Characterization of Charging Lithium Niobate and Lithium Tantalate Ferroelectrics Under Irradiation With Defocused Electron and Ion Beams

Abstract

This article presents the experimental characteristics of charging lithium niobate and lithium tantalate ferroelectrics under irradiation with wide electron and ion beams. Electron irradiation has carried out in the scanning electron microscope (SEM) over the range of primary electron energies from 0.2 to 10 keV. Ion irradiation has performed using Ar <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{\mathbf {+}}$ </tex-math></inline-formula> ions with the energy of 6 keV. The density of particle beams is of the order of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10^{\mathbf {-6}} \text {A} \cdot \text {cm}^{\mathbf {-2}}$ </tex-math></inline-formula> . Calculations of the charges and fields in the frameworks of the proposed models of four-layer charge distributions under electron irradiation and three-layer distribution under ion irradiation were discussed. Anomalies in the emission characteristics under bombardment with particles of various energies are found. The charging efficiency factor for ion irradiation is almost an order of magnitude of the irradiation dose higher than in the case of electron irradiation. In turn, smaller irradiation doses are required for charging customary dielectrics than for charging ferroelectrics. A possible explanation of these differences is proposed.