Direct-write of PZT thick films

Lead zirconate titanate (PZT) thick films have been prepared on alumina substrates using a Direct-Write technology. Thick films of 50 to 200 μm were deposited, dried and then sintered at 1000° to 1200°C for 30 minutes in PbO-rich atmosphere. Comparison of the thick film properties revealed that the dielectric constant and remnant polarization of the films sintered at 1100°C were maximum, likely due to a balance between densification and lead loss. The effects of three sintering aids, i.e., lead oxide, lithium bismuth oxide, and a borosilicate glass, have been investigated on the microstructure and electrical properties of the PZT thick films. It was observed that a 2 wt% lithium bismuth oxide additive has a positive effect on the dielectric constant and remnant polarization of the PZT thick films sintered at 1100°C. The microstructures of the films revealed that 3 wt% additives would result in excessive shrinkage and formation of large pores and cracks at a sintering temperature of 1100°C and above. PZT films with 2 wt.% lithium bismuth oxide showed improved dielectric constant (∼40-50%) and remanent polarization (∼65%) compared to additive-free PZT thick films. It was also found that the properties are strongly thickness dependent.