Silicon carbide seed crystal and method for reducing penetration type dislocation density in silicon carbide single crystal

Abstract

The invention provides a silicon carbide seed crystal and a method for reducing the penetration type dislocation density in a silicon carbide single crystal. A groove is formed in the back of the seedcrystal, the groove is filled with a material with the heat conductivity different from that of silicon carbide, or the back of the seed crystal is directly plated with a film with the heat conductivity different from that of the silicon carbide, so that two substances with the different heat conductivities exist on the back of the seed crystal, and uneven distribution of a temperature field on the surface of the seed crystal is caused when heat dissipation is uneven. Therefore, periodic distribution of the two substances with different thermal conductivities on the back of the seed crystal can be utilized, 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 is carried out, so that the purposeof 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 silicon carbide seed crystal and a method for reducing threading dislocation density in a 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 crys...

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Problems solved by technology

For dislocations in SiC single crystals, the "Repeated A-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-plane growth can obtain high-quality SiC single crystals with low dislocation density. However, this method requires multiple repeated growths, and the steps are complicated and other defects are easily introduced during repeated growths; there is also the possibility of setting SiC along the non-polar growth plane. Growth, compared with growth along the c-axis polar plane, shows completely different growth kinetics and defect generation mechanism, and the threading dislocation density is greatly reduced compared with growth along the c-axis, but this method will generate a large number of stacking fault defects

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