Fabrication of piezoelectric diaphragm using lead zirconate titanate (PZT) films

E. Hong, S. V. Krishnaswamy, C. B. Freidhoff, S. Trolier-McKinstry

Research output: Contribution to journalArticle

12 Scopus citations

Abstract

Piezoelectric diaphragms were fabricated using bulk micromachining. The diaphragms had a unimorph structure, where Pb(Zr0.52Ti0.48)O3 (PZT) and thermally grown silicon oxide (SiO2) films were used as the active and passive layers, respectively. To actuate the diaphragms, two modes were designed: d31 and d33-mode. For d31-mode diaphragms, a Si wafer with Pt/Ti/SiO2 (0.5 μm) was coated with ∼1.2 μm PZT. A Cr/Au top electrode was then evaporated. Each layer including the bottom electrode was patterned into a circular shape. To fabricate d33-mode diaphragms, a Si wafer with thermal SiO2 (0.5 μm) was coated with ∼0.3 μm ZrO2 and ∼1.6 μm of PZT. On top of these layers, a Cr/Au top electrode was deposited and patterned into a ring-shaped interdigitated transducer. Finally, both d31 and d33-mode diaphragms were released using deep reactive ion etching. Diameters of the fabricated diaphragms were in the range of 600 μm and 1000 μm. For d31-mode diaphragms, the dielectric constant and loss of the released piezoelectric layer at 1 kHz were > 800 and < 2%, respectively. The remanent polarization was ∼20 μC/cm2 and the coercive field was ∼61 kV/cm. Ferroelectric measurements showed well-developed hysteresis loops for the d33-mode diaphragms. Both d31 and d33-mode diaphragms behave as membranes rather than plates. Their measured resonance frequencies were consistent with calculations from an analytic model for circular membranes and ANSYS finite element analysis.

Original languageEnglish (US)
Pages (from-to)131-136
Number of pages6
JournalMaterials Research Society Symposium - Proceedings
Volume687
StatePublished - Jan 1 2002

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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