Device for inhibiting shrinkage of casting method gallium oxide single crystal growth crucible

Abstract

The utility model discloses a device for inhibiting shrinkage of a casting method gallium oxide single crystal growth crucible, which relates to the technical field of single crystal growth equipment, and comprises a crucible opening anti-shrinkage ring, the outer side wall of the crucible opening anti-shrinkage ring is an inverted conical surface, and the crucible opening anti-shrinkage ring is arranged at the top end of the crucible and abuts against the inner wall; the crucible bottom anti-shrinkage mechanism comprises a center cushion block, a fixed block, a movable block and the like, and cooperation is achieved through the design of a specific inclined face, a tooth-shaped structure, a pin groove and the like. The device effectively inhibits shrinkage from the top and the bottom of the crucible, prevents the crystal from cracking due to the shrinkage of the crucible, can obviously improve the crystal quality and the crystal forming rate, provides a higher-quality material basis for the application of the gallium oxide single crystal in multiple fields, and has important practical value.

Description

Technical Field

[0001] The utility model relates to the technical field of single crystal growth equipment, in particular to a device for suppressing the shrinkage of a crucible for growing gallium oxide single crystals using a casting method. Background Art

[0002] Semiconductor materials are the cornerstone of the semiconductor industry. Gallium oxide, a new-generation ultra-wide bandgap semiconductor material, boasts numerous significant advantages, including a wide bandgap, high breakdown electric field strength (up to 8 MV / cm), a high Baliga quality factor, and stable physical and chemical properties. These advantages have enabled gallium oxide to demonstrate significant application value in a wide range of fields, including power devices, optoelectronic devices, and sensors, and has become a key alternative to wide-bandgap semiconductor materials such as silicon carbide and gallium nitride.

[0003] Invention patent CN114561701A proposes a method for growing gallium oxide single crystals by casting, which mainly includes a heating and material processing process and a cooling process. The casting method has many advantages in the mass production of gallium oxide single crystal substrates: In terms of size: it is easy to obtain large-sized gallium oxide single crystals, and they can be further processed to obtain large-sized single crystal substrates with different crystal planes. In terms of process simplification: the growth of gallium oxide single crystals is spontaneous nucleation, and there is no need to introduce and use single crystal seed crystals, which greatly simplifies the crystal growth process, effectively reduces the process difficulty and improves the process efficiency. In terms of crystal quality and process simplification: the crystal is located in the crucible, and the thermal stress is small due to the small temperature gradient. No additional annealing treatment is required, which further simplifies the process flow while ensuring the crystal quality. In terms of crucible protection: it can overcome the problem of volatilization and decomposition of gallium oxide melt, reducing corrosion and loss to the crucible.

[0004] However, during the casting method for growing gallium oxide single crystals, particularly during the second cooling step, a problem seriously affects crystal quality and yield. Because the iridium crucible has a greater coefficient of thermal expansion than the gallium oxide crystal, it contracts during cooling, squeezing the crystal. This leads to excessive stress in the crystal, which in turn increases defect density and can even cause cracking. This has a severe negative impact on crystal quality and significantly reduces the yield. Utility Model Content

[0005] The purpose of the utility model is to provide a device for suppressing the shrinkage of a crucible for growing gallium oxide single crystals by a casting method, so as to solve the problems existing in the above-mentioned prior art, suppress the shrinkage of the crucible during the single crystal growth process, and avoid the crystal cracking caused by the shrinkage of the crucible.

[0006] To achieve the above purpose, the present invention provides the following solutions:

[0007] The utility model provides a device for suppressing the shrinkage of a crucible for growing gallium oxide single crystals by a casting method, comprising:

[0008] A crucible mouth anti-shrinkage ring, wherein the outer side wall of the crucible mouth anti-shrinkage ring is an inverted cone surface, and the crucible mouth anti-shrinkage ring is used to be arranged on the top of the crucible, and the inner wall of the top of the crucible abuts against the outer side wall of the crucible mouth anti-shrinkage ring;

[0009] The crucible bottom anti-shrinkage mechanism comprises a central pad, multiple fixed blocks and multiple movable blocks, the central pad is in the shape of a regular polygonal column, the side walls of the central pad, the fixed blocks, the movable blocks and the pins at the bottom end of the crucible correspond one to one; one side of the fixed block is tightly attached to the corresponding side wall on the central pad, the top surface of the fixed block is an inclined surface, and the top surface of the fixed block gradually moves away from the central pad from top to bottom, the bottom surface of the movable block is an inclined surface, and the bottom surface of the movable block gradually moves away from the central pad from top to bottom, and the bottom surface of the movable block abuts against the top surface of the corresponding fixed block; a pin groove for placing the corresponding pin is provided on the movable block, and the size of the pin groove is the same as the size of the pin.

[0010] Preferably, the outer side wall of the crucible mouth anti-shrinkage ring has a plurality of continuous first steps, wherein the first step is an annular surface extending along the axial direction of the crucible mouth anti-shrinkage ring, and two adjacent first steps are connected by a first connecting surface, which is an annular surface extending along the radial direction of the crucible mouth anti-shrinkage ring, and the first step and the first connecting surface are both coaxial with the crucible mouth anti-shrinkage ring;

[0011] An inner wall of the top end of the crucible abuts against one of the first steps.

[0012] Preferably, the top surface of the fixed block has a plurality of continuous second steps, the second steps are vertical surfaces, and two adjacent second step surfaces are connected by a second connecting surface, and the second connecting surface is a horizontal surface; the bottom surface of the movable block has a plurality of continuous third steps, the third steps are vertical surfaces, and two adjacent third step surfaces are connected by a third connecting surface, and the third connecting surface is a horizontal surface;

[0013] All the second steps and the second connecting surface constitute a first tooth structure, all the third steps and the third connecting surface constitute a second tooth structure, and the second tooth structure on the movable block is engaged with the first tooth structure on the corresponding fixed block.

[0014] Preferably, the thickness of the central pad is greater than the thickness of the movable block.

[0015] Preferably, the side wall of the central pad, the fixed block, the movable block and the bottom end of the crucible all have 8 pins.

[0016] Preferably, the thermal expansion coefficients of the materials of the crucible mouth anti-shrinkage ring, the central spacer, the fixed block and the movable block are all smaller than the thermal expansion coefficient of iridium.

[0017] Preferably, the inner diameter of the crucible mouth anti-shrinkage ring is smaller than the inner diameter of the crucible, and the outer diameter is larger than the outer diameter of the crucible; and the number of the first steps is at least two.

[0018] Preferably, the pins are slidably engaged with the corresponding pin slots.

[0019] Preferably, the central spacer needs to be placed coaxially with the crucible.

[0020] Preferably, the width of the side wall of the central pad is greater than the width of the corresponding fixing block.

[0021] Compared with the prior art, the utility model has achieved the following technical effects:

[0022] The device for suppressing the shrinkage of a crucible for growing gallium oxide single crystals by a casting method of the utility model can suppress the radial shrinkage of the crucible mouth and the crucible bottom surface, thereby reducing the stress generated by the crucible wall squeezing the crystal, reducing the crystal defect density and cracking probability, and improving the crystal quality and crystal formation rate.

[0023] Furthermore, the casting method for growing gallium oxide single crystals uses induction heating, with the crucible wall serving as the primary heating element. Crucible shrinkage can cause the crucible wall to bend laterally, changing the induced heat distribution on the crucible wall and, in turn, the melt temperature distribution within the crucible, making the crystal growth process uncontrollable. The present invention can suppress crucible shrinkage, avoiding temperature changes caused by crucible wall bending, and enhancing the controllability of crystal growth.

[0024] Furthermore, the outer wall of the crucible mouth anti-shrinkage ring is an inverted cone, which is located at the top of the crucible and abuts the inner wall of the crucible top. This structure ensures that when the crucible tends to shrink, the crucible mouth anti-shrinkage ring can, through its close abutment with the inner wall of the crucible top, hinder the shrinkage of the crucible mouth, effectively suppressing the occurrence of shrinkage from the top of the crucible.

[0025] The outer wall of the crucible mouth anti-shrinkage ring has multiple continuous first steps and a first connecting surface connecting adjacent steps. The inner wall of the crucible top can abut against one of the first steps. This design not only increases the stability of the contact between the crucible mouth anti-shrinkage ring and the inner wall of the crucible top, but also better adapts to changes in the crucible top's size under different working conditions, further ensuring the effective implementation of the anti-shrinkage function.

[0026] Furthermore, the crucible bottom anti-shrinkage mechanism consists of a central pad, multiple fixed blocks, and multiple movable blocks, with each component achieving synergy through a specific structural design. One side of the fixed block abuts against the sidewall of the central pad, with its top surface being inclined and the bottom surface of the movable block also being inclined, and they abut against each other. The movable block is also provided with a pin slot for receiving the pins at the bottom of the crucible, and the two slide together. When the crucible tends to shrink, this structure can effectively disperse the stress generated by the shrinkage of the crucible bottom through the relative sliding and supporting relationship between the various components, preventing the squeeze of the crystal due to the shrinkage of the crucible bottom.

[0027] Furthermore, the second step on the top surface of the fixed block and the connecting surface form a first tooth-like structure, while the third step on the bottom surface of the movable block and the connecting surface form a second tooth-like structure, and the two mesh with each other. This tooth-like structure design makes the connection between the fixed block and the movable block more stable, and can more evenly distribute the force when subjected to the shrinkage stress of the crucible bottom, further enhancing the crucible bottom anti-shrinkage mechanism's ability to suppress crucible shrinkage.

[0028] This utility model effectively suppresses crucible shrinkage at two key locations: the top and bottom of the crucible, through the coordinated cooperation of the crucible mouth anti-shrinkage ring and the crucible bottom anti-shrinkage mechanism. Compared to existing technologies that fail to effectively address crucible shrinkage, this comprehensive suppression measure significantly reduces the adverse effects of crucible shrinkage on crystal growth, thereby significantly improving crystal quality and crystallization rate. This provides a higher-quality crystal material foundation for the further application of gallium oxide single crystals in power devices, optoelectronic devices, sensors, and other fields, and has important practical application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0030] Figure 1 This is a schematic structural diagram of a device for suppressing crucible shrinkage in a casting method for growing gallium oxide single crystals according to the present invention;

[0031] Figure 2 A perspective view of the crucible mouth anti-shrinkage ring in the present invention;

[0032] Figure 3 This is a bottom view of the crucible in the present invention;

[0033] Figure 4 This is a bottom view of the crucible bottom anti-shrinkage mechanism in the present invention;

[0034] Figure 5 This is a partial structural diagram of a device for suppressing crucible shrinkage in a casting method for growing gallium oxide single crystals according to the present invention;

[0035] In the figure: 1. Crucible mouth anti-shrinkage ring; 2. Crucible; 3. Movable block; 4. Fixed block; 5. Center pad; 6. Pin; 7. Pin slot. DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0037] The purpose of the utility model is to provide a device for suppressing the shrinkage of a crucible for growing gallium oxide single crystals by a casting method, so as to solve the problems existing in the above-mentioned prior art, suppress the shrinkage of the crucible during the single crystal growth process, and avoid the crystal cracking caused by the shrinkage of the crucible.

[0038] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0039] like Figures 1 to 5 As shown, this embodiment provides a device for suppressing the shrinkage of a crucible for growing gallium oxide single crystals by a casting method, comprising:

[0040] The crucible mouth anti-shrinkage ring 1 has an outer wall formed into an inverted cone. The ring is used to be installed at the top of the crucible 2, and the inner wall of the top of the crucible 2 abuts the outer wall of the crucible mouth anti-shrinkage ring 1. The outer wall of the crucible mouth anti-shrinkage ring 1 has an inverted cone. It is installed at the top of the crucible 2 and abuts the inner wall of the top of the crucible 2. This structure ensures that when the crucible 2 shows a tendency to shrink, the crucible mouth anti-shrinkage ring 1 can, by virtue of its close abutment with the inner wall of the top of the crucible 2, hinder the shrinkage of the crucible 2 mouth, effectively suppressing the occurrence of shrinkage from the top of the crucible 2.

[0041] The crucible bottom anti-shrinkage mechanism includes a central pad 5, multiple fixed blocks 4, and multiple movable blocks 3. The central pad 5 is in the shape of a regular polygonal column. The side walls of the central pad 5, the fixed blocks 4, the movable blocks 3, and the pins 6 at the bottom of the crucible 2 correspond one to one. One side of the fixed block 4 is in close contact with the corresponding side wall on the central pad 5. The top surface of the fixed block 4 is an inclined surface, and the top surface of the fixed block 4 gradually moves away from the central pad 5 from top to bottom. The bottom surface of the movable block 3 is an inclined surface, and the bottom surface of the movable block 3 gradually moves away from the central pad 5 from top to bottom. The bottom surface of the movable block 3 abuts against the top surface of the corresponding fixed block 4. The movable block 3 is provided with a pin groove 7 for placing the corresponding pin 6. The size of the pin groove 7 is the same as the size of the pin 6. The crucible bottom anti-shrinkage mechanism consists of a central pad 5, multiple fixed blocks 4, and multiple movable blocks 3. The various components achieve synergy through a specific structural design. One side of the fixed block 4 rests against the sidewall of the central spacer 5. Its top surface is inclined, and the bottom surface of the movable block 3 is also inclined, abutting each other. The movable block 3 is also provided with a pin slot 7 for receiving a pin 6 at the bottom of the crucible 2, and the two slide together. When the crucible 2 tends to shrink, this structure effectively dissipates the stress generated by the bottom of the crucible 2 through the relative sliding and supporting relationship between the various components, preventing the shrinkage of the crucible 2 from squeezing the crystal.

[0042] This embodiment effectively suppresses crucible 2 shrinkage at two key locations: the top and bottom of the crucible 2, through the coordinated cooperation of the crucible mouth anti-shrinkage ring 1 and the crucible bottom anti-shrinkage mechanism. Compared to the prior art, which did not take effective measures to address crucible 2 shrinkage, this comprehensive suppression measure significantly reduces the adverse effects of crucible 2 shrinkage during crystal growth, thereby significantly improving crystal quality and crystallization rate. This provides a higher-quality crystal material foundation for the further application of gallium oxide single crystals in power devices, optoelectronic devices, sensors, and other fields, and has important practical application value.

[0043] In the optional scheme of this embodiment, it is more preferred that the outer side wall of the crucible mouth anti-shrinkage ring 1 has multiple continuous first steps, the first step is an annular surface extending axially along the crucible mouth anti-shrinkage ring 1, and two adjacent first steps are connected by a first connecting surface, the first connecting surface is an annular surface extending radially along the crucible mouth anti-shrinkage ring, and the first step and the first connecting surface are coaxial with the crucible mouth anti-shrinkage ring 1; the inner wall of the top end of the crucible 2 abuts against one of the first steps; such a design not only increases the stability of the contact between the crucible mouth anti-shrinkage ring 1 and the inner wall of the top end of the crucible 2, but also can better adapt to the size changes of the top end of the crucible 2 under different working conditions, and further ensures the effective realization of the anti-shrinkage function.

[0044] In an optional solution of this embodiment, it is more preferred that the top surface of the fixed block 4 has a plurality of continuous second steps, the second steps are vertical surfaces, and two adjacent second step surfaces are connected by a second connecting surface, and the second connecting surface is a horizontal surface; the bottom surface of the movable block 3 has a plurality of continuous third steps, the third steps are vertical surfaces, and two adjacent third step surfaces are connected by a third connecting surface, and the third connecting surface is a horizontal surface;

[0045] The entire second step and the second connecting surface form a first tooth structure, while the entire third step and the third connecting surface form a second tooth structure. The second tooth structure on the movable block 3 meshes with the corresponding first tooth structure on the fixed block 4. This tooth structure design strengthens the connection between the fixed block 4 and the movable block 3, more evenly distributing the force when subjected to the contraction stress of the bottom of the crucible 2, and further enhancing the crucible bottom anti-contraction mechanism's ability to suppress crucible 2 contraction. Furthermore, this tooth structure allows the movable block 3 to move outward via the pins 6 when the crucible 2 expands due to heat, without affecting the expansion of the crucible 2.

[0046] In the optional scheme of this embodiment, it is more preferred that the thickness of the central pad 5 is greater than the thickness of the movable block 3. In the overall structure of the crucible bottom anti-shrinkage mechanism, the central pad 5 plays a key supporting role. Its thickness is greater than the thickness of the movable block 3, which means that it has a larger size and mass distribution in the vertical direction. When the crucible 2 shows a shrinkage trend and exerts pressure on the bottom, the thicker central pad 5 can rely on its own greater mass and structural strength to more effectively withstand the pressure from above, providing a more stable support foundation for the entire crucible bottom anti-shrinkage mechanism. Just like when building a house, a thicker foundation can better bear the weight of the building, the central pad 5, with its greater thickness, ensures that it will not easily deform or shift when responding to the shrinkage pressure of the crucible 2, thereby ensuring the stability and reliability of the entire anti-shrinkage mechanism.

[0047] In this embodiment, the side walls of the center pad 5, the fixed block 4, the movable block 3 and the pins 6 at the bottom of the crucible 2 are all 8; the inner diameter of the crucible mouth anti-shrinkage ring 1 is smaller than the inner diameter of the crucible 2, and the outer diameter is larger than the outer diameter of the crucible 2, and the number of the first steps is 8; the pins 6 slide in conjunction with the corresponding pin grooves 7; the center pad 5 needs to be placed coaxially with the crucible 2.

[0048] Among the optional solutions of this embodiment, the crucible 2 and pins 6 are preferably made of iridium. The crucible mouth anti-shrinkage ring 1, center pad 5, fixed block 4, and movable block 3 all have a lower thermal expansion coefficient than iridium, such as sapphire or zirconium oxide. The materials of the crucible mouth anti-shrinkage ring 1, center pad 5, fixed block 4, and movable block 3 are required to have a melting point higher than that of gallium oxide (1800°C), be non-reactive with oxygen within the operating temperature range, and have a lower thermal expansion coefficient than the crucible material (e.g., 6.4×10-6 / °C, the thermal expansion coefficient of iridium metal). Only when the materials of the crucible mouth anti-shrinkage ring 1, center pad 5, fixed block 4, and movable block 3 have a lower thermal expansion coefficient than iridium and shrink less than iridium can the iridium crucible be prevented from shrinking and deforming.

[0049] In the optional scheme of this embodiment, it is more preferred that the width of the side wall of the center pad 5 is greater than the width of the corresponding fixed block 4. In the layout of the crucible bottom anti-contraction mechanism, the center pad 5 is in the core support position. When the crucible 2 shows a tendency to shrink and generates lateral pressure, the wider side wall of the center pad 5 means that it has a larger size and mass distribution in the horizontal direction, and can more effectively withstand the lateral pressure from the bottom of the crucible 2. This more reliable lateral support is like using thicker columns to resist lateral wind or other external forces when building a building frame, ensuring that the entire crucible bottom anti-contraction mechanism will not easily deform or shift when facing the lateral force that may be caused by the contraction of the crucible 2, thereby enhancing the stability of the entire structure. The wider side wall of the center pad 5 can distribute the lateral pressure from the bottom of the crucible 2 more evenly to its various parts. Compared to the narrower fixed block 4, the central pad 5, with its wider sidewalls, can absorb and handle lateral pressure over a larger area, distributing the pressure more evenly before transmitting it to other components (such as the fixed block 4 and movable block 3). This helps prevent excessive lateral pressure on the fixed block 4 or other related components, which could lead to damage or failure, due to lateral force being concentrated in a single area, thereby ensuring the effectiveness of the coordinated operation of the entire anti-collapse mechanism.

[0050] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. A device for suppressing the shrinkage of a crucible for growing gallium oxide single crystals by a casting method, characterized in that: include: A crucible mouth anti-shrinkage ring, wherein the outer side wall of the crucible mouth anti-shrinkage ring is an inverted cone surface, and the crucible mouth anti-shrinkage ring is used to be arranged on the top of the crucible, and the inner wall of the top of the crucible abuts against the outer side wall of the crucible mouth anti-shrinkage ring; The crucible bottom anti-shrinkage mechanism comprises a central pad, multiple fixed blocks and multiple movable blocks, the central pad is in the shape of a regular polygonal column, the side walls of the central pad, the fixed blocks, the movable blocks and the pins at the bottom end of the crucible correspond one to one; one side of the fixed block is tightly attached to the corresponding side wall on the central pad, the top surface of the fixed block is an inclined surface, and the top surface of the fixed block gradually moves away from the central pad from top to bottom, the bottom surface of the movable block is an inclined surface, and the bottom surface of the movable block gradually moves away from the central pad from top to bottom, and the bottom surface of the movable block abuts against the top surface of the corresponding fixed block; a pin groove for placing the corresponding pin is provided on the movable block, and the size of the pin groove is the same as the size of the pin.

2. The device for suppressing crucible shrinkage during growth of gallium oxide single crystals by casting method according to claim 1, characterized in that: The outer side wall of the crucible mouth anti-shrinkage ring has a plurality of continuous first steps, wherein the first steps are annular surfaces extending along the axial direction of the crucible mouth anti-shrinkage ring, and two adjacent first steps are connected by a first connecting surface, which is an annular surface extending along the radial direction of the crucible mouth anti-shrinkage ring, and the first steps and the first connecting surface are coaxial with the crucible mouth anti-shrinkage ring; An inner wall of the top end of the crucible abuts against one of the first steps.

3. The device for suppressing crucible shrinkage during growth of gallium oxide single crystals by casting method according to claim 1, characterized in that: The top surface of the fixed block has a plurality of continuous second steps, the second steps are vertical surfaces, and two adjacent second step surfaces are connected by a second connecting surface, and the second connecting surface is a horizontal surface; the bottom surface of the movable block has a plurality of continuous third steps, the third steps are vertical surfaces, and two adjacent third step surfaces are connected by a third connecting surface, and the third connecting surface is a horizontal surface; All the second steps and the second connecting surface constitute a first tooth structure, all the third steps and the third connecting surface constitute a second tooth structure, and the second tooth structure on the movable block is engaged with the first tooth structure on the corresponding fixed block.

4. The device for suppressing crucible shrinkage during growth of gallium oxide single crystals by casting method according to claim 1, characterized in that: The thickness of the central pad is greater than the thickness of the movable block.

5. The device for suppressing crucible shrinkage during growth of gallium oxide single crystals by casting method according to claim 1, characterized in that: The side wall of the central pad, the fixed block, the movable block and the bottom end of the crucible are all provided with 8 pins.

6. The device for suppressing crucible shrinkage during growth of gallium oxide single crystals by casting method according to claim 1, characterized in that: The thermal expansion coefficients of the materials of the crucible mouth anti-shrinkage ring, the central pad, the fixed block and the movable block are all smaller than the thermal expansion coefficient of iridium.

7. The device for suppressing crucible shrinkage during growth of gallium oxide single crystals by casting method according to claim 2, characterized in that: The inner diameter of the crucible mouth anti-shrinkage ring is smaller than the inner diameter of the crucible, and the outer diameter is larger than the outer diameter of the crucible.

8. The device for suppressing crucible shrinkage during growth of gallium oxide single crystals by casting method according to claim 1, characterized in that: The pins are slidably matched with the corresponding pin slots.

9. The device for suppressing crucible shrinkage during growth of gallium oxide single crystals by casting method according to claim 1, characterized in that: The central spacer needs to be placed coaxially with the crucible.

10. The device for suppressing crucible shrinkage during growth of gallium oxide single crystals by casting method according to claim 1, characterized in that: The width of the side wall of the central pad is greater than the width of the corresponding fixing block.

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