METHOD OF PRODUCTION OF PYROLYTIC BORON NITRIDE Russian patent published in 2000 - IPC

FIELD: manufacture of semiconductors. SUBSTANCE: boron - containing charge, for example, amorphous boron, boron carbide or boron nitride waste is placed in reactor and is heated to 1800-2000 C. Then, BF₃ is fed through boron-containing charge which is enriched with lower boron fluoride. Substrate is placed to settling chamber which is heated to 1750-2000 C, evacuated to residual pressure of 1 to 5 mm Hg. Enriched BF₃ is fed to settling chamber simultaneously with NH₃. Volume ratio of BF₃: NH₃=1:(1-6). Rate of precipitation of BN is 0.20 to 0.32 mm/h; density of BN is 1.95 to 2.00 g/cu. cm and content of wastes per gram of BN does not exceed 2.4 g. EFFECT: enhanced efficiency. 4 cl, 3 dwg, 1 tbl, 13 dwg