Effect of electrically induced cracks on the properties of PZT thin film capacitors

We present a study of the effect of electrically induced cracks on both the ferroelectric and piezoelectric properties of Pt/PbZr0.52Ti0.48O3 (PZT)/Pt capacitors and correlations with domain structures of PZT films. Above a threshold bipolar electric field, cracks appear inside the PZT layer thickness leading to an increase in the ferroelectric polarization (+50% for the remnant polarization, from 16 to 25  μC/cm2) and the longitudinal piezoelectric coefficient d33,f (from ∼150 to ∼220 pm/V). The use of x-ray diffraction during in situ biasing provides direct evidence for a modification of the PZT crystalline structure as well as the a/ c domain configuration. After cracking, the fraction of c-domains is strongly increased, thus contributing to higher polarization and larger strain in the out-of-plane direction.