Epitaxial ferroelectric oxides on semiconductors- A route towards negative capacitance devices

Abstract

Graphical abstractDisplay Omitted Single crystal ferroelectric oxides were grown on both Si and GaAs.Molecular beam epitaxy of BaTiO3 using molecular oxygen.STEM reveals oxide/GaAs interface is more stable to reaction with diffused oxygen.PFM and PFS measurements demonstrate ferroelectricity on both Si and GaAs substrates. Epitaxial ferroelectric BaTiO3 layers were deposited on both Si and compound semiconductor substrates using molecular beam epitaxy. The films were grown using molecular oxygen and were found to be c-axis oriented as determined from X-ray diffraction measurements. High resolution transmission electron microscopy indicated the interface between the oxide and GaAs is free of structural defects while a thick layer of amorphous SiO2 layer is present at the interface of the oxide and Si. Ferroelectric properties of the BaTiO3 films were measured using piezoresponse force microscopy and spectroscopy. The BTO films show a piezoresponse amplitude ~5pm/V, and a coercive voltage of Vc=1-2V with an as-grown polarization along the growth direction consistent with TEM observations.