Preparation device for low-stress SiC single crystal

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-...

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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 isostati

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