Manufacturing process of a structured substrate

A method for fabricating a structured substrate provided with a trap-rich layer whereon rests a stack consisting of, in the following order and from said trap-rich layer:

• an insulating layer and a layer of single-crystal material, the method comprising the following steps:
• a) forming an amorphous silicon layer that extends from a front face of a silicon substrate according to a thickness E less than 500 nm, advantageously between 50 nm and 200 nm,
• b) heat treating intended to convert the amorphous silicon layer into a trap-rich layer consisting of single-crystal silicon grains mutually joined by grain boundaries and of a size less than 200 nm, preferably less than 100 nm,
• c) forming a stack by overlapping the trap-rich layer, and consisting of, in the order and from said trap-rich layer, an insulating layer and of a layer of single-crystal material.