Development of piezoelectric microelectromechanical systems for multiaxial motion and sensing

Research output: ThesisDoctoral ThesisCollection of Articles

Abstract

Piezoelectric materials offer several advantages for MEMS applications due to their superior direct electromechanical coupling and low voltage consumption, especially when compared to electrostatic-based MEMS. Integrating piezoelectric thin films in MEMS also allows for a significantly smaller chip footprint than devices employing other transduction techniques. Furthermore, thin piezoelectric films can be integrated into the fabrication of multifunctional devices capable of three-dimensional motion (3D motion). Such 3D piezoMEMS enable driving and sensing along the x, y, or z-axes using components of a single element. This distinguishes 3D piezoMEMS from conventional MEMS that utilize elements that often facilitate motion in only one direction. This dissertation investigates the development of a new fabrication approach and adapting and optimizing existing fabrication techniques for 3D piezoMEMS fabrication. Pure lateral motion of a single MEMS element is implemented by placing metal organic chemical vapour deposited aluminium nitride (MOCVD AlN) thin films on the vertical surfaces of the Si cantilever. The fabrication approach demonstrated in the work unlocks the piezoelectric and electrode material deposition potential on vertical sidewall structures in the fabrication of advanced 3D piezoMEMS.
Translated title of the contributionDevelopment of piezoelectric microelectromechanical systems for multiaxial motion and sensing
Original languageEnglish
QualificationDoctor's degree
Awarding Institution
  • Aalto University
Supervisors/Advisors
  • Paulasto-Kröckel, Mervi, Supervising Professor
  • Ross, Glenn, Thesis Advisor
Publisher
Print ISBNs978-952-64-1694-6
Electronic ISBNs978-952-64-1695-3
Publication statusPublished - 2024
MoE publication typeG5 Doctoral dissertation (article)

Keywords

  • aluminium nitride
  • microelectromechanical systems
  • metal organic chemical vapour deposition
  • vertical sidewalls
  • vertical surfaces
  • aluminium scandium nitride
  • piezoelectric materials
  • piezoelectricity
  • microstructure
  • thin films
  • X-ray diffraction
  • microfabrication
  • scanning transmission electron microscopy
  • finite-element method
  • surface quality
  • cavity first approach
  • motion test

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