Pt-ion-implantation-induced suppression of leakage conduction in Pt/Pb)(Zr_xTi_1−x)O₃/Pt capacitors

Abstract

The effect of 1 MeV ion implantation on leakage conduction, dielectric and ferroelectric properties of the Pt/Pb(Zr_xTi_1−x)O₃/Pt capacitors is studied for a wide range of implantation doses (10¹⁰–10¹⁶cm⁻²). It is shown that the implantation of Pt⁺, with an implant and vacancy profile peaking at the bottom interface and a dose within the range of 10¹³–10¹⁶cm⁻², provokes a strong suppression of the leakage conduction and ferroelectric hysteresis. In addition, ion implantation results in a decrease of the static dielectric constant. Annealing of the specimens at 650°C restores the initial conduction and dielectric properties. The phenomena observed can be interpreted in terms of formation of a non-switching dielectric layer at the interface of the ferroelectric film.

For doses ranging from 10¹³ to 10¹⁴cm⁻² the specimen shows the behavior of a linear capacitor with dielectric constant of 120–270 and low level of leakage currents (about 10⁻⁹ A/cm² at dc electric field of 150kV/cm). The results obtained indicate that ion bombardment of the ferroelectric film surface can be of practical interest for creation of high dielectric constant hysteresis-free low-leakage capacitor materials.

Key Words:

• PZT
• film
• conduction
• ion bombardment