title: Miniaturized acceleration sensors with in-plane polarized piezoelectric thin films produced by micromachining.
abstract: Miniaturized acceleration sensors employing piezoelectric thin films were fabricated through batch micromachining with silicon and silicon-on-insulator (SOI) wafers. The acceleration sensors comprised multiple suspension beams supporting a central seismic mass. Ferroelectric (Pb,La)(Zr,Ti) O(3) (PLZT) thin films were coated and in-plane polarized on the surfaces of the suspension beams for realizing electromechanical conversion through the piezoelectric effect. Interdigital electrodes were formed on the PLZT films and connected in parallel. Finite element analyses were conducted for the stress and strain distributions, providing guidance to the structural design, including optimizing electrode positioning for collecting the electrical output constructively. Uniformity of the beam thickness and sample consistency were significantly improved by using SOI wafers instead of silicon wafers. The measurement results showed that all the sensor samples had fundamental resonances of symmetric out-of-plane vibration mode at frequencies in the range of 8 to 35 kHz, depending on the sample dimensions. These sensors exhibited stable electrical outputs in response to acceleration input, achieving a high signal-to-noise ratio without any external amplifier or signal conditioning.
authors.affiliation: Institute of Materials Research and Engineering, A-STAR (Agency for Science, Technology and Research), Singapore.
authors.forename: Saravanan
authors.initials: S
authors.lastname: Shanmugavel
authors.forename: Kui
authors.initials: K
authors.lastname: Yao
authors.forename: Trung Dung
authors.initials: TD
authors.lastname: Luong
authors.forename: Sharon Roslyn
authors.initials: SR
authors.lastname: Oh
authors.forename: Yifan
authors.initials: Y
authors.lastname: Chen
authors.forename: Chin Yaw
authors.initials: CY
authors.lastname: Tan
authors.forename: Ajit
authors.initials: A
authors.lastname: Gaunekar
authors.forename: Peter Hon Yu
authors.initials: PH
authors.lastname: Ng
authors.forename: Marchy Hing Leung
authors.initials: MH
authors.lastname: Li
mesh_terms: D000054:Acceleration; D000162:Acoustics / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008567:Membranes, Artificial; D055617:Micro-Electrical-Mechanical Systems / Q000295:instrumentation*; D008904:Miniaturization; D014159:Transducers
chemical_list: D008567:Membranes, Artificial