METHOD FOR PRODUCING 4H POLYTYPE SILICON CARBIDE POWDER Russian patent published in 2023 - IPC C01B32/97 C30B29/36 

FIELD: microelectronics.

SUBSTANCE: method for producing single-crystal SiC - a widely applicable material used for the manufacture of integration chips, in particular, the synthesis of silicon carbide powder used as a source for growing silicon carbide single crystals. A method for producing 4H polytype silicon carbide powder, in which carbon and silicon dioxide powders are mixed, the resulting mixture is placed in a vacuum furnace, the furnace is filled with an inert gas, and the mixture is subjected to heat treatment in an inert gas atmosphere, followed by annealing of excess carbon in air. The initial powders of silicon dioxide and carbon are used in a ratio of 3.2≤ C:SiO₂ < 4 (mol.). Heat treatment is carried out in two stages, and after the first stage of heat treatment, the vacuum furnace is cooled and depressurized, the synthesized silicon carbide powder is removed and mixed with aluminum oxide powder Al₂O₃ in the ratio SiC:Al₂O₃ = 10-20 (mol.), after whereby the mixture is again loaded into a vacuum furnace and re-heat treatment is carried out. The first heat treatment is carried out for 4-5 hours at an inert gas pressure of 0.02-0.03 MPa and a temperature of 1600-1700°C. The second heat treatment is carried out at an inert gas pressure of 0.02-0.05 MPa and a temperature of 1900-2000°C for 1-20 hours.

EFFECT: improving the polytype homogeneity of the synthesized silicon carbide powder of the 4H polytype.

2 cl, 4 dwg, 7 ex