Leakage current mechanism and accelerated unified test of lead zirconate titanate thin film capacitors

Leakage current was investigated for lead zirconate titanate (PZT) thin films on platinum (Pt) and ruthenium oxide (RuO_x) electrodes. Schottky emission was observed for both PZT capacitors. An accelerated unified test technique which can measure fatigue and time-dependent dielectric breakdown (TDDB) simultaneously in a short period of time was suggested. Schottky barrier heights are asymmetric between top and bottom electrodes, probably because of different electrode processing conditions during capacitor fabrication. PZT capacitors with RuO_x show earlier electrical degradation than those with Pt electrodes under DC electric field. However, films on RuO _x show better breakdown properties under AC field because of a healing effect due to better lattice match between PZT and electrodes