阅读说明：本技术 晶体生长装置和晶体生长方法 (Crystal growth apparatus and crystal growth method ) 是由 彭程 张洁 廖弘基 陈华荣 于 2021-08-19 设计创作，主要内容包括：本发明涉及晶体生长技术领域,具体而言,涉及一种晶体生长装置和晶体生长方法。晶体生长装置包括坩埚盖和坩埚体；坩埚体包括相互配合的侧壁和底壁；沿坩埚体的高度,侧壁包括多个壁体和多个连接段,壁体和连接段依次错开连接；坩埚盖、底壁和壁体均由第一石墨材质制成,连接段由第二石墨材质制成；且第一石墨材质的密度大于第二石墨材质的密度。如此能够提高坩埚内部的N-(2)含量,以增加原料及生长器件中吸附更多的N-(2),加大参与晶体生长反应的N-(2)含量,从而减小碳化硅晶片的电阻率。(The invention relates to the technical field of crystal growth, in particular to a crystal growth device and a crystal growth method. The crystal growth device comprises a crucible cover and a crucible body; the crucible body comprises a side wall and a bottom wall which are matched with each other; along the height of the crucible body, the side wall comprises a plurality of wall bodies and a plurality of connecting sections, and the wall bodies and the connecting sections are sequentially connected in a staggered manner; the crucible cover, the bottom wall and the wall body are all made of a first graphite material, and the connecting section is made of a second graphite material; and the density of the first graphite material is greater than the density of the second graphite material. Thus, N in the crucible can be increased 2 To increase the adsorption of more N in the raw material and the growth device 2 Increasing the N participating in the crystal growth reaction 2 And thereby reducing the resistivity of the silicon carbide wafer.)

1. A crystal growth apparatus, comprising:

a crucible cover (100) and a crucible body (200);

the crucible body (200) comprises a side wall (201) and a bottom wall (202) which are matched with each other;

along the height of the crucible body (200), the side wall (201) comprises a plurality of wall bodies (211) and a plurality of connecting sections (212), and the wall bodies (211) and the connecting sections (212) are sequentially connected in a staggered manner;

the crucible cover (100), the bottom wall (202) and the wall (211) are all made of a first graphite material (410), and the connecting section (212) is made of a second graphite material (420); and the density of the first graphite material (410) is greater than the density of the second graphite material (420).

2. The crystal growth apparatus of claim 1, wherein:

the density of the first graphite material (410) is 1.4-1.8 g/cm³。

3. The crystal growth apparatus of claim 1, wherein:

the density of the second graphite material (420) is 0.9-1.1 g/cm³。

4. The crystal growth apparatus of claim 1, wherein:

along the height direction of the crucible body (200), the height of the wall body (211) is greater than that of the connecting section (212).

5. The crystal growth apparatus of claim 1, wherein:

the spacing between adjacent connecting sections (212) is equal.

6. The crystal growth apparatus of claim 5, wherein:

along the direction of height of the crucible body (200), be located the bottommost the linkage segment (212) apart from the distance of diapire (202) is L, and is a plurality of the interval between the linkage segment (212) is Q, and L is become to Q.

7. The crystal growth apparatus of claim 1, wherein:

and a graphite carbon felt heat-insulating layer (310) is arranged on the outer side of the side wall (201).

8. The crystal growth apparatus of claim 1, wherein:

the top of the crucible cover (100) and/or the lower part of the bottom wall (202) is/are provided with a carbon felt heat preservation layer (320).

9. The crystal growth apparatus of claim 8, wherein:

and a temperature measuring hole (321) which penetrates through the carbon felt heat insulating layer (320) positioned at the top of the crucible cover (100) is arranged.

10. A crystal growth method, characterized by:

providing a crystal growth device, wherein the crystal growth device comprises a crucible cover (100) and a crucible body (200), the crucible cover (100) is provided with a seed crystal clamping part, and a seed crystal is combined on the seed crystal clamping part;

the crucible body (200) comprises a side wall (201) and a bottom wall (202) which are matched with each other, wherein the side wall (201) is arranged on the bottom wall (202) to form a cylindrical structure; along the height of the crucible body (200), the side wall (201) comprises a plurality of wall bodies (211) and a plurality of connecting sections (212), and the wall bodies (211) and the connecting sections (212) are sequentially connected in a staggered manner; the crucible cover (100), the bottom wall (202) and the wall (211) are all made of a first graphite material (410), and the connecting section (212) is made of a second graphite material (420); and the density of the first graphite material (410) is greater than the density of the second graphite material (420);

after SiC raw material powder is filled in the crucible body (200), the crucible cover (100) is covered on the crucible body (200) and crystal growth is carried out in a crystal growth furnace, wherein the condition of the crystal growth is as follows,

introduction of N₂Controlling the pressure at a first pressure and maintaining the pressure for a first time;

then argon and N are introduced₂And mixing the gases, controlling the pressure at a second pressure and maintaining the pressure for a second time, wherein the second pressure is less than the first pressure.

Technical Field

The invention relates to the technical field of crystal growth, in particular to a crystal growth device and a crystal growth method.

Background

Physical vapor deposition (PVT) uses medium frequency induction heating and a high density graphite crucible as a heating element. The bottom of the graphite crucible is provided with silicon carbide powder with high densityThe quality silicon carbide seed crystal is adhered to the top of the graphite crucible, and 4H-SiC is grown by generally adopting a C surface as a growth surface for crystal growth. The silicon carbide powder is sublimated into Si and Si at the temperature of more than 2100 ℃ and in a low-pressure environment₂C、SiC₂The gas is conveyed from the powder region to the seed crystal along the axial temperature gradient to deposit and crystallize the silicon carbide single crystal.

Although the PVT method is well established in the field of silicon carbide growth, there are still drawbacks to the preparation of low resistance conductive silicon carbide single crystals. At present, the introduction of flowing N into a growth chamber is commonly adopted₂To increase the N ion concentration in the silicon carbide single crystal and at the same time to increase the nitrogen doping efficiency in the crystal is an inevitable problem in the production of low resistivity silicon carbide wafers.

However, it is difficult to effectively incorporate N into the crystal in the prior art, which results in a silicon carbide wafer with an unsatisfactory resistivity.

Disclosure of Invention

The object of the present invention includes, for example, providing a crystal growth apparatus and a crystal growth method capable of increasing the adsorption of more N in the raw material and the growth device₂To increase the N in the crucible₂Content of N participating in crystal growth reaction is increased₂And thereby reducing the resistivity of the silicon carbide wafer.

Embodiments of the invention may be implemented as follows:

in a first aspect, the present invention provides a crystal growth apparatus comprising:

a crucible cover and a crucible body;

the crucible body comprises a side wall and a bottom wall which are matched with each other;

along the height of the crucible body, the side wall comprises a plurality of wall bodies and a plurality of connecting sections, and the wall bodies and the connecting sections are sequentially connected in a staggered manner;

the crucible cover, the bottom wall and the wall body are all made of a first graphite material, and the connecting section is made of a second graphite material; and the density of the first graphite material is greater than that of the second graphite material.

In the prior art, along with the silicon carbide gas in the crucibleThe partial pressure is gradually increased, and at the moment, N is generated in the common crucible due to overhigh compactness₂The molecular diffusion force is less than the driving force caused by pressure difference, and the N cannot effectively enter the crucible to cause₂The concentration is too low.

The crystal growth device of the scheme adopts the low-density graphite material on the upper part of the wall body, so that the low-density graphite parts are respectively arranged on the middle upper part and the upper part of the crucible body, and the effect of increasing the N inside and outside the crucible is achieved₂The ability to penetrate. Specifically, inside the crucible of this scheme can effectively get into the crucible through low density graphite part, low density graphite still can the inside carborundum gas of effectual prevention crucible go out simultaneously, and such arrangement mode can not influence the heating efficiency and the thermal field distribution of crucible. Thus, the device for preparing the crystal by the physical vapor deposition method, which not only improves the permeability coefficient of the designated boundary position, but also keeps the crucible with high heating efficiency, is obtained.

In an optional embodiment, the density of the first graphite material is 1.4 to 1.8g/cm³。

In an optional embodiment, the density of the second graphite material is 0.9 to 1.1g/cm³。

In an alternative embodiment, the height of the wall in the height direction of the crucible body is greater than the height of the connecting section.

In an alternative embodiment, the spacing between adjacent ones of the connecting segments is equal.

In an alternative embodiment, the distance between the connecting section located at the lowest position and the bottom wall is L, and the distance between the connecting sections is Q, and Q is L.

In an alternative embodiment, the outside of the side wall is provided with a graphite carbon felt insulating layer.

In an alternative embodiment, the top of the crucible cover and/or the lower part of the bottom wall is provided with a carbon felt insulating layer.

In an alternative embodiment, the carbon felt insulating layer on the top of the crucible cover is provided with a temperature measuring hole penetrating through the carbon felt insulating layer.

In a second aspect, the invention provides a crystal growth method, and provides a crystal growth device, wherein the crystal growth device comprises a crucible cover and a crucible body, the crucible cover is provided with a seed crystal clamping part, and a seed crystal is combined on the seed crystal clamping part;

the crucible body comprises a side wall and a bottom wall which are matched with each other, and the side wall is arranged on the bottom wall to form a cylindrical structure; along the height of the crucible body, the side wall comprises a plurality of wall bodies and a plurality of connecting sections, and the wall bodies and the connecting sections are sequentially connected in a staggered manner; the crucible cover, the bottom wall and the wall body are all made of a first graphite material, and the connecting section is made of a second graphite material; the density of the first graphite material is greater than that of the second graphite material;

after SiC raw material powder is filled in the crucible body, covering the crucible cover on the crucible body, and carrying out crystal growth in a crystal growth furnace, wherein the crystal growth condition is that,

introduction of N₂Controlling the pressure at a first pressure and maintaining the pressure for a first time;

then argon and N are introduced₂And mixing the gases, controlling the pressure at a second pressure and maintaining the pressure for a second time, wherein the second pressure is less than the first pressure.

The scheme also provides a process scheme before crystal growth, longer vacuumizing time is carried out before temperature rise, the internal pressure of the crucible is ensured to be minimum, and N is introduced for a longer time₂Time, increased material and more N adsorbed in the growth device₂To increase the N in the crucible₂Content of N participating in crystal growth reaction is increased₂And (4) content.

The beneficial effects of the embodiment of the invention include, for example:

the crystal growth device of the scheme comprises a crucible cover and a crucible body, because the side wall comprises a plurality of wall bodies and connecting sections which are connected in a staggered manner, the density of the graphite of the connecting sections is smaller than that of other parts of the crucible, and therefore the density of the outer N in the crucible can be increased₂The ability to penetrate. Namely, the crucible can effectively enter the crucible through the low-density graphite part, and simultaneously, the low-density graphite still can effectively prevent the silicon carbide gas in the crucible from running out, so thatThe arrangement mode of the crucible can not influence the heating efficiency and the distribution of the thermal field of the crucible. Thus, a crucible device is obtained which not only improves the permeability coefficient of the designated boundary position, but also retains high heat generation efficiency.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

Fig. 1 is a schematic structural diagram of a crystal growth apparatus according to an embodiment of the present invention.

Icon: 10-a crystal growth apparatus; 100-crucible cover; 200-a crucible body; 201-side wall; 202-bottom wall; 211-wall body; 212-a connecting segment; 310-a graphite carbon felt insulating layer; 320-a carbon felt heat-insulating layer; 321-temperature measuring holes; 410-a first graphite material; 420-a second graphite material; 21-raw material; 22-an induction coil; 23-seed crystal; 24-silicon carbide single crystal.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

In the description of the present invention, it should be noted that if the terms "upper", "lower", "inside", "outside", etc. indicate an orientation or a positional relationship based on that shown in the drawings or that the product of the present invention is used as it is, this is only for convenience of description and simplification of the description, and it does not indicate or imply that the device or the element referred to must have a specific orientation, be constructed in a specific orientation, and be operated, and thus should not be construed as limiting the present invention.

Furthermore, the appearances of the terms "first," "second," and the like, if any, are used solely to distinguish one from another and are not to be construed as indicating or implying relative importance.

It should be noted that the features of the embodiments of the present invention may be combined with each other without conflict.

Silicon carbide materials are widely used in the manufacture of precision devices. The main preparation method of the SiC monocrystal is a physical vapor transport physical vapor deposition method (PVT) which adopts medium-frequency induction heating and a high-density graphite crucible as a heating body.

The silicon carbide powder is placed at the bottom of the graphite crucible, the high-quality silicon carbide seed crystal is adhered to the top of the graphite crucible, and the growing 4H-SiC generally adopts the C surface as a growing surface to carry out crystal growth. The silicon carbide powder is sublimated into Si and Si at the temperature of more than 2100 ℃ and in a low-pressure environment₂C、SiC₂The gas is conveyed from the powder region to the seed crystal along the axial temperature gradient to deposit and crystallize the silicon carbide single crystal.

Although the PVT method is well established in the field of silicon carbide growth, there are still drawbacks to the preparation of low resistance conductive silicon carbide single crystals. At present, the introduction of flowing N into a growth chamber is commonly adopted₂(Nitrogen, which will not be described in detail below) to increase the N ion concentration in the silicon carbide single crystal, but the results are far from ideal. A large number of experiments show that the N ion content of the silicon carbide single crystal does not have positive correlation with the flow of the introduced nitrogen, but existsThe upper limit is defined. Increasing the nitrogen doping efficiency in the crystal is an inevitable problem in the preparation of low resistivity silicon carbide wafers.

The participation of N atoms is a necessary link in the growth process of N-type SiC, but the prior art is difficult to effectively mix N into the crystal, which is related to the temperature and the mode of crystal growth on one hand and the N atom in the crystal growth atmosphere on the other hand₂And (4) deficiency.

When the crystal grows, the pressure inside the crucible is far higher than that outside the crucible, and due to the compactness of the graphite, the N injected into the chamber₂The failure to effectively enter the crucible will cause N to participate in the process₂Large amount of N actually participating in growth₂And very few.

To improve the above technical problem, a crystal growth apparatus and a crystal growth method are provided in the following embodiments to effectively improve N from both the apparatus and the method₂The problem of not being able to enter the crucible interior.

Referring to fig. 1, the present embodiment provides a crystal growing apparatus 10 including a crucible cover 100 and a crucible body 200.

The crucible body 200 includes a sidewall 201 and a bottom wall 202, the sidewall 201 being disposed on the bottom wall 202 to form a cylindrical structure;

along the height of the crucible body 200, the side wall 201 comprises a plurality of wall bodies 211 and a plurality of connecting sections 212, and the wall bodies 211 and the connecting sections 212 are sequentially connected in a staggered manner;

the crucible cover 100, the bottom wall 202 and the wall 211 are all made of a first graphite material 410, and the connecting section 212 is made of a second graphite material 420; and the density of the first graphite material 410 is greater than the density of the second graphite material 420.

In the prior art, as the partial pressure of the silicon carbide gas in the crucible is gradually increased, the N in the common crucible is too high due to too high compactness₂The molecular diffusion force is less than the driving force caused by pressure difference, and the N cannot effectively enter the crucible to cause₂The concentration is too low.

The crystal growth device 10 of the present embodiment is made of low-density graphite material through the upper portion of the wall body 211, so that the upper portion of the crucible body 200 is provided with the low-density graphite portion, thereby defining the effect of the low-density graphite portionIncrease N inside and outside the crucible₂The ability to penetrate. Specifically, inside the crucible of this scheme can effectively get into the crucible through low density graphite part, low density graphite still can the inside carborundum gas of effectual prevention crucible go out simultaneously, and such arrangement mode can not influence the heating efficiency and the thermal field distribution of crucible. Thus, the device for preparing the crystal by the physical vapor deposition method, which not only improves the permeability coefficient of the designated boundary position, but also keeps the crucible with high heating efficiency, is obtained.

Optionally, in this embodiment of the present invention, the density of the first graphite material 410 is 1.4 to 1.8g/cm³The density of the second graphite material 420 is 0.9-1.1 g/cm³。

As can also be seen from fig. 1, in the present embodiment, the height of the wall 211 is greater than that of the connection section 212 in the height direction of the crucible body 200. Optionally, the height of wall 211 is about twice the height of connecting section 212.

In the present embodiment, the adjacent connecting segments 212 are equally spaced. Further, in the height direction of the crucible body 200, the distance between the lowermost connecting section 212 and the bottom wall 202 is L, and the distance between the plurality of connecting sections 212 is Q, and Q is L. Such an arrangement enables nitrogen gas to uniformly permeate in the height direction of the side wall 201 to increase the N inside the crucible₂Content of N participating in crystal growth reaction is increased₂And (4) content.

As can also be seen from the figure, in the present embodiment of the invention, the outside of the sidewall 201 is provided with a graphite carbon felt insulation layer 310. Optionally, 2-3 graphite carbon felt heat preservation layers 310 with the thickness of 5-10 mm are wrapped around the side wall 201.

The top of the crucible cover 100 and/or the lower portion of the bottom wall 202 is provided with a carbon felt insulating layer 320. In this embodiment, the top of the crucible cover 100 and the lower portion of the bottom wall 202 are simultaneously provided with the carbon felt insulating layer 320. It is understood that in other embodiments, only the top or lower portion of the bottom wall 202 of the crucible cover 100 is provided with the carbon felt insulating layer 320.

Optionally, the crucible cover 100 and the bottom wall 202 are respectively provided with 2 layers of carbon felt heat preservation layers 320 with the thickness of 5-10 mm. The graphite carbon felt insulating layer 310 and the carbon felt insulating layer 320 can both guarantee the temperature requirement of crystal growth.

Further, in the present embodiment, the carbon felt insulating layer 320 on the top of the crucible cover 100 is provided with a temperature measuring hole 321 therethrough. The carbon felt heat preservation layer 320 at the top is provided with a circular temperature measuring hole 321 of 5-10 mm for observing the temperature at the upper part of the crucible in real time.

In this embodiment, the thickness of the crucible is 10 to 20 mm. The total height of the crucible is 500mm, most of the crucible body 200 is made of a first graphite material 410 with high density, and the height of the crucible body is 50mm at the positions of 150mm, 250mm and 350mm respectively and is made of a second graphite material 420 with low density.

The lower surface of the crucible cover 100 is adhered with a silicon carbide seed crystal 23 for inducing the gas components of Si, Si2C and SiC2 in a low-temperature region to condense and grow into a silicon carbide single crystal 24.

When the crucible is used, the crucible cover 100 bonded with the seed crystal 23 and a crucible with a thermal field placed inside are sealed, 2-3 layers of growth crucible are wrapped around, and 2 layers of graphite carbon felt heat preservation layers 310 with the thickness of 5-10 mm are wrapped at the top and the bottom of the growth crucible;

then putting the growth crucible into a crystal growth furnace, evacuating the chamber to below 0.05mbar, and maintaining the current state for 1-2 h;

then 100sccm of N is introduced₂And after the pressure is controlled at 100mbar and maintained for 1-2 h, introducing argon and N₂Mixing the gases and controlling the pressure of the chamber to be 1-50 mbar;

the induction coil 22 is electrified by the medium-frequency induction power supply, the graphite crucible generates heat under the condition of changing a magnetic field, and when the temperature rises to 2100-2200 ℃, the silicon carbide powder begins to sublimate to become Si and Si₂C、SiC₂And (3) conveying the gas to the periphery of the seed crystal 23 piece in the low temperature region under the action of the axial temperature gradient driving force, condensing the silicon carbide gas into a single crystal at low temperature and low pressure, and finishing the preparation of the silicon carbide crystal after 7-9 days.

In a second aspect, the invention provides a crystal growth method, and provides a crystal growth device, wherein the crystal growth device comprises a crucible cover 100 and a crucible body 200, the crucible cover 100 is provided with a seed crystal clamping part, and a seed crystal is combined on the seed crystal clamping part;

the crucible body 200 comprises a side wall 201 and a bottom wall 202 which are matched with each other, wherein the side wall 201 is arranged on the bottom wall 202 to form a cylindrical structure; along the height of the crucible body 200, the side wall 201 comprises a plurality of wall bodies 211 and a plurality of connecting sections 212, and the wall bodies 211 and the connecting sections 212 are sequentially connected in a staggered manner; the crucible cover 100, the bottom wall 202 and the wall 211 are all made of a first graphite material 410, and the connecting section 212 is made of a second graphite material 420; and the density of the first graphite material 410 is greater than the density of the second graphite material 420;

after SiC raw material powder is filled in the crucible body 200, the crucible cover 100 is covered on the crucible body 200, and crystal growth is carried out in a crystal growth furnace, wherein the crystal growth condition is that,

introduction of N₂Controlling the pressure at a first pressure and maintaining the pressure for a first time;

then argon and N are introduced₂And mixing the gases, controlling the pressure at a second pressure and maintaining the pressure for a second time, wherein the second pressure is less than the first pressure.

The scheme also provides a process scheme before crystal growth, longer vacuumizing time is carried out before temperature rise, the internal pressure of the crucible is ensured to be minimum, and N is introduced for a longer time₂Time, increase of N in the crucible₂In order to increase the amount of the raw material 21 and adsorb more N in the grown device₂Increasing the N participating in the crystal growth reaction₂And (4) content.

Further, first, 2kg of SiC raw material 21 is charged into the bottom of the crucible, and after the raw material 21 is flattened and compacted, the crucible cover 100 to which the silicon carbide seed crystal 23 is attached is closed. Evacuating the chamber to below 0.05mbar, maintaining the current state for 1-2 h, and introducing 100sccm N₂And after the pressure is controlled at 100mbar and maintained for 1-2 h, introducing argon and N₂Mixing the gas and controlling the pressure of the chamber to be 1-50 mbar.

The induction coil 22 is electrified by the medium-frequency induction power supply, the graphite crucible generates heat under the changing magnetic field, and when the temperature rises to 2100-2200 ℃, the silicon carbide powder (namely the raw material 21, which is not described any more) begins to sublimate into silicon carbide gas. The silicon carbide gas is conveyed to the periphery of the seed crystal 23 in the low temperature area under the action of the axial temperature gradient driving force, the silicon carbide gas is condensed into a single crystal at low temperature and low pressure, and the preparation of the silicon carbide crystal is finished after 7-9 days.

The low-pressure control state of the chamber for 1-2 h means that all pre-stored gas in the crucible penetrates into the chamber through the crucible wall. Keeping the N introduction for 1-2 h₂In this state, the lower portion of the crucible body 200 is provided with a graphite portion of 50mm low density, meaning that the original graphite portion and the graphite member are maintained at a high N₂Soaking in concentration environment to increase N participating in reaction in the initial stage of crystal growth as much as possible₂Amount of the compound (A).

The middle upper part and the upper part of the crucible body 200 are respectively provided with 50mm of low-density graphite parts, which means that the N at the inner part and the outer part of the crucible is increased₂The ability to penetrate. With the gradual increase of the partial pressure of the silicon carbide gas in the crucible, the N in the common crucible is too high due to the overhigh compactness₂The molecular diffusion force is less than the driving force caused by pressure difference, and the N cannot effectively enter the crucible to cause₂The concentration is too low.

Such crucible can effectively get into the crucible inside through low density graphite part, and low density graphite still can effectually prevent the inside carborundum gas of crucible to run out simultaneously. The graphite material of the 5mm crucible is replaced at 3 positions at equal intervals, and the heating efficiency and the thermal field distribution of the crucible are not influenced.

In summary, the embodiments of the present invention provide a crystal growth apparatus 10 and a crystal growth method, which have at least the following advantages:

1. the graphite density of the connecting section 212 is lower than that of other parts of the crucible, so that the inner and outer N of the crucible can be increased₂The ability to penetrate.

2. The crucible can effectively get into the crucible through the low-density graphite part inside, and low-density graphite still can effectually prevent the inside carborundum gas of crucible to run out simultaneously, and such arrangement mode can not influence the heating efficiency and the thermal field distribution of crucible.

3. A crucible device is obtained which not only improves the permeability coefficient of a prescribed boundary position, but also retains high heat generation efficiency.

The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.