Search

CN-121610887-B - Device and method for dynamically adjusting axial temperature gradient in crystal growth process

CN121610887BCN 121610887 BCN121610887 BCN 121610887BCN-121610887-B

Abstract

The invention provides a device and a method for dynamically adjusting axial temperature gradient in a crystal growth process, and belongs to the technical field of silicon carbide crystal production. The device comprises a crucible main body, a crucible cover provided with an opening, a seed rod and a temperature adjusting device, wherein one end of the seed rod is connected with a seed crystal support for bearing seed crystals, the seed crystal support is arranged in the crucible main body in the growth process, the other end of the seed rod is sleeved with the temperature adjusting device, the temperature adjusting device comprises an adjusting component, a connecting component and a transmission component, the adjusting component is made of graphite soft felt, a through hole is formed in the center of the adjusting component, the seed rod penetrates through the through hole, the transmission component is connected with the adjusting component through the connecting component and controls the adjusting component to move up and down along the seed rod to realize axial temperature regulation, the adjusting component is in a contracted state in the up-down moving process, and when the adjusting component is in contact with the crucible cover or the seed crystal support, the adjusting component is unfolded through the transmission component. The scheme realizes the axial temperature regulation and control in the crystal growth process.

Inventors

  • ZHANG GUANGYU
  • ZHANG ZESHENG
  • WANG GUOBIN

Assignees

  • 北京晶格领域半导体有限公司

Dates

Publication Date
20260508
Application Date
20260130

Claims (12)

  1. 1. The device for dynamically adjusting the axial temperature gradient in the crystal growth process is characterized by comprising a crucible main body, a crucible cover provided with an opening, a seed rod, a temperature adjusting device, a rotation turntable and a sensor module; One end of the seed rod is connected with a seed crystal support for bearing seed crystals, the seed crystal support is arranged in the crucible main body in the growth process, and the other end of the seed rod is sleeved with the temperature regulating device; The temperature regulating device comprises a regulating component, a connecting component and a transmission component; The adjusting component is made of graphite soft felt, and a through hole is formed in the center of the adjusting component, the seed rod penetrates through the through hole, the transmission component is connected with the adjusting component through the connecting component and controls the adjusting component to move up and down along the seed rod to realize axial temperature regulation, wherein the adjusting component is in a contracted state in the up and down moving process, and when the adjusting component moves to the crucible cover or the seed crystal support, the transmission component is used for realizing the expansion of the adjusting component, so that the adjusting component is flatly paved on the upper surface of the crucible cover or the seed crystal support; The device comprises a crucible cover, an adjusting component, a seed crystal support, a connecting component, a transmission component and a control component, wherein the width of the adjusting component after being unfolded is larger than the opening size of the crucible cover when the adjusting component can be unfolded on the upper surface of the crucible cover; The rotating disc comprises a plurality of different adjusting components and is used for adjusting and controlling the axial temperature by rotating and selecting the needed adjusting components; The method comprises the steps of obtaining the current position of an adjusting component detected by a sensor module, dynamically adjusting the descending speed of the adjusting component according to the pressure and the air flow speed in the furnace detected by the sensor module in real time until the descending speed reaches a target surface, wherein the target surface is the upper surface of a crucible cover or the upper surface of a seed crystal holder.
  2. 2. The device of claim 1, wherein the thickness of the adjusting component is 2-30 mm; the diameter of the through hole is 20-100 mm, and the diameter of the through hole is larger than that of the seed crystal rod.
  3. 3. The device of claim 1, wherein the width of the adjustment assembly after deployment is 25-250 mm.
  4. 4. The device of claim 1, wherein the adjustment assembly is connected to at least 8 of the mechanical connecting strings, and the connection points of the mechanical connecting strings are evenly distributed at the outer edge of the adjustment assembly.
  5. 5. The apparatus of claim 1, wherein the mechanical connecting rope is a molybdenum wire with a purity of greater than 99.5% or a tungsten wire with a purity of greater than 99.5%, wherein the length of the mechanical connecting rope is greater than 1/2 of the size of the opening of the crucible cover; The lantern ring is made of silicon carbide, metallic molybdenum or metallic tungsten.
  6. 6. The device according to claim 4, wherein the transmission assembly is capable of lifting and retracting the mechanical connecting rope by moving and/or rotating.
  7. 7. The apparatus of claim 4, wherein the drive assembly comprises a robot or a drive rod.
  8. 8. The apparatus according to any one of claims 1 to 7, further comprising a heating device, an insulating layer, and a pulling device, wherein the crucible main body is disposed in the heating device, the heating device is disposed in the insulating layer, and the pulling device is used for controlling lifting and rotation of the seed rod.
  9. 9. The apparatus of claim 8, further comprising a tunnel in the middle of the insulating layer, the seed rod passing through the tunnel and the crucible cover into the interior of the crucible body, wherein the width of the adjustment assembly in the contracted state is smaller than the diameter of the tunnel, and the diameter of the tunnel is larger than the diameter of the seed holder.
  10. 10. A method of dynamically adjusting an axial temperature gradient during crystal growth, using an apparatus as claimed in any one of claims 1 to 9, comprising: (1) Placing the growth raw materials into a crucible main body and heating to obtain a melt; (2) Placing a seed crystal support bearing seed crystals in the crucible main body and contacting the melt to perform growth of silicon carbide; (3) In the growth process, the transmission assembly drives the connecting assembly to move so as to control the adjusting assembly in a contracted state to move downwards along the seed rod until contacting the crucible cover or the seed crystal holder, and the transmission assembly is controlled to be unfolded, so that the axial temperature regulation and control are realized.
  11. 11. The method of claim 10, further comprising rotating a turntable, the rotating turntable including a plurality of different adjustment assemblies for axial temperature regulation by rotating the adjustment assemblies as selected, the method further comprising: Determining a target temperature required by the current growth stage according to the detected temperature of the seed crystal holder; The conditioning assembly is selected from the rotating dial based on the target temperature.
  12. 12. The method of claim 10 or 11, wherein the connecting assembly comprises a mechanical connecting rope and a collar, one end of the mechanical connecting rope is fixedly connected to the outer edge of the adjusting assembly, the other end of the mechanical connecting rope is connected with the collar, the collar is used for penetrating the seed rod and being connected with the transmission assembly, the device further comprises a heating device, an insulating layer and a pulling device, the crucible main body is arranged in the heating device, the heating device is arranged in the insulating layer, the pulling device is used for controlling lifting and rotation of the seed rod, and in step (3), the method further comprises: The transmission assembly is used for controlling the lantern ring to move so as to drive the mechanical connecting rope to shrink, the adjusting assembly is in a shrinkage state, then the adjusting assembly in the shrinkage state is downwards moved along the seed rod through the transmission assembly, sequentially passes through the pore canal of the heat insulation layer and the crucible cover until the crucible cover is contacted with the seed crystal support, and then the transmission assembly is used for controlling the lantern ring to move so as to drive the mechanical connecting rope to expand, so that the adjusting assembly is flatly paved on the upper surface of the seed crystal support.

Description

Device and method for dynamically adjusting axial temperature gradient in crystal growth process Technical Field The invention relates to the technical field of silicon carbide crystal production, in particular to a device and a method for dynamically adjusting axial temperature gradient in a crystal growth process. Background Silicon carbide is one of extremely important third-generation semiconductor materials, and has the characteristics of large forbidden bandwidth, high critical breakdown field intensity and the like, so that the silicon carbide becomes an ideal material for manufacturing high-frequency, high-power, radiation-resistant and illumination integrated devices, and is widely applied to various fields such as new energy automobiles, 5G communication, aerospace and the like. For liquid phase silicon carbide single crystal growth techniques, the axial temperature gradient requirements are typically different throughout the time period of crystal growth for different growth requirements. The growth stage needs a larger axial temperature gradient, which is beneficial to improving the crystal growth speed, and the cooling stage needs a smaller temperature gradient, which can lead the whole crystal to be cooled slowly and uniformly, weaken the internal stress difference and reduce the cracking rate. However, because the long crystal system is in the black box and the temperature is high, the dynamic regulation and control of the process of the temperature field is always a difficult problem for the growth of the silicon carbide single crystal by the liquid phase method. Accordingly, there is a need for an apparatus and method for dynamically adjusting the axial temperature gradient during crystal growth. Disclosure of Invention The invention provides a device and a method for dynamically adjusting the axial temperature gradient in the crystal growth process, which realize the axial temperature adjustment and control in the crystal growth process, reduce the cracking probability of crystals and improve the crystal quality. In a first aspect, the present invention provides a device for dynamically adjusting an axial temperature gradient during crystal growth, the device comprising a crucible body, a crucible cover provided with an opening, a seed rod, and a temperature adjustment device; One end of the seed rod is connected with a seed crystal support for bearing seed crystals, the seed crystal support is arranged in the crucible main body in the growth process, and the other end of the seed rod is sleeved with the temperature regulating device; The temperature regulating device comprises a regulating component, a connecting component and a transmission component; The adjusting component is made of graphite soft felt, a through hole is formed in the center of the adjusting component, the seed rod penetrates through the through hole, the transmission component is connected with the adjusting component through the connecting component and controls the adjusting component to move up and down along the seed rod to realize axial temperature regulation, the adjusting component is in a shrinkage state in the up-down moving process, and when the adjusting component moves to the crucible cover or the seed crystal support, the transmission component is used for realizing the expansion of the adjusting component, so that the adjusting component is flatly paved on the upper surface of the crucible cover or the seed crystal support. Preferably, the thickness of the adjusting component is 2-30 mm; the diameter of the through hole is 20-100 mm, and the diameter of the through hole is larger than that of the seed crystal rod. Preferably, the width of the unfolded adjusting assembly is 25-250 mm. Preferably, the width of the unfolded regulating assembly is larger than the size of the opening of the crucible cover when the regulating assembly can be flatly paved on the upper surface of the crucible cover, and the width of the unfolded regulating assembly is the same as the size of the seed crystal support when the regulating assembly can be flatly paved on the upper surface of the seed crystal support. Preferably, the connecting assembly comprises a mechanical connecting rope and a lantern ring, one end of the mechanical connecting rope is fixedly connected to the outer edge of the adjusting assembly, the other end of the mechanical connecting rope is connected with the lantern ring, and the lantern ring is used for penetrating through the seed rod and is connected with the transmission assembly. Preferably, the adjusting component is connected with at least 8 mechanical connecting ropes, and the connecting points of the mechanical connecting ropes are uniformly distributed on the outer edge of the adjusting component. Preferably, the mechanical connecting rope is molybdenum wire with purity more than 99.5% or tungsten wire with purity more than 99.5%, wherein the length of the mechanical connecting rope is more than