阅读说明：本技术 一种减少4H-SiC多型缺陷产生的装置及方法 (Device and method for reducing generation of 4H-SiC polytype defects ) 是由 不公告发明人 于 2021-08-26 设计创作，主要内容包括：一种减少4H-SiC多型缺陷产生的装置及方法,属于晶体长晶装置领域。本发明解决了现有的用于生长4H-SiC晶体的长晶装置在长晶过程中容易出现多种晶型,晶体生长质量差的问题。本发明包括坩埚上盖、外坩埚、内坩埚、连接板、支撑台、感应线圈和石英管,外坩埚设置在支撑台上侧,外坩埚内套装有内坩埚,外坩埚上设置有坩埚上盖,坩埚上盖内壁上设置有籽晶,内坩埚内填充有原料,内坩埚设置在连接板上,连接板与螺纹杆螺纹连接,螺纹杆设置在支撑台内并穿过连接板与内坩埚连接,支撑台与外坩埚设置在石英管内,石英管外侧设置有感应线圈。通过本发明的长晶装置及方法,实现晶体生长速率稳定,减少晶体生长缺陷的产生。(A device and a method for reducing generation of 4H-SiC polytype defects belong to the field of crystal growth devices. The invention solves the problems that the existing crystal growth device for growing 4H-SiC crystals is easy to have various crystal forms in the crystal growth process and the crystal growth quality is poor. The crucible induction device comprises an upper crucible cover, an outer crucible, an inner crucible, a connecting plate, a supporting table, an induction coil and a quartz tube, wherein the outer crucible is arranged on the upper side of the supporting table, the inner crucible is sleeved in the outer crucible, the upper crucible cover is arranged on the outer crucible, seed crystals are arranged on the inner wall of the upper crucible cover, raw materials are filled in the inner crucible, the inner crucible is arranged on the connecting plate, the connecting plate is in threaded connection with a threaded rod, the threaded rod is arranged in the supporting table and penetrates through the connecting plate to be connected with the inner crucible, the supporting table and the outer crucible are arranged in the quartz tube, and the induction coil is arranged on the outer side of the quartz tube. By the crystal growth device and the crystal growth method, the stable crystal growth rate is realized, and the generation of crystal growth defects is reduced.)

1. An apparatus for reducing the generation of 4H-SiC polytype defects, comprising: the induction crucible comprises a crucible upper cover (1), an outer crucible (3), an inner crucible (4), a connecting plate (6), a supporting table (7), an induction coil (8) and a quartz tube (9), wherein the outer crucible (3) is arranged on the upper side of the supporting table (7), the inner crucible (4) is sleeved in the outer crucible (3), the crucible upper cover (1) is arranged on the outer crucible (3), seed crystals (2) are arranged on the inner wall of the crucible upper cover (1), raw materials (5) are filled in the inner crucible (4), the inner crucible (4) is arranged on the connecting plate (6), the connecting plate (6) is in threaded connection with a threaded rod (11), the threaded rod (11) is arranged in the supporting table (7) and penetrates through the connecting plate (6) to be connected with the inner crucible (4), the supporting table (7) and the outer crucible (3) are arranged in the quartz tube (9), and the induction coil (8) is arranged on the outer side of the quartz tube (9).

2. The apparatus of claim 1, wherein the apparatus further comprises: still include motor (10), motor (10) set up in brace table (7), and motor (10) are connected with the one end of threaded rod (11).

3. The apparatus of claim 2, wherein the apparatus further comprises: the inner wall of the supporting platform (7) is provided with a lifting device (12), the lifting device (12) comprises a first lifting device (13) and a second lifting device (14), and the first lifting device (13) and the second lifting device (14) are respectively connected with the connecting plate (6).

4. The apparatus of claim 3, wherein the apparatus further comprises: the first lifting device (13) comprises a first fixing piece (17) and a first lifting rod (15), the first fixing piece (17) is fixedly installed on the inner wall of the supporting table (7), the first lifting rod (15) is arranged on the first fixing piece (17), and the first lifting rod (15) penetrates through the connecting plate (6) to be arranged in a gap between the outer crucible (3) and the inner crucible (4).

5. The apparatus of claim 3, wherein the apparatus further comprises: the second lifting device (14) comprises a second fixing piece (18) and a second lifting rod (16), the second fixing piece (18) is fixedly installed on the inner wall of the supporting platform (7), the second lifting rod (16) is arranged on the second fixing piece (18), and the second lifting rod (16) penetrates through the connecting plate (6) to be arranged in a gap between the outer crucible (3) and the inner crucible (4).

6. A method for reducing generation of 4H-SiC polytype defects according to any one of claims 1-5, comprising the steps of:

the method comprises the following steps: putting the raw material (5) into an inner crucible (4), sticking the seed crystal (2) on the inner wall of an upper cover (1) of the crucible, putting the inner crucible (4) on a connecting plate (6) and penetrating a threaded rod (11), and sleeving the outer crucible (3) outside the inner crucible (4);

step two: adjusting the height of the induction coil (8) to locate the thermal field at 2/3 height of the induction coil (8);

step three: starting the induction coil (8), raising the temperature of the induction coil (8) to a crystal growth temperature within 4-5 h, wherein the temperature of the seed crystal (2) reaches 2000-2100 ℃, the bottom area of the raw material (5) reaches 2200 ℃, and crystal growth begins;

step four: crystal growth is carried out for 30-40 h, the threaded rod (11) is controlled to rotate to drive the connecting plate (6) to slowly move downwards so as to drive the inner crucible (4) to descend, the speed is kept at 110-179 mu m/h, and meanwhile, the induction coil (8) is controlled to move downwards so as to keep the temperature of a crystal growth interface and a raw material area constant;

step five: after the growth stage is finished, reducing the processing power of the induction coil (8), and enabling the outer crucible (3) and the inner crucible (4) to enter a cooling stage;

step six: and after the outer crucible (3) and the inner crucible (4) are naturally cooled, taking out the crystal.

Technical Field

The invention relates to a crystal growing device and a crystal growing method, in particular to a crystal growing device for 4H-SiC crystals.

Background

At present, a physical vapor transport method (PVT) is a mainstream preparation method of a wide-bandgap semiconductor material, but at present, the problems of poor crystal quality, nonuniform growth, insufficient market demand and the like are caused by the problems of a thermal field and a raw material bearing device, the temperature change at a crystal growth interface is large due to the change of factors such as an induction heating principle, the crystal growth interface and the like, the growth temperature range of 4H-SiC is narrow, the growth interface temperature is slightly higher than the growth temperature of 4H-SiC, 6H-SiC is easy to occur, so that polytype is generated, and crystal grain boundaries and cracks occur due to different crystal orientations of different crystal forms, so that the quality of a grown crystal is influenced;

in view of the foregoing, there is a need for an apparatus and method for preventing polytype crystal growth during the growth of 4H-SiC crystals to solve the above problems.

Disclosure of Invention

The invention solves the problems that the existing crystal growth device for growing 4H-SiC crystals is easy to have various crystal forms and has poor crystal growth quality in the crystal growth process, and further discloses a device and a method for reducing the generation of 4H-SiC polytype defects. The following presents a simplified summary of the invention in order to provide a basic understanding of some aspects of the invention. It should be understood that this summary is not an exhaustive overview of the invention. It is not intended to determine the key or critical elements of the present invention, nor is it intended to limit the scope of the present invention.

The technical scheme of the invention is as follows:

the first scheme is as follows: the utility model provides a reduce device that 4H-SiC polytype defect produced, including crucible upper cover, outer crucible, interior crucible, the connecting plate, a supporting bench, induction coil and quartz capsule, outer crucible sets up at a supporting bench upside, outer crucible endotheca is equipped with interior crucible, be provided with the crucible upper cover on the outer crucible, be provided with the seed crystal on the crucible upper cover inner wall, interior crucible intussuseption is filled with the raw materials, interior crucible sets up on the connecting plate, connecting plate and threaded rod threaded connection, the threaded rod sets up in a supporting bench and passes the connecting plate and be connected with interior crucible, a supporting bench and outer crucible setting are in the quartz capsule, quartz capsule outside is provided with induction coil.

Further, still include the motor, the motor setting is in a supporting bench, and the motor is connected with the one end of threaded rod.

Furthermore, a lifting device is installed on the inner wall of the supporting table and comprises a first lifting device and a second lifting device, and the first lifting device and the second lifting device are respectively connected with the connecting plate.

Furthermore, first elevating gear includes first mounting and first lifter, and first mounting fixed mounting is provided with first lifter on the inner wall of brace table, first lifter, and first lifter passes the connecting plate and sets up the space department of outer crucible and interior crucible.

Furthermore, the second lifting device comprises a second fixing piece and a second lifting rod, the second fixing piece is fixedly installed on the inner wall of the supporting table, the second lifting rod is arranged on the second fixing piece, and the second lifting rod penetrates through the connecting plate and is arranged at the gap between the outer crucible and the inner crucible.

Scheme II: the method for reducing the generation of the 4H-SiC polytype defects based on the first scheme comprises the following steps of:

the method comprises the following steps: putting raw materials into an inner crucible, adhering seed crystals to the inner wall of an upper cover of the crucible, placing the inner crucible on a connecting plate, penetrating a threaded rod, and sleeving an outer crucible outside the inner crucible;

step two: adjusting the height of the induction coil, and positioning the thermal field at 2/3 height of the induction coil;

step three: starting the induction coil, and raising the temperature of the induction coil to the crystal growth temperature within 4-5 h, wherein the temperature of the seed crystal reaches 2000-2100 ℃, the bottom area of the raw material reaches 2200 ℃, and crystal growth begins;

step four: crystal growth is carried out for 30-40 h, the threaded rod is controlled to rotate to drive the connecting plate to move downwards slowly, so that the inner crucible is driven to descend, the speed is kept at 110-179 mu m/h, and meanwhile, the induction coil is controlled to move downwards to keep the temperature of a crystal growth interface and a raw material area constant;

step five: after the growth stage is finished, reducing the processing power of the induction coil, and enabling the outer crucible and the inner crucible to enter a cooling stage;

step six: and after the outer crucible and the inner crucible are naturally cooled, taking out the crystal.

The invention has the beneficial effects that:

1. according to the device and the method for reducing the generation of the 4H-SiC polytype defects, the connecting plate is controlled by the threaded rod to move downwards so as to drive the inner crucible to move downwards, the induction coil synchronously moves downwards along with the inner crucible, the temperature gradient is kept stable, the sublimation speed and the deposition speed of powder can be kept basically consistent, the crystal growth rate is kept stable, and the generation of crystal growth defects can be reduced;

2. the device for reducing the generation of the 4H-SiC polytype defects adopts the matching use of the inner crucible and the outer crucible, the gas growth cavity is arranged in the inner crucible, the outer crucible is hardly contacted with all growth gas, further, the loss of the growth gas to the crucible can be effectively avoided, the heating efficiency of the crucible cannot be influenced, and the crucible is more stable;

3. the device for reducing the generation of the 4H-SiC polytype defects adopts a mode of separating the inner crucible from the outer crucible, and places the raw materials in the inner crucible to ensure that the outer crucible cannot be adhered with the raw materials, so that the investment of crucible consumables can be saved;

4. the device for reducing the generation of the 4H-SiC polytype defects ensures that the connecting plate is more stable and does not generate transverse displacement in the up-and-down moving process through the upgrading device, and improves the stability of the inner crucible in the down-moving process.

Drawings

FIG. 1 is a schematic diagram of the overall structure of an apparatus for reducing the generation of 4H-SiC polytype defects;

figure 2 is a schematic view of the internal structure of the support table.

In the figure, 1-a crucible upper cover, 2-a seed crystal, 3-an outer crucible, 4-an inner crucible, 5-a raw material, 6-a connecting plate, 7-a supporting table, 8-an induction coil, 9-a quartz tube, 10-a motor, 11-a threaded rod, 12-a lifting device, 13-a first lifting device, 14-a second lifting device, 15-a first lifting rod, 16-a second lifting rod, 17-a first fixing part and 18-a second fixing part.

Detailed Description

In order that the objects, aspects and advantages of the invention will become more apparent, the invention will be described by way of example only, and in connection with the accompanying drawings. It should be understood that the description is intended to be exemplary, and not intended to limit the scope of the invention. In the following description, moreover, descriptions of well-known structures and techniques are omitted so as to not unnecessarily obscure the concepts of the present invention.

The first embodiment is as follows: the embodiment is described with reference to fig. 1-2, the device for reducing the generation of 4H-SiC polytype defects of the embodiment comprises a crucible upper cover 1, an outer crucible 3, an inner crucible 4, a connecting plate 6, a supporting plate 7, an induction coil 8 and a quartz tube 9, wherein the outer crucible 3 is arranged on the upper side of the supporting plate 7, the inner crucible 4 is sleeved in the outer crucible 3, the crucible upper cover 1 is arranged on the outer crucible 3, a seed crystal 2 is arranged on the inner wall of the crucible upper cover 1, a raw material 5 is filled in the inner crucible 4, the inner crucible 4 is arranged on the connecting plate 6, the connecting plate 6 is in threaded connection with a threaded rod 11, the threaded rod 11 is arranged in the supporting plate 7 and is connected with the inner crucible 4 through the connecting plate 6, the supporting plate 7 and the outer crucible 3 are arranged in the quartz tube 9, the induction coil 8 is arranged on the outer side of the quartz tube 9, the seed crystal 5 is heated in the inner crucible 4 to form a crystal gas which sublimates to the position 2 to form crystals, in the process of crystal growth, the connecting plate 6 is driven to move downwards by the adjusting threaded rod 11, and meanwhile, the induction coil 8 and the inner crucible 4 synchronously move downwards, so that the temperature gradient is kept stable, and the generation of crystal growth defects is reduced.

The second embodiment is as follows: the embodiment is described with reference to fig. 1-2, and the apparatus for reducing generation of the 4H-SiC polytype defect of the embodiment further includes a motor 10, the motor 10 is disposed in the support table 7, the motor 10 is connected to one end of a threaded rod 11, the threaded rod 11 is driven to rotate by the motor 10, and the threaded rod 11 can also be driven to rotate by a hand wheel or other manners that may occur to those skilled in the art.

The third concrete implementation mode: the embodiment is described with reference to fig. 1-2, and the apparatus for reducing generation of the 4H-SiC polytype defect of the embodiment includes a lifting device 12 mounted on an inner wall of a support table 7, the lifting device 12 includes a first lifting device 13 and a second lifting device 14, the first lifting device 13 and the second lifting device 14 are respectively connected with a connecting plate 6, the first lifting device 13 includes a first fixing member 17 and a first lifting rod 15, the first fixing member 17 is fixedly mounted on the inner wall of the support table 7, the first fixing member 17 is provided with the first lifting rod 15, the first lifting rod 15 passes through the connecting plate 6 and is arranged at a gap between an outer crucible 3 and an inner crucible 4, the second lifting device 14 includes a second fixing member 18 and a second lifting rod 16, the second fixing member 18 is fixedly mounted on the inner wall of the support table 7, the second fixing member 18 is provided with the second lifting rod 16, the second lifting rod 16 penetrates through the connecting plate 6 and is arranged at the gap between the outer crucible 3 and the inner crucible 4, when the threaded rod 11 drives the connecting plate 6 to move up and down, the first lifting rod 15 and the second lifting rod 16 are used for ensuring that the connecting plate 6 cannot generate transverse displacement in the moving process, and the stability of the device in the crystal growing process is improved.

The fourth concrete implementation mode: the present embodiment is described with reference to the first embodiment and the second embodiment, and the method for reducing the generation of 4H — SiC polytype defects of the present embodiment includes the steps of:

the method comprises the following steps: putting the raw material 5 into an inner crucible 4, sticking a seed crystal 2 on the inner wall of an upper cover 1 of the crucible, placing the inner crucible 4 on a connecting plate 6 and penetrating a threaded rod 11, and sleeving an outer crucible 3 outside the inner crucible 4;

step two: adjusting the height of the induction coil 8 to locate the thermal field at 2/3 height of the induction coil 8;

step three: starting the induction coil 8, and raising the temperature of the induction coil 8 to the crystal growth temperature when the induction coil 8 is started for 4-5 hours, wherein the temperature of the seed crystal 2 reaches 2000-2100 ℃, the bottom area of the raw material 5 reaches 2200 ℃, and crystal growth is started;

step four: crystal growth is carried out for 30-40 h, the threaded rod 11 is controlled to rotate to drive the connecting plate 6 to move downwards slowly, so that the inner crucible 4 is driven to descend, the speed is kept at 110-179 mu m/h, and meanwhile, the induction coil 8 is controlled to move downwards to keep the temperature of a crystal growth interface and a raw material area constant;

step five: after the growth phase is finished, the processing power of the induction coil 8 is reduced, and the outer crucible 3 and the inner crucible 4 enter a cooling phase;

step six: after the outer crucible 3 and the inner crucible 4 are naturally cooled, the crystal is taken out.

This embodiment is only illustrative of the patent and does not limit the scope of protection thereof, and those skilled in the art can make modifications to its part without departing from the spirit of the patent.