| AVS 64th International Symposium & Exhibition | |
| MEMS and NEMS Group | Tuesday Sessions |
| Session MN+BI+EM+SS+TR-TuM |
| Session: | Microelectromechanics: Relays to RF/Surfaces in Micro- and Nano- Systems |
| Presenter: | Sidney Cohen, Weizmann Institute of Science, Israel |
| Authors: | S.R. Cohen, Weizmann Institute of Science, Israel E. Mishuk, Weizmann Institute of Science, Israel E. Makagon, Weizmann Institute of Science, Israel E. Wachtel, Weizmann Institute of Science, Israel K. Rechav, Weizmann Institute of Science, Israel R. Popovitz-Biro, Weizmann Institute of Science, Israel I. Lubomirsky, Weizmann Institute of Science, Israel |
| Correspondent: | Click to Email |
Gd-doped ceria (GDC) recently attracted great interest due to its non-classical (non-Newnham) electrostrictive behavior. Although the material is well-known for its ionic conduction properties and use in solid-oxide fuel-cells, it also holds great promise for incorporation into MEMS devices because it is completely inert with respect to silicon compounds. The fact that GDC is lead-free is particularly appealing.
Here, we demonstrate fabrication and testing of membrane actuators formed with near 100% yield by a relatively simple, low temperature process. Preparation of these devices involves magnetron-sputtering of a thin film of GDC onto Si, and further processing using standard micromachining, resulting in free-standing membranes. Bridge and cantilever structures have been fabricated as well, to explore the possibility for diverse functional devices. The films were structurally characterized by electron microscopy and by x-ray diffraction, whereas electrical characterization was performed using impedance spectroscopy and cyclic voltammetry. These electrical tests revealed details of the conduction mechanism, role of the contacts, and charge-trapping.
Scanning probe microscopy was applied to quantitatively characterize the energetics and mechanics of the electromechanical response: Displacement of a circular membrane was measured by recording displacement of the cantilever probe under feedback as a function of frequency and applied voltage, and temporal Joule heating recorded using a scanning thermal probe. These measurements support calculations of heat-induced strain at high frequencies. These measurements showed that displacements obtained are sufficient for practical applications and provided insights on the factors controlling performance.