Abstract
The manufacturing process of Mn modified Pb(Sn1/2Sb1/2)O3-PbTiO3-PbZrO3 ceramics was investigated to get pore-free piezoelectric ceramics with fine grains and less fluctuation in the electrical properties for surface acoustic wave filters. These were obtained when fired in an oxygen atmosphere. In the solid state reaction of the composition, a pyrochlore compound Pb2SnSbO13/2 was observed as an intermediate phase, which suppressed the grain growth and generated spherical. The polished surface of the ceramics was satisfactory for 90MHz interdigital transducers of 6.7μm finger width to be fixed. The longitudinal wave and the SAW velocities of the ceramics increased by 20m/s (0.8%) and 27m/s (1.1%), respectively compared with those fired in air. The fluctuation of SAW velocity σ/x was less than 0.10% in a wafer and 0.15% in a firing lot. The attenuation of surface acoustic wave in the frequency range below 90MHz depends on the internal friction.
