Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10409671 | Sensors and Actuators A: Physical | 2005 | 7 Pages |
Abstract
Piezoelectric diaphragms actuated by interdigitated transducer (IDT) electrodes were fabricated by bulk micromachining. To fabricate the diaphragms, a Si wafer with â¼0.5 μm of thermal SiO2 was coated with â¼0.3 μm ZrO2 and â¼1.6 μm thick Pb(Zr0.52Ti0.48)O3 (PZT) layers. A Cr/Au top electrode was then deposited and patterned into ring-shaped IDT electrodes. The diaphragms were released using deep reactive ion etching. The fabricated diaphragms had three different IDT diameters of 500, 600 or 700 μm and their diameters were â¼40% larger than the IDT diameters. The PZT films on these diaphragms exhibited good ferroelectric properties. Their remanent polarizations were â¼20 μC/cm2 and the coercive fields were about 50 kV/cm. Resonance measurements for these diaphragms indicated that the diaphragms behaved as membranes. Without an electric field, the diaphragms were almost flat to within â¼0.3 μm. At an electric field of 120 kV/cm, the diaphragm was depressed by â¼4.3 μm in the case of a 700 μm diaphragm with 10 μm electrode spacing. The deflection profiles were modeled via finite element analysis; deflections larger than the structure thickness can be achieved. This makes these devices useful for micropumps and other actuator applications.
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Authors
Eunki Hong, S.V. Krishnaswamy, C.B. Freidhoff, S. Trolier-McKinstry,