A large-size silicon carbide single crystal, substrate, preparation method and device used

Abstract

The invention discloses a large-size silicon carbide single crystal, a substrate, a preparation method and a device used for preparing the large-size silicon carbide single crystal, belonging to the field of semiconductor material preparation. The preparation method for the large-size silicon carbide single crystal comprises the following steps: providing a crucible and a seed crystal column; putting raw materials into a raw material cavity formed by an interlayer on the side wall of the crucible, mounting the seed crystal column in the crucible, carrying out assembling, and putting an assembled crucible into a crystal growth furnace; raising the temperature of a crystal growth furnace, allowing sublimation gas obtained after raw material sublimation to penetrate through the inner side wall of the interlayer and to be conveyed to the surface of the seed crystal column along a radial direction in a gas phase mode, and carrying out crystal growth so as to obtain the silicon carbide single crystal. The preparation method provided by the invention can prepare silicon carbide single crystals with any volume, specifically the silicon carbide single crystals which are large in volume, high in thickness, high in crystal growth efficiency and large in number of cut substrates. The zero microtube of the silicon carbide single crystal prepared by using the method provided by the inventionhas screw dislocation of lower than 100 cm<-2> and a blade dislocation density of lower than 220 cm<-2>. The method lays a technical foundation for large-scale commercialization of high-quality and low-cost silicon carbide substrates.

Description

technical field [0001] The application relates to a crucible assembly and a crystal growth furnace for preparing single crystals by PVT method, belonging to the field of semiconductor material preparation. Background technique [0002] The existing silicon carbide preparation technology is mainly based on the physical vapor transport (PVT) method. The PVT method is formed by sublimation and decomposition of the silicon carbide raw material placed at the bottom and transported to the seed crystal along the axial temperature gradient for crystallization. In the prior art, the flaky seed crystal used in the PVT method is placed on the top of the crucible, and the silicon carbide single crystal grows vertically downward along a certain radial direction of the single crystal. [0003] Since the silicon carbide single crystal grows downward due to the limitation of the distance from the single crystal growth surface and the raw material surface, the crystal growth thickness is us...

AI Technical Summary

Problems solved by technology

These defects will continue to be inherited into the newly grown single crystal during the single crystal growth process and continue to form through defects. Therefore, it is difficult to control the defect density in the single crystal and the substrate, and the cost is high, and it is difficult to improve the quality of the substrate.

[0004] Nature reported a silicon carbide single crystal preparation method that avoids defects such as micropipes and dislocations through crystal cross-sectional growth. However, the preparation process of this method is cumbersome. Although the defect density can be reduced, the cost is high and it is not suitable for industrial production.

Images