Liquid phase method silicon carbide single crystal furnace

Abstract

The utility model discloses a liquid phase method silicon carbide single crystal furnace, which comprises a furnace body of the single crystal furnace and a furnace body support frame, and is characterized by further comprising a superconducting magnet device which is arranged on the furnace body and provides a superconducting magnetic field, and a magnet lifting device, the magnet lifting device comprises a lifting frame and a lifting arm arranged on a walking mechanism of the lifting frame, and the lifting arm is connected to the superconducting magnet device in a supporting mode.

Description

Technical Field

[0001] The utility model belongs to the technical field of semiconductors, and in particular relates to a liquid phase method silicon carbide single crystal furnace. Background Art

[0002] As a third-generation semiconductor material, SiC offers advantages in high-voltage, high-frequency, and high-temperature resistance. The liquid-phase method, a silicon carbide crystal growth process, boasts high quality, easy diameter expansion, stable P-type doping, and observable growth. It is expected to become a future method for producing larger, higher-quality, and lower-cost silicon carbide single crystals.

[0003] At 1800°C, carbon and silicon solutions are dissolved together, and silicon carbide crystals precipitate from the supercooled, saturated solution. Metal cosolvents are added during the crystal growth process. Too much cosolvent can lead to excessive metal impurities in the crystal during growth, while too little can affect the surface quality of the crystal. Internal consumption of cosolvents is disordered, with both evaporation and reaction, which can affect the long-term growth of the crystal.

[0004] Therefore, in view of the above technical problems, it is necessary to provide a liquid phase silicon carbide single crystal furnace.

[0005] The information disclosed in this background technology section is only intended to increase the understanding of the overall background of the present invention, and should not be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to those skilled in the art. Utility Model Content

[0006] The purpose of the utility model is to provide a liquid phase method silicon carbide single crystal furnace, which can.

[0007] In order to achieve the above-mentioned purpose, the technical solution provided by a specific embodiment of the present invention is as follows:

[0008] A liquid phase silicon carbide single crystal furnace includes a furnace body and a furnace body support frame of the single crystal furnace, a superconducting magnet device arranged on the furnace body and providing a superconducting magnetic field, and a magnet lifting device. The magnet lifting device includes a lifting frame and a lifting arm arranged on the walking mechanism of the lifting frame, and the lifting arm is supported and connected to the superconducting magnet device.

[0009] In one or more embodiments of the present invention, the superconducting magnet device includes a superconducting coil device in a hollow cylindrical shape, and the superconducting coil device is sleeved on the outer periphery of the furnace body.

[0010] In one or more embodiments of the present invention, the superconducting magnet device includes a magnet controller having at least a control switch, and the magnet controller controls the device connected to the superconducting coil device to adjust the magnetic field state.

[0011] In one or more embodiments of the present invention, the furnace body support frame and the lifting frame are both fixed to the base, and at least two lifting frames are symmetrically arranged on the outside of the furnace body support frame.

[0012] In one or more embodiments of the present invention, the lifting frame includes a vertically arranged supporting body, the supporting body is provided with an inwardly concave sliding groove, and the sliding end of the lifting arm is matchedly arranged in the sliding groove and can move along the sliding groove.

[0013] In one or more embodiments of the present invention, the supporting body is further provided with a lifting screw rod, and the sliding end is provided with a lifting screw hole that cooperates with the lifting screw rod, and the lifting screw hole is engaged with the lifting screw rod.

[0014] In one or more embodiments of the present invention, the lifting screw is further matched with a driving device, which is drivingly connected to the lifting screw to drive it to rotate around the axis in a working state.

[0015] In one or more embodiments of the present invention, the drive device is fixedly connected to the support body or base.

[0016] In one or more embodiments of the present invention, the drive device includes a drive assembly, the drive assembly includes a motor and a power transmission device connected to the motor, the power transmission device includes a plurality of transmission rods connected to each other by gear meshing, a driving gear is provided on the transmission rod, and the driving gear is meshedly connected to the driven gear on the lifting screw.

[0017] In one or more embodiments of the present invention, the transmission rod is further provided with a bearing, a bearing seat is provided on the base, and the bearing is cooperatively connected to the bearing seat.

[0018] Compared to existing technologies, the distribution of magnetic flux lines within the magnetic field of this utility model guides the movement of internal molecules, particularly stabilizing the liquid surface, thereby ensuring a stable liquid surface at high temperatures during crystal growth. By optimizing the coil configuration of the superconducting magnet device, the liquid flow rate and direction are altered, increasing the amount of oxygen evaporating from the liquid and reducing the oxygen content of the central silicon rod. The intensity distribution of the magnetic field significantly guides the distribution of metallic impurities, removing them from the crystal and improving its quality. Overall, this ensures longer crystal growth, increases growth thickness, and improves quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] 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 or the description of the prior art. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 This is a schematic structural diagram of a liquid phase silicon carbide single crystal furnace in one embodiment of the present invention;

[0021] Figure 2 This is a schematic diagram of the working state of a liquid phase silicon carbide single crystal furnace in one embodiment of the present utility model;

[0022] Figure 3 This is a diagram showing the magnetic flux distribution of a liquid phase silicon carbide single crystal furnace in one embodiment of the present invention;

[0023] Figure 4 This is a schematic diagram of the magnetic field strength of a liquid phase silicon carbide single crystal furnace in one embodiment of the present invention;

[0024] Figure 5 The field intensity distribution at different positions on the Z axis of a liquid phase silicon carbide single crystal furnace in one embodiment of the present invention is shown;

[0025] Figure 6 The field intensity distribution at different positions on the Z axis of a liquid phase silicon carbide single crystal furnace in one embodiment of the present invention is shown;

[0026] Figure 7 The field intensity distribution at different positions on the Z axis of a liquid phase silicon carbide single crystal furnace in one embodiment of the present invention is shown;

[0027] Figure 8 The field intensity distribution at different positions on the Z axis of a liquid phase silicon carbide single crystal furnace in one embodiment of the present invention is shown;

[0028] Figure 9 The field intensity distribution at different positions on the Z axis of a liquid phase silicon carbide single crystal furnace in one embodiment of the present invention is shown;

[0029] Figure 10 This is the field intensity distribution at different positions on the Z axis of a liquid phase silicon carbide single crystal furnace in one embodiment of the present invention. DETAILED DESCRIPTION

[0030] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the following will be combined with the drawings of the embodiments of the present invention to clearly and completely describe the technical solutions of 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 should fall within the scope of protection of the present invention.

[0031] like Figure 1-2As shown, a liquid phase silicon carbide single crystal furnace 3 in one embodiment of the present invention includes a furnace body and a furnace body support frame 4 of the single crystal furnace 3, a superconducting magnet device 1 provided on the furnace body and providing a superconducting magnetic field, and a magnet lifting device. The magnet lifting device includes a lifting frame and a lifting arm provided on the traveling mechanism of the lifting frame, and the lifting arm is supported and connected to the superconducting magnet device 1. The superconducting magnet device 1 includes a superconducting coil device in the shape of a hollow column, which is sleeved on the outer periphery of the furnace body. The flux and raw materials are heated to a solution state inside the cavity of the furnace body, and the external superconducting magnet device 1 is controlled to move up and down in the Z-axis direction by the magnet lifting device to ensure that the center plane of the magnetic field of the superconducting magnet in the Z-axis direction is coplanar with the liquid surface of the solution in the cavity.

[0032] Furthermore, in order to ensure the movement stability of the superconducting magnet device 1, the furnace body support frame 4 and the lifting frame of the magnet lifting device are both fixed to the base 5, and at least two lifting frames are symmetrically arranged on the outside of the furnace body support frame 4, so that the furnace body is firmly supported in the operating state.

[0033] Furthermore, in order to meet the controllable movement of the superconducting magnet device 1, the lifting frame includes a vertically arranged support body, and the support body is provided with an inward-concave slide groove. The sliding end of the lifting arm (the sliding end can be a slider matching the slide groove, and of course a pulley can also be provided on the slider) is matched to the slide groove and can move along the slide groove, thereby controlling the movement range of the lifting arm to be limited to the range restricted by the slide groove.

[0034] Furthermore, in order to realize the movement of the lifting arm, it is necessary to provide it with power to drive it up and down. The supporting body can also be provided with a lifting screw, and the sliding end is provided with a lifting screw hole that cooperates with the lifting screw. The lifting screw hole is engaged with the lifting screw, so that when the lifting screw rotates around the axis, the engaged thread generates a driving force, thereby forcing the lifting screw with the lifting screw hole to move along the extension direction of the screw.

[0035] Furthermore, to drive the lifting screw, i.e., to controllably move it in a clockwise or counterclockwise direction, the lifting screw may be further equipped with a driving device. The driving device is connected to the lifting screw to drive it to rotate about its axis in operation. For example, the driving device may be directly connected to the screw via a motor, or a gear driven by the motor may be used as a first driving gear connected to a first driven gear provided on the screw. Of course, the driving device, such as the motor, may be directly fixed to the base 5, or connected to an adjacent support body via a connecting frame, such as an angle steel frame.

[0036] Furthermore, in order to match and implement the synchronous operation of multiple lifting arms, that is, to synchronously complete the synchronous operation of the lifting screws, it is also possible to Figure 2As shown, a drive assembly 2 is provided. The drive assembly 2 includes a motor and a power transmission device connected to the motor. The power transmission device includes a plurality of transmission rods connected to each other by gears. The transmission rods are provided with driving gears, which are meshed with driven gears on the lifting screw. A transmission gear can be provided on one of the transmission rods, and the transmission gear meshes with the first driving gear. This allows the meshed transmission rods to operate synchronously, and in turn, the lifting screw is driven synchronously by the driving gear.

[0037] Furthermore, in order to ensure long-term smooth operation of the transmission rod, the transmission rod is also provided with a bearing, and a bearing seat is provided on the base 5. The bearing is cooperatively connected to the bearing seat. At this time, the driving motor is also provided on the base 5.

[0038] In the crystal growth operation using the solution of the utility model:

[0039] The seed crystal rod 6 moves downward, and the silicon carbide seed crystal 7 is extended to about 10 mm above the liquid surface of the melt 8 for preheating, and then immersed in the solution to melt back. After melting back, it rises to 5 mm above the liquid surface for crystal growth.

[0040] During the crystal growth process, the Z-axis center plane of the magnetic field formed by the superconducting magnet device 1 is always coplanar with the liquid surface, and the solution inside the cavity is always in the magnetic field generated by the superconducting magnet. The magnetic flux lines in the magnetic field are distributed as follows: Figure 1 As shown, the magnetic flux lines extend along the X-axis, with a central magnetic field strength of 5000 gauss. The intensity increases from the center toward the sides in the X-axis direction and decreases from the center toward the sides in the Y-axis direction. The distribution of magnetic flux lines is consistent across each cross-section along the Z-axis. In a solution, especially at the liquid surface, metal molecules, influenced by the magnetic field, move along the magnetic flux lines, ensuring regular internal motion. This significantly contributes to stable liquid surface conditions and improves crystal growth quality. Due to the high edge magnetic field strength, metal molecules tend to concentrate at the edges, significantly reducing the metal impurity content in crystals located at the center of the cavity.

[0041] like Figure 3-10 In the field strength diagrams at different positions on the Z axis shown, there is no specific requirement for the rising or falling trend of the magnetic field intensity, as long as the transition is smooth.

[0042] "The distribution of magnetic induction lines in each cross section of the Z axis is the same" means that the directions of the magnetic induction lines at each position of the Z axis are roughly the same, and generally point in the X direction.

[0043] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the present invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be encompassed within the present invention. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

[0044] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A liquid phase silicon carbide single crystal furnace, comprising a furnace body and a furnace body support frame, characterized in that: It also includes a superconducting magnet device and a magnet lifting device arranged on the furnace body and providing a superconducting magnetic field. The magnet lifting device includes a lifting frame and a lifting arm arranged on a walking mechanism of the lifting frame. The lifting arm is supported and connected to the superconducting magnet device.

2. The liquid phase silicon carbide single crystal furnace according to claim 1, characterized in that: The superconducting magnet device includes a superconducting coil device in a hollow column shape, and the superconducting coil device is sleeved on the outer periphery of the furnace body.

3. The liquid phase silicon carbide single crystal furnace according to claim 2, characterized in that: The superconducting magnet device includes a magnet controller having at least a control switch, and the magnet controller controls a superconducting coil device to adjust a magnetic field state.

4. The liquid phase silicon carbide single crystal furnace according to claim 1, characterized in that: The furnace body supporting frame and the lifting frame are both fixed to the base, and at least two lifting frames are symmetrically arranged on the outside of the furnace body supporting frame.

5. The liquid phase silicon carbide single crystal furnace according to claim 4, characterized in that: The lifting frame includes a vertically arranged supporting body, the supporting body is provided with an inwardly concave sliding groove, and the sliding end of the lifting arm is matchedly arranged in the sliding groove and can move along the sliding groove.

6. The liquid phase silicon carbide single crystal furnace according to claim 5, characterized in that: The supporting body is further provided with a lifting screw rod, and the sliding end is provided with a lifting screw hole matched with the lifting screw rod, and the lifting screw hole is engaged with the lifting screw rod.

7. The liquid phase silicon carbide single crystal furnace according to claim 6, characterized in that: The lifting screw rod is also matched with a driving device, which is drivingly connected to the lifting screw rod to drive it to rotate around the axis in a working state.

8. The liquid phase silicon carbide single crystal furnace according to claim 7, characterized in that: The drive means is fixedly connected to a support body or base.

9. The liquid phase silicon carbide single crystal furnace according to claim 8, characterized in that: The drive device includes a drive assembly, which includes a motor and a power transmission device connected to the motor. The power transmission device includes a plurality of transmission rods connected to each other by gear meshing. A driving gear is provided on the transmission rod, and the driving gear is meshedly connected to the driven gear on the lifting screw.

10. The liquid phase silicon carbide single crystal furnace according to claim 9, characterized in that: The transmission rod is further provided with a bearing, and a bearing seat is provided on the base, and the bearing is cooperatively connected to the bearing seat.

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