On the Effect of Water-Induced Degradation of Thin-Film Piezoelectric Microelectromechanical Systems

Lifetime and reliability in realistic operating conditions are important parameters for the application of thin-film piezoelectric microelectromechanical systems (piezoMEMS) based on lead zirconate titanate (PZT). Humidity can induce time-dependent dielectric breakdown at a higher rate compared to dry conditions, significantly alter dynamic behavior piezoMEMS-devices. Here we assess lifetime PZT-based micromirrors with without humidity barriers operated 23°C an ambient 0 95 % relative humidity. The correlation response, as well ferroelectric, dielectric, leakage properties, degradation time was investigated. In humid median timeto-failure increased from 2.7×10 4 [1.9×10 -4.0×10 ] s 1.1×10 xmlns:xlink="http://www.w3.org/1999/xlink">6 [0.9×10 -1.5×10 20 VAC continuous unipolar actuation, by using 40 nm thick Al 2 O xmlns:xlink="http://www.w3.org/1999/xlink">3 barrier. However, initial maximum angular deflection, polarization, permittivity decreased about 6, 11, 12 %, respectively, capped devices. For both bare encapsulated devices, onset electrothermal breakdown-events dominant cause degradation. Severe distortions device's behavior, together failure loss preceded 95% Moreover, due film-substrate stress transfer sensitivity water-induced affects piezoMEMS differently than bulk piezoMEMS.