AC Reliability of Integrated Low-Temperature PVD PZT Films

Lead Zirconate Titanate (PZT) thin films are important for many applications in MEMS e.g. micro-mirrors, micro-speakers, or print heads. In this work reliability of an integrated low-temperature PVD PZT thin film stack for the important case of unipolar AC electric stress over temperature and DC offset is discussed. Closing the literature gap, time to breakdown data with statistical relevance is presented employing high-resolution current and polarization monitoring also during failure progression. Comparison with results obtained under DC electric stress reveals that DC degradation still dominates under unipolar AC load. This observation holds over tested AC frequency, DC offset, and temperature ranges. Within this range, AC lifetime can be predicted based on DC time to breakdown experiments.