Electrical conductivity and interface phenomena in thin-film heterostructures based on lithium niobate and lithium tantalate

Abstract

In this work, the electrophysical properties of metal-ferroelectric-semiconductor structures --- Cu/LiNbO3/Si and Ag/LiTaO3/Si --- with a ferroelectric layer thickness of 200 nm have been studied. The ferroelectric layers were deposited by RF magnetron sputtering. A topography study of thin film surface revealed a grain structure. The electrical conductivity mechanisms in Cu/LiNbO3/Si and Ag/LiTaO3/Si were considered. In a dependence of bias voltage value, there are a space charge-limited current, hopping conduction, and Schottky emission in Cu/LiNbO3/Si structures. For Ag/LiTaO3/Si structures, the space charge-limited current and hopping conduction were observed. An asymmetry of the current-voltage characteristics may indicate the presence of a potential barrier at the interface. For the studied structures, the value of the potential barrier was determined Keywords: metal-ferroelectric-semiconductor structures, thin films, lithium niobate, lithium tantalate, electrophysical properties, electrical conductivity, potential barrier.