| The advent of commercially available giant piezoelectric coefficient monocrystalline materials such as PMN-PT (lead magnesium niobate - lead titanate) or PZN-PT (lead zinc niobate - lead titanate) broadens the gate for silicon-integrated applications (PiezoMEMS). Becoming more compatible with microtechnology batch processes, further advances are expected in terms of miniaturization, optimization, functionality or integration with electronics, all while reducing manufacturing costs. Subsequently, operating voltage will be lower and devices response time will improve dramatically. The paper compiles a base knowledge for composite bimorph actuators in line with a bottom-up approach for further more complex piezoelectric device designs such as "microrobots-on-chip". Material properties and constitutive equations of piezoelectric bimorph cantilevers are initially overviewed. Analytical and finite elements modeling (FEM) are afterwards performed on two designs: classical PZT on copper cantilevers and innovative PMN-PT and PZN-PT on silicon. Comparative results clearly report quantitative improvement of PMN-PT on Si design in terms of tip displacement and blocking force. |
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