Method for manufacturing a composite structure comprising a thin layer of monocrystalline SiC on an SiC carrier substrate

A method for manufacturing a composite structure comprising a thin layer of monocrystalline silicon carbide arranged on a polycrystalline silicon carbide carrier substrate, the method comprising:

• a) a step of providing an initial substrate made of monocrystalline silicon carbide;
• b) a step of epitaxial growth of a monocrystalline silicon carbide donor layer (110) on the initial substrate to form a donor substrate, the donor layer having a density of crystal defects less than that of the initial substrate;
• c) a step of ion implantation of light species into the donor layer to form a buried brittle plane delimiting the thin layer between the buried brittle plane and a free surface of the donor layer;
• d) a step of direct liquid injection-chemical vapor deposition, at a temperature below 1000° C., to form a carrier layer directly on the free surface of the donor layer, the carrier layer being formed by an at least partially amorphous SiC matrix;
• e) a step of separating along the buried brittle plane to form an intermediate composite structure comprising the thin layer on the carrier layer, and a remainder of the donor substrate;
• f) a step of heat treatment at a temperature of between 1000° C. and 1800° C., applied to the intermediate composite structure, to crystallize the carrier layer and to form the polycrystalline carrier substrate;
• and
• g) a step of mechanical and/or chemical treatment(s) of the composite structure, the treatment(s) being applied to a free face of the carrier substrate at a rear face of the composite structure, and/or to a free face of the thin layer at a front face of the composite structure.