channel 1232, the cross-sectional area of the flow guiding inlet 1235 is S1, the projected area of the main body 111 in the reference plane is S2, and the ratio of S1 to S2 is in the range of: S1/S2 is more than or equal to 0.6 and less than or equal to 1, for example, the ratio of S1 to S2 can be 0.6, 0.7, 0.8, 0.9 or 1, so that the phenomenon that gas is easily gathered around the diversion inlet 1235 to form vortex when the diversion inlet 1235 is too small can be avoided, the circulation efficiency of the gas is influenced, and the growth rate of crystals is further influenced.

A single crystal growing apparatus 100 according to an embodiment of the second aspect of the present invention is described below with reference to fig. 1.

The single crystal growth apparatus 100 according to the embodiment of the second aspect of the present invention includes: the crucible assembly 1 and the heating apparatus 2 according to the above-described embodiments of the present invention.

Wherein the heating means 2 is adapted to heat the raw material to sublimate the raw material to generate gas, for example, the heating means 2 may be an induction coil, and the heating means 2 may be provided outside the crucible 11 and disposed opposite to the cavity wall of the second chamber 114, whereby the heating means 2 may heat the raw material to sublimate the raw material to generate gas by heating, so as to facilitate the growth of the seed crystal 200.

It should be noted that, the heating device 2 may provide a high temperature environment of 2000-2400 ℃ for the SiC raw material, and the heating device 2 may form a temperature gradient distribution space with a difference of 10-100 ℃ between the raw material and the seed crystal 200, so that the SiC raw material sublimates to form SiC vapor (including Si, si2C, si C) under the heating condition, rapidly gathers under the action of the guiding body 121, diffuses toward the first chamber 113 under the action of the temperature gradient and the like, and when reaching the ventilation portion 124 of the guiding device 12, the gas may deposit at the growth interface in a tiled manner due to the special structure thereof, and the seed crystal 200 forms a flat or slightly convex growth interface due to the difference of the permeability of different ventilation areas of the ventilation portion 124 and the influence of the shape of the seed crystal 200, thereby facilitating the growth of high quality silicon carbide single crystal.

According to the single crystal growth apparatus 100 of the embodiment of the present invention, by providing the crucible assembly 1 of the above embodiment, the crystal can have a flat or slightly convex growth interface, thereby greatly improving the growth quality of the crystal and improving the yield.

According to some embodiments of the present invention, the crucible 11 is formed with an air inlet and an air outlet 115, the air inlet is formed in a wall of the second chamber 114, the air outlet 115 is formed in a wall of the first chamber 113, and the single crystal growing apparatus 100 further comprises: purge device 3, purge device 3 is adapted to blow inert gas into crucible 11 from the gas inlet to drive gas from second chamber 114 to first chamber 113 and out of gas outlet 115.

For example, the crucible 11 may include a body portion 111 and a seed crystal placement portion 112. Wherein, the seed crystal setting part 112 is located at the center of the top of the main body part 111, the projection of the seed crystal setting part 112 on the reference surface is smaller than the projection of the main body part 111 in the reference surface, the seed crystal setting part 112 can define a seed crystal setting space 1121, the seed crystal 200 is arranged in the seed crystal setting space 1121, the air inlet can be formed on the main body part 111 and communicated with the second chamber 114, the air outlet 115 can be formed on the seed crystal setting part 112 and communicated with the seed crystal setting space 1121, or the air outlet 115 can be formed on the main body part 111 and communicated with the first chamber 113, the purging device 3 can be arranged outside the crucible 11, the purging device 3 is suitable for blowing inert gas into the second chamber 114 from the air inlet so as to drive gas generated by sublimation of the silicon carbide raw material to flow from the second chamber 114 to the first chamber 113 and deposit on the seed crystal 200, and then the redundant gas can be discharged from the air outlet 115. The inert gas may be argon, helium, etc., so that by setting the purge device 3, the rate of gas diffusing from the communication port to the seed crystal 200 can be increased, the growth rate of silicon carbide crystal can be increased, and the adhesion of a part of gas on the inner wall of the growth crucible 11 and the outer wall of the inner crucible 11 can be avoided, thereby increasing the utilization rate of raw materials. In addition, the purge gas, i.e., the inert gas, enters the gas flow channel from the gas inlet and is then exhausted from the gas outlet 115, so that a portion of the carbon-rich and silicon-rich gas can be taken away, thereby reducing the deposition of silicon-rich or carbon-rich silicon carbide in the silicon carbide crystal and improving the quality of the silicon carbide crystal.

A single crystal growing apparatus 100 according to an embodiment of the present invention is described below with reference to fig. 1 to 8.

As shown in fig. 1, a single crystal growth apparatus 100 according to an embodiment of the present invention includes: a crucible assembly 1, a heating device 2 and a purging device 3. The crucible assembly 1 includes a crucible 11 and a deflector 12 disposed within the crucible 11.

The crucible 11 includes: a main body portion 111 and a seed crystal placement portion 112. The seed crystal placing portion 112 is located at the center of the top of the main body portion 111, the projection of the seed crystal placing portion 112 on the reference plane is smaller than the projection of the main body portion 111 on the reference plane, the seed crystal placing portion 112 defines a seed crystal placing space 1121, the seed crystal placing space 1121 is communicated with the inner cavity of the main body portion 111, the seed crystal 200 is located in the seed crystal placing space 1121 and located on the inner top wall of the seed crystal placing portion 112, and the crucible 11 is formed to be convex along the vertical section.

The flow guiding device 12 defines a flow guiding channel 123 constituted by a first channel 1231, a second channel 1232 and a third channel 1233, the flow guiding device 12 comprising: a deflector body 121 and an auxiliary deflector 122. Wherein the flow directing body 121 defines a first channel 1231 and a second channel 1232; the auxiliary flow guide 122 is disposed at the upper end of the flow guide body 121, the auxiliary flow guide 122 defines a third channel 1233, the flow guide outlet is formed at the upper end of the third channel 1233, the flow guide outlet is opposite to and coaxial with the seed crystal 200, the auxiliary flow guide 122 is formed with a ventilation portion 124 covering the flow guide outlet, and the ventilation portion 124 includes: a first ventilation zone 1241 and a second ventilation zone 1242. The first ventilation area 1241 and the second ventilation area 1242 are arranged radially inward and outward, wherein the first ventilation area 1241 is circular, the second ventilation area 1242 is formed in a ring shape surrounding the outer peripheral side of the first ventilation area 1241, and the second ventilation area 1242 is coaxial with the first ventilation area 1241.

The flow guide body 121 includes: a constriction 1211 and an acceleration 1212. The constriction 1211 defines a first passage 1231, and the cross-sectional area of the first passage 1231 is gradually reduced in a direction along the axis of the flow guiding device 12 and from bottom to top, so that gas is easily collected and the flow rate of the gas is increased, and for example, the inner surface of the constriction 1211 may be formed in a tapered shape or may be formed in an arc-shaped surface. The lower end of the accelerating part 1212 is connected to the upper end of the contracting part 1211, the upper end of the accelerating part 1212 is connected to the auxiliary flow guide 122, the accelerating part 1212 defines a second passage 1232, the sectional area of the second passage 1232 is maintained constant in the direction from bottom to top along the axis of the flow guide 12, and the diameter of the second passage 1232 is smaller than that of the seed crystal 200, so that the second passage 1232 and the first passage 1231 form an inverted funnel-shaped passage to facilitate accelerating the gas flow, and at the same time, the second passage 1232 can ensure stable and accurate transfer of the silicon carbide gas to the surface of the seed crystal 200.

The guide body 121 of the guide device 12 is formed in an inverted funnel shape as a whole, the lower edge of the guide device 12 is located in the inner cavity of the body portion 111 and detachably connected with the peripheral wall of the body portion 111, the portion of the constricted portion of the guide body 121 and the accelerating portion are located in the seed crystal placing space 1121, the auxiliary guide 122 is located in the seed crystal placing space 1121, the portion of the inner cavity of the body portion 111 located below the guide device 12 constitutes the second chamber 114, the portion of the inner cavity of the body portion 111 located above the guide device 12 and located outside the guide channel 123 and the seed crystal placing space 1121 together constitute the first chamber 113, the crucible 11 is formed with the air inlet and the air outlet 115, the air inlet is formed in the chamber wall of the second chamber 114, and the air outlet 115 is formed in the chamber wall of the first chamber 113.

3kg of silicon carbide crystal powder is filled in the second chamber 114 of the crucible 11, the seed crystal 200 in the first chamber 113 is 4H silicon carbide seed crystal 200, the diameter d1 of the seed crystal 200 is 150mm, the distance L1 between the ventilation part 124 of the diversion device 12 and the seed crystal 200 is 75mm, the diameter d2 of the ventilation part 124 is 155mm, the diameter d3 of the first ventilation area 1241 and the diameter of the accelerating section 12312 of the first diversion section 1231 are both 30mm, the height H of the auxiliary diversion piece 122 is 31mm, the area covered by the gas inlet 1232 of the diversion channel 123 is 60% of the surface area of the silicon carbide raw material, and the gas flux ratio of the first ventilation area 1241 to the second ventilation area 1242 is 1.1:1.

The heating means 2 may be provided outside the crucible 11 and disposed opposite to the cavity wall of the second chamber 114, and the purging means 3 may be adapted to blow an inert gas into the crucible 11 from the gas inlet to drive the gas from the second chamber 114 to the first chamber 113 and deposit on the seed crystal 200, and the surplus gas may be discharged from the gas outlet 115.

In producing silicon carbide crystals, crucible 11 is heated to raise the temperature of the raw material to 2160 ℃ and sublimate into SiC vapor (Si, si2C, si C), the temperature at seed crystal 200 is 2130 ℃, argon is purged into second chamber 114 by purge device 3, the gas pressure of the argon is 10 torr, the pressure of the inert gas in crucible 11 is 30 torr, and heating is continued for 17 hours to grow the crystals. The gas is rapidly gathered under the action of the guide body 121 and is diffused to the first chamber 113 under the action of a temperature gradient and the like, and when reaching the ventilation part 124 of the guide device 12, the gas is deposited to the growth interface in a flat manner due to the special structure, and the seed crystal 200 forms a slightly convex growth interface due to the influence of different ventilation areas of the ventilation part 124 on the gas permeability difference and the shape of the seed crystal 200, so that the growth of high-quality silicon carbide single crystal is facilitated. And the surplus exhaust gas is discharged from the gas outlet 115 of the seed crystal 200.

The silicon carbide crystal grown by the single crystal growth apparatus 100 of this example had slightly convex growth interface, crystal diameter of 150mm, ingot weight of 2.1kg, and few crystal defects such as micropipes with a micropipe density of 0.8cm were detected ^-2 The dislocation density is about 6.9 x 103cm ^-2 。

In summary, in the single crystal growth apparatus 100 of the present embodiment, the ventilation portion 124 is disposed at the air-guiding outlet 1234 of the air-guiding channel 123, and the ventilation portion 124 is configured to include a plurality of ventilation areas, where the gas fluxes of different ventilation areas are different in any two adjacent ventilation areas among the plurality of ventilation areas, so that the gas fluxes of different ventilation areas of the ventilation portion 124 can be changed to change the gas deposition amounts of the seed crystal 200 corresponding to the different ventilation areas, thereby achieving the purpose of controlling the crystal growth interface, and the gas fluxes of the ventilation areas located inside the ventilation portion 124 are greater than the gas fluxes of the ventilation areas located outside the ventilation portion 124, so that the gas deposition amounts of the middle portion of the seed crystal 200 are greater than the gas deposition amounts of the surrounding portions, which is favorable for forming a slightly convex growth interface for crystals, avoiding the crystal growth interface in a concave shape and the quality defects caused thereby in the related art, improving the yield, and in addition, the air guiding apparatus 12 can accelerate the transmission of silicon carbide gas, and improve the growth rate of crystals.

In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the device or element being referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present invention.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present invention, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.

In the present invention, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; the device can be mechanically connected, electrically connected and communicated; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.

In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.

While embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that: many changes, modifications, substitutions and variations may be made to the embodiments without departing from the spirit and principles of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A crucible assembly, comprising:

a crucible;

the flow guiding device is arranged in the crucible and divides the inner cavity of the crucible into a first cavity positioned at the upper side of the flow guiding device and a second cavity positioned at the lower side of the flow guiding device, the first cavity is suitable for placing seed crystals, an air outlet is formed on the cavity wall of the first cavity, the second cavity is suitable for placing raw materials, an air inlet is formed on the cavity wall of the second cavity, a flow guiding channel is limited at the inner side of the flow guiding device, the flow guiding channel and the seed crystals are opposite and coaxially arranged along the up-down direction, the flow guiding channel comprises a first channel, a second channel and a third channel which are sequentially connected from bottom to top, one side of the first channel away from the second channel is communicated with the second cavity, one end of the third channel away from the second channel is communicated with the first cavity, the inner diameter of the second channel is not more than the diameter of the seed crystals,

The gas inlet is suitable for introducing inert gas to drive gas generated by heating raw materials in the second cavity to enter the first cavity through the diversion channel and deposit on the seed crystal, and the gas outlet is suitable for discharging redundant gas;

the flow guiding device comprises:

a deflector body, the deflector body comprising:

a constriction defining the first passage, the first passage having a cross-sectional area that gradually decreases in a bottom-to-top direction along an axis of the deflector;

an accelerating portion, the lower end of the accelerating portion being connected to the upper end of the contracting portion, the upper end of the accelerating portion being connected to an auxiliary flow guide, the accelerating portion defining the second passage, the cross-sectional area of the second passage being constant in a bottom-to-top direction along the axis of the flow guide device and the flow guide body defining the first passage and the second passage having a diameter smaller than that of the seed crystal;

the auxiliary flow guide piece is arranged at the upper end of the flow guide main body, the inner side of the auxiliary flow guide piece is used for defining the third channel, and the sectional area of the third channel is gradually increased or kept unchanged in the direction from bottom to top along the axis of the flow guide device;

The diameter of the third channel is greater than the diameter of the second channel when the cross-sectional area of the third channel remains unchanged;

one end of the third channel adjacent to the seed crystal is formed into a guide flow outlet, the guide device is provided with a gas permeable part covering the guide flow outlet, the projection of the seed crystal in a reference plane is positioned in the projection of the gas permeable part in the reference plane, the gas permeable part comprises a plurality of gas permeable areas which are arranged radially inwards and outwards, the gas flux of the gas permeable areas positioned on the inner side is not less than the gas flux of the gas permeable areas positioned on the outer side in the radial direction and the direction from the inner side to the outer side, the reference plane is perpendicular to the central axis of the seed crystal, and the plurality of gas permeable areas at least comprise: the first ventilation zone and the second ventilation zone, the first ventilation zone is circular, the second ventilation zone encircles the periphery side of the first ventilation zone and is coaxial with the first ventilation zone, the value range of the ratio a of the gas flux of the first ventilation zone to the gas flux of the second ventilation zone is: a is more than or equal to 1 and less than or equal to 1.5.

2. The crucible assembly of claim 1, wherein the auxiliary current guide member is detachably connected to the current guide body, or the auxiliary current guide member is integrally formed with the current guide body.

3. The crucible assembly of claim 2, wherein the seed crystal and the gas permeable portion are coaxial, the seed crystal has a diameter d1, the gas permeable portion has a diameter d2, and the difference between d2 and d1 has a value in the range of: d2-d1 is more than or equal to 0 and less than or equal to 10mm.

4. The crucible assembly of claim 3, wherein the first venting zone is axially opposite the second passage, and wherein a surface area of the first venting zone is equal to a cross-sectional area of the second passage.

5. The crucible assembly of claim 4, wherein the seed crystal has a diameter d1, the first venting zone has a diameter d3, and the ratio of d3 to d1 has a value in the range of: d3/d1 is more than or equal to 0.15 and less than or equal to 0.30.

6. The crucible assembly of claim 1, wherein a distance between an upper end of the flow guiding device and the seed crystal is L1, a diameter of the seed crystal is d1, and a ratio of L1 to d1 is in a range of: l1/d1 is more than or equal to 0.25 and less than or equal to 0.75.

7. The crucible assembly of claim 1, wherein the crucible includes:

a main body portion;

a seed crystal placement part, which is positioned at the upper side of the main body part and at the center of the top wall of the main body part, wherein the projection of the seed crystal placement part on a reference surface is smaller than the projection of the main body part in the reference surface, the seed crystal placement part defines a seed crystal placement space communicated with the inner cavity of the main body part, the seed crystal is arranged in the seed crystal placement space, the reference surface is perpendicular to the central axis of the seed crystal, and the cross section of the crucible is formed into a convex shape;

And one part of the flow guiding device is positioned in the inner cavity of the main body part, and the other part of the flow guiding device extends into the seed crystal placement space.

8. The crucible assembly of claim 7, wherein the height of the main body is H, the distance between the bottom end of the flow guiding device and the bottom wall of the main body is L2, and the ratio of L2 to H is in the range of: L2/H is more than or equal to 0.3 and less than or equal to 0.55.

9. The crucible assembly according to claim 7, wherein a flow guiding inlet is formed at one end of the first channel facing away from the second channel, a sectional area of the flow guiding inlet is S1, a projected area of the main body portion in the reference plane is S2, and a ratio of S1 to S2 is in a range of: S1/S2 is more than or equal to 0.6 and less than or equal to 1.

10. A single crystal growing apparatus, comprising:

a crucible assembly according to any one of claims 1 to 9;

heating means adapted to heat the feedstock to produce a gas;

and a purge device adapted to blow an inert gas into the crucible from the gas inlet to drive a portion of the gas from the second chamber to the first chamber and to discharge excess gas from the gas outlet.