Effects of post-deposition annealing ambient on the electrical characteristics and phase transformation kinetics of sputtered lead zirconate titanate (65/35) thin film capacitors

Abstract

The fabrication of high dielectric constant lead zirconate titanate thin films for dynamic random access memory application involves post-deposition annealing to convert the low dielectric constant pyrochlore phase to the desired high dielectric constant perovskite phase. The results of our experiments detailing the dielectric characteristics such as degradation field (the electric field at which a sudden increase in leakage takes place), leakage current density, time-dependent dielectric breakdown characteristics, charge storage density, coercive field, and charge storage density are reported. The charge storage density was measured using both double-bipolar pulses and quasistatic capacitance-voltage techniques. The results of these two measurement techniques are discussed for oxygen and nitrogen annealed films. Additionally, a comparative study of the phase transformation kinetics when the post-deposition annealing is carried out in a nonoxidizing ambient such as nitrogen, as against an oxidizing ambient (pure oxygen), is detailed.