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Preparation device for low-stress SiC single crystal

A preparation device, low stress technology, applied in the direction of single crystal growth, single crystal growth, crystal growth, etc., can solve the problems of large mismatch stress, proliferation, internal stress at the contact of seed crystal and crystal edge, etc. Good bending resistance and small elastic modulus

Inactive Publication Date: 2019-07-30
HEBEI SYNLIGHT CRYSTAL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In the process of growing SiC single crystal by PVT method, the seed crystal needs to be fixed or bonded on the upper part of the isostatic graphite heat field. The side of the lower crystal pre-growth position uses the ring structure of isostatic graphite to limit the diameter of the crystal. Due to the huge difference in the material properties of isostatic graphite and SiC, for example, the thermal expansion coefficient of isostatic graphite is 3 times that of SiC. , while the Young's modulus is only 1 / 30 of that of SiC, resulting in a large mismatch stress due to thermal expansion at the contact point between the crystal and the isostatic graphite, and squeezing the crystal will cause internal stress at the contact point of the seed crystal and at the edge of the crystal become larger, the stress-derived defects in the crystal will proliferate in large numbers

Method used

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  • Preparation device for low-stress SiC single crystal

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Embodiment Construction

[0017] like figure 1 As shown, a low-stress SiC single crystal preparation device includes a graphite crucible 1, the bottom of which is equipped with SiC raw material 2, and the inside of the upper cover of the crucible 1 is fixed with a stress buffer layer 3 made of a high-temperature-resistant flexible material. The seed crystal 8 is bonded on the stress buffer layer 3, and a stress buffer ring 4 made of a high-temperature-resistant flexible material for limiting the diameter of the crystal is arranged next to the seed crystal outside the seed crystal 8, and the outer peripheral side of the graphite crucible 1 is provided with A thermal insulation layer 5 with high temperature resistance and low thermal conductivity, an induction coil 6 made of metal material is wound around the outer peripheral side of the thermal insulation layer 5, an infrared temperature measuring probe 7 is arranged on the top of the graphite crucible 1, and the infrared temperature measuring probe 7 is...

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Abstract

The invention discloses a preparation device for a low-stress SiC single crystal. The device comprises a crucible made from a material with high temperature resistance and high thermal conductivity, the bottom of the inner portion of the crucible is provided with a SiC polycrystalline raw material, the inner side of an upper cover of the crucible is fixedly provided with a stress buffer layer madefrom a high-temperature-resistant flexible material, a seed crystal is bonded to the stress buffer layer, the stress buffer layer of an annular structure made from the high-temperature-resistant flexible material and used for limiting the diameter of the crystal is arranged at the outer side of the seed crystal and next to the seed crystal, a heat insulating and preserving layer with high temperature resistance and low thermal conductivity is arranged at the peripheral side of the crucible, and induction coils made from a metal material are wound around the peripheral side of the heat insulating and preserving layer. The preparation device effectively reduces various defects and the cracking probability of the SiC crystal.

Description

technical field [0001] The invention relates to a device for preparing a low-stress SiC single crystal. Background technique [0002] In recent years, SiC has become an ideal material for making high-frequency, high-power, high-temperature-resistant and radiation-resistant devices, so the growth of high-quality SiC matrix materials has become a research hotspot. The most important thing that affects the application of SiC power devices is the existence of a large number of defects, such as dislocations, micropipes, heteromorphs, and small-angle grain boundaries. These defects seriously affect the performance of SiC devices, especially the largest number of dislocations is generally considered to be the main reason for the degradation of power devices. For example, micropipe and triangular defects will degrade the reverse voltage characteristics of p-n junction and Schottky barrier diode; screw dislocations will increase the reverse leakage current of the device and cause p-...

Claims

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Application Information

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IPC IPC(8): C30B23/00C30B29/36
CPCC30B23/00C30B29/36
Inventor 刘新辉杨昆张福生路亚娟牛晓龙郑清超
Owner HEBEI SYNLIGHT CRYSTAL CO LTD
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