A useful layer (1) is initially attached by a sacrificial layer (2) to a layer (3) forming a substrate. Before etching of the sacrificial layer (2), at least a part of the surface (4, 5) of at least one of the layers in contact with the sacrificial layer (2) is doped. After etching of the sacrificial layer (2), the surface (4, 5) is superficially etched so as to increase the roughness of its doped part. After doping, a mask (9) is deposited on a part of the useful layer (1) so as to delineate a doped zone and a non-doped zone of the surface (4, 5), one of the zones forming a stop after the superficial etching phase.