Fabrication of Piezoelectric Micro Bending Actuators Using Sol-Gel Thick PZT films

Fabrication and electrical and mechanical properties of piezoelectric micro bending actuators (PMBA) using sol-gel-multi-coated thick PZT films and MEMS processes were investigated. PMBA could be used for design and fabrication of micro fluidic devices, for example, micro-pumps, micro dispensers, and so on. PMBA were fabricated using 2 um thick PZT films on Pt (350 nm)/$SiO_2$ (500 nm)/Si ($300\mu\textrm{m}$) substrates and MEMS processes. 7 types of PMBA were fabricated with areas of silicon diaphragms, PZT films and top electrodes. When the sizes of silicon diaphragms, PZT films and Pt top electrodes were reduced from 3000$\times$$1389\mu\textrm{m}$, 4000$\times$$1000\mu\textrm{m}$ and 4000$\times$$900\mu\textrm{m}$ down to 14%, 14% and 11 % of them, respectively, the center displacements of PMBA were decreased from 0.68 um to 0.10 um at 5 Hz and 12 Vpp. So, PMBA with large areas showed larger displacements than PMBA with small areas and experimental results were also good agreement with the plate and shell theory.