Fabrication and investigation of ultrathin, and smooth Pb(Zr,Ti)O3 films for miniaturization of microelectronic devices

Pb ( Zr 0.52 Ti 0.48 ) O 3 (PZT) thin films were fabricated on Pt(111)/TiOx/SiO2/Si substrates at 375 °C by radio frequency magnetron sputtering. A mixture of (110) and (100) orientations was found in all the PZT thin films. However, the in-plane grain size increased with an increase in film thickness, all films had smooth surfaces, and the root mean square roughness of the PZT films was in the range of 1–1.5 nm. As the film thickness increased, a decrease in residual stress and volume density of the PZT films was observed. PZT films become poorly crystallized with a decrease in film thickness. The magnitude of the maximum displacement from atomic force microscopy in local piezoresponse hysteresis mode increased from 187.25±9.363 in 40 nm to 418.5±20.925 in 152 nm. We suggest that the degradation in piezoelectric properties with a decrease in film thickness resulted from degradation of the crystallinity observed using transmission electron microscopy analysis, size effects derived from the grain size, and the residual stress evaluated using a laser reflectance method.