WO2023143297A1

WO2023143297A1 - Device and method for manufacturing silicon carbide polycrystal

Info

Publication number: WO2023143297A1
Application number: PCT/CN2023/072842
Authority: WO
Inventors: 郭超; 母凤文
Original assignee: 北京青禾晶元半导体科技有限责任公司
Priority date: 2022-01-29
Filing date: 2023-01-18
Publication date: 2023-08-03
Also published as: CN114481325A

Abstract

A device and method for manufacturing a silicon carbide polycrystal. The device for manufacturing a silicon carbide polycrystal comprises a chamber (1), an induction coil (2), a graphite crucible (3), a crystal rod (4), and a graphite support (5), wherein the induction coil (2) is arranged inside the chamber (1), the graphite crucible (3) is arranged inside the chamber (1), the graphite crucible (3) is configured for containing a cosolvent, and an inner wall of the bottom of the graphite crucible (3) can be configured for silicon carbide polycrystal growth; one end of the crystal rod (4) is positioned in the graphite crucible (3), and the other end of the crystal rod (4) is positioned outside the chamber (1); and the graphite support (5) is fixedly connected to one end of the crystal rod (4), and the bottom surface of the graphite support (5) facing a bottom wall of the graphite crucible (3) can be configured for silicon carbide polycrystal growth.

Description

Device and method for manufacturing silicon carbide polycrystalline

This application claims the priority of the Chinese patent application with application number 202210112585.0 submitted to the China Patent Office on January 29, 2022, and the entire content of the above application is incorporated in this application by reference.

technical field

The present application relates to the technical field of semiconductor manufacturing, for example, to a silicon carbide polycrystalline manufacturing device and method.

Background technique

Silicon carbide is a wide bandgap semiconductor material. Devices made of silicon carbide substrates have the advantages of high temperature resistance, high voltage resistance, high frequency, high power, radiation resistance, and high efficiency. They are important in the fields of radio frequency and new energy vehicles. application value.

Silicon carbide includes silicon carbide single crystal and silicon carbide polycrystal.

Contents of the invention

The present application provides a silicon carbide polycrystalline manufacturing device and method.

The present application provides a silicon carbide polycrystalline manufacturing device, including:

Chamber;

an induction coil is arranged in the chamber;

A graphite crucible is arranged in the chamber, and the graphite crucible is used for accommodating a cosolvent, and the inner wall of the bottom of the graphite crucible can grow polycrystalline silicon carbide;

A crystal rod, one end of the crystal rod is located in the graphite crucible, and the other end of the crystal rod is located outside the chamber;

The graphite support is fixedly connected to one end of the crystal rod, and the bottom surface of the graphite support facing the bottom wall of the graphite crucible can grow polycrystalline silicon carbide.

The present application provides a silicon carbide polycrystalline manufacturing method, which is applied to the above-mentioned silicon carbide polycrystalline manufacturing device, including:

Put the auxiliary solvent into the graphite crucible;

heating the co-solvent through an induction coil to melt the co-solvent;

Drive the graphite support to move close to the co-solvent through the crystal rod, so that the lower surface of the graphite support is flush with the liquid level of the co-solvent or the distance is smaller than the preset distance;

Controlling the crystal rod to drive the graphite holder to move away from the co-solvent, so that the lower surface of the graphite holder The bottom surface of the formed silicon carbide polycrystal is always flush with the liquid level of the co-solvent or the distance is smaller than the preset distance.

Description of drawings

FIG. 1 is a schematic structural view of a silicon carbide polycrystalline manufacturing device provided in Embodiment 1 of the present application;

Fig. 2 is the schematic diagram of the assembly of the graphite crucible, the crystal rod and the graphite holder provided in the first embodiment of the present application;

Fig. 3 is a reference diagram of the use state of the graphite crucible, the crystal rod and the graphite support provided in the first embodiment of the present application;

Fig. 4 is a schematic structural view of a crystal rod and a graphite holder provided in Embodiment 1 of the present application;

Fig. 5 is a top view of the crystal rod provided in Embodiment 1 of the present application;

Fig. 6 is a schematic structural view of a crucible holder and a graphite crucible provided in Embodiment 1 of the present application;

FIG. 7 is a flowchart of a method for manufacturing a silicon carbide polycrystal provided in Embodiment 2 of the present application.

In the picture:

1. Chamber; 2. Induction coil; 3. Graphite crucible; 4. Crystal rod; 41. First cooling channel; 411. First sub-channel; 412. Second sub-channel; 413. Cooling inlet; 414 , cooling outlet; 5, graphite support; 6, carbon film layer; 7, crucible support; 71, the second cooling channel; 711, the third sub-channel; 712, the fourth sub-channel; 713, the entrance; 714, Export; 8. Heat insulation sleeve; 10. Silicon carbide polycrystalline; 100. Cosolvent.

Detailed ways

Silicon carbide includes silicon carbide single crystal and silicon carbide polycrystal. In related technologies, a solution method is used to grow silicon carbide single crystal. The basic principle of the solution method is: put a silicon-containing flux in a graphite crucible and melt it by induction heating Flux, the carbon in the graphite crucible is dissolved in the flux; then the silicon carbide seed crystal is placed on the liquid level of the flux, and due to the supercooling of the seed crystal, carbon is precipitated on the solid-liquid interface of the seed crystal, and with the flux The silicon in the flux combines to form a single crystal of silicon carbide. However, there is no document in the related art describing how to grow silicon carbide polycrystals by a solution method. Therefore, there is an urgent need for a silicon carbide polycrystalline manufacturing device and method.

In view of the above situation, embodiments of the present application provide a silicon carbide polycrystalline manufacturing device and method.

Embodiments of the present application will be described below in conjunction with the accompanying drawings and through specific implementation methods.

In the description of this application, unless otherwise clearly specified and limited, the terms "connected", "connected" and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integrated ; It can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediary, and it can be the internal communication of two components or the interaction relationship between two components. Those of ordinary skill in the art can understand the specific meanings of the above terms in this application in specific situations.

In this application, unless otherwise expressly specified and limited, the first feature is "on" the second feature Alternatively, "under" may include that the first and second features are in direct contact, and may also include that the first and second features are not in direct contact but are in contact through another feature therebetween. Moreover, "above", "above" and "above" the first feature on the second feature include that the first feature is directly above and obliquely above the second feature, or simply means that the first feature is horizontally higher than the second feature. "Below", "beneath" and "under" the first feature to the second feature include that the first feature is directly below and obliquely below the second feature, or simply means that the first feature has a lower level than the second feature.

In the description of this embodiment, the terms "up", "down", "right", and other orientations or positional relationships are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operations, rather than indicating Or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be construed as limiting the application. In addition, the terms "first" and "second" are only used to distinguish in description, and have no special meaning.

Embodiment one

This embodiment provides a silicon carbide polycrystalline manufacturing device, which can be used to grow and manufacture silicon carbide polycrystalline, and has higher efficiency and lower cost.

As shown in FIG. 1 , a silicon carbide polycrystalline manufacturing device includes a chamber 1 , an induction coil 2 , a graphite crucible 3 , a crystal rod 4 and a graphite holder 5 .

Wherein, the cavity 1 is used to provide a relatively sealed space for the growth of polycrystalline silicon carbide, and the cavity 1 has at least one gas extraction port, through which the cavity 1 can be evacuated. In some embodiments, the pumping port is connected to a vacuum device, so that the vacuum device can pump the chamber 1 through the pumping port, so as to reduce the air pressure in the chamber 1 to a required value. It should be noted that the chamber 1 is also connected with at least one vacuum gauge, and the vacuum gauge is used to measure the pressure in the chamber 1 . In this embodiment, the chamber 1 also has at least one gas filling port, through which nitrogen, argon, helium or other inert gases can be filled into the chamber 1, so that the silicon carbide polycrystalline grow.

The induction coil 2 and the graphite crucible 3 are respectively arranged in the chamber 1, and the graphite crucible 3 is used for accommodating a cosolvent. As shown in FIG. 2 , the induction coil 2 is used to inductively heat the co-solvent 100 in the graphite crucible 3 to melt the co-solvent 100 in the graphite crucible 3 . In some embodiments, the induction coil 2 has multiple turns, which are arranged at intervals around the graphite crucible 3 to achieve uniform heating. The current frequency of the induction coil 2 is 1-100kHz, and the induction coil 2 is hollow and can be cooled by water. For the principle of induction heating by the induction coil 2 , reference may be made to related technologies, which will not be introduced here in this embodiment.

One end of the crystal rod 4 is located in the graphite crucible 3, the other end of the crystal rod 4 is located outside the chamber 1, and the graphite holder 5 is fixedly connected to one end of the crystal rod 4 and is located in the graphite crucible 3, and the crystal rod 4 can drive the graphite holder 5 to be opposite to each other. The graphite crucible 3 moves, such as driving the graphite holder 5 to rotate or move along the up and down direction in FIG. 1 . in some implementations In an example, the other end of the crystal rod 4 is connected with a driving member, and the driving member can provide driving force to the crystal rod 4 .

Both the bottom surface of the graphite holder 5 facing the bottom wall of the graphite crucible 3 and the bottom inner wall of the graphite crucible 3 can grow silicon carbide polycrystals, so that multiple pieces of silicon carbide polycrystals can be obtained in one process.

The silicon carbide polycrystalline manufacturing device provided in this embodiment can adopt the solution method to manufacture silicon carbide polycrystalline. By setting the graphite holder 5 and the graphite crucible 3, it can realize direct crystallization on the graphite material, and then obtain the silicon carbide polycrystalline. The seed crystal is set, and the graphite holder 5 and the graphite crucible 3 can be crystallized at the same time, so that one device can obtain two silicon carbide polycrystals at the same time, which improves the manufacturing efficiency of silicon carbide polycrystals and reduces the cost of manufacturing silicon carbide polycrystals.

In one embodiment, as shown in Figure 3, the inner wall of the bottom of the graphite crucible 3 is fixed with a carbon film layer 6, the setting of the carbon film layer 6 can reduce the stress of the crystallization process, and avoid the occurrence of cracks in the grown silicon carbide polycrystalline At the same time, it can also facilitate the separation of the silicon carbide polycrystal and the graphite crucible 3, avoid destructive separation due to too strong bonding between the silicon carbide polycrystal and the graphite crucible 3, and ensure the quality of the silicon carbide polycrystal. It should be noted that the carbon film layer 6 can completely cover the bottom inner wall of the graphite crucible 3 to ensure the growth uniformity and growth area of the silicon carbide polycrystal.

Similarly, the bottom surface of the graphite holder 5 has a carbon film layer 6. At this time, the carbon film layer 6 can facilitate the separation between the silicon carbide polycrystal and the graphite holder 5, ensuring the stability of the silicon carbide polycrystal grown on the graphite holder 5. quality. It should be noted that the carbon film layer 6 can completely cover the bottom surface of the graphite support 5 to ensure the growth uniformity and growth area of the silicon carbide polycrystal.

In this embodiment, the carbon film layer 6 can be prepared by chemical vapor deposition, and can also be deposited by physical vapor deposition, magnetron sputtering, electron beam evaporation, high-temperature curing after coating graphite glue or sugar glue, etc. This embodiment does not limit it.

As shown in Figure 3, after a period of growth, blocky silicon carbide polycrystal 10 can be obtained under the carbon film layer 6 on the bottom surface of the graphite holder 5, and block can be obtained on the carbon film layer 6 at the bottom of the graphite crucible 3 SiC polycrystalline 10. Wherein, the bottom surface of the graphite crucible 3 is connected with the silicon carbide polycrystal 10 through the carbon film layer 6, and the sidewall of the silicon carbide polycrystal 10 and the graphite crucible 3 may be bonded, that is, the silicon carbide polycrystal 10 appears sticking to the pot and grows. To facilitate the smooth separation of the silicon carbide polycrystalline 10 and the sidewall of the graphite crucible 3, a carbon film layer 6 of a certain height can be plated on the sidewall of the graphite crucible 3, so that the carbon in the graphite crucible 3 is dissolved in the cosolvent 100 without hindering it. Under the premise of , the polycrystalline silicon carbide 10 and the graphite crucible 3 can be separated better. After the silicon carbide polycrystalline manufacturing device is cooled, the silicon carbide polycrystalline 10 can be separated from the carbon film layer 6 on the graphite support 5 , and the silicon carbide polycrystalline 10 can be separated from the carbon film layer 6 at the bottom of the graphite crucible 3 .

In an embodiment, the thickness of the carbon film layer 6 in this embodiment is 1-1000 microns, for example, the thickness of the carbon film layer 6 is 10-100 microns.

In this embodiment, as shown in FIG. 4 , the crystal rod 4 has a first cooling channel 41 , and the cooling fluid in the first cooling channel 41 is used to cool the graphite holder 5 . Due to the need for supercooling at the graphite support 5 during the formation of silicon carbide polycrystals, the carbon in the co-solvent 100 is precipitated on the solid-liquid interface between the graphite support 5 and the co-solvent 100, and combines with the silicon in the co-solvent Silicon carbide polycrystalline is formed, therefore, in order to ensure that the graphite support 5 has the required supercooling, a first cooling flow channel 41 can be set on the crystal rod 4, and the heat on the graphite support 5 can be taken away by the first cooling flow channel 41 , so that the graphite support 5 is in a supercooled state. In some embodiments, the first cooling channel 41 is connected to one end of the graphite support 5 through the crystal rod 4 to better cool the graphite support 5 .

In one embodiment, the cooling fluid flowing in the first cooling channel 41 can be helium. In this embodiment, the flow rate of helium in the first cooling channel 41 can be controlled, thereby controlling the temperature near the graphite support 5 Gradient, so as to control the growth rate and quality of silicon carbide polycrystals on the graphite support 5, so that the obtained silicon carbide polycrystals meet the requirements.

In one embodiment, as shown in FIG. 4, the crystal rod 4 includes a first tube body 42 and a second tube body 43 sleeved outside the first tube body 42. In some embodiments, the first tube body 42 is suspended in the air. in the second pipe body 43 . One end of the second tube body 43 is fixedly connected to the graphite holder 5 , and the other end of the second tube body 43 extends out of the chamber 1 . The first cooling channel 41 includes a first sub-channel 411 formed by the first tube body 42 and a second sub-channel 412 formed by the gap between the first tube body 42 and the second tube body 43. The flow channel 411 communicates with the second sub-channel 412, so that the cooling fluid can flow from the first sub-channel 411 into the second sub-channel 412 or from the second sub-channel 412 into the first sub-channel 411, thereby forming a loop . In some embodiments, the first end of the first tube body 42 close to the end of the second tube body 43 is an open end, and the first end of the first tube body 42 is spaced apart from one end of the second tube body 43, so that the first The cooling fluid in the pipe body 42 can flow out from the first end of the first pipe body 42 and enter between the first pipe body 42 and the second pipe body 43. One end of the second pipe body 43 is a sealed end or an open end. When one end of the second pipe body 43 is an open end, the second pipe body 43 is sealed and connected with the graphite holder 5 . In some other embodiments, the first end of the first tube body 42 close to the end of the second tube body 43 is a sealed end. Moreover, the first end of the first pipe body 42 is provided with a through hole, and the cooling fluid in the first pipe body 42 can flow into the space between the first pipe body 42 and the second pipe body 43 through the through hole.

It should be noted that the first tube body 42 and the second tube body 43 can move relative to each other. For example, when the graphite holder 5 needs to be driven to rotate, the second tube body 43 can be directly driven to rotate, while the first tube body 42 remains stationary. .

In one embodiment, the end surface of the second end of the first tube body 42 away from the end of the second tube body 43 can be flush with the end surface of the second tube body 43, that is, the end surface of the end surface of the crystal rod 4 not connected to the graphite holder 5 It is a plane, please continue to refer to FIG. 4, the first cooling channel 41 has a cooling inlet 413 and a cooling outlet 414 located at the end surface of the crystal rod 4, and the cooling channel can flow into the first cooling channel 41 through the cooling inlet 413, for example, into the first cooling channel 41. A sub-channel 411 , and flows to the vicinity of the graphite holder 5 , absorbs the heat of the graphite holder 5 , passes through the second sub-channel 412 and flows out from the cooling outlet 414 . As shown in FIG. 5 , the cooling inlet 413 in this embodiment is a central hole, and the cooling outlet 414 is an annular hole arranged around the cooling inlet 413 . It can be understood that the end surface of the crystal rod 4 not connected to the graphite holder 5 may not be a plane, that is, the length of the first tube body 42 is greater than the length of the second tube body 43 . In some embodiments, the first cooling channel 41 may be connected to a driving pump, and the driving pump provides driving force for the helium in the first cooling channel 41. When the crystal rod 4 includes a first tube body 42, the first tube Body 42 is connected to the drive pump.

Please continue to refer to FIG. 1 , the silicon carbide polycrystalline manufacturing device also includes a crucible holder 7 . Wherein, one end of the crucible holder 7 is fixedly connected to the bottom wall of the graphite crucible 3 , and the other end of the crucible holder 7 is located outside the chamber 1 . In some embodiments, the crucible holder 7 can drive the graphite crucible 3 to rotate. In one embodiment, the crucible holder 7 can rotate under the drive of the driving mechanism, thereby driving the graphite crucible to rotate. In this embodiment, the crucible holder 7 can also drive the graphite crucible 3 to move in the up and down direction shown in FIG. 1 to adjust the position of the graphite crucible 3 in the induction coil 2 . In some embodiments, the rotation direction of the crucible holder 7 is opposite to the rotation direction of the crystal rod 4; in other embodiments, the rotation speed of the crucible holder 7 or the crystal rod 4 may also be periodically changed or rotated forward periodically and reverse.

In one embodiment, as shown in FIG. 6 , the crucible holder 7 has a second cooling channel 71 , and the cooling fluid in the second cooling channel 71 is used to cool the bottom wall of the graphite crucible 3 . Due to the need for supercooling at the graphite crucible 3 during the formation of silicon carbide polycrystals, the carbon in the co-solvent 100 is precipitated on the solid-liquid interface between the graphite crucible 3 and the co-solvent 100, and combines with the silicon in the co-solvent Form silicon carbide polycrystal, therefore, in order to ensure that the graphite crucible 3 place has the required supercooling, a second cooling flow channel 71 can be set on the crucible holder 7, and the heat on the graphite crucible 3 can be taken away by the second cooling flow channel 71 , so that the graphite crucible 3 is in a supercooled state. In some embodiments, the second cooling channel 71 is connected to one end of the graphite crucible 3 through the crucible holder 7 so as to better cool the graphite crucible 3 .

In one embodiment, the cooling fluid flowing in the second cooling channel 71 can be helium, in this embodiment, the flow rate of helium in the second cooling channel 71 can be controlled, and then the temperature near the graphite crucible 3 can be controlled Gradient, so as to realize the control of the growth rate and quality of the silicon carbide polycrystal on the graphite crucible 3, so that the obtained silicon carbide polycrystal meets the requirements.

In one embodiment, as shown in FIG. 6, the crucible holder 7 includes a third tube body 72 and a fourth tube body 73 sleeved outside the third tube body 72. In some embodiments, the third tube body 72 is suspended in the air. in the fourth tube body 73 . One end of the fourth tube body 73 is fixedly connected to the graphite crucible 3 , and the other end of the fourth tube body 73 extends out of the chamber 1 . The second cooling channel 71 includes a third sub-channel 711 formed by the third tube body 72 and a fourth sub-channel 712 formed by the gap between the third tube body 72 and the fourth tube body 73. The runner 711 is connected with the fourth sub-runner 712 so that the cooling fluid can flow from the third sub-channel 711 into the fourth sub-channel 712 or from the fourth sub-channel 712 into the third sub-channel 711, thereby forming a loop. In some embodiments, the third end of the third pipe body 72 close to the end of the fourth pipe body 73 is an open end, and the third end of the third pipe body 72 is spaced from the end of the fourth pipe body 73, so that the third The cooling fluid in the pipe body 72 can flow out from the third end of the third pipe body 72 and enter between the third pipe body 72 and the fourth pipe body 73. One end of the fourth pipe body 73 is a sealed end or an open end. When one end of the fourth pipe body 73 is an open end, the fourth pipe body 73 is in sealing connection with the graphite crucible 3 . In some other embodiments, the third end of the third tube body 72 close to the end of the fourth tube body 73 is a sealed end. Moreover, the pipe wall at the third end of the third pipe body 72 is provided with a through hole, and the cooling fluid in the third pipe body 72 can flow into the third pipe body 72 and the fourth pipe body 73 through the through hole on the third pipe body 72 between.

It should be noted that the third pipe body 72 and the fourth pipe body 73 can move relative to each other. For example, when the graphite crucible 3 needs to be driven to rotate, the fourth pipe body 73 can be directly driven to rotate, while the third pipe body 72 remains stationary .

In one embodiment, the end face of the fourth end of the third pipe body 72 away from the end of the fourth pipe body 73 can be flush with the end face of the fourth pipe body 73, that is, the end face of the end face of the crucible holder 7 that is not connected to the graphite crucible 3 It is a plane, please continue to refer to FIG. 6, the second cooling channel 71 has an inlet 713 and an outlet 714 on the end surface of the crucible holder 7, the cooling channel can flow into the second cooling channel 71 through the inlet 713, for example, into the third sub- flow channel 711 , and flow to the vicinity of the graphite crucible 3 , absorb the heat of the graphite crucible 3 , pass through the fourth sub-channel 712 and flow out from the outlet 714 . In this embodiment, the inlet 713 is a central hole, and the outlet 714 is an annular hole arranged around the inlet 713 . It can be understood that the end surface of the crucible holder 7 not connected to the end of the graphite crucible 3 may not be a plane, that is, the length of the third tube body 72 is greater than the length of the fourth tube body 73 . In some embodiments, the second cooling channel 71 may be connected to a driving pump, and the driving pump provides driving force for the helium in the second cooling channel 71. When the crucible holder 7 includes a third tube body 72, the third tube Body 72 is connected to the drive pump.

As shown in Figure 1, the silicon carbide polycrystalline manufacturing device also includes a heat insulating cover 8, the graphite crucible 3 is arranged in the heat insulating cover 8, the induction coil 2 is located outside the heat insulating cover 8, and the crucible holder 7 and the crystal rod 4 respectively pass through the heat insulating cover 8. Set in the heat insulation sleeve 8, the heat insulation sleeve 8 is made of heat insulation material, and is used for heat insulation of the graphite crucible 3.

The silicon carbide polycrystal manufacturing device provided in this embodiment can form two silicon carbide polycrystals in one manufacturing process, which improves the manufacturing efficiency of the silicon carbide polycrystal and has a lower cost.

Embodiment two

This embodiment provides a silicon carbide polycrystalline manufacturing method, which is applied to the silicon carbide polycrystalline manufacturing device in Embodiment 1. As shown in FIG. 7, the silicon carbide polycrystalline manufacturing method includes the following steps:

S1. Put the auxiliary solvent 100 into the graphite crucible 3 .

It should be noted that the co-solvent 100 in this embodiment is a co-solvent containing silicon, so that silicon in the co-solvent 100 can form silicon carbide polycrystals with carbon. It can be understood that, in addition to silicon, the co-solvent 100 can also include titanium Ti, chromium Cr, scandium Sc, nickel Ni, aluminum Al, cobalt Co, manganese Mn, magnesium Mg, germanium Ge, arsenic As, boron P, nitrogen One or more elements of N, oxygen O, boron B, dysprosium Dy, yttrium Y, niobium Nb, neodymium Nd, and iron Fe.

S2 , heating the co-solvent through the induction coil 2 to melt the co-solvent 100 .

In step S2, the induction coil 2 is energized to heat the induction coil 2 and melt the co-solvent 100, so that the co-solvent 100 is in a liquid state.

S3. Drive the graphite support 5 to move close to the co-solvent 100 through the crystal rod 4, so that the lower surface of the graphite support 5 is flush with the liquid level of the co-solvent 100 or the distance is smaller than the preset distance.

The fact that the lower surface of the graphite support 5 is flush with the liquid surface of the co-solvent 100 means that the lower surface of the graphite support 5 is just in contact with the liquid surface of the co-solvent 100 . The preset spacing is up to 5mm to ensure the smooth growth of SiC polycrystalline. It should be noted that, when the lower surface of the graphite support 5 is provided with the carbon film layer 6, the lower surface of the carbon film layer 6 is controlled to be flush with the liquid level of the co-solvent 100 or the distance is smaller than the preset distance.

S4. Control the crystal rod 4 to drive the graphite support 5 to move away from the co-solvent 100, so that the bottom surface of the polycrystalline silicon carbide formed on the lower surface of the graphite support 5 is always flush with the liquid level of the co-solvent 100 or the distance is smaller than the preset distance.

With the growth of polycrystalline silicon carbide, it is necessary to control the bottom surface of polycrystalline silicon carbide to be always flush with the liquid level of the co-solvent or the distance is smaller than the preset distance, so as to ensure a certain thickness of polycrystalline silicon carbide growth. It should be noted that both the lower surface of the graphite holder 5 and the inner wall at the bottom of the graphite crucible 3 can grow polycrystalline silicon carbide.

In one embodiment, when the silicon carbide polycrystalline manufacturing device includes a crucible holder 7, and the crucible body 7 has a second cooling flow channel 71, and the crystal rod 4 has a first cooling flow channel 41, in step S4, simultaneously The flow rate of the cooling fluid in the first cooling channel 41 and the second cooling channel 71 is controlled, thereby controlling the temperature gradient near the graphite support 5 and the graphite crucible 3 , and then controlling the growth rate and quality of the silicon carbide polycrystal.

The silicon carbide polycrystalline manufacturing method provided in this embodiment can adopt the solution method to manufacture silicon carbide polycrystalline, and by setting the graphite support 5 and the graphite crucible 3, it can realize direct crystallization on the graphite material, and then obtain the silicon carbide polycrystalline, without The seed crystal is set, and the graphite holder 5 and the graphite crucible 3 can be crystallized at the same time, so that one device can obtain two silicon carbide polycrystals at the same time, which improves the manufacturing efficiency of silicon carbide polycrystals and reduces the cost of manufacturing silicon carbide polycrystals.

In this embodiment, the p-type silicon carbide polycrystal and the n-type silicon carbide polycrystal can be obtained by controlling the growth environment of the silicon carbide polycrystal and the parameters of the cosolvent 100 .

For example, when manufacturing p-type silicon carbide polycrystals, the bottom inner wall of the graphite crucible 3 and the bottom surface of the graphite holder 5 have a carbon film layer 6 respectively, and the above-mentioned silicon carbide polycrystal manufacturing method also includes filling helium into the chamber , The gas pressure in the chamber 1 is 0.5-1 atmosphere, and the co-solvent 100 is adjusted to include Si, Cr and Al elements, and the temperature of the co-solvent 100 is controlled to 1800° C. through the induction coil 2 . In step S4, the crystal rod 4 is controlled to drive the graphite holder 5 to move away from the cosolvent while driving the graphite holder 5 to rotate, for example, the pulling speed of the crystal rod 4 is 1-2 mm/hour, and the graphite crucible 3 is controlled to reversely Rotate in the direction of the rotation direction of the graphite holder 5 to simultaneously crystallize on the carbon film layer 6 below the graphite holder 5 and on the carbon film layer 6 on the bottom wall of the graphite crucible 3 to obtain two p-type silicon carbide polycrystals. The resistivity of the p-type silicon carbide polycrystalline obtained in this embodiment is lower than 30 mΩ·cm (milliohm·cm).

For example, when making n-type silicon carbide polycrystal, the bottom inner wall of graphite crucible 3 and the bottom surface of graphite holder 5 have carbon film layer 6 respectively, and the manufacture method of silicon carbide polycrystal also comprises filling helium in chamber 1 and nitrogen. It should be noted that nitrogen gas is filled into the chamber 1 at a fixed flow rate, and the main growth atmosphere of silicon carbide polycrystalline is helium gas. The pressure of the gas in the chamber 1 is controlled to be 0.5-1 atmosphere, the co-solvent includes Si element and Cr element, and the temperature of the co-solvent is 2000°C. In step S4, the crystal rod 4 is controlled to drive the graphite holder 5 to move away from the cosolvent while driving the graphite holder 5 to rotate, for example, the pulling speed of the crystal rod 4 is 1-2 mm/hour, and the graphite crucible 3 is controlled to reversely Rotate in the direction of the rotation direction of the graphite holder 5 to simultaneously crystallize on the carbon film layer 6 below the graphite holder 5 and on the carbon film layer 6 on the bottom wall of the graphite crucible 3 to obtain two n-type silicon carbide polycrystals. The n-type silicon carbide polycrystalline resistivity obtained in this embodiment is lower than 30 mΩ·cm (milliohm·cm).

In summary, it can be seen that the growth rate and quality of silicon carbide polycrystalline can be controlled by controlling the following three process parameters. Wherein, one process parameter is the flow rate of the cooling helium in the crystal rod 4 and the crucible holder 7 . A process parameter is growth atmosphere and pressure. The growth atmosphere is at least one of helium, argon, nitrogen, and hydrogen, and the pressure is between 0.2-2 atmospheres. One process parameter is the rotation speed of the crystal rod 4 , the upward pulling speed, and the rotation speed of the graphite crucible 3 . One process parameter is the power of the induction heating to control the temperature of the flux 100 .

Claims

A silicon carbide polycrystalline manufacturing device, comprising:

chamber(1);

An induction coil (2) is arranged in the chamber (1);

A graphite crucible (3) is arranged in the chamber (1), and the graphite crucible (3) is used to accommodate a cosolvent, and the bottom inner wall of the graphite crucible (3) can grow polycrystalline silicon carbide;

A crystal rod (4), one end of the crystal rod (4) is located in the graphite crucible (3), and the other end of the crystal rod (4) is located outside the chamber (1);

The graphite holder (5) is fixedly connected to one end of the crystal rod (4), and the bottom surface of the graphite holder (5) facing the bottom wall of the graphite crucible (3) can grow polycrystalline silicon carbide.
The silicon carbide polycrystalline manufacturing device according to claim 1, further comprising a carbon film layer (6), at least one of the bottom inner wall of the graphite crucible (3) or the bottom surface of the graphite holder (5) has the The carbon film layer (6).
The silicon carbide polycrystalline manufacturing device according to claim 2, wherein the carbon film layer (6) has a thickness of 1-1000 microns.
The silicon carbide polycrystalline manufacturing device according to any one of claims 1-3, wherein the crystal rod (4) has a first cooling flow channel (41), and in the first cooling flow channel (41) The cooling fluid is used to cool the graphite holder (5).
The silicon carbide polycrystalline manufacturing device according to claim 4, wherein the crystal rod (4) comprises a first tube body (42) and a second tube sleeved outside the first tube body (42) body (43), the second tube body (43) is fixed to the graphite holder (5), and the first cooling channel (41) includes a first cooling channel (41) formed by the first tube body (42). The sub-flow channel (411) and the second sub-flow formed by the gap between the first pipe body (42) and the second pipe body (43) and communicated with the first sub-flow channel (411) Road (412).
The silicon carbide polycrystalline manufacturing device according to any one of claims 1-3, further comprising a crucible holder (7), one end of the crucible holder (7) is affixed to the bottom wall of the graphite crucible (3) , the other end of the crucible holder (7) is located outside the chamber (1).
The manufacturing device of silicon carbide polycrystal according to claim 6, wherein, the crucible holder (7) has a second cooling channel (71), and the cooling fluid in the second cooling channel (71) is used for Cool the bottom wall of the graphite crucible (3).
A silicon carbide polycrystalline manufacturing method, applied to the silicon carbide polycrystalline manufacturing device described in any one of claims 1-7, comprising:

Put into cosolvent in graphite crucible (3);

heating the co-solvent through an induction coil (2) to melt the co-solvent;

The crystal rod (4) drives the graphite support (5) to move close to the co-solvent, so that the lower surface of the graphite support (5) is flush with the liquid level of the co-solvent or the distance is smaller than the preset distance;

Control the crystal rod (4) to drive the graphite support (5) to move away from the co-solvent, so that the bottom surface of the polycrystalline silicon carbide formed on the lower surface of the graphite support (5) is always in contact with the liquid level of the co-solvent Flush or spaced less than the preset spacing.
The method for manufacturing polycrystalline silicon carbide according to claim 8, wherein the apparatus for manufacturing polycrystalline silicon carbide further comprises a crucible holder (7), and the crystal rod (4) has a first cooling channel (41) , the crucible holder (7) has a second cooling channel (71);

Also includes:

Simultaneously control the flow of cooling fluid in the first cooling channel (41) and the second cooling channel (71), thereby controlling the temperature near the graphite holder (5) and the graphite crucible (3) Gradient, and then control the growth rate and quality of silicon carbide polycrystalline.
The method for manufacturing silicon carbide polycrystalline according to claim 8, further comprising:

Fill helium into the chamber (1), the cosolvent includes Si element, Cr element and Al element, on the carbon film layer (6) below the graphite support (5) and the graphite crucible (3) Crystallization on the carbon film layer (6) of the bottom wall to obtain two p-type silicon carbide polycrystals; or

Charge helium and nitrogen into the chamber (1), the cosolvent includes Si elements and Cr elements, on the carbon film layer (6) below the graphite holder (5) and the graphite crucible ( 3) Crystallization on the carbon film layer (6) on the bottom wall to obtain two n-type silicon carbide polycrystals.