Sol–gel derived PMN–PT thick films for high frequency ultrasound linear array applications

A 12-µm PMN–PT [0.65Pb(Mg1/3Nb2/3)O3–0.35PbTiO3] thick film was produced by alternate spin-coating of a ceramic powder/sol–gel composite and infiltration of the sol–gel. Using this technique, a high quality PMN–PT thick film was obtained, showing a permittivity εr of ~3300 and dielectric loss factor of ~0.02 at 1 kHz. Photolithographic and wet etching techniques were used to fabricate a 32-element linear array from the film. The completed array showed a center frequency of approximately 110 MHz and a bandwidth of 60% at −6 dB without a matching layer. The performance of the kerfless array was studied and compared to a kerfed array simulated with finite element analysis.