Structural and electrical investigations revealed that a direct wafer bonding and layer transfer process yields good quality ferroelectric/Si interfaces for SBT, PZT and BiT ferroelectric thin films. C-V characteristics and interface trap measurements show a large difference for Au-Ferroelectric-Si structures depending on whether the interface is fabricated by bonding or by direct deposition. For reacted interfaces the trap densities are ranging from 2x 10(12) cm(-2) ev(-1) for SBT/Si and BiT/Si to 2x 10(13) cm(-2)eV(-1) for PZT/Si. For bonded interfaces, independent of the top ferroelectric layer, the trap density is about 4x 10(11) cm(-2)eV(-1). [References: 15]