CN218989471U - Silicon carbide crystal growing device and crystal growing system - Google Patents

Abstract

The present disclosure provides a silicon carbide crystal growth apparatus and a crystal growth system, relates to the technical field of crystal growth, wherein the silicon carbide crystal growth apparatus includes: the device comprises a first crucible, a second crucible, a first crucible and a second crucible, wherein a seed crystal table is arranged at the bottom of the first crucible and used for placing seed crystals, and a crucible cover is connected to the top of the first crucible; the second crucible is connected in the first crucible and is positioned above the seed crystal table; at least one baffle plate is arranged in the second crucible and divides the second crucible into at least a first raw material area and a second raw material area which are sequentially arranged from bottom to top; the porous air guide sleeve covers the top of the second crucible and is connected to the inner wall of the first crucible; the seed crystal platform and the bottom of the second crucible form a gas chamber, the first raw material area is used for containing first growth raw materials, and the second raw material area is used for containing second growth raw materials. The second crucible is at least divided into a first raw material area and a second raw material area through the partition plate, and the first raw material area and the second raw material area are respectively used for containing growth raw materials with different carbon-silicon ratios, so that gas growth is more controllable.

Description

Silicon carbide crystal growing device and crystal growing system

Technical Field

The disclosure relates to the technical field of crystal growth, in particular to a silicon carbide crystal growth device and a crystal growth system.

Background

Among semiconductor materials, silicon carbide (SiC) has excellent semiconductor characteristics and is widely used in various industries. The growth of silicon carbide is typically performed by physical vapor transport (Physical Vapor Transport, PVT for short).

Depending on the relative positions of the feedstock and seed crystals in the graphite crucible, PVT crystal growth systems have two basic forms, one in which the seed crystal is located below the silicon carbide feedstock in the on-axis direction of the graphite crucible, and such growth systems may be referred to as bottom-seeded PVT methods; another form is in a graphite crucible where a seed crystal is fixed on top of the graphite crucible and a silicon carbide feedstock is placed under the seed crystal, a process known as top-seeded PVT process. At present, a top seed crystal PVT method is adopted for crystal growth in a common mode, but the mode has certain defects, such as high difficulty in a process of fixing a seed crystal at the top of a crucible, and influence on the quality and stress of crystals, and meanwhile, the seed crystal is connected to the crucible through bonding, so that the defects of the crystals are caused due to uneven thermal stress at a bonding part. For bottom-seeded PVT methods, the seed is placed under the silicon carbide feedstock to avoid bonding defects. However, both the bottom seed crystal PVT method and the top seed crystal PVT method are adopted, the silicon carbide raw material is heated and sublimated to form gas, the gas grows on the surface of the seed crystal through temperature guidance, and finally the crystal is obtained.

Therefore, there is a need for a silicon carbide crystal growth apparatus that solves at least the above problems.

Disclosure of Invention

One technical problem to be solved by the present disclosure is: how to improve the controllability of the gas growth process and the growth speed of silicon carbide crystals.

To solve the above technical problems, an embodiment of the present disclosure provides a silicon carbide crystal growth device, including: the device comprises a first crucible, a second crucible, a first crucible and a second crucible, wherein a seed crystal table is arranged at the bottom of the first crucible and used for placing seed crystals, and a crucible cover is connected to the top of the first crucible; the second crucible is connected in the first crucible and is positioned above the seed crystal table; at least one partition board arranged in the second crucible and used for dividing the second crucible into at least a first raw material area and a second raw material area which are sequentially arranged from bottom to top; the porous air guide sleeve covers the top of the second crucible and is connected to the inner wall of the first crucible; the seed crystal platform and the bottom of the second crucible form a gas chamber, the first raw material area is used for containing first growth raw materials, and the second raw material area is used for containing second growth raw materials.

In some embodiments, the axial height of the second feedstock zone is one third to one half of the axial height of the second crucible; the first growth raw material is a first carbon powder and silicon powder mixture, the second growth raw material is a second carbon powder and silicon powder mixture, and the carbon-silicon ratio of the first carbon powder and silicon powder mixture is smaller than that of the second carbon powder and silicon powder mixture.

In some embodiments, the partition plates are a pair, the pair of partition plates divide the second crucible into a first raw material area, a third raw material area and a second raw material area, which are sequentially arranged from bottom to top, and the third raw material area is used for containing a third carbon powder and silicon powder mixture; the silicon-carbon ratio of the first carbon powder-silicon powder mixture, the second carbon powder-silicon powder mixture and the third carbon powder-silicon powder mixture is 1:1.05-1:1.2, and are different.

In some embodiments, the porous dome is attached to the crucible cover, and the porosity of the porous dome is 20% -40%; the outer diameter of the second crucible is smaller than the inner diameter of the first crucible, and is in threaded connection with the porous air guide sleeve.

In some embodiments, the separator and the porous pod are each made of graphite, the porous pod having a thickness of 2mm to 10mm and the separator having a thickness of 1mm to 3mm.

In some embodiments, the second crucible is made of tantalum, the second crucible having a wall thickness of 5mm to 20mm; the first crucible was made of graphite having a purity of 5N.

In some embodiments, the seed crystal table and the first crucible are made of the same material, a positioning groove is formed in the top surface of the seed crystal table, the seed crystal is placed in the positioning groove, and the surface of the seed crystal does not protrude out of the positioning groove; the middle part of the first crucible is provided with a flow guiding part extending from the inner wall to the seed crystal table.

In some embodiments, the seed crystal has a thickness of 200 μm to 1200 μm, and the seed crystal is grown to obtain silicon carbide crystals having a thickness of 3mm to 20mm.

In some embodiments, the surface of the seed crystal facing away from the second crucible is covered with a carbon film having a thickness of 5 μm to 50 μm.

The embodiment of the disclosure also provides a crystal growth system, which comprises the silicon carbide crystal growth device.

Through the technical scheme, the silicon carbide crystal growing device provided by the disclosure has the advantages that the seed crystal is placed at the bottom of the first crucible, so that crystal defects caused by bonding of the seed crystal are avoided; the second crucible is at least divided into a first raw material area and a second raw material area through the partition plate, and different raw material areas arranged up and down can be respectively used for containing growth raw materials with different carbon-silicon ratios, so that the type and flow of sublimation gas can be regulated in the crystal growth process, the gas growth is more controllable, the sublimation gas can be better and faster deposited on the seed crystal, and the crystal growth speed is accelerated.

The crystal growth system provided by the present disclosure has the same or similar technical effects as the silicon carbide crystal growth device provided by the present disclosure.

Drawings

In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present disclosure, and other drawings may be obtained according to these drawings without inventive effort to a person of ordinary skill in the art.

FIG. 1 is a schematic diagram of a silicon carbide crystal growth apparatus according to an embodiment of the present disclosure;

fig. 2 is a schematic structural view of a seed stage of a silicon carbide growth apparatus according to an embodiment of the present disclosure.

Reference numerals illustrate:

1. a first crucible; 2. a seed crystal table; 3. seed crystal; 4. a second crucible; 5. a first feedstock zone; 6. a second feedstock zone; 7. a porous pod; 8. a gas chamber; 9. a crucible cover; 10. a partition plate; 11. a flow guiding part; 12. and a positioning groove.

Detailed Description

Embodiments of the present disclosure are described in further detail below with reference to the drawings and examples. The following detailed description of the embodiments and the accompanying drawings are provided to illustrate the principles of the disclosure and not to limit the scope of the disclosure, which may be embodied in many different forms and not limited to the specific embodiments disclosed herein, but rather to include all technical solutions falling within the scope of the claims.

The present disclosure provides these embodiments in order to make the present disclosure thorough and complete, and fully convey the scope of the disclosure to those skilled in the art. It should be noted that: the relative arrangement of parts and steps, the composition of materials, numerical expressions and numerical values set forth in these embodiments should be construed as exemplary only and not limiting unless otherwise specifically stated.

In the description of the present disclosure, unless otherwise indicated, the meaning of "plurality" is greater than or equal to two; the terms "upper," "lower," "left," "right," "inner," "outer," and the like indicate an orientation or positional relationship merely for convenience of describing the present disclosure and simplifying the description, and do not indicate or imply that the devices or elements being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus are not to be construed as limiting the present disclosure. When the absolute position of the object to be described is changed, the relative positional relationship may be changed accordingly.

Furthermore, the use of the terms first, second, and the like in this disclosure do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. The "vertical" is not strictly vertical but is within the allowable error range. "parallel" is not strictly parallel but is within the tolerance of the error. The word "comprising" or "comprises" and the like means that elements preceding the word encompass the elements recited after the word, and not exclude the possibility of also encompassing other elements.

It should also be noted that, in the description of the present disclosure, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be directly connected or indirectly connected through an intermediate medium. The specific meaning of the terms in the present disclosure may be understood as appropriate by those of ordinary skill in the art. When a particular device is described as being located between a first device and a second device, there may or may not be an intervening device between the particular device and either the first device or the second device.

All terms used in the present disclosure have the same meaning as understood by one of ordinary skill in the art to which the present disclosure pertains, unless specifically defined otherwise. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

Techniques, methods, and apparatus known to one of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the techniques, methods, and apparatus should be considered part of the specification.

In the growth process of silicon carbide crystals by adopting a PVT method, according to the relative positions of raw materials and seed crystals in a graphite crucible, a crystal growth system of the single crystal PVT method has two basic forms, wherein one form is in the axial direction of the graphite crucible, the position of the seed crystals is lower than that of the silicon carbide raw materials, and the growth system can be called a bottom seed crystal PVT method; another form is in a graphite crucible where a seed crystal is fixed on top of the graphite crucible and a silicon carbide feedstock is placed under the seed crystal, a process known as top-seeded PVT process. At present, a top seed crystal PVT method is adopted for crystal growth, but the method has certain defects, the process difficulty of fixing the seed crystal at the top of the crucible is high, the quality and the stress of crystals can be influenced, meanwhile, the seed crystal is connected to the crucible through bonding, and the defect of the crystals is caused by uneven thermal stress between the seed crystal and the crucible at the bonding position. For the bottom seed PVT method, the seed is placed under the silicon carbide feedstock and bonding defects can be avoided without bonding to the crucible. However, both the bottom seed crystal PVT method and the top seed crystal PVT method are adopted, the silicon carbide raw material is heated, the silicon carbide raw material is contained in an integrated raw material crucible in a powdery form, the silicon carbide raw material is synthesized in advance, each component of the synthesized powdery silicon carbide raw material, carbon powder, silicon powder and silicon carbide powder is fixed and contained in the raw material crucible in a fixed proportion, the carbon powder, the silicon powder and the silicon carbide powder in the silicon carbide raw material sublimate to form gas phases such as Si (q), siC2 (q), si2C (q), siC (q) and the like, the gas phases flow to the seed crystal through the change of temperature, and the silicon carbide crystal is finally obtained through deposition growth on the seed crystal. In the crystal growth process, the gas growth process can only be controlled by temperature, the controllability is more general, the crystal growth time is relatively longer, one week is usually taken as one growth period, the crystal thickness of the silicon carbide in one growth period is about 20mm, and compared with the silicon carbide, the yield of the silicon carbide in unit time is extremely low. Therefore, how to avoid defects in the crystal caused by uneven thermal stress and at the same time to improve the controllability of the gas growth process and to increase the growth rate of silicon carbide crystals has become a problem to be solved.

To solve the problems in the prior art, an embodiment of the present disclosure provides a silicon carbide crystal growth apparatus, as shown in fig. 1 to 2, including: the first crucible 1, the bottom of the first crucible 1 is provided with a seed crystal table 2 for placing seed crystals 3, and the top of the first crucible 1 is connected with a crucible cover 9; a second crucible 4, the second crucible 4 being connected to the first crucible 1 and being located above the seed table 2; at least one partition plate 10, wherein the at least one partition plate 10 is arranged in the second crucible 4 and divides the second crucible 4 into at least a first raw material zone 5 and a second raw material zone 6 which are arranged in sequence from bottom to top; and a porous air guide sleeve 7, wherein the porous air guide sleeve 7 covers the top of the second crucible 4 and is connected to the inner wall of the first crucible 1; wherein the seed crystal stage 2 and the bottom of the second crucible 4 form a gas chamber 8, the first raw material region 5 is used for containing a first growth raw material, and the second raw material region 6 is used for containing a second growth raw material.

According to the silicon carbide crystal growth device provided by the embodiment of the disclosure, the seed crystal 3 is placed at the bottom of the first crucible 1, so that crystal defects caused by bonding of the seed crystal 3 are avoided; the second crucible 4 is at least divided into the first raw material area 5 and the second raw material area 6 by the partition plate 10, compared with the raw material crucible in an integrated manner, the different raw material areas arranged up and down in the embodiment of the disclosure can be respectively used for containing growth raw materials with different carbon-silicon proportions, so that the variety and flow of sublimation gas can be regulated in the crystal growth process, the gas growth is more controllable, and the sublimation gas is better and faster deposited on the seed crystal 3, thereby accelerating the crystal growth speed.

In some embodiments, the axial height of the first feedstock zone 5 is one third to one half of the axial height of the second crucible 4; the first growth raw material is a first carbon powder and silicon powder mixture, the second growth raw material is a second carbon powder and silicon powder mixture, and the carbon-silicon ratio of the first carbon powder and silicon powder mixture is larger than that of the second carbon powder and silicon powder mixture.

In the prior art, silicon carbide powder is generally adopted as a growth raw material for forming silicon carbide crystals, the powder is mainly formed by mixing carbon powder, silicon powder and silicon carbide powder, the powder is required to be synthesized and prepared in a synthesis furnace in advance, the carbon powder and the silicon powder are promoted to react to generate the silicon carbide powder through high temperature, the process is complex and high in price, the synthesis cost is high, the silicon carbide raw material is generally arranged above or below a seed crystal 3 through a cylindrical crucible, the silicon carbide raw material is uniformly distributed according to a fixed proportion in the axial direction of a graphite crucible, and the gas growth process can only be controlled through the change of temperature difference and is general in controllability.

According to the silicon carbide crystal growth device provided by the disclosure, the carbon powder and silicon powder mixture is adopted as the growth raw material, compared with the silicon carbide powder synthesized in advance in the prior art, the silicon powder mixture is directly filled into the second crucible 4, under the action of high temperature, silicon atoms are preferentially mixed in a gas phase to obtain Si (q), carbon atoms in the growth raw material react with the Si (q) to obtain gas phases SiC2 (q), si2C (q) and SiC (q), so that the process of synthesizing and obtaining the silicon carbide powder in a synthesis furnace is saved, and compared with the prior art, the cost of the silicon carbide crystal growth device is further reduced; meanwhile, the second crucible 4 for containing silicon carbide crystal growth raw materials is divided into different raw material areas by the partition plate 10, so that carbon powder and silicon powder mixtures with different carbon-silicon ratios can be filled, the sublimation process of the crystal growth process gas is more controllable, the effect of growing silicon in the early stage of crystal growth is better, and the crystal growth speed can be further accelerated.

The silicon powder content in the first carbon powder silicon powder mixture is smaller than that in the second carbon powder silicon powder mixture, and the growth raw material with high silicon powder content is positioned in the second raw material area 6 above, so that the content of the gas which sublimates preferentially in the growth raw material at the upper part is more, one part of the sublimated gas flows to the seed crystal 3 through the porous guide cover 7, the effect of growing silicon in the early stage of crystal growth is better, the gas controllability of crystal growth is improved, the other part reacts with carbon powder to generate gas phases such as SiC2 (q), si2C (q), siC (q) and the like, and then the gas flows to the seed crystal 3 for continuous growth. The axial height of the second raw material zone 6 can ensure the capacity of the growth raw material with high silicon powder content, namely the second carbon powder and silicon powder mixture, so as to further ensure the long silicon effect and the gas controllability.

During crystal growth, the silicon carbide crystal growth device is placed in a crystal growth furnace, each raw material area can be separated through the pair of partition plates 10, growth raw materials in different raw material areas are prevented from being mixed or moved in a solid state, when the temperature in the furnace reaches a sublimation temperature, carbon powder and silicon powder are decomposed in a gas phase at high temperature, a second carbon powder silicon powder mixture in a second raw material area 6 above the furnace is preferentially evaporated and sublimated to form gas comprising Si (q), siC2 (q), si2C (q) and SiC (q), wherein silicon atoms are easier to mix in the gas phase than carbon atoms, silicon carbon atoms in the second carbon powder silicon powder mixture are smaller, silicon powder content is higher, silicon powder is preferentially evaporated and sublimated to form gas phases such as SiC2 (q), si2C (q) and SiC (q), and the like, in the process, part of gas phase Si (q) preferentially upwards passes through the porous guide cover 7 due to the upper part of the second carbon powder mixture in the second raw material area 4, and flows to the surface of seed crystal 3 under the gradient effect of temperature, so that the silicon crystal can be more easily deposited on the surface of the seed crystal 3, and the crystal growth effect of the crystal growth is easier to realize the growth of the seed crystal 3.

In some embodiments, the first and second growth materials may be silicon carbide powders of different silicon to carbon ratios, respectively, and the silicon powder content in the second growth material is higher than the silicon powder content of the first growth material.

In some embodiments, the second crucible 4 is made of tantalum, the wall thickness of the second crucible 4 being 5mm to 20mm; the first crucible 1 is made of graphite having a purity of 5N. The second crucible 4 is used for holding the growth raw materials, and the second crucible 4 is the tantalum crucible, has better high temperature resistance, performance such as corrosion resistance, provides good environmental support to carbon powder silica flour mixture receives high temperature and generates the carborundum powder in the second crucible 4, and in addition, compared with graphite crucible, this disclosure adopts the tantalum crucible, can avoid carbon atom and gaseous phase Si (q) reaction in the graphite crucible, influences gaseous phase Si (q) gas quantity, and then influences the long silicon effect in earlier stage of seed crystal 3.

Wherein, the purity of the graphite is 99.999 percent by 5N, and the oxidation resistance of the crucible can be ensured by adopting high-purity graphite. Blocking resistance and the like. The materials of the seed crystal table 2 and the crucible cover 9 are the same as those of the first crucible 1, and graphite materials are adopted, so that the crystal growth environment inside the first crucible 1 is consistent.

The crucible cover 9 is buckled on the top of the first crucible 1, and a closed space is formed between the crucible cover 9 and the first crucible 1, and the crucible cover 9 and the first crucible 1 are in threaded connection, so that the connection strength can be ensured. The top of first crucible 1 is equipped with the turn-ups, and the inner wall is equipped with the internal thread, and crucible cover 9 covers in the turn-ups upside to crucible cover 9 is connected with the internal thread of first crucible 1 inner wall towards the extension of first crucible 1.

In some embodiments, the outer wall of the porous dome 7 is provided with external threads, the porous dome 7 is connected to the internal threads of the first crucible 1, so as to fix the first crucible 1, and the porous dome 7 is connected to the first crucible 1 through the threads, so that the connection strength can be ensured, so as to be capable of bearing the weight of the second crucible 4 and the growth raw material inside the second crucible 4.

In some embodiments, the porous air guide sleeve 7 is attached to the crucible cover 9, the porous air guide sleeve 7 is provided with a plurality of air gap holes, and the porosity of the porous air guide sleeve 7 is 20% -40%; the outer diameter of the second crucible 4 is smaller than the inner diameter of the first crucible 1, and is in threaded connection with the porous air guide sleeve 7. The porous guide cover 7 is attached to the crucible cover 9, so that when gas passes through the air gap hole of the porous guide cover 7, the gas is blocked by the crucible cover 9 and can only move downwards, and the gas seed crystal 3 for crystal growth moves in the direction, so that deposition is attached to the seed crystal 3.

The outer diameter of the second crucible 4 is smaller than the inner diameter of the first crucible 1, and the height of the second crucible 4 is smaller than the height of the first crucible 1, so that a gas channel is formed between the outer wall of the second crucible 4 and the inner wall of the first crucible 1, a gas chamber 8 is formed between the second crucible 4 and the seed crystal table 2, and the gas flows downwards to the gas chamber 8 along the gas channel under the action of pressure, thereby facilitating the growth on the surface of crystals.

The middle part of the porous air guide sleeve 7 is provided with a threaded hole, and the top of the second crucible 4 is in threaded connection with the threaded hole to realize the fixation with the porous air guide sleeve 7; or, the middle part of the porous air guide sleeve 7 is provided with a connecting cylinder part protruding towards the second crucible 4, the connecting cylinder part is provided with external threads, the inner wall of the top of the second crucible 4 is provided with internal threads, the second crucible 4 and the porous air guide sleeve 7 are fixed through the threaded fit of the connecting cylinder part and the second crucible 4, and growth raw material sublimation gas in the second crucible 4 enters the porous air guide sleeve 7 from the connecting cylinder part and flows to a gas channel through an air gap hole, so that crystal growth is carried out at the seed crystal 3.

In some embodiments, the partition board 10 and the porous air guide cover 7 are respectively made of graphite, the thickness of the porous air guide cover 7 is 2 mm-10 mm, the thickness of the partition board 10 is 1 mm-3 mm, the thickness of the porous air guide cover 7 ensures that the porous air guide cover 7 has stronger connection strength, the porous air guide cover 7 is provided with air gap holes, and after the carbon powder silicon powder mixture in the second crucible 4 sublimates into Si (q), siC2 (q), si2C (q) and SiC (q), the gases can flow downwards to the seed crystal 3 through the porous air guide cover 7 and through a gas channel between the first crucible 1 and the second crucible 4. The porous air guide sleeve 7 made of graphite is an existing product, and the specific structure is not repeated.

The thickness of the baffle plate 10 is thinner, and the inner area of the second crucible 4 is divided by the thinner baffle plate 10, so that sublimated gas can flow to the porous guide cover 7 through the graphite baffle plate 10, and the crystal growth effect is ensured. When in use, the carbon powder and silicon powder mixture in the first raw material area 5 can be sequentially filled from bottom to top, then the partition board 10 is placed, and then the next raw material area is filled.

In some embodiments, the partition plates 10 are a pair, and the pair of partition plates 10 divide the second crucible 4 into a first raw material area 5, a third raw material area and a second raw material area 6, which are sequentially arranged from bottom to top, wherein the third raw material area is used for containing a third carbon powder and silicon powder mixture; the silicon-carbon ratio of the first carbon powder-silicon powder mixture, the second carbon powder-silicon powder mixture and the third carbon powder-silicon powder mixture is 1:1.05-1:1.2, and are different.

The second crucible 4 is divided into three raw material areas by the pair of partition boards 10, so that the three-material-area-free crucible can be used for placing carbon powder and silicon powder mixtures with three different carbon-silicon ratios, and further the controllability of gas can be further realized.

In some embodiments, the carbon to silicon ratio of the carbon powder to silicon powder mixture of the first feedstock zone 5 may be 1:1.0X, where X is a natural number other than 0, the carbon to silicon ratio of the carbon powder to silicon powder mixture of the first feedstock zone 5 may be 1:1.1-1:1.2, and the carbon to silicon ratio of the carbon powder to silicon powder mixture of the third feedstock zone may be 1:1.05-1:1.2, thereby being capable of adjusting the content proportion of Si (q), siC2 (q), si2C (q) and SiC (q) obtained by sublimation of each raw material area, and further improving the controllability of gas.

In some embodiments, the seed crystal table 2 is made of the same material as the first crucible 1, a positioning groove 12 is formed in the top surface of the seed crystal table 2, the seed crystal 3 is placed in the positioning groove 12, and the surface of the seed crystal 3 does not protrude out of the positioning groove 12; the middle part of the first crucible 1 is provided with a flow guiding part 11 extending from the inner wall to the seed crystal stage 2.

The seed crystal 3 is placed in the positioning groove 12 and is only in contact connection with the groove bottom of the positioning groove 12, the silicon carbide seed crystal 3 is not required to be fixed in a bonding mode, crystal defects including hexagonal cavities, microtubes, screw dislocation and the like caused by inconsistent thermal stress when the silicon carbide seed crystal 3 is bonded with the graphite crucible are avoided, meanwhile, the seed crystal 3 is not fixed, the crystal is almost free of binding force in a three-dimensional space in the crystal growth process, natural thermal expansion and contraction can be achieved, internal stress of the crystal is fully released, and the crystal growth quality is improved.

The middle part of the first crucible 1 is provided with a flow guiding part 11, the flow guiding part 11 is made of graphite and is obliquely arranged towards the seed crystal table 2, and the downward flowing gas can be guided by the flow guiding part 11 so as to quickly move towards the seed crystal table 2 to reach the seed crystal 3, so that the crystal growth speed is further improved.

In some embodiments, the baffle 11 is attached to the inner wall of the first crucible 1 below the second crucible 4.

In some embodiments, the notch range of the positioning groove 12 is slightly larger than the external dimension of the seed crystal 3, wherein the first crucible 1 and the second crucible 4 are both in a cylindrical structure, the seed crystal table 2 is arranged at the bottom center of the first crucible 1, the radial cross section of the positioning groove 12 can be circular, and the cross section of the positioning groove 12 along the axial direction of the first crucible 1 can be in an inverted trapezoid or rectangle.

In some embodiments, the thickness of the seed crystal 3 is 200 μm to 1200 μm, and the seed crystal 3 is grown to obtain silicon carbide crystals, and the thickness of the silicon carbide crystals is 3mm to 20mm.

In some embodiments, the surface of the seed crystal 3 facing away from the second crucible 4 is covered with a carbon film having a thickness of 5 μm to 50 μm. The carbon film can prevent the gas from growing on the surface of the seed crystal 3, so that the seed crystal 3 can only grow upwards, namely in a growth space, and meanwhile, the carbon film can reduce or avoid the problem of uneven heat transfer at the contact position of the seed crystal 3 and the graphite seed crystal table 2.

A gas chamber 8 is formed between the bottom of the second crucible 4 and the seed crystal stage 2, the gas chamber 8 communicates with the gas passage, the gas chamber 8 simultaneously forms a growth space for the crystal, and the bottom surface of the seed crystal 3 is covered with a carbon film so that the seed crystal 3 can only proceed toward the growth space when the crystal grows.

When the silicon carbide crystal growth device provided by the disclosure is used for crystal growth, the silicon carbide crystal growth device is placed in a crystal growth furnace, the crystal growth temperature in the crystal growth furnace is 2000-2300 ℃, and the pressure is 300-600 Pa. The pressure in the growth furnace may be maintained by an inert gas such as nitrogen, argon, etc.

The embodiment of the disclosure also provides a crystal growth system, which comprises the silicon carbide crystal growth device.

In some embodiments, the crystal growth system provided by the present disclosure includes a crystal growth furnace, a silicon carbide crystal growth device is placed in the crystal growth furnace, and a seed crystal 3 is placed at the bottom of the first crucible 1, so that crystal defects caused by bonding of the seed crystal 3 are avoided; the second crucible 4 is at least divided into the first raw material area 5 and the second raw material area 6 by the partition plate 10, and the different raw material areas arranged up and down can be respectively used for containing growth raw materials with different carbon-silicon ratios, so that the type and flow of sublimated gas can be regulated in the crystal growth process, the gas growth is more controllable, and the long silicon effect in the early stage of crystal growth is better. The crystal growth speed is further accelerated by controlling the temperature gradient, such as increasing the temperature difference. The crystal growth system provided by the disclosure adopts the carbon powder and silicon powder mixture as the growth raw material, so that the process of synthesizing and obtaining the silicon carbide powder in a synthesis furnace is omitted, and compared with the prior art, the cost of the crystal growth system is further reduced.

Thus, various embodiments of the present disclosure have been described in detail. In order to avoid obscuring the concepts of the present disclosure, some details known in the art are not described. How to implement the solutions disclosed herein will be fully apparent to those skilled in the art from the above description.

Although some specific embodiments of the present disclosure have been described in detail by way of example, it should be understood by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present disclosure. It will be understood by those skilled in the art that the foregoing embodiments may be modified and equivalents substituted for elements thereof without departing from the scope and spirit of the disclosure. In particular, the technical features mentioned in the respective embodiments may be combined in any manner as long as there is no structural conflict.

Claims (10)

1. A silicon carbide crystal growth apparatus, comprising:

the device comprises a first crucible (1), wherein a seed crystal table (2) is arranged at the bottom of the first crucible (1) and used for placing seed crystals (3), and a crucible cover (9) is connected to the top of the first crucible (1);

a second crucible (4), wherein the second crucible (4) is connected in the first crucible (1) and is positioned above the seed crystal table (2);

at least one partition board (10), wherein at least one partition board (10) is arranged in the second crucible (4) and divides the second crucible (4) into at least a first raw material area (5) and a second raw material area (6) which are sequentially arranged from bottom to top; the method comprises the steps of,

the porous air guide sleeve (7), the porous air guide sleeve (7) covers the top of the second crucible (4) and is connected to the inner wall of the first crucible (1);

the seed crystal table (2) and the bottom of the second crucible (4) form a gas chamber (8), the first raw material area (5) is used for containing first growth raw materials, and the second raw material area (6) is used for containing second growth raw materials.

2. Silicon carbide growth device according to claim 1, characterized in that the axial height of the second feed zone is one third to one half of the axial height of the second crucible (4).

3. The silicon carbide crystal growth apparatus according to claim 2, wherein the partition plates (10) are a pair, and the second crucible (4) is partitioned by the pair of partition plates (10) into the first raw material region (5), the third raw material region, and the second raw material region (6) which are arranged in this order from bottom to top.

4. The silicon carbide crystal growth apparatus according to claim 1, wherein the porous guide cover (7) is attached to the crucible cover (9), and the porosity of the porous guide cover (7) is 20% -40%;

the outer diameter of the second crucible (4) is smaller than the inner diameter of the first crucible (1), and is in threaded connection with the porous air guide sleeve (7).

5. Silicon carbide crystal growth apparatus according to claim 1, characterized in that the separator (10) and the porous guide cover (7) are made of graphite, respectively, the thickness of the porous guide cover (7) is 2 mm-10 mm, and the thickness of the separator (10) is 1 mm-3 mm.

6. Silicon carbide growing device according to claim 1, characterized in that the second crucible (4) is made of tantalum, the wall thickness of the second crucible (4) being 5-20 mm; the first crucible (1) is made of graphite with a purity of 5N.

7. The silicon carbide crystal growth apparatus according to claim 1, wherein the seed crystal stage (2) is made of the same material as the first crucible (1), a positioning groove (12) is provided on the top surface of the seed crystal stage (2), the seed crystal (3) is placed in the positioning groove (12), the surface of the seed crystal (3) does not protrude out of the positioning groove (12), and a flow guiding portion (11) extending from the inner wall to the seed crystal stage (2) is provided in the middle of the first crucible (1).

8. A silicon carbide crystal growth apparatus according to claim 1, wherein the thickness of the seed crystal (3) is 200 μm to 1200 μm, and the seed crystal (3) is grown to obtain a silicon carbide crystal having a thickness of 3mm to 20mm.

9. Silicon carbide growth device according to claim 1, characterized in that the surface of the seed crystal (3) facing away from the second crucible (4) is covered with a carbon film having a thickness of 5-50 μm.

10. A crystal growth system comprising a silicon carbide crystal growth apparatus according to any one of claims 1 to 9.

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