Effect of applied mechanical strain on the ferroelectric and dielectric properties of Pb(Zr0.35Ti0.65)O3 thin films

Abstract

A wafer bending method has been devised to impose biaxial strains on Pb(Zr0.35Ti0.65)O3 (PZT) thin films ranging in thickness from 700 to 4000 Å grown by metal-organic chemical vapor deposition. The ferroelectric and dielectric properties of PZT capacitors were investigated while the film was placed under biaxial tension. It was observed that biaxial strains as small as 0.08% can reversibly reduce the remanent polarization of PZT films by 12 to 14% for all film thicknesses. The small-signal capacitance measured at voltages significantly larger than the switching voltage increased with increasing biaxial tension. These observations present clear evidence of room temperature strain accommodation in PZT thin films by reversible 90° domain wall motion that changes the volume fraction of the film that switches during electrical testing.