Residual stress effects on piezoelectric response of sol-gel derived PZT thin films

摘要

Piezoelectric properties of three sol-gel derived Pb(Zr0.53Ti0.47)O3 thin film samples integrated on to Pt/Ti/SiO 2//Si substrates are investigated to delineate the influence of residual stress on the strain-field response from other thickness related effects. Residual tensile stresses are determined from wafer curvature measurements for identical films ranging in thickness from 190nm to 500nm. Field-induced strains are measured interferometically for each film under either a large AC driving voltage or a small AC ripple applied over a range of DC biases. Higher residual stresses decrease measured piezoelectric response, while thickness variations with no accompanying change in residual stress state produce little change in strain-field behavior. The diminished performance associated with high residual stresses is attributed to reductions in both linear and nonlinear contributions, including decreased polarization switching and domain motion.