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Links between humidity-induced resistance-degradation and recovery of PZT-based piezoMEMS

Links between humidity-induced resistance-degradation and recovery of PZT-based piezoMEMS

Category
Journal publication
Abstract
Pb(Zr, Ti)O3 (PZT) is a piezoelectric material with large dielectric and piezoelectric compliances and is one of the most technologically important materials for thin film piezoelectric microelectromechanical systems. Reliability in humid conditions is a key concern for deploying devices in realistic and harsh environments. This paper describes how the combination of ambient humidity, electrode-size, and surface-currents affect the resistance-degradation of PZT thin films. It was found that the leakage and resistance-degradation of Au/TiW/PZT/Pt/Ti/SiO2 stacks increased considerably above 50 % relative humidity. Surface protonics dominates over bulk in humid conditions contributing to a resistance-drop from ~1012 Ω in dry to ~108 Ω. This enables electrochemically driven reversible and irreversible degradation in the form of leakage transients, cracking and electrothermal breakdown events. The median time to failure decreased with electrode size due to the increase in electrochemically active area, yet comparable degradation was present for all pad-sizes post-failure. The pristine state of the samples could not be recovered by either flushing with dry nitrogen or annealing at 150 due to irreversible degraded samples.
Client
  • Norges forskningsråd / NBRIX: Prosjektnummer: 247781
  • Norges forskningsråd / NBRIX: PROSJEKTNUMMER: 247781
Language
English
Author(s)
Affiliation
  • Norwegian University of Science and Technology
  • SINTEF Industry / Sustainable Energy Technology
  • SINTEF Digital / Microsystems and Nanotechnology
Year
2019
Published in
Journal of Applied Physics
ISSN
0021-8979