Pb(Zr0.52Ti0.48)O3 (PZT) films
with (001) orientation were deposited on Pt(111)/Ti/SiO2/Si(100) substrates using pulsed laser deposition. Variation of the
laser pulse rate during the deposition of the PZT films was found
to play a key role in the control of the microstructure and to change
strongly the piezoelectric response of the thin film. The film deposited
at low pulse rate has a denser columnar microstructure, which improves
the transverse piezoelectric coefficient (d31f) and ferroelectric remanent polarization (Pr), whereas the less densely packed columnar grains in the
film deposited at high pulse rates give rise to a significantly higher
longitudinal piezoelectric coefficient (d33f) value. The effect of film thickness on the ferroelectric and piezoelectric
properties of the PZT films was also investigated. With increasing
film thickness, the grain column diameter gradually increases, and
also the average Pr and d33f values become larger. The largest piezoelectric coefficient
of d33f = 408 pm V–1 was found for a 4-μm film thickness. From a series of films
in the thickness range 0.5–5 μm, the z-position dependence of the piezoelectric coefficient could be deduced.
A local maximum value of 600 pm V–1 was deduced
in the 3.5–4.5 μm section of the thickest films. The
dependence of the film properties on film thickness is attributed
to the decreasing effect of the clamping constraint imposed by the
substrate and the increasing spatial separation between the grains
with increasing film thickness.