Micromachined piezoelectric diaphragms actuated by ring shaped interdigitated transducer electrodes

Eunki Hong, S. V. Krishnaswamy, C. B. Freidhoff, S. Trolier-Mckinstry

Research output: Contribution to journalArticlepeer-review

35 Scopus citations

Abstract

Piezoelectric diaphragms actuated by interdigitated transducer (IDT) electrodes were fabricated by bulk micromachining. To fabricate the diaphragms, a Si wafer with ∼0.5 μm of thermal SiO2 was coated with ∼0.3 μm ZrO2 and ∼1.6 μm thick Pb(Zr 0.52Ti0.48)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 ∼40% larger than the IDT diameters. The PZT films on these diaphragms exhibited good ferroelectric properties. Their remanent polarizations were ∼20 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 ∼0.3 μm. At an electric field of 120 kV/cm, the diaphragm was depressed by ∼4.3 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.

Original languageEnglish (US)
Pages (from-to)521-527
Number of pages7
JournalSensors and Actuators, A: Physical
Volume119
Issue number2
DOIs
StatePublished - Apr 13 2005

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Instrumentation
  • Condensed Matter Physics
  • Surfaces, Coatings and Films
  • Metals and Alloys
  • Electrical and Electronic Engineering

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