A process is described for integrating, on an inert substrate, a device having at least one passive component and one active component. The process comprises: deposition of a protection dielectric layer on the inert substrate; formation of a polysilicon island on the protection dielectric layer; integration of the active component on the polysilicon island; deposition of the covering dielectric layer on the protection dielectric layer and on the active component; integration of the passive component on the covering dielectric layer; formation of first contact structures in openings realised in the covering dielectric layer in correspondence with active regions of the active component; and formation of second contact structures in correspondence with the passive component. An integrated device obtained through this process is also described.