Enhanced electrical properties of ferroelectric Pb(Zr_0.5,Ti_0.5)O₃ thin films grown with low-energy oxygen ion assistance

Abstract

Electrical properties pertinent to memory applications of ferroelectrics are systematically characterized for multi-ion-beam reactive sputter deposited Pb(Zr_0.5, Ti_0.5)O₃ thin films. The processing dependence of electrical properties of the films offers an opportunity for property modification. Low-energy oxygen ion bombardment assistance is useful in this aspect. Under optimal bombardment conditions (ion/atom ratios between 1.0 and 1.3; ion/energies ranging from 60 to 80 eV), many electrical properties can be beneficially modified. Relative to the nonbombarded films, the bombarded films exhibit increases in remanent polarization and resistivity, and reductions in coercive field. Bombardment-enhanced properties also include switching characteristics, dielectric responses, switching endurance, polarization retention, dc current-voltage behavior, and time-dependent dielectric breakdown strength. The experimental results are explained in correlation to processing and structure of the films. The roles of preferential orientation, crystallinity, degree of imperfection, grain size, and grain boundaries of the films are emphasized.