Patent ID: 8693835

Claim:
A method for transferring a thin layer from a first substrate including lithium ions, the method comprising: proton exchange between the first substrate and a first electrolyte comprising an acid, through a free face of the first substrate so as to replace the lithium ions of the substrate with protons, in a proportion between 10% and 80%, to a first depth; reverse proton exchange between the first substrate and a second electrolyte, through the free face, so as to replace substantially all of the protons with lithium ions to a second depth less than the first depth, and so as to leave an intermediate layer between the first and second depths including the protons incorporated during the proton exchange, wherein the second depth defines a thin layer between the free face and the intermediate layer; after reverse proton exchange, carrying out a thermal treatment under conditions suitable for weakening the intermediate layer, and separating the thin layer with respect to the rest of the substrate at the level of the intermediate layer.