Abstract: An implantation wheel for forming a plane of weakness in a plurality of donor wafers comprises a main disk and a plurality of wafer supports arranged on one face of the main disk. Each wafer support has a host surface on which a so-called “rear” face of a donor wafer is placed. According to a first aspect, the host surface at least partially comprises a superficial elastomer layer, the superficial elastomer layer having a dimension at least equal to that of the rear face of the donor wafer. According to another aspect, each host surface of the plurality of wafer supports has a convex shape, the convex shape being chosen to correspond to the shape of the donor wafer as the donor wafer deforms under the effect of temperature.

Abstract: The invention relates to a method for transferring a thin film onto a support substrate, which comprises: providing a bonded assembly that comprises a donor substrate and the support substrate, assembled by direct bonding at their respective front faces, following a bonding interface, the bonded assembly having a local unbonded area within this bonding interface, the donor substrate further comprising a buried brittle plane; separating along the buried brittle plane, initiated at the local unbonded area after microcrack growth in said plane by thermal activation, the separation resulting in the transfer of a thin film from the donor substrate to the support substrate. The method is characterised in that the local unbonded area is generated solely by a roughened area, produced deliberately on at least one of the front faces of the donor and support substrates prior to assembly, free of topology and having a predetermined roughness with an amplitude of between 0.5 nm RMS and 60.0 nm RMS.

Abstract: A method for transferring a useful layer to a carrier substrate comprises: joining a front face of a donor substrate to a carrier substrate along a bonding interface to form a bonded structure; annealing the bonded structure to apply a weakening thermal budget thereto and bring a buried weakened plane in the donor substrate to a defined level of weakening, the anneal reaching a maximum hold temperature; and initiating a self-sustained and propagating splitting wave in the buried weakened plane by applying a stress to the bonded structure to lead to the useful layer being transferred to the carrier substrate. The initiation of the splitting wave occurs when the bonded structure experiences a thermal gradient defining a hot region and a cool region of the bonded structure, the stress being applied locally in the cool region, and the hot region experiencing a temperature lower than the maximum hold temperature.