Silicon carbide single crystal growth equipment with crystal heat exchange device

Abstract

The utility model discloses silicon carbide single crystal growth equipment with a crystal heat exchange device, which comprises a furnace body, a thermal insulation layer, a crucible and a heater, the crucible and the heater are arranged in the thermal insulation layer, the crucible comprises a crucible body and a crucible cover, and the crystal heat exchange device capable of sliding up and down is arranged right above the crucible cover. The crystal heat exchange device capable of sliding up and down is arranged right above the crucible cover, and the silicon carbide seed crystal is arranged at the bottom of the crucible cover, so that when the temperature of the seed crystal is too high, the crystal heat exchange device can be controlled to slide down to the crucible cover, and heat on the crucible cover is transferred to the crystal heat exchange device in time, so that the temperature of the crucible cover is reduced; the purpose of accurately controlling the temperature of the silicon carbide seed crystal is achieved.

Description

Technical Field

[0001] This utility model relates to the field of silicon carbide semiconductor technology, and in particular to a silicon carbide single crystal growth device with a crystal heat exchanger. Background Technology

[0002] Silicon carbide (SiC) single crystal, as an important third-generation wide-bandgap semiconductor material, has broad application prospects in power electronic devices used under extreme conditions such as high frequency, high power, radiation resistance, corrosion resistance, and high temperature resistance due to its advantages such as wide bandgap, high thermal conductivity, high critical breakdown electric field and high electron saturation migration rate.

[0003] Physical vapor transport (PVT) is a commonly used method for growing silicon carbide single crystals. It involves placing polycrystalline silicon carbide material at the bottom of a cylindrical graphite crucible, covering it with a graphite crucible lid to form a sealed space. A silicon carbide seed crystal is mounted on the lower surface of the lid. By heating the system consisting of the crucible and lid, the polycrystalline silicon carbide material inside the crucible sublimates, maintaining a suitable temperature gradient between the material and the seed crystal. The sublimated silicon carbide particles then deposit and grow on the seed crystal, thus obtaining a silicon carbide single crystal.

[0004] Because the growth of silicon carbide single crystals is greatly affected by temperature differences, the control of the silicon carbide seed crystal temperature is extremely stringent. It should not be too high or too low, but rather controlled within a specific temperature range. Current technologies typically control the seed crystal temperature by controlling the operation of the heater. When the seed crystal temperature is too low, the heater operating voltage is increased; when the seed crystal temperature is too high, the heater operating voltage is decreased. However, at this point, the furnace temperature is already very high, requiring an additional water-cooling system to lower the furnace temperature. But lowering the furnace temperature affects the vaporization of silicon carbide, making precise control of the silicon carbide seed crystal temperature difficult. Utility Model Content

[0005] The technical problem to be solved by this utility model is that the temperature of silicon carbide seed crystal cannot be accurately controlled in the existing silicon carbide single crystal growth equipment. The present invention provides a silicon carbide single crystal growth equipment with a crystal heat exchange device that can uniformly heat the silicon carbide gas in each region of the crucible.

[0006] The technical solution to this problem is: to construct a silicon carbide single crystal growth device with a crystal heat exchanger, including a furnace body, an insulation layer, a crucible and a heater disposed in the insulation layer, the crucible including a crucible body and a crucible cover, and a crystal heat exchanger that can slide up and down is provided directly above the crucible cover.

[0007] Furthermore, the crystal heat exchange device includes a heat exchange plate that matches the top surface of the crucible cover, a lifting guide rod that passes through the insulation layer and the furnace body and is connected to the heat exchange plate, and a driver that is set on the top of the furnace body and drives the lifting guide rod to move up and down; the driver drives the lifting guide rod to slide up and down, and the lifting guide rod drives the heat exchange plate to move up and down, so that the heat exchange plate contacts or detaches from the top surface of the crucible cover, thereby timely reducing the temperature of the seed crystal fixed on the bottom surface of the crucible cover and controlling the seed crystal temperature to meet the process requirements.

[0008] Furthermore, the driver includes a drive motor mounted on the top of the furnace body, a lead screw driven by the drive motor, and a slider sleeved on the lead screw. The slider is fixed to the top side of the lifting guide rod. By driving the lead screw to rotate through the drive motor, the slider moves up and down along the lead screw, thereby causing the lifting guide rod to slide up and down, thus enabling the drive motor to reliably drive the lifting guide rod to move up and down.

[0009] Furthermore, a positioning frame is provided on the top of the furnace body, the lead screw is vertically rotatably mounted on the positioning frame, and the drive motor is mounted on the top of the positioning frame; ensuring that the drive motor and lead screw are reliably mounted on the top of the furnace body.

[0010] Furthermore, the crystal heat exchange device also includes a temperature measuring device capable of detecting the temperature of the crucible lid. The temperature measuring device includes an infrared thermometer with a detection head installed at the top of the lifting guide rod and a temperature measuring channel installed inside the lifting guide rod. One end of the temperature measuring channel passes through the heat exchange plate and faces the top surface of the crucible lid, while the other end is matched with the infrared thermometer. The temperature of the seed crystal can be determined by the temperature of the top surface of the crucible lid detected by the detection head of the infrared thermometer through the temperature measuring channel.

[0011] Furthermore, it also includes a control system, which is electrically connected to the driver and the infrared thermometer. The control system controls the driver to move the heat exchange plate up and down according to the temperature of the top surface of the crucible lid detected by the infrared thermometer. The control system can automatically control the heat exchange plate to contact or detach from the top surface of the crucible lid according to the temperature detected by the infrared thermometer, thereby realizing automatic adjustment of the seed crystal temperature.

[0012] Furthermore, the top of the furnace body is provided with a shaft hole that matches the lifting guide rod, and a sliding sealing bushing is provided between the shaft hole and the lifting guide rod to ensure reliable gas sealing inside the furnace when the lifting guide rod slides up and down.

[0013] Furthermore, the insulation layer includes an upper movable insulation block, which is fixed around the lifting guide rod and sleeved on the top of the heat exchange plate; this allows the upper movable insulation block to rise and fall together with the heat exchange plate, ensuring the thermal sealing of the internal space of the insulation layer without affecting the lifting and lowering movement of the heat exchange plate.

[0014] The silicon carbide single crystal growth equipment with crystal heat exchange device described in this utility model has the following beneficial effects: By setting a crystal heat exchange device that can slide up and down directly above the crucible cover, and setting the silicon carbide seed crystal at the bottom of the crucible cover, when the seed crystal temperature is too high, the crystal heat exchange device can be controlled to slide down onto the crucible cover, so as to transfer the heat on the crucible cover to the crystal heat exchange device in time, thereby reducing the temperature of the crucible cover and achieving the purpose of accurately controlling the temperature of the silicon carbide seed crystal. Attached Figure Description

[0015] Figure 1 The diagram shown is a preferred embodiment of the silicon carbide single crystal growth equipment with crystal heat exchange device of this utility model.

[0016] Figure 1a As shown Figure 1 Enlarged view of Part I;

[0017] Figure 2 The diagram shown is a schematic representation of the structure of the silicon carbide single crystal growth equipment with crystal heat exchange device in a preferred embodiment of the present invention, when the heat exchange device descends. Detailed Implementation

[0018] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] It should also be noted that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0021] like Figure 1 , 1aAs shown in Figure 2, in a preferred embodiment of the silicon carbide single crystal growth equipment with crystal heat exchange device described in this utility model, it mainly includes a furnace body 10, an insulation layer 20, a crucible 30, and a heater 40. The furnace body 10 may be equipped with an upper furnace cover 11 and / or a lower furnace cover 12 as needed, allowing for quick opening of the furnace body 10 after removing the upper furnace cover 11 and / or the lower furnace cover 12. Before preparing silicon carbide single crystals, the polycrystalline silicon carbide raw material 3 is placed in the crucible 30, and the silicon carbide seed crystal 1 is installed inside the crucible 30. Simultaneously, the upper furnace cover 11 and / or the lower furnace cover 12 are reliably sealed to the furnace body 10, ensuring that the space inside the furnace body 10 is airtight during the preparation process, preventing contamination of the silicon carbide inside the furnace body 10. The insulation layer 20 is uniformly attached to the inner wall of the furnace body, forming an insulation cavity 21 inside the furnace body. The crucible 30 and the heater 40 are disposed within the insulation cavity 21, with the heater 40 positioned around the crucible 30.

[0022] like Figure 1 , 2 As shown, in this preferred embodiment, the crucible preferably includes a crucible cover 31 and a crucible body 32, with the crucible cover 31 being sealed at the open end of the crucible body 32.

[0023] In this preferred embodiment, a crystal heat exchange device 50 is preferably provided directly above the crucible lid 31 to adjust the temperature of the crucible lid 31 in a timely manner, that is, to adjust the temperature of the silicon carbide seed crystal 1 base plate, so that the temperature of the silicon carbide seed crystal 1 meets the process requirements. The crystal heat exchange device 50 preferably includes a heat exchange plate 51, a lifting guide rod 52, and a driver 53. The heat exchange plate 51 is disposed within the insulation layer 20 and located directly above the crucible lid 31. The bottom surface of the heat exchange plate 51 matches the top surface of the crucible lid 31, that is, its bottom surface shape adapts to the top surface shape of the crucible lid 31. This ensures that when the heat exchange plate 51 contacts the crucible lid 31, the bottom surface of the heat exchange plate 51 is completely in contact with the top surface of the crucible lid 31, ensuring that the heat from the crucible lid 31 can be quickly transferred to the heat exchange plate 51, thereby reducing the temperature of the silicon carbide seed crystal located at the bottom of the crucible lid.

[0024] The lifting guide rod 52 passes through the insulation layer 20 and the upper furnace cover 11, and can slide up and down relative to the insulation layer 20 and the furnace body 10. Its bottom end is fixedly connected to the heat exchange plate 51, while its top end is located outside the furnace body 10. Specifically, a shaft hole 13 matching the lifting guide rod can be opened on the furnace top, and a sliding sealing bushing 14 is provided between the shaft hole 13 and the lifting guide rod 52. In this preferred embodiment, it is best to set the shaft hole 13 at the top of the upper furnace cover 11, embed the sliding sealing bushing 14 in the shaft hole 13, and slide the lifting guide rod 52 in the sliding sealing bushing 14.

[0025] Preferably, the insulation layer 20 includes an upper movable insulation block 22, which is fixed around the lifting guide rod 52 and sleeved on the top of the heat exchange plate 51, so that the upper movable insulation block 22 rises and falls together with the heat exchange plate 51. Specifically, an upper opening 23 matching the outline of the upper movable insulation block 22 can be provided at a corresponding position on the insulation layer 20. When the upper movable insulation block 22 rises and falls with the heat exchange plate 51, the upper movable insulation block 22 fits precisely into the upper opening 23, ensuring the thermal seal of the internal space of the insulation layer 20 and avoiding heat loss caused by thermal radiation.

[0026] The insulation layer 20 may also include a lower movable insulation block 24 as needed. A lower opening 25 matching the lower movable insulation block is opened at the bottom of the insulation layer 20. The maximum outline size of the lower movable insulation block 24 on the horizontal plane is set to be greater than the maximum outline size of the crucible so that after the lower furnace cover 12 is opened, the lower movable insulation block 24 can be taken out and the crucible can be put into or taken out from the bottom of the furnace body 10.

[0027] In this preferred embodiment, the driver 53 is preferably located at the top of the furnace body, i.e., the top of the upper furnace cover 11, and can drive the lifting guide rod 52 to rise and fall. Specifically, the driver 53 may include a drive motor 54, a lead screw 55, and a slider 56. The drive motor 54 may be a servo motor or a frequency converter motor. The lead screw 55 is rotatably located at the top of the furnace body, i.e., the top of the upper furnace cover 11, and is driven to rotate by the drive motor 54. Preferably, a positioning frame 58 is provided at the top of the furnace body; that is, the positioning frame 58 is located at the top of the upper furnace cover 11, and the lead screw 55 is vertically rotatably mounted on the positioning frame. The drive motor 54 is located at the top of the positioning frame 58, and the motor shaft of the drive motor is connected to the end of the lead screw 55. The slider 56 is sleeved on the lead screw 55 and fixed to the top side of the lifting guide rod 52. Specifically, a threaded hole 57 that mates with the lead screw 55 may be provided at the center of the slider 56, and the slider 56 is fixed to the side of the lifting guide rod 52. When the drive motor 54 drives the lead screw 55 to rotate, the slider 56 can move up and down along the lead screw 55, causing the lifting guide rod 52 to slide up and down, so that the heat exchange plate 51 located at the bottom of the lifting guide rod can also move up and down; so that the heat exchange plate contacts or detaches from the top surface of the crucible cover 31, and takes away the heat of the crucible cover 31 in time, reducing the temperature of the silicon carbide seed crystal 1 fixed on the bottom surface of the crucible cover, so that the temperature of the silicon carbide seed crystal meets the process requirements.

[0028] In this preferred embodiment, the preferred crystal heat exchanger 50 further includes a temperature measuring device 60, which can detect the temperature of the crucible lid 31 in a timely manner. The temperature measuring device 60 includes an infrared thermometer 61 with a detection head 62 and a temperature measuring channel 63 disposed within the lifting guide rod 52. Specifically, it is preferable to make the lifting guide rod 52 hollow, with the hollow part serving as the temperature measuring channel 63. Since the heat exchange plate 51 is fixed to the bottom end of the lifting guide rod 52, it is preferable to provide a through hole 64 on the heat exchange plate 51 that matches the temperature measuring channel 63, so that the temperature measuring channel 63, after passing through the heat exchange plate 51, is directly facing the top surface of the crucible lid 31. The infrared thermometer 61 is positioned at the top end of the lifting guide rod 52, ensuring that the detection head 62 can pass through the temperature measuring channel 63 and irradiate the top surface of the crucible lid 31. In this way, the detection head 62 of the infrared thermometer 61 can directly detect the real-time temperature of the top surface of the crucible lid 31 through the temperature measuring channel 63.

[0029] In this preferred embodiment, a control system (not shown in the figure) is also included. The control system is electrically connected to the drive motor 54 and the infrared thermometer 61. The control system automatically controls the drive motor 54 to drive the lifting guide rod 52 to slide up and down based on the temperature of the top surface of the crucible lid 31 detected by the infrared thermometer 61. This causes the heat exchange plate 51 to rise and fall, ensuring that the heat exchange plate 51 is in close contact with or detached from the crucible lid 31. This allows the heat from the crucible lid 31 to be rapidly transferred to the heat exchange plate 51, regulating the temperature of the silicon carbide seed crystal 1 located at the bottom surface of the crucible lid 31 and ensuring it meets process requirements. Specifically, when the temperature of the top surface of the crucible lid 31 detected by the infrared thermometer 61 is higher than a preset value, the control system automatically controls the heat exchange plate 51 to descend to a preset position, ensuring close contact between the heat exchange plate 51 and the crucible lid 31. When the temperature of the top surface of the crucible lid 31 detected by the infrared thermometer 61 is lower than the preset value, the control system automatically controls the heat exchange plate 51 to rise to a preset position, detaching the heat exchange plate 51 from the crucible lid 31.

[0030] Based on the embodiments of this utility model, any modifications, equivalent substitutions, improvements, etc., made by all other embodiments obtained by those skilled in the art without creative effort should be included within the protection scope of this utility model.

Claims

1. A silicon carbide single crystal growth apparatus with a crystal heat exchange device, comprising a furnace body, an insulation layer, a crucible provided in the insulation layer, and a heater, characterized in that, The crucible comprises a crucible body and a crucible cover, and a crystal heat exchange device is arranged above the crucible cover and can slide up and down; the crystal heat exchange device comprises a heat exchange plate matched with the top surface of the crucible cover, a lifting guide rod penetrating through the heat preservation layer and the furnace body and connected with the heat exchange plate, and a driver arranged at the top of the furnace body and driving the lifting guide rod to lift.

2. The apparatus for growing a silicon carbide single crystal with a crystal heat exchange device according to claim 1, wherein The driver comprises a driving motor arranged at the top of the furnace body, a screw rod driven by the driving motor, and a sliding block sleeved on the screw rod and fixed on the top side of the lifting guide rod.

3. The apparatus for growing a silicon carbide single crystal with a crystal heat exchanger according to claim 2, wherein A positioning frame is fixedly arranged at the top of the furnace body, the screw rod is vertically arranged on the positioning frame, and the driving motor is arranged at the top end of the positioning frame.

4. The apparatus for growing a silicon carbide single crystal with a crystal heat exchanging device according to Claim 1, wherein The crystal heat exchange device further comprises a temperature measuring device capable of detecting the temperature of the crucible cover, the temperature measuring device comprises an infrared temperature measuring instrument with a detection head arranged at the top of the lifting guide rod and a temperature measuring channel arranged in the lifting guide rod, one end of the temperature measuring channel penetrates through the heat exchange plate and faces the top surface of the crucible cover, and the other end of the temperature measuring channel is matched with the infrared temperature measuring instrument.

5. The apparatus for growing a silicon carbide single crystal with a crystal heat exchanging device according to Claim 4, wherein A control system is further arranged, the control system is electrically connected with the driver and the infrared temperature measuring instrument, and the control system controls the driver to drive the heat exchange plate to lift according to the temperature of the top surface of the crucible cover detected by the infrared temperature measuring instrument.

6. The apparatus for growing a silicon carbide single crystal with a crystal heat exchanging device according to Claim 1, wherein An axle hole matched with the lifting guide rod is arranged at the top of the furnace body, and a sliding sealing sleeve is arranged between the axle hole and the lifting guide rod.

7. The apparatus for growing a silicon carbide single crystal with a crystal heat exchanging device according to Claim 1, wherein The heat preservation layer comprises an upper movable heat preservation block, and the upper movable heat preservation block is fixed around the lifting guide rod and sleeved on the top of the heat exchange plate.

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