Silicon nitride based substrate for semi-conductor components

A substrate contains silicon nitride, silicon carbide and silicon oxynitride as crystalline phases with a crystalline silicon amount of not more than 5 %, a shrinkage during manufacture of less than 5% and an open porosity of less than 15%. An independent claim is also included for the production of the substrate comprising intensively mixing a starting mixture, molding by pressing, slip casting, hot pressing, extruding or foil casting, crosslinking in an inert atmosphere, pyrolyzing, nitriding and optionally sintering. Preferred Features: The substrate is made from carbides, nitrides, carbonitrides, oxynitrides, silicides and/or borides of silicon, aluminum, titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, manganese and/or iron. The substrate contains less than 20 wt.% sintering additives made from silica, alkaline earth oxides, group IIIB and IVB oxides, and oxides of vanadium, niobium, tantalum, chromium, molybdenum, tungsten, manganese, iron, calcium and/or nickel alone or in combination with B 2O 3, Al 2O 3 and/or TiO 2.