Electric and longitudinal piezoelectric properties of PZT(52/48) films as a function of thickness prepared by diol based sol-gel method.

Abstract

Piezoelectric and electrical properties were investigated in PZT (52/48) films as a function of thickness. Films are prepared by diol based sol-gel method by spin coating in order to achieve much thicker films on Si wafer. The optimized thickness of each layer individual was 0.2 mum and crack-free films could be successfully deposited on 4 inches Pt/Ti/SiO2/Si substrate. Thickness dependence of microstructure on piezoelectric and electrical properties was characterized over the range of 0.2-3.8 mum. The films exhibited (111) preferred orientation in the range of thickness below 1 mum. As the thickness increased, the (111) preferred orientation disappeared and the orientation of films became random above 3 gm. Effective longitudinal piezoelectric coefficient, d(33), measured by pneumatic method, remanent polarization and dielectric constants were saturated around the value of about 300 pC/N, 45 muC/cm(2) and 1400 respectively above the thickness of 1 mum.