Thermoelastic damping in bilayered micromechanical beam resonators

• Published in: Journal of micromechanics and microengineering Vol. 17; no. 3; pp. 532 - 538
• Main Authors: Prabhakar, Sairam, Vengallatore, Srikar
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 01.03.2007; Institute of Physics
• Subjects: Applied sciences; Electronics; Exact sciences and technology; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Mechanical engineering. Machine design; Mechanical instruments, equipment and techniques; Microelectronic fabrication (materials and surfaces technology); Micromechanical devices and systems; Physics; Precision engineering, watch making; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Composite materials; Micromechanical resonators; Friction; Silicon oxides; Silicon carbides; Thermomechanical properties; Thermoelasticity; Modelling; Bernoulli Euler model; Microelectromechanical device; Cantilever beam; Bilayers
• ISSN: 0960-1317; 1361-6439
• DOI: 10.1088/0960-1317/17/3/016

A detailed analysis of thermoelastic damping (TED) is essential in the design of the next generation of layered composite microresonators employed in microelectromechanical systems (MEMS) for sensing and communications. Here, we present an exact theory to compute the frequency dependence of thermoelastic damping in asymmetric, bilayered, micromechanical Euler-Bernoulli beam resonators. Comparison of the computed values for thermoelastic damping with previously measured internal friction in Au/SiO2 microcantilevers suggests that TED contributes significantly to damping at higher modes and frequencies (~1 MHz), but is negligible at lower frequencies, in these structures. The utility of the theory for MEMS design is illustrated by considering the representative example of Al/SiC bilayered microresonators.