Method for transferring a useful layer

A method for transferring a useful layer onto a support comprising the following steps:

• forming an embrittlement plane by implanting light elemental species into a first substrate, so as to define a useful layer between the embrittlement plane and one surface of the first substrate;
• applying the support onto the surface of the first substrate so as to form an assembly to be fractured;
• applying a heat treatment for embrittling the assembly to be fractured;
• and
• initiating and propagating a fracture wave in the first substrate along the embrittlement plane;
• wherein:
• the fracture wave is initiated in a central area of the embrittlement plane;
• the propagation speed of the fracture wave is controlled so that the velocity thereof is sufficient to cause interactions of the fracture wave with acoustic vibrations emitted upon the initiation and/or propagation thereof, if any, are confined to a peripheral area of the useful layer;
• the fracture wave is initiated by energy input at the central area of the embrittlement plane;
• and
• the propagation speed is controlled by causing the embrittlement plane to have a maturing rate at least equal to a target maturing rate during the embrittlement heat treatment.

A method for transferring a useful layer onto a support comprising the following steps:

• forming an embrittlement plane by implanting light elemental species into a first substrate, so as to define a useful layer between the embrittlement plane and one surface of the first substrate;
• applying the support onto the surface of the first substrate so as to form an assembly to be fractured;
• applying a heat treatment for embrittling the assembly to be fractured;
• and
• initiating and propagating a fracture wave in the first substrate along the embrittlement plane;
• wherein:
• the fracture wave is initiated in a central area of the embrittlement plane;
• the propagation speed of the fracture wave is controlled so that the velocity thereof is sufficient to cause interactions of the fracture wave with acoustic vibrations emitted upon the initiation and/or propagation thereof, if any, are confined to a peripheral area of the useful layer;
• and
• the peripheral area comprises an annular area, an inner radius of the annular area being greater than ⅔ of the radius of the first substrate.