Impurity Behavior of High Purity SiC Powder during SiC Crystal Growth

Abstract

Two kinds of SiC powder having a different impurity contents and particle size were prepared by carbothermal reduction under different conditions from traditional process for controlling the purity of product. SiC single crystal was grown in the RF heating PVT machine at the temperature above 2,100 °C. After crystal growth, boule was cut to wafers in 1mm thickness and fine polished using diamond abrasive slurry. The impurity in the powder and wafer was analyzed using glow discharged mass spectroscopy (GDMS). Major impurities in the SiC wafer were aluminum, boron, iron and titanium which were accorded in the SiC powder and these impurities were decreasing in proportional to those in the powder. However, behavior of each elemental impurity was different from each other during the crystal growth. In case of boron was increased after crystal growth while aluminum decreased. In case of titanium and boron were higher in the wafer than in the powder. It can be explained to other impurity source such as graphite crucible and insulation felt.