Total Ionizing Dose Effects on Piezoelectric Thin-Film Cantilevers With Oxide Electrodes

Abstract

This paper reports on the ionizing radiation effects in lead-zirconate-titanate (PZT) with varied top electrode material and bias condition during radiation. A technique to characterize the piezoelectric performance of films unclamped from the substrate is described, and used to demonstrate the effects of radiation on the material's electromechanical behavior. Both platinum and iridium oxide top electrodes were examined, and iridium oxide appears to significantly mitigate radiation-induced damage that is observed in platinum top electrode samples. This mitigation of radiation damage is attributed to the reduced number of oxygen vacancies within the PZT films when an iridium oxide top electrode is used. Devices with applied bias during radiation were compared with devices under applied bias only. Applied bias appears to slightly enhance the electromechanical response in the negative bias polarity for irradiated platinum electrode samples suggesting that the bias can cause defects to orient and therefore improve electromechanical response. Ultimately, iridium oxide top electrodes appear to mitigate radiation damage.

Reliable Pb(Zr,Ti)O3-based thin film piezoelectric micromirrors for space-applications

“…kV/cm at room temperature is inadequate to markedly enhance device-poling. Despite that the total dose of 1 kGy used here is well below typical literature doses 27,[29][30][31][32] and well below the radiation hardness of PZT (~50 kGy 31,32 ), the results indicate that 𝛾𝛾-radiation and bias still induce some radiationdamages even at lower exposure doses. Figure 4 (a) exemplifies typical leakage vs. time curves for eight inner, eight outer, and eight capacitors, plotted on top of each other in the same graph.…”

“…Despite the indication of increased large-signal leakage, Figure 3 (c) and (d) shows that the permittivity and loss were not significantly affected. Zhu et al have shown that UV radiation can be used as a tool to enhance poling and also enable cold-poling 28,29 . Though 𝛾𝛾radiation and bias are expected to cause similar effects, neither the small-signal deflection nor 𝑑𝑑 𝐿𝐿𝐿𝐿 of the micromirrors increased more than the other stress tests.…”