Effects of disturbing pulses on the switchable polarization of Pb(ZrTi)O3 thin film capacitors

The effect of disturbing pulses on the switchable polarization in ferroelectric films of PbZrxTi1−xO3 with x=0.36 and 0.71 has been investigated. The two compositions were selected because of their different hysteresis shapes. Pulse measurements were carried out with a varying number of disturbing pulses at different amplitudes, interrupted by single shot read/write pulses. It was found that the composition with the squarer loop (x=0.36) showed less sensitivity to disturbing pulses, i.e., the switchable polarization did not significantly degrade with 109 disturbing pulses of amplitude 1.2 V. In addition, these results demonstrate that degradation of the stored polarization due to parasitic disturbing voltages in high density ferroelectric random access memories can be kept at an acceptable level.