Heat treating apparatuses for semiconductors and high purity silicon carbide parts for the apparatuses and a method of making thereof

A heat treating apparatus for semiconductors comprising high purity silicon carbide parts integrated in the high temperature portions of said apparatus, said parts comprising .alpha. silicon carbide and high purity silicon and are formed from:

• an .alpha. silicon carbide powder with a particle size of not greater than 44 .mu.m and a weight means particle size of from 2 to 25 .mu.m;
• a high purity silicon which is used to impregnate the .alpha. silicon carbide;
• and
• an iron impurity concentration of not greater than 5 ppm.

A method of making high purity silicon carbide parts suitable for use in heat treating apparatuses for semiconductors, said parts comprising .alpha. silicon carbide and silicon;

• comprising the steps of;
• crushing .alpha. silicon carbide into a powder having a particle size distribution such that no particles are larger than 44 .mu.m and a weight means particle size of from 2 to 25 .mu.m;
• cleaning by washing with a mixed acid consisting of hydrofluoric acid, nitric acid and pure water so that the iron content in the powder is not larger than 5 ppm;
• forming the powder with an organic binder into a formed body;
• sintering the formed body at a temperature in the range of from 1,500.degree. to 2,300.degree. C.;
• and
• impregnating molten high purity silicon into the sintered body.