Metal-ferroelectric-silicon (MFS) structures were fabricated by a layer transfer process and direct wafer bonding (DWB) and by direct deposition of ferroelectric films onto Si. Detailed transmission electron microscope (TEM) investigations revealed that a direct wafer bonding and layer transfer process yields good quality ferroelectric/Si interfaces. C-V characteristics and interface trap measurements show a large difference for Au-ferroelectric-Si structures fabricated by bonding or by direct deposition. For directly deposited interfaces the trap densities are ranging from 2x10(12)cm(-2)eV(-1) for SBT/Si to 2x10(13) cm(-2)eV(-1) for PZT/Si. For bonded interfaces, irrespective of the top ferroelectric layer, the trap density is about 4x10(11)cm(2)eV(-1). [References: 18]