Method for reducing seed crystal growth face defects of silicon carbide crystals

Abstract

The invention relates to a method for reducing seed crystal growth face defects of silicon carbide crystals. The method comprises the following steps of: tightly pasting the Si faces of two seed crystals together, and putting the tightly pasted Si faces to a corrosive consisting of molten KOH and K2CO3; and heating up the mixture to 400 DEG C and corroding the C faces of the seed crystal growth faces under the constant-temperature condition of 400 DEG C, so that the seed crystal growth face defects of the silicon carbide crystals are reduced by corroding off the defects caused by grinding and polishing. According to the method disclosed by the invention, the defects, which are caused by grinding and polishing, on the C faces of the growth faces are quickly and simply corroded off on the condition of effectively protecting the Si faces on the growth back faces from being not corroded, so that the quantity of the defects on the growth faces is lower than that of the un-corroded defects by about five times, thereby reducing the crystal defects obtained by regeneration, improving the crystal quality and preventing the defects on the Si faces from being reversely sublimated and extended to the growth faces due to expansion.

Description

technical field [0001] The invention relates to a method for reducing defects on the growth surface of a silicon carbide crystal seed crystal. Background technique [0002] During the growth process of silicon carbide crystal, most of the defects in the crystal will come from the seed crystal. At present, the silicon carbide seed crystal used for growth is a single-sided or double-sided ground and polished single wafer. Due to grinding and polishing on the surface, such as Defects such as scratches, screw dislocations, edge dislocations, and basal plane dislocations increase the number of defects on the surface of the seed crystal several times on the basis of growth. [0003] As a representative of the third-generation Wide Band-gap Semiconductor (WBS) semiconductor material, SiC has wide band gap, high critical breakdown electric field, high thermal conductivity, high carrier saturation drift velocity and excellent chemical stability. And other characteristics, in the fie...

AI Technical Summary

Problems solved by technology

During the growth of silicon carbide crystals, the quality of silicon carbide seed crystals is the main factor determining the quality of the grown crystals. There are not only inherent defects caused by growth but also defects caused by grinding and polishing on the surface of the seed crystals. These defects will affect The quality of regrown crystals, the current methods to solve these problems are H etching and chemical polishing (CMP) method, the H etching method is costly, takes a long time, is difficult to operate and the corrosion depth is only about 1 μm, and cannot reach grinding The depth of defects caused by polishing cannot achieve the desired effect. The chemical polishing (CMP) method is also costly and must be in a clean room. It takes about two hours per plate and is difficult to operate (in terms of ingredients) with certain precision)