Process for producing a composite structure comprising a thin layer of monocrystalline sic on a carrier substrate made of polycrystalline sic

A method for producing a composite silicon carbide structure comprises:providing an initial substrate of monocrystalline silicon carbide;depositing an intermediate layer of polycrystalline silicon carbide at a temperature higher than 1000° C. on the initial substrate, the intermediate layer having a thickness greater than or equal to 1.5 microns;implanting light ionic species through the intermediate layer to form a buried brittle plane in the initial substrate, delimiting the thin layer between the buried brittle plane and the intermediate layer, anddepositing an additional layer of polycrystalline silicon carbide at a temperature higher than 1000° C. on the intermediate layer, the intermediate layer and the additional layer forming a carrier substrate, and separating the buried brittle plane during the deposition of the additional layer.