METHOD FOR FABRICATING A STRUCTURE

This method for fabricating a structure (3) comprising, in succession, a support substrate (2), a dielectric layer (10), an active layer (11), a separator layer (20) of polycrystalline silicon, comprises the steps of: a) providing a donor substrate, b) forming an embrittlement area in the donor substrate, c) providing the support structure (2), d) forming the separator layer (20) on the support substrate (2), e) forming the dielectric layer (10), f) assembling the donor substrate (1) and the support substrate (2),. g) fracturing the donor substrate (1) along the embrittlement area, h) subjecting the structure (3) to a strengthening annealing of at least 10 minutes, the fabrication method being noteworthy in that the step d) is executed in such a way that the polycrystalline silicon of the separator layer (20) exhibits an entirely random grain orientation, and in that the strengthening annealing is executed at a temperature strictly greater than 950 DEG C and less than 1200 DEG C.