| 摘要 |
PROBLEM TO BE SOLVED: To obtain a purified silicon carbide powdery raw material for producing a highly pure member for semiconductor devices obtained from general silicon carbide powder on the market, which contains impurity metal elements in relatively high contents, and to provide a method capable of easily and inexpensively purifying the silicon carbide powder. SOLUTION: This purified silicon carbide powder substantially consists of α-type crystal and contains impurities of Fe, Ni and Cr, each content being not more than 0.1 ppm and Al in an amount of >=10 ppm. In this purification method, a crude silicon carbide powder, which has such a concentration gradient that the concentration of impurities becomes higher toward the surface consists of an outer shell part having a thickness of at least 0.2 μm where the impurities exist in high concentration and an inner core part almost free from impurities and consists of the particles substantially composed of only α-type crystal, and is subjected to oxidation treatment to form an oxidized film having a thickness thicker than that of the outer shell part and the removement treatment of the formed oxidized film. |
