Characterization of Post - Annealed PZT Thin Films Deposited Using Pulsed Laser Ablation

Abstract

ABSTRACTPulsed laser ablation was used to deposit Nd-doped lead zirconate titanate (PZT) thin films with a thickness of from 100 to 800 nm from a Pb0.97 Nd0.02(Zr0.55Ti0.45)O3 target. The films were ablated onto sapphire and MgO substrates using a XeCl excimer laser (pulse energy 50 mJ, wavelength 308 nm, pulse duration 20 ns). The distance between the target and the substrates was 40 mm, and the angle between the target normal and the incident beam was 45 °. The films were post-annealed in air at various temperatures (600 – 900 °C) with PZT powder. It was found that the laser beam energy density on the surface of the target had a significant effect on the composition of the films, the number of particulates on the surface of the films and the growth rates of the films. Lead deficiency was found in the films in the case of high fluence (> 1.5 J/cm2) while low fluence values (< 1.0 J/cm2) gave an excess of lead and too low Zr/(Zr+Ti) ratios. The particulate number density was low for fluence values between 0.5 and 1.5 J/cm2. EDS and X-ray diffraction was used to determine the composition and the crystal structure of the annealed films. The films deposited using a low fluence showed increasing tetragonal c/a-ratio with increasing post-annealing temperatures. Raman spectra measured from annealed films were found to be typical of PZT.