The Field Effect in a Metal–Ferroelectric–Semiconductor System of Multilayer Ferroelectric Films with Various Structure Types

Abstract

The ability to grow the interfacial defect-poor Sr_0.5Ba_0.5Nb₂O₆ + Ba_0.2Sr_0.8TiO₃ and Ba_0.8Sr_0.2TiO₃ + Ba_0.4Sr_0.6TiO₃ ferroelectric films onto the doped silicon substrates is discussed. A study of piezo-response via the quasi-static method (using the electrode area of 0.07 mm²) reveals that heterostructures possess an initial polarized ferroelectric state with a spontaneous polarization vector perpendicular to the substrate at any type of Si conductivity. The polarized state is established to refer to two-dimension stresses in the ferroelectric, which is tunable through a preprepared Ba_xSr_{1 – x}TiO₃ onto a sublayer substrate as well as to a thickness of this sublayer. Polarization switching in Sr_0.5Ba_0.5Nb₂O₆/Si and Ba_0.8Sr_0.2TiO₃/Si heterostructures under the external field arises at only using the barium–strontium titanate sublayer predeposited onto silicon. A 15% decrease in switching polarization in Ba_0.8Sr_0.2TiO₃/Ba_0.4Sr_0.6TiO₃/Si structures is observed after 500 h.