Lead Zirconate Titanate Thin Films on Silicon-on-Sapphire Substrates

Pb(Zr ₅₂ Ti ₄₈ )O ₃ (PZT) thin films have been grown by chemical solution deposition on 150 mm Silicon-on-Sapphire (SOS) substrates for RF MEMS applications. Film properties are compared to similar films deposited on typical Si/SiO ₂ substrates. PZT films deposited on SOS show improvement in P _MAX (37.8 vs. 32.1 μC/cm ² ) and PREM (22.7 vs. 10.9 μC/cm ² ) over films deposited on Si. A decrease in maximum εr from 1650 (Si) to 1031 (SOS) is also noted. Crystal structure is examined using x-ray diffraction. Ferroelectric polarization hysteresis curves, dielectric constant tuning, and loss tangent are studied using fabricated capacitors. Piezoelectric coefficients calculated from cantilever LDV measurements are also presented.