Method for forming a handling substrate for a composite structure intended for RF applications and handling substrate

A method of forming a handle substrate for a composite structure, the method comprising:

• action a) providing a monocrystalline silicon wafer obtained by Czochralski pulling exhibiting a resistivity of between 10 and 500 ohm.cm;
• action b) growing an epitaxial layer of silicon on the monocrystalline silicon wafer obtained by Czochralski pulling to form a base substrate, the epitaxial layer of silicon exhibiting a resistivity of greater than 2,000 ohm.cm and a thickness ranging from 2 to 100 microns;
• action c) forming a passivation layer on the epitaxial layer of silicon, the passivation layer being amorphous or polycrystalline, wherein forming the passivation layer includes:
• a carbonization of the surface of the epitaxial layer of silicon so as to form the passivation layer made of polycrystalline silicon carbide, or
• a nitridation of the surface of the epitaxial layer of silicon so as to form the passivation layer made of silicon nitride;
• and
• action d) growing a polycrystalline charge-trapping layer on the passivation layer.