CN111321461B

CN111321461B - Device for growing high-quality crystal by PVT method

Info

Publication number: CN111321461B
Application number: CN202010217926.1A
Authority: CN
Inventors: 赵丽丽; 袁文博; 张胜涛; 范国峰
Original assignee: Harbin Keyou Semiconductor Industry Equipment and Technology Research Institute Co Ltd
Current assignee: Harbin Keyou Semiconductor Industry Equipment and Technology Research Institute Co Ltd
Priority date: 2020-03-25
Filing date: 2020-03-25
Publication date: 2022-02-08
Anticipated expiration: 2040-03-25
Also published as: CN111321461A

Abstract

The invention relates to a device for growing high-quality crystals by a PVT method, belonging to the technical field of growth of aluminum nitride or silicon carbide crystals. The utilization rate of the raw materials is improved, the component ratio and the pressure in vapor generated by sublimation of the raw materials are ensured, the difficulty in fixing and disassembling the crystal is solved, the generation of internal stress of the crystal is avoided, and the high-quality crystal is obtained. The crucible comprises a crucible body, a bearing tray, a shaft, a filter plate, a crucible cover and a seed crystal support, wherein the seed crystal support is detachably arranged on the upper part of the crucible body; the crucible body includes growth room and powder room, and the growth room is located the upside of powder room, installs the filter in the growth room, and the tray slidable mounting is indoor in the powder, and the upper portion of powder room is the round platform shape.

Description

Device for growing high-quality crystal by PVT method

Technical Field

The invention relates to a device for growing high-quality crystals by a PVT method, belonging to the technical field of growth of aluminum nitride or silicon carbide crystals.

Background

In the process of growing aluminum nitride or silicon carbide crystals by using a PVT method, a heater is needed to heat raw materials in a crucible body, however, in the heating process, the raw materials close to the edge of the crucible body are quickly sublimated under the influence of an axial temperature gradient, the raw materials in the middle are not utilized, and the sublimated vapor of the raw materials is condensed in the middle of a furnace body when reaching the middle of the furnace body, so that the raw materials are wasted and the sublimated vapor of the raw materials reaching seed crystals is not uniform; meanwhile, the raw material is continuously consumed along with the prolonging of the growth time, and the component ratio and the pressure in vapor sublimated from the raw material are seriously imbalanced in the later growth stage, so that the quality of the grown crystal cannot be ensured; in addition, in general, the seed crystal is grown by directly adhering the seed crystal to the adhesive sheet or the crucible cover, such a structure generates severe stress due to the difference in expansion coefficient between the adhesive sheet and the seed crystal during cooling, and it is difficult to separate the crystal from the adhesive sheet after the growth is completed, and even if the crystal is separated by a cutting method, the vibration generated during the cutting process may cause the crystal to be broken, thereby damaging the finished product.

In view of the above problems, it is desirable to provide an apparatus for growing high quality crystals by PVT method to solve the above technical problems.

Disclosure of Invention

The invention provides a device for growing high-quality crystals by a PVT method, which has the advantages of improving the utilization rate of raw materials, ensuring the component ratio and pressure in vapor generated by sublimation of the raw materials, solving the difficulty of fixing and disassembling the crystals, avoiding the generation of internal stress of the crystals and obtaining the high-quality crystals. 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:

a device for growing high-quality crystals by a PVT method comprises a crucible body, a bearing tray, a shaft, a filter plate, a crucible cover and a seed crystal support, wherein the seed crystal support is detachably mounted on the upper part of the crucible body;

the crucible body includes growth room and powder room, and the growth room is located the upside of powder room, installs the filter in the growth room, and the tray slidable mounting is indoor in the powder, and the upper portion of powder room is the round platform shape.

Preferably: the inner wall of the powder chamber is provided with a first limiting groove, and the first limiting groove and the filter plate are installed.

Preferably: the bearing tray comprises a tray body and a connecting cavity, the lower end of the connecting cavity is processed with a connecting cavity thread, the center of the tray body is processed with a guiding through hole, and the connecting cavity and the tray body are fixedly connected with each other coaxially.

Preferably: the shaft is sequentially provided with a solid cylindrical section, a threaded section and a connecting and supporting section, a second limiting pin is processed on the solid cylindrical section, the second limiting pin is installed with the filter plate, the shaft and the tray body are coaxially installed, a guide through hole is processed in the center of the solid cylindrical section and the center of the tray body and is in sliding connection, and the threaded section is connected with the bearing tray through a connecting cavity thread.

Preferably: the filter includes that the outside takes the round pin to support the ring body, branch, porous filter screen and inboard grooved support ring body, the outside takes the round pin to support the ring body and the grooved support ring body coaxial arrangement of inboard side, the outside takes the round pin to support the ring body and the grooved support ring body of inboard side passes through branch fixed connection, fixed mounting has porous filter screen between the outside takes the round pin to support the ring body and the grooved support ring body of inboard side, the outside takes the round pin to support the ring body and can dismantle with first spacing groove and be connected, the outside takes the round pin to support the ring body and radially fixed by first spacing groove, the second spacing pin can dismantle with the grooved support ring body of inboard side, the grooved support ring body of inboard side is through the second spacing pin with the axle radial fixation.

Preferably: the support comprises a first supporting beam, a second supporting beam, a third supporting beam and a mounting plate, the number of the first supporting beam and the number of the second supporting beam are four, the four second supporting beams are fixedly connected into a square, the four first supporting beams are respectively positioned at four corners of the square second supporting beam, the upper portion of the first supporting beam is fixedly connected with the square second supporting beam, the lower portion of the first supporting beam is fixedly connected with the mounting plate, and the crucible body is fixedly connected with the support through the third supporting beam.

Preferably: still include actuating mechanism, actuating mechanism includes step motor, the first free bearing of rotator, the second free bearing, first connecting rod, thrust ball bearing, second connecting rod and first free bearing, step motor and mounting panel fixed connection, step motor's output and rotator fixed connection, the quantity of second free bearing is three, second free bearing circumference array is in the outside of rotator, second free bearing and rotator fixed connection, the lower extreme and the second free bearing of first connecting rod are articulated, the upper end and the second connecting rod of first connecting rod are articulated, the second connecting rod is articulated with first free bearing, the rotator passes through thrust ball bearing and is connected the support section, the quantity of first free bearing is three, first free bearing circumference array fixed mounting is in the downside of tray disk body.

The invention has the following beneficial effects:

1. by changing the volume of the crucible body, the component ratio and the pressure in the vapor of the raw material sublimation are ensured, and the utilization rate of the raw material is improved;

2. the filter plate can filter impurities, improve the purity of crystals, avoid the generation of polycrystal deposited at cold spots around the crucible, and meanwhile, the filter plate can be disassembled, so that the replacement and cleaning are convenient;

3. the upper part of the powder chamber is conical, and the sublimed raw materials are guided in a centralized manner;

4. the upper part of the crucible body is detachably provided with the seed crystal support, and the upper part of the seed crystal support is detachably provided with the crucible cover, so that the crystal is convenient to detach, the generation of internal stress of the crystal is avoided, and the high-quality crystal with smooth surface and low internal stress can be obtained;

5. the powder closer to the edge of the crucible body is faster in sublimation speed under the influence of the radial temperature gradient, the centrifugal force generated by the rotation of the bearing tray enables the powder to move radially, the powder at the edge of the crucible body is supplemented to reduce the influence of the radial temperature gradient on the sublimation speed of the powder, and the shaft can avoid the condensation of the raw material steam generated by the low central temperature of the raw material in the powder chamber.

Drawings

FIG. 1 is a front view of an apparatus for growing high quality crystals by the PVT method;

FIG. 2 is a cross-sectional view of an apparatus for growing high quality crystals by PVT method

FIG. 3 is a close-up view of the body of the crucible;

FIG. 4 is a block diagram of a retainer tray and shaft;

FIG. 5 is a block diagram of a filter plate;

FIG. 6 is a perspective view of an apparatus for growing high quality crystals by the PVT method;

FIG. 7 is a top view of an apparatus for PVT growth of high quality crystals;

FIG. 8 is a structural view of the drive mechanism;

in the figure, 1-a crucible body, 1-1-a growth chamber, 1-2-a powder chamber, 2-a bearing tray, 2-2-a tray body, 2-3-a connecting cavity body, 2-4-a connecting cavity body thread, 3-an axis, 3-1-an axis section, 3-2-a second limit pin, 3-3-a thread section, 3-4-a connecting support section, 4-a filter plate, 4-1-a support ring body with a pin at the outer side, 4-2-a support rod, 4-3-a porous filter screen, 4-4-a support ring body with a groove at the inner side, 5-a support, 5-1-a first support beam, 5-2-a second support beam and 5-3-a third support beam, 5-4-mounting plate, 6-driving mechanism, 6-1-stepping motor, 6-2-rotating body, 6-3-second hinged support, 6-4-first connecting rod, 6-5-thrust ball bearing, 6-6-second connecting rod, 6-7-first hinged support, 7-crucible cover and 8-seed crystal support.

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 is to be understood that such description is merely illustrative and not intended to limit the scope of the present invention. Moreover, in the following description, descriptions of well-known structures and techniques are omitted so as to not unnecessarily obscure the concepts of the present invention.

The connection mentioned in the present invention is divided into a fixed connection and a detachable connection, the fixed connection (i.e. the non-detachable connection) includes but is not limited to a folding connection, a rivet connection, an adhesive connection, a welding connection, and other conventional fixed connection methods, the detachable connection includes but is not limited to a screw connection, a snap connection, a pin connection, a hinge connection, and other conventional detachment methods, when the specific connection method is not clearly defined, the function can be realized by always finding at least one connection method from the existing connection methods by default, and a person skilled in the art can select the connection method according to needs. For example: the fixed connection selects welding connection, and the detachable connection selects hinge connection.

The first embodiment is as follows: the embodiment is described with reference to fig. 1-8, and the device for growing high-quality crystals by the PVT method of the embodiment comprises a crucible body 1, a supporting tray 2, a shaft 3, a filter plate 4, a crucible cover 7 and a seed crystal holder 8, wherein the seed crystal holder 8 is detachably mounted on the upper portion of the crucible body 1, the crucible cover 7 is detachably mounted on the upper portion of the seed crystal holder 8, the filter plate 4 is positioned inside the crucible body 1, the supporting tray 2 is slidably mounted inside the crucible body 1, the shaft 3 penetrates through the supporting tray 2 and is connected with the filter plate 4, the seed crystal holder 8 is used for placing seed crystals, generated crystals are condensed on the seed crystals, the detachment is convenient, the generation of internal stress of the crystals is avoided, and high-quality crystals with flat surfaces and low internal stress can be obtained;

the crucible body 1 comprises a growth chamber 1-1 and a powder chamber 1-2, the growth chamber 1-1 is positioned at the upper side of the powder chamber 1-2, a filter plate 4 is arranged in the growth chamber 1-1, a bearing tray 2 is slidably arranged in the powder chamber 1-2, the upper part of the powder chamber 1-2 is in a round table shape, and sublimed raw materials are guided in a centralized manner.

The second embodiment is as follows: the embodiment is described by combining figures 1 and 3, and the device for growing high-quality crystals by the PVT method of the embodiment is characterized in that a first limiting groove 1-3 is processed on the inner wall of a powder chamber 1-2, and the first limiting groove 1-3 is installed with a filter plate 4.

The third concrete implementation mode: the embodiment is described with reference to fig. 1-4, and the apparatus for growing high quality crystals by the PVT method of the embodiment includes a supporting tray 2 including a tray body 2-2 and a connecting cavity 2-3, a connecting cavity thread 2-4 is processed at the lower end of the connecting cavity 2-3, a guiding through hole is processed at the center of the tray body 2-2, the connecting cavity 2-3 is coaxially and fixedly connected with the tray body 2-2, a guiding through hole is processed at the center of the tray body 2-2, and the connecting cavity 2-3 is coaxially and fixedly connected with the tray body 2-2.

The fourth concrete implementation mode: the device for growing high-quality crystals by the PVT method is described by combining the figures 1, 2, 3, 4, 5 and 8, the device for growing high-quality crystals by the PVT method of the embodiment comprises a solid cylindrical section 3-1, a thread section 3-3 and a connecting and supporting section 3-4 which are sequentially processed on a shaft 3, a second limit pin 3-2 is processed on the solid cylindrical section 3-1, the second limit pin 3-2 is installed with a filter plate 4, the shaft 3 is coaxially installed with a tray body 2-2, a guide through hole is processed in the centers of the solid cylindrical section 3-1 and the tray body 2-2 and is in sliding connection, the thread section 3-3 is connected with the tray 2 through a connecting cavity thread 2-4, the guide through hole in the center of the tray body 2-2 prevents the shaft 3 from inclining, the thread section 3-3 is connected with the tray 2 through a connecting cavity thread 2-4, the shaft section 3-1 can avoid the condensation of raw material steam generated by low temperature of the center of the raw material in the powder chamber.

The fifth concrete implementation mode: referring to fig. 1, 2, 3, 4, 5, 6 and 8, the device for growing high quality crystals by the PVT method according to the present embodiment is described, in which the filter plate 4 includes an outer support ring body with pins 4-1, a support rod 4-2, a porous filter screen 4-3 and an inner support ring body with slots 4-4, the outer support ring body with pins 4-1 and the inner support ring body with slots 4-4 are coaxially installed, the outer support ring body with pins 4-1 and the inner support ring body with slots 4-4 are fixedly connected by the support rod 4-2, the porous filter screen 4-3 is fixedly installed between the outer support ring body with pins 4-1 and the inner support ring body with slots 4-4, the outer support ring body with pins 4-1 is detachably connected with a first limit slot 1-3, the outer support ring body with pins 4-1 is radially fixed by the first limit slot 1-3, the second limiting pin 3-2 is detachably connected with the supporting ring body 4-4 with the inner side provided with the groove, the supporting ring body 4-4 with the inner side provided with the groove radially fixes the shaft 3 through the second limiting pin 3-2, the porous filter screen 4-3 can filter impurities, the crystal purity is improved, polycrystal generation caused by deposition of cold spots around the crucible is avoided, meanwhile, the filter plate can be detached and is convenient to replace and clean, the connecting strength of the supporting ring body 4-1 with the outer side provided with the pin and the supporting ring body 4-4 with the inner side provided with the groove is increased through the support rod 4-2, and meanwhile, the porous filter screen 4-3 is protected.

The sixth specific implementation mode: the device for growing high-quality crystals by the PVT method of the embodiment is described by combining with the figures 1, 2, 3, 6, 7 and 8, and further comprises a support 5, wherein the support 5 comprises a first support beam 5-1, a second support beam 5-2, a third support beam 5-3 and a mounting plate 5-4, the number of the first support beam 5-1 and the second support beam 5-2 is four, the four second support beams 5-2 are fixedly connected into a square, the four first support beams 5-1 are respectively positioned at four corners of the square second support beam 5-2, the upper part of the first support beam 5-1 is fixedly connected with the square second support beam 5-2, the lower part of the first support beam 5-1 is fixedly connected with the mounting plate 5-4, the crucible body 1 is fixedly connected with the support 5 through the third support beam 5-3, the mounting plate 5-4 is used for mounting the driving mechanism 6, meanwhile, the mounting plate 5-4 also increases the supporting strength of the support 5, and the diameter of an inscribed circle formed by fixedly connecting the four second supporting beams 5-2 into a square is larger than the maximum diameter required by the movement of the driving mechanism 6, so that collision is prevented.

The seventh embodiment: the embodiment is described with reference to fig. 1-8, and the apparatus for growing high quality crystals by the PVT method of the embodiment further comprises a driving mechanism 6, wherein the driving mechanism 6 comprises a stepping motor 6-1, a first hinge base 6-2 of a rotating body, a second hinge base 6-3, a first connecting rod 6-4, a thrust ball bearing 6-5, a second connecting rod 6-6 and a first hinge base 6-7, the stepping motor 6-1 is fixedly connected with a mounting plate 5-4, an output end of the stepping motor 6-1 is fixedly connected with the rotating body 6-2, the number of the second hinge bases 6-3 is three, the second hinge bases 6-3 are circumferentially arrayed on the outer side of the rotating body 6-2, the second hinge bases 6-3 are fixedly connected with the rotating body 6-2, a lower end of the first connecting rod 6-4 is hinged with the second hinge bases 6-3, the upper end of the first connecting rod 6-4 is hinged with the second connecting rod 6-6, the second connecting rod 6-6 is hinged with the first hinged support 6-7, the rotating body 6-2 is connected with the connecting support section 3-4 through the thrust ball bearing 6-5, the number of the first hinged supports 6-7 is three, the circumferential array of the first hinged supports 6-7 is fixedly arranged at the lower side of the tray body 2-2, in the process of heating the powder chamber 1-2, due to the influence of radial temperature gradient, the sublimation speed of raw materials at the edge of the powder chamber 1-2 is high, along with the sublimation of the raw materials, the component ratio and the pressure in raw material vapor are changed, the stepping motor 6-1 is started, the stepping motor 6-1 drives the rotating body 6-2 to rotate, the rotating body 6-2 drives the first connecting rod 6-4 to rotate through the second hinged support 6-3, the first connecting rod 6-4 drives the second connecting rod 6-6 to rotate, finally the second connecting rod 6-6 drives the tray body 2-2 to rotate through the first hinge seat 6-7, at the moment, the raw material on the tray body 2-2 moves to the edge of the powder chamber 1-2 under the action of centrifugal force to supplement the raw material at the edge of the powder chamber 1-2, meanwhile, in the process of rotating the tray body 2-2, because the rotating body 6-2 is connected with the connecting support section 3-4 through the thrust ball bearing 6-5, the thrust ball bearing 6-5 axially fixes the shaft 3, the support ring body 4-1 with pins at the outer side is radially fixed by the first limiting groove 1-3, the support ring body 4-4 with grooves at the inner side radially fixes the shaft 3 through the second limiting pin 3-2, the tray body 2-2 drives the connecting cavity 2-3 to rotate, the connection cavity 2-3 drives the connection cavity thread 2-4 to rotate, and the connection angle between the upper end of the first connecting rod 6-4 and the second connecting rod 6-6 is changed, so that the vertical height between the upper end of the first connecting rod 6-4 and the second connecting rod 6-6 is changed, the axial movement of the bearing plate 2 is realized, the volume of the crucible body 1 is changed, the pressure in the crucible body 1 and the component ratio in steam are controlled, and the utilization rate of raw materials is improved.

It should be noted that, in the above embodiments, as long as the technical solutions can be aligned and combined without contradiction, those skilled in the art can exhaust all possibilities according to the mathematical knowledge of the alignment and combination, and therefore, the present invention does not describe the technical solutions after alignment and combination one by one, but it should be understood that the technical solutions after alignment and combination have been disclosed by the present invention.

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.

Claims

1. An apparatus for growing high quality crystal by PVT method is characterized in that: comprises a crucible body (1), a bearing tray (2), a shaft (3), a filter plate (4), a crucible cover (7) and a seed crystal holder (8), wherein the seed crystal holder (8) is detachably arranged on the upper part of the crucible body (1), the crucible cover (7) is detachably arranged on the upper part of the seed crystal holder (8), the filter plate (4) is positioned inside the crucible body (1), the bearing tray (2) is slidably arranged inside the crucible body (1) and comprises a tray body (2-2) and a connecting cavity body (2-3), the shaft (3) penetrates through the bearing tray (2) to be connected with the filter plate (4) and consists of a solid cylindrical section (3-1), a thread section (3-3) and a connecting and supporting section (3-4), the crucible body (1) is fixedly connected with a support (5) through a third supporting beam (5-3), and a mounting plate (5-4) is used for mounting a driving mechanism (6), the support (5) comprises a first support beam (5-1), a second support beam (5-2), a third support beam (5-3) and a mounting plate (5-4);

the crucible body (1) comprises a growth chamber (1-1) and a powder chamber (1-2), the growth chamber (1-1) is positioned at the upper side of the powder chamber (1-2), a filter plate (4) is arranged in the growth chamber (1-1), a bearing plate (2) is slidably arranged in the powder chamber (1-2), and the upper part of the powder chamber (1-2) is in a circular truncated cone shape;

the driving mechanism (6) comprises a stepping motor (6-1), a first hinged support (6-2) of a rotating body, a second hinged support (6-3), a first connecting rod (6-4), a thrust ball bearing (6-5), a second connecting rod (6-6) and a first hinged support (6-7) of the rotating body, wherein the stepping motor (6-1) is fixedly connected with the mounting plate (5-4), the output end of the stepping motor (6-1) is fixedly connected with the rotating body (6-2), the number of the second hinged supports (6-3) is three, the second hinged supports (6-3) are circumferentially arrayed on the outer side of the rotating body (6-2), the second hinged support (6-3) is fixedly connected with the rotating body (6-2), the lower end of the first connecting rod (6-4) is hinged with the second hinged support (6-3), the upper end of the first connecting rod (6-4) is hinged with the second connecting rod (6-6), the second connecting rod (6-6) is hinged with the first hinged support (6-7), the rotating body (6-2) is connected with the connecting and supporting section (3-4) through the thrust ball bearing (6-5), the number of the first hinged supports (6-7) is three, and the first hinged supports (6-7) are fixedly arranged on the lower side of the tray body (2-2) in a circumferential array mode.

2. The device for growing high-quality crystals by the PVT method according to claim 1, wherein: the inner wall of the powder chamber (1-2) is provided with a first limiting groove (1-3), and the first limiting groove (1-3) is installed with the filter plate (4).

3. The device for growing high-quality crystals by the PVT method according to claim 2, wherein: the bearing tray (2) comprises a tray body (2-2) and a connecting cavity (2-3), a connecting cavity thread (2-4) is processed at the lower end of the connecting cavity (2-3), a guide through hole is processed at the center of the tray body (2-2), and the connecting cavity (2-3) and the tray body (2-2) are fixedly connected with each other in the same axis.

4. The device for growing high-quality crystals by the PVT method according to claim 3, wherein: a solid cylindrical section (3-1), a threaded section (3-3) and a connection support section (3-4) are sequentially processed on a shaft (3), a second limiting pin (3-2) is processed on the solid cylindrical section (3-1), the second limiting pin (3-2) is installed with a filter plate (4), the shaft (3) and a tray body (2-2) are coaxially installed, a guide through hole is processed in the centers of the solid cylindrical section (3-1) and the tray body (2-2) in a sliding connection mode, and the threaded section (3-3) is connected with a bearing tray (2) through a connection cavity thread (2-4).

5. The device for growing high-quality crystals by the PVT method according to claim 4, wherein: the filter plate (4) comprises an outer side pin-bearing support ring body (4-1), a support rod (4-2), a porous filter screen (4-3) and an inner side grooved support ring body (4-4), the outer side pin-bearing support ring body (4-1) and the inner side grooved support ring body (4-4) are coaxially arranged, the outer side pin-bearing support ring body (4-1) and the inner side grooved support ring body (4-4) are fixedly connected through the support rod (4-2), the porous filter screen (4-3) is fixedly arranged between the outer side pin-bearing support ring body (4-1) and the inner side grooved support ring body (4-4), the outer side pin-bearing support ring body (4-1) is detachably connected with the first limit groove (1-3), the outer side pin-bearing support ring body (4-1) is radially fixed by the first limit groove (1-3), the second limiting pin (3-2) is detachably connected with the supporting ring body (4-4) with the groove at the inner side, and the supporting ring body (4-4) with the groove at the inner side radially fixes the shaft (3) through the second limiting pin (3-2).

6. The device for growing high-quality crystals by the PVT method according to claim 4, wherein: also comprises a bracket (5), the bracket (5) comprises a first supporting beam (5-1) and a second supporting beam (5-2), the crucible comprises a third supporting beam (5-3) and a mounting plate (5-4), the number of the first supporting beam (5-1) and the number of the second supporting beam (5-2) are four respectively, the four second supporting beams (5-2) are fixedly connected into a square, the four first supporting beams (5-1) are respectively positioned at four corners of the square second supporting beam (5-2), the upper part of the first supporting beam (5-1) is fixedly connected with the square second supporting beam (5-2), the lower part of the first supporting beam (5-1) is fixedly connected with the mounting plate (5-4), and the crucible body (1) is fixedly connected with the support (5) through the third supporting beam (5-3).