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

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 5 pm/V, and a coercive voltage of V-c = 1-2 V with an as-grown polarization along the growth direction consistent with TEM observations. (C) 2013 Elsevier B.V. All rights reserved.