Effect of sputtering working pressure on microstructures and properties of PZT thin films

In this work, PZT (52/48) and PZT (30/70) thin films were deposited at a substrate temperature of 600°C with Argon gas pressure ranging from 2.8 × 10^-2 mbar to 4.3 × 10^-3 mbar by r. f. magnetron sputtering on LNO/Si substrates. Highly (100)-oriented rhombohedral structured PZT (52/48) thin films were formed. We found that the out-of-plane lattice constant increased commensurately with a decrease in Ar pressure, while remnant polarization and dielectric constant increased with decreasing Ar pressure. On the other hand, the PZT (30/70) thin films sputter-deposited on LNO/Si(100) at substrate temperatures of 600°C with various Ar gas pressures formed a tetragonal structure. The fraction of c-domain, hence the remnant polarization, increased with decreasing Ar pressure, while the dielectric constant decreased with decreasing Ar pressure.