High quality PZT thick films using silicon mold technique for MEMS applications

The present paper proposes a simple fabrication technique of high quality PZT thick films that call for silicon mold technique. The fabrication process adopts the silicon with back window obtained from silicon anisotropic etching as the silicon mold, and the improved PZT sol is dispensed in the silicon mold. The PZT films obtained using single spin coating with the thickness of l00 /spl mu/ m or higher, which is over the depth of back window of the silicon substrate, are crack-free and have good morphology. The PZT films with perfect perovskite structure have excellent piezoelectric property and the d/sub 33/ is about 170pC/N. Ferroelectric hysteresis loops are measured, and the remnant polarization (P/sub r/) of the PZT ceramics pellet is about 25 /spl mu/C/cm/sup 2/ and the coercive field (E/sub C/) is about 27kV/cm. In the radio-frequency (RF) region, the dielectric constant is about 350 and the dielectric loss is less than 0.01.