CVD 법으로 증착된 PZT 박막의 누설잔류 및 강유전 특성

Abstract

Leakage current characteristics and ferroelectric properties of lead zirconate titanate(PZT) films deposited by electron cyclotron resonance plasma enhanced chemical vapor deposition were investigated. Pt/Ti and RuO₂ were used as bottom electrodes for PZT film. The nucleation of PZT perovskite phase was more difficult on RuO₂ electrodes than on Pt electrodes, and the PZT films grown on RuO₂ tend to have PbO_x second phase. PZT film without PbO_x phase could be grown on RuO₂ by introducing a proper seed layer and by controlling the flow rates of Metal-organic source (particularly Pb(DPM)₂). For the PZT films on RuO₂ with improved microstructure, an excellent leakage current density of 10^(-6)A/㎠ at 100 ㎸/㎝ was obtained from the Pt(top)/PZT/RuO₂ capacitor. Leakage current characteristics and ferroelectric properties of PZT capacitors with four different electrode configurations were investigated. The RuO₂∥ RuO₂ capacitor showed a leakage current density of as high as 10^(-4) A/ ㎠ at 100 ㎸/㎝, which was attributed to the high temperature processes for RuO₂ top electrodes fabrications. The fatigue characteristics of PZT capacitors depend on the electrode material rather than the microstructure of PZT films.