Seed crystal support and method for reducing penetration type dislocation density in silicon carbide single crystal

Abstract

The invention provides a seed crystal support and a method for reducing penetration type dislocation density in a silicon carbide single crystal. The grooves are formed in the seed crystal support, the grooves are filled with the materials with the heat conductivity different from that of graphite, or the seed crystal support is directly plated with the thin film with the heat conductivity different from that of the graphite, so that two substances with the different heat conductivities exist on the surface of the seed crystal support during crystal growth, heat dissipation is uneven, and thenuneven distribution of a temperature field on the surface of the seed crystal is caused. Therefore, periodic distribution of two substances with different thermal conductivities on the seed crystal support can be utilized; according to the method, the distribution of a seed crystal surface temperature field in the SiC physical vapor transport growth process is modulated, preferential nucleation is forced to be carried out in a low-temperature area corresponding to a predefined pattern, selective preferential growth is carried out according to the predefined pattern, and then lateral growth iscarried out, so that the purpose of reducing the penetration type dislocation density is achieved.

Description

technical field [0001] The present application relates to the technical field of silicon carbide single crystal growth, in particular to a seed crystal support and a method for reducing threading dislocation density in silicon carbide single crystal. Background technique [0002] As a representative of the third-generation wide bandgap semiconductor materials, silicon carbide materials have excellent physical and chemical properties such as large band gap, high carrier saturation migration velocity, high thermal conductivity, high critical breakdown electric field strength, and good chemical stability. . Based on these excellent characteristics, SiC materials are considered to be ideal materials for making high-frequency, high-power, high-temperature-resistant and radiation-resistant electronic devices. , nuclear reactor systems and military equipment and other fields have a wide range of applications. [0003] Growing large-diameter, high-quality SiC single crystals is th...

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Problems solved by technology

For dislocations in SiC single crystals, the "RepeatedA-Face (RAF)" method is currently used, that is, the alternate growth of the a-plane (11-20) and the m-plane (1-100) is repeated many times, and then the c However, this method requires repeated growth, the steps are complicated and other defects are easily introduced during repeated growth; there is also a setting for SiC to grow along the non-polar growth plane , compared with the growth along the c-axis polar plane, it shows completely different growth kinetics and defect generation mechanism, and the threading dislocation density is greatly reduced compared with the growth along the c-axis, but this method will generate a large number of stacking fault defects

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