Physical properties of radio-frequency magnetron sputtered Pb(Zr,Ti)O3 thin films: Direct determination of oxygen composition by Rutherford backscattering spectroscopy and nuclear reaction analysis*

Abstract

Ferroelectric thin films of lead zirconate titanate were deposited on platinum covered Si substrates by rf magnetron sputtering from an oxide target of nominal composition [Pb(Zr0.55, Ti0.45)O3 (PZT)] in argon. The PZT films were deposited at different pressures different powers, and different substrate temperatures ranging from floating temperature to 400 °C. The thicknesses of the sputtered films were in the 15–720 nm range. The kinetics of the sputtering process and the effect of sputtering parameters on film composition have been studied and related to the continuously monitored optical emission of the plasma. The relative and absolute cation and oxygen compositions of the thin films were determined by a new method based on the simultaneous use of Rutherford backscattering spectroscopy and nuclear reaction analysis induced by a deuteron beam. The conditions for the deposition at floating temperature of stoichiometric PZT thin films were established. The effect of postdeposition anneal on the structure and the ferroelectric properties are discussed. The remanent polarization Pr was in the range 5 μC/cm2, the coercitive field Ec was between 15 and 25 kV/cm, and the dielectric constant εr evaluated from capacitance measurements, was around 1200, depending on the process parameters.