Effects of electrodes on the electric properties of Pb(Zr,Ti)O-3 films deposited by electron cyclotron resonance plasma enhanced chemical vapor deposition

The effects of electrodes on the deposition characteristics and electrical properties of lead zirconate titanate (PZT) films deposited by electron cyc lotron resonance plasma enhanced chemical vapor deposition (ECR-PECVD) were investigated. Pt/Ti/SiO2/Si and RuO2/SiO2/Si were used as bottom electrode s (substrates) for PZT capacitors. Pt and RuO2 were used as top electrodes. The nucleation of the perovskite phase was more difficult on RuO2 substrat es than on Pt/Ti substrates, and the PZT films grown on RuO2 substrates ten d to have Pb-based second phases. Precise control of the flow rates of meta lorganic sources (particularly the lead source) and the introduction of a p roper seed layer are required to obtain films of the single perovskite phas e and good electrical properties on the RuO2 substrate. An excellent leakag e current density of 10(-6) A/cm(2) at 150 kV/cm was obtained from the Pt(t op)/PZT/RuO2(bottom) capacitor with the introduction of a 4 nm-thick Ti-oxi de seed layer. The polarization fatigue and current leakage characteristics of the PZT capacitors with four different electrode configurations (Pt \\ Pt, RuO2 \\ Pt, Pt \\ RuO2, and RuO2 \\ RuO2) were also investigated. Only the RuO2/PZT/RuO2 capacitor did not show any polarization fatigue even afte r 10(10) cycles, while the other capacitors, whose either top or bottom ele ctrode was Pt, showed distinct polarization fatigues. The RuO2/PZT/RuO2 cap acitor, however, showed a leakage current density of as high as 10(-4) A/cm (2) at 100 kV/cm.