  We have studied the effect of chemical-mechanical polishing (CMP) on the
ferroelectric, piezoelectric, and microwave dielectric properties of
Ba-substituted PZT (BPZT), deposited by pulsed laser deposition. CMP allowed
for the reduction of the root mean square surface roughness of 600 nm thick
BPZT films from 12.1nm to 0.79 nm. Ammonium peroxide (SC-1) cleaning was
effective to remove Si CMP residuals. Measurements of the ferroelectric
hysteresis after CMP indicated that the ferroelectric properties of BPZT were
only weakly affected by CMP, while the piezoelectric d33 coefficient and the
microwave permittivity were reduced slightly by 10%. This can be attributed to
the formation of a thin dead layer at the BPZT surface. Moreover, the intrinsic
dielectric permittivity at microwave frequencies between 1 and 25 GHz was not
influenced by CMP, whereas the dead layer series capacitance decreased by 10%.
The results indicate that the CMP process can be used to smoothen the BPZT
surface without affecting the film properties strongly.
