Abstract: This invention relates to a method of producing a silicon carbide substrate having desirable electrical insulation properties. The silicon carbide substrate is produced by applying to a surface of a silicon carbide plate a film-forming composition which consists essentially of at least one oxide or substance with produces an oxide by decomposition of an element selected from the group consisting of aluminum, phosphorus, boron, germanium, arsenic, antimony, bismuth, vanadium, zinc, lead, cadmium, sodium, potassium, lithium, beryllium, calcium, magnesium, barium and strontium and heating the silicon carbide body in an oxidizing atmosphere to form a eutectic oxide layer thereon.

Abstract: A silicon carbide substrate having excellent electrical insulation properties is disclosed. The silicon carbide substrate is produced by closely adhering to a surface of a silicon carbide plate body a eutectic oxide layer comprising SiO.sub.2 produced by partial oxidation of the plate body and at least one oxide selected from Al.sub.2 O.sub.3, P.sub.2 O.sub.5, B.sub.2 O.sub.3, GeO.sub.2, As.sub.2 O.sub.3, Sb.sub.2 O.sub.3, Bi.sub.2 O.sub.3, V.sub.2 O.sub.5, ZnO, PbO, Pb.sub.3 O.sub.4, PbO.sub.2, CdO, Na.sub.2 O, K.sub.2 O, BeO, CaO, MgO, BaO and SrO.