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CN-108018604-B - Crystal growth crucible and crystal growth furnace

CN108018604BCN 108018604 BCN108018604 BCN 108018604BCN-108018604-B

Abstract

The invention provides a crystal growth crucible, wherein the top wall of the crucible is provided with a mounting position for fixing seed crystals, the mounting position is also provided with a heat transfer layer, and the heat conductivity coefficient of the plane of the heat transfer layer is larger than that of the heat transfer layer in the thickness direction. The crystal growth crucible and the crystal growth furnace provided by the invention can effectively reduce the radial temperature gradient of the thermal field of the crystal, thereby solving the problem that the crystal is easy to crack when growing large-size crystal.

Inventors

  • LI LONGYUAN

Assignees

  • 北京七星华创电子股份有限公司

Dates

Publication Date
20260512
Application Date
20161103

Claims (7)

  1. 1. The crystal growth crucible is characterized in that a heat transfer layer is further arranged on the mounting position, and the heat conduction coefficient of the heat transfer layer on a plane of the heat transfer layer is larger than that of the heat transfer layer in the thickness direction of the heat transfer layer so as to reduce the radial temperature gradient of a crystal thermal field in the crystal growth process; The heat transfer layer is graphite paper, and the total thickness of all the graphite paper is 1mm-10mm; And a planarization layer is further arranged on the mounting position, the planarization layer is a graphite sheet, and the graphite paper and the graphite sheet are laminated.
  2. 2. The crystal growth crucible of claim 1, wherein the thermal conductivity of the plane differs from the thermal conductivity in the thickness direction by at least two orders of magnitude.
  3. 3. The crystal growth crucible according to claim 1, wherein the graphite paper and the planarizing layer are alternately laminated.
  4. 4. The crystal growth crucible of claim 1, wherein the entire back surface of the seed crystal is adhesively secured to the mounting location.
  5. 5. The crystal growth crucible of claim 1, wherein the number of graphite sheets is 2 or 3.
  6. 6. The crystal growth crucible of claim 5, wherein the thickness of each of the graphite sheets has a value in the range of 2mm to 3mm.
  7. 7. A crystal growth furnace comprising a crystal growth crucible and heating means for heating the crystal growth crucible to bring the growth environment within the crucible to a process temperature, wherein the crystal growth crucible employs the crystal growth crucible of any one of claims 1-6.

Description

Crystal growth crucible and crystal growth furnace Technical Field The invention belongs to the technical field of crystal growth, and particularly relates to a crystal growth crucible and a crystal growth furnace. Background Silicon carbide is used as a third-generation semiconductor material, has excellent physical and chemical properties, and has wide application prospect and market space in the fields of high-end photoelectricity, high power, microwave radio frequency and the like. Currently, physical Vapor Transport (PVT) is the most mature and popular method of forming grown silicon carbide. The PVT method mainly comprises the working principle that a silicon carbide raw material is placed at the bottom of a crucible, a seed crystal is fixed at the top of the crucible, the silicon carbide raw material is sublimated at a high temperature (more than 2200 ℃ for example) and a low pressure, and sublimated gas is crystallized on the seed crystal finally by utilizing a temperature gradient of a crystal thermal field, wherein the temperature gradient comprises an axial temperature gradient and a radial temperature gradient. The temperature gradient is one of the stress sources in the growth of the silicon carbide crystal, and the larger the stress is, the more easily the crystal is cracked in the growth process of the large-size silicon carbide crystal, so the temperature gradient is one of the reasons for influencing the crystal cracking in the growth of the large-size silicon carbide crystal, wherein the radial temperature gradient has relatively larger influence on the crystal stress relative to the axial temperature gradient, and the important aspect of the radial temperature gradient is the convexity of the crystal, and the convexity refers to the difference between the maximum thickness and the minimum thickness of the crystal. Therefore, how to reduce the radial temperature gradient is the key to solving the problem of easy cracking of the crystal, and a crystal growth crucible and a crystal growth furnace capable of reducing the radial temperature gradient are needed. Disclosure of Invention The invention aims at least solving one of the technical problems in the prior art, and provides a crystal growth crucible and a crystal growth furnace, which can effectively reduce the radial temperature gradient of a crystal thermal field, thereby solving the problem that crystals are easy to crack when large-size crystals are grown. In order to solve one of the problems, the invention provides a crystal growth crucible, wherein a mounting position for fixing a seed crystal is arranged on the top wall of the crystal growth crucible, and a heat transfer layer is further arranged on the mounting position, and the heat conduction coefficient of the heat transfer layer on a plane of the heat transfer layer is larger than that of the heat transfer layer in the thickness direction of the heat transfer layer. Preferably, the thermal conductivity of the plane differs from the thermal conductivity in the thickness direction by at least two orders of magnitude. Preferably, the heat transfer layer is graphite paper. Preferably, a planarization layer is further arranged on the installation position, and the graphite paper and the planarization layer are arranged in a layer-by-layer mode. Preferably, the graphite paper and the planarization layer are alternately stacked. Preferably, the planarization layer is a graphite sheet. Preferably, the entire back surface of the seed crystal is adhesively secured to the mounting location. Preferably, the total thickness of all the graphite papers is in the range of 1mm-10mm. Preferably, the number of the graphite sheets is 2 or 3. Preferably, the thickness of each graphite sheet is in the range of 2mm to 3mm. The invention also provides a crystal growth furnace, which comprises a crystal growth crucible and a heating device, wherein the heating device is used for heating the crystal growth crucible so as to enable the growth environment in the crucible to reach the process temperature, and the crystal growth crucible adopts the crystal growth crucible provided by the invention. The invention has the following beneficial effects: According to the crystal growth crucible provided by the invention, the heat conduction coefficient of the heat transfer layer on the plane is larger than that of the heat transfer layer in the thickness direction, namely, the heat conduction effect of the crystal thermal field in the radial direction is good, but the heat conduction effect in the axial direction is poor, the heat conduction effect of the crystal thermal field in the radial direction is good, so that the crystal thermal field is balanced in the radial direction, the radial heat conduction effect is good, the radial heat transfer is facilitated, the radial temperature gradient can be reduced, and the radial temperature gradient can be further reduced due to the poor heat conduction effect in t