Device for growing multiple silicon carbide crystals by liquid phase method
By employing a multi-zone heating design and an independently controlled liquid pipeline system in the apparatus for growing silicon carbide crystals using the liquid phase method, the crystal quality problems caused by temperature differences and mechanical stress during the liquid phase growth process were solved, and the efficient and stable growth of multiple silicon carbide single crystals was achieved.
Patent Information
- Application Number
- CN202520488239.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-20
- Publication Date
- 2026-02-03
- Estimated Expiration
- 2035-03-20
AI Technical Summary
During the liquid phase growth of silicon carbide crystals, poor crystal growth quality and defects are caused by changes in the liquid surface position due to temperature differences within the crucible, uneven consumption of carbon source, and the influence of mechanical stress.
The system employs a multi-zone heating design and an independently controlled liquid piping system, combined with a drive mechanism and support columns, to ensure the uniform growth of multiple seed crystals within the graphite crucible. The temperature field and raw material supply are controlled by independent heating coils, avoiding competition between adjacent seed crystals and mechanical stress.
This method enables the simultaneous high-quality growth of multiple silicon carbide single crystals, maintains a stable solid-liquid interface, reduces crystal defects, and improves growth efficiency and crystal quality.
Smart Images
Figure CN223866825U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of silicon carbide crystal growth technology, specifically to an apparatus for growing multiple silicon carbide crystals using a liquid phase method. Background Technology
[0002] Silicon carbide has a larger band gap than silicon; silicon carbide single crystals have excellent physical properties, relatively high thermal and chemical stability, and strong radiation resistance, excellent mechanical strength, higher breakdown voltage and thermal conductivity, etc. As a new generation of semiconductor materials, researchers' expectations for high-quality single crystals are constantly increasing.
[0003] Liquid phase method is one of the important methods for growing silicon carbide single crystals. SiC single crystals grown by liquid phase method have advantages such as low dislocation density, lower growth temperature, favorable p-type doping and easy diameter expansion, making it a very promising SiC growth method.
[0004] However, the growth of silicon carbide in the liquid phase is affected by the temperature difference within the crucible. This is due to the skin effect, where the solution temperature is highest at the crucible wall, where solute dissolution occurs. As the flux solution melts the crucible wall and consumes silicon and carbon in the solution during growth, this process directly leads to changes in the composition and total amount of flux solution. The decrease in the liquid level causes changes in the temperature at the seed crystal, the carbon saturation, and the growth rate. The temperature field within the solution changes, and the dynamic equilibrium is disrupted. Spontaneous nucleation at the liquid surface leads to polycrystalline growth, affecting the quality of silicon carbide single crystal growth.
[0005] 1. Due to the temperature difference inside the crucible, the liquid level continuously decreases during the liquid phase growth process, causing the temperature field at the solid-liquid interface to deviate significantly from the initial design, making it difficult to maintain the concave meniscus morphology throughout the crystal growth process.
[0006] 2. During the growth process, the graphite crucible serves as the carbon source. The limited carbon source greatly restricts the simultaneous growth of multiple crystals. At the same time, the continuous dissolution and consumption of the carbon source causes changes in the geometry of the crucible, which not only affects the carbon dissolution rate but also alters the thermal and flow fields of the solution, thereby affecting the transport of carbon to the growth interface.
[0007] 3. During the growth of silicon carbide crystals, the seed crystal is usually fixed to the top of the growth crucible by an adhesive or a seed crystal clamp. This applied external force will cause stress in the silicon carbide seed crystal, which will eventually lead to defects in the silicon carbide crystal, thus affecting the quality of the silicon carbide crystal.
[0008] Therefore, there is an urgent need for a suitable growth device to achieve simultaneous liquid-phase Czochralski growth of multiple silicon carbide structures with concave meniscus morphology and high quality. Utility Model Content
[0009] This invention overcomes the shortcomings of the prior art and proposes an apparatus for growing multiple silicon carbide crystals by liquid phase method;
[0010] This utility model is achieved through the following technical solution:
[0011] An apparatus for growing multiple silicon carbide crystals using a liquid-phase method includes a reaction vessel; the reaction vessel is provided with a first cover plate, a second cover plate, a third cover plate, and a fourth cover plate arranged from top to bottom; an auxiliary powder material zone is formed between the first and second cover plates, a cavity is formed between the second and third cover plates, and a main powder material zone is formed between the third and fourth cover plates; a liquid pipe is connected between the second and third cover plates, connecting the auxiliary powder material zone and the main powder material zone; a one-way valve is provided on the liquid pipe; multiple seed crystal support plates are slidably connected to the fourth cover plate; a first heating coil is provided outside the auxiliary powder material zone, a second heating coil is provided outside the main powder material zone, and a third heating coil is provided outside the seed crystal support plates.
[0012] Furthermore, a plurality of crystal lifting cylinders are provided below the fourth cover plate, and a seed crystal support plate is slidably connected inside each crystal lifting cylinder.
[0013] Furthermore, a third heating coil is installed on the outside of each crystal lifting tube.
[0014] Furthermore, each seed crystal support plate is connected to a crystal lifting motor at its bottom.
[0015] Furthermore, multiple seed crystal support plates are evenly distributed around the center of the fourth cover plate.
[0016] Furthermore, multiple liquid channels are evenly arranged around each seed crystal support plate, with the inlet of the liquid channels located above the seed crystal support plate.
[0017] Furthermore, the first cover plate is provided with a connection hole, and a drive motor is provided at the connection hole.
[0018] The beneficial effects of this utility model compared to the prior art are as follows:
[0019] First, this utility model's technical solution utilizes a special structural design to effectively solve the problem of "competition" and insufficient liquid carbon between adjacent seed crystals that may occur during the simultaneous growth of multiple silicon carbide single crystals. By using multiple seed crystals within the same graphite crucible, and simultaneously placing raw materials in the main chamber at the bottom and the auxiliary chamber at the top of the graphite crucible, the silicon carbide single crystals on the multiple seed crystal holders in the main chamber can obtain sufficient and controllable liquid carbon and silicon, fully meeting the requirements for the simultaneous normal growth of multiple silicon carbide single crystals.
[0020] Secondly, this utility model also employs an independent heating component design for different locations, making the adjustment of the growth atmosphere precise and controllable. The three sets of heating coils are each connected to their own independent power supply, ensuring no interference between them. The first heating coil set heats the source material in the auxiliary chamber, while the second heating coil set heats the raw material in the main chamber. The raw material required for the growth of silicon carbide single crystals on the seed crystal holder is mainly obtained by sublimation of silicon carbide source powder in the main chamber. By adjusting the power of the second heating coil set, the heating temperature and rate of the silicon carbide auxiliary material in the second auxiliary material tank can be controlled, thereby controlling and replenishing the liquid phase raw material required between different seed crystal holders. This effectively solves the crystal defects that may result from competition between adjacent seed crystals. The third heating coil set, in conjunction with the second heating coil set, can adjust the temperature field of the solid-liquid surface to achieve a concave meniscus crystal morphology.
[0021] Third, the technical solution of this utility model allows for easier adjustment of the growth atmosphere and is more suitable for the simultaneous growth of multiple silicon carbide single crystals. The design of the driving mechanism and support pillars allows the seed crystal holder to move up and down within the graphite crucible, thus ensuring that the relative position of the solid-liquid interface and the growth container remains unchanged throughout the growth process, thereby helping to maintain the temperature field of the meniscus throughout the crystal growth process.
[0022] Fourth, in this invention, when the seed crystal is located at the bottom of the crucible, there is no need to fix the seed crystal with an adhesive or seed crystal clamp, thereby reducing the mechanical stress caused by material thermal mismatch during the heating and cooling process and growing high-quality crystals. Attached Figure Description
[0023] Figure 1 This is a schematic diagram of the overall structure of an embodiment of the present utility model;
[0024] Figure 2 This is a top view of the first cover plate in the embodiment;
[0025] Figure 3 This is a structural diagram showing the arrangement of liquid pipes on the second cover plate in an embodiment.
[0026] Figure 4 This is a top view of the fourth cover plate in the embodiment;
[0027] Figure 5 This is a schematic diagram of the one-way valve in an embodiment;
[0028] Wherein: 1 is the drive motor; 2 is the first cover plate; 3 is the reaction vessel; 401 is the second cover plate; 402 is the third cover plate; 5 is the liquid pipeline; 6 is the fourth cover plate; 7 is the seed crystal support plate; 8 is the crystal lifting motor; 901 is the first heating coil; 902 is the second heating coil; 903 is the third heating coil; 10 is the crystal lifting cylinder; 11 is the one-way valve; 12 is the graphite block; 1301 is the main powder area; 1302 is the auxiliary powder area. Detailed Implementation
[0029] To make the technical problem to be solved, the technical solution, and the beneficial effects of this utility model clearer, this utility model will be further described in detail with reference to the embodiments and accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of this utility model and are not intended to limit it. The technical solution of this utility model will be described in detail below with reference to the embodiments and accompanying drawings, but the scope of protection is not limited thereto.
[0030] See Figures 1 to 5 This embodiment proposes an apparatus for growing multiple silicon carbide crystals using a liquid-phase method, including a reaction vessel 3. A first cover plate 2, a second cover plate 401, a third cover plate 402, and a fourth cover plate 6 are arranged from top to bottom inside the reaction vessel 3. The first cover plate 2, second cover plate 401, third cover plate 402, and fourth cover plate 6 are all fixedly connected to the inner wall of the reaction vessel 3. The first cover plate 2 has a connection hole, and a drive motor 1 is installed at the connection hole.
[0031] An auxiliary powder material area 1302 is formed between the first cover plate 2 and the second cover plate 401. There is a cavity between the second cover plate 401 and the third cover plate 402. A main powder material area 1301 is formed between the third cover plate 402 and the fourth cover plate 6. The auxiliary powder material area 1302 is used to place multiple graphite blocks 12 and silicon powder. A liquid pipe 5 is connected between the second cover plate 401 and the third cover plate 402, and the auxiliary powder material area 1302 and the main powder material area 1301 are connected through the liquid pipe 5. A one-way valve 11 is provided on the liquid pipe 5.
[0032] In this embodiment, three crystal lifting cylinders 10 are provided below the fourth cover plate 6, and a seed crystal support plate 7 is slidably connected inside each crystal lifting cylinder 10. The three seed crystal support plates 7 are slidably connected to the fourth cover plate 6; corresponding through holes are provided on the fourth cover plate 6 to facilitate the seed crystal support plates 7 to move up and down through the fourth cover plate 6. A crystal lifting motor 8 is connected to the bottom of each seed crystal support plate 7. Seed crystals are placed on the top of the seed crystal support plate 7, and the crystal lifting motor 8 is used to drive the seed crystal support plate 7 to move up and down.
[0033] A first heating coil 901 is installed outside the auxiliary powder area 1302, and a second heating coil 902 is installed outside the main powder area 1301; a third heating coil 903 is installed outside each crystal pulling cylinder 10. The installation of heating coils in the upper, middle, and lower areas allows for individual temperature control based on the temperature changes in each area, enabling more precise temperature control according to the crystal growth process.
[0034] In this embodiment, in order to improve the uniformity of the material around the seed crystal, the three seed crystal support plates 7 are evenly distributed around the center of the fourth cover plate 6; multiple liquid pipes 5 are evenly arranged around the perimeter of each seed crystal support plate 7, and the discharge port of the liquid pipes 5 is located above the seed crystal support plate 7.
[0035] The working principle of the apparatus for growing multiple silicon carbide crystals by liquid phase method proposed in this embodiment is as follows:
[0036] The device has two powder loading areas: an auxiliary powder area 1302 and a main powder area 1301. During the crystal liquid phase growth process, the powder in the auxiliary powder area and the graphite block 12 are heated by the first heating coil 901 to a temperature of 1900-2000℃, melting into a liquid. This liquid flows into the main powder area 1301 through the liquid pipe 5, replenishing the main powder area 1301 with raw materials. After the seed crystal is placed on the seed crystal support plate 7, it is preheated in the crystal lifting cylinder 10 by the third heating coil 903. Then, it is raised along the crystal lifting cylinder 10 by the crystal lifting motor 8 and enters the fourth cover plate 6, so that the seed crystal is located in the main powder area 1301 and immersed in the liquid material for crystal growth. The crystal growth temperature is adjusted in real time by adjusting the temperature of the second heating coil 902, thereby improving the crystal growth efficiency.
[0037] The one-way valve 11 in the liquid pipeline 5 can control the flow rate of liquid at different locations, which can solve the problem of "competition" for liquid phase powder between adjacent seed crystals, and can also solve the problem of insufficient raw materials in the main powder area 1301 during the later stage of crystal growth.
[0038] The three sets of heating coils can be controlled independently. The first heating coil 901 controls the carbon concentration in the auxiliary powder area 1302, and the second heating coil 902 controls the carbon concentration in the main powder area 1301. The second and third heating coils can work together to achieve the concave meniscus temperature field. The crystal pulling motor 8 can independently control the crystal selection and vertical movement. This device can realize the liquid phase growth of multiple silicon carbide crystals; the relative position of the solid-liquid interface remains unchanged, realizing concave liquid surface growth throughout the crystal growth process; and the seed crystal is located at the bottom of the crucible, reducing defects caused by thermal mismatch between the seed crystal and the support material due to mechanical fixation.
[0039] The above description is a further detailed explanation of the present invention in conjunction with specific preferred embodiments. It should not be considered that the specific embodiments of the present invention are limited to this. For those skilled in the art, several simple deductions or substitutions can be made without departing from the present invention, and all such deductions or substitutions should be considered to fall within the scope of patent protection determined by the submitted claims.
Claims
1. An apparatus for growing multiple silicon carbide crystals by liquid phase method, comprising a reaction vessel (3); characterized in that, The reaction vessel (3) is provided with a first cover plate (2), a second cover plate (401), a third cover plate (402), and a fourth cover plate (6) arranged from top to bottom; an auxiliary powder area (1302) is formed between the first cover plate (2) and the second cover plate (401), a cavity is formed between the second cover plate (401) and the third cover plate (402), and a main powder area (1301) is formed between the third cover plate (402) and the fourth cover plate (6); the second cover plate (401) and the third cover plate (402) are connected by a... A liquid pipe (5) connects the auxiliary powder area (1302) and the main powder area (1301); a one-way valve (11) is provided on the liquid pipe (5); multiple seed crystal support plates (7) are slidably connected to the fourth cover plate (6); a first heating coil (901) is provided outside the auxiliary powder area (1302); a second heating coil (902) is provided outside the main powder area (1301); and a third heating coil (903) is provided outside the seed crystal support plate (7).
2. The apparatus for growing multiple silicon carbide crystals by liquid phase method according to claim 1, characterized in that, Multiple crystal lifting cylinders (10) are provided below the fourth cover plate (6), and a seed crystal support plate (7) is slidably connected inside each crystal lifting cylinder (10).
3. The apparatus for growing multiple silicon carbide crystals by liquid phase method according to claim 2, characterized in that, Each crystal lifting tube (10) is equipped with a third heating coil (903) on its exterior.
4. The apparatus for growing multiple silicon carbide crystals by liquid phase method according to claim 1, characterized in that, Each seed crystal support plate (7) is connected to a crystal lifting motor (8) at its bottom.
5. The apparatus for growing multiple silicon carbide crystals by liquid phase method according to claim 1, characterized in that, Multiple seed crystal support plates (7) are evenly distributed around the center of the fourth cover plate (6).
6. The apparatus for growing multiple silicon carbide crystals by liquid phase method according to claim 5, characterized in that, Multiple liquid pipes (5) are evenly arranged around each seed crystal support plate (7), and the discharge port of the liquid pipes (5) is located above the seed crystal support plate (7).
7. The apparatus for growing multiple silicon carbide crystals by liquid phase method according to claim 1, characterized in that, The first cover plate (2) is provided with a connection hole, and a drive motor (1) is provided at the connection hole.