Production of bulk silicon carbide with hot-filament chemical vapor deposition

A method to deposit a crystalline silicon carbide boule on a substrate, the method comprising:

• providing a vapor deposition chamber comprising a plurality of filaments, a substrate pedestal, and a substrate that is in operable communication with the substrate pedestal, wherein the distance between the substrate surface and the plurality of filaments ranges from 18 to 25 mm, and wherein the position of the substrate pedestal relative to the plurality of filaments is adjustable;
• heating the plurality of filaments to at least 2300° C.;
• depositing the crystalline silicon carbide on the substrate surface by flowing a silicon-containing precursor and a carbon-containing precursor proximate to the plurality of heated filaments thereby thermally activating gaseous deposition precursors and reacting the activated precursors at the substrate surface to form a silicon carbide boule having a thickness of at least 5 mm;
• during the deposition, moving the position of the substrate pedestal relative to the plurality of filaments so as to maintain a distance of 18 to 25 mm between the plurality of heated filaments and the surface of the boule.