Microstructure and ferroelectric properties of sol–gel graded PZT (40/52/60) and (60/52/40) thin films

Graded Pb(Zrx,Ti1−x)O3 films with Zr compositions varied across the thickness direction were deposited on Pt/Ti/SiO2/Si substrate using a conventional spin-coating method. The up- and down-graded PZT films exhibited the perovskite polycrystalline structure. Microstructure investigations of the films showed a dense texture and successive layers of different compositions. The relative permittivities of the up- and down-graded PZT films measured at 1 kHz and room temperature were 1846 and 1019, respectively. Good dielectric and ferroelectric properties as well as the low-temperature processing suggested that the compositionally graded PZT films were promising for memory device applications.