Interface losses in multimaterial resonators

Abstract

We present an extensive study shedding light on the role of surface and bulk losses in micromechanical resonators. We fabricate thin silicon nitride membranes of different sizes and we coat them with different thicknesses of metal. We later characterize the 81 lowest out-of-plane flexural vibrational modes to achieve a total of more than 3000 experimental points that allow us to quantify the contribution of surface and volume intrinsic (material related) losses in MEMS resonators. We conclude that the losses in the interface between silicon nitride and aluminum is a very important contributor to the overall energy loss.

Exploring the Q-factor limit of temperature compensated CMOS-MEMS resonators

“…Unlike intrinsic loss mechanism such as interface loss [9], the anchor loss of a MEMS resonator can be minimized by appropriate designs. For in-plane vibrating resonators, balanced dual-resonator design turns out to be an effective solution for high Q Anchor .…”

“…By using (4), the material Q-factors can be extracted from the previously-developed CMOS-MEMS resonators [5][6] [8]. Please note that the interface loss caused by the elastic modulus mismatch between materials (ΔE) [9] is merged with the extracted Q-factor of the j-th material layer in this empirical model since the interface loss cannot be solely extracted by experimental results. The flow chart for Q j extraction is shown in Fig.…”

“…Therefore, the energy loss mechanism is studied in this work by extracting the "intrinsic material Q-factor" throughout a number of CMOS-MEMS resonators we developed in past few years [8]. Since interface loss [9] is very difficult to be extracted in multi-material resonators, an empirical model is used to evaluate the upper-bond of the Q-factor in this study.…”

Reducing anchor loss In thin-film aluminum nitride-on-diamond contour mode MEMS resonators with support tethers based on phononic crystal strip and reflector

“…Energy dissipations (i.e., losses) in the MEMS resonators can be caused by thermoelastic damping (TED), interface damping, surface damping (classified into instrinsic damping); air damping, squeeze damping (classified into external damping) and anchor (i.e., support) damping (classified into clamp damping) (Harrington and Abdolvand 2011;Duwel et al 2006;Villanueva et al 2014;Hajhashemi et al 2014;Gologanu et al 2012). Among these phenomena, the energy dissipation via the support tethers has been recognized as one of the most dominant mechanisms in lowering the Q.…”

“…Similar to the WS mode one with three-unit cell PnC strip based support tethers, this Q is up to 591.1 %. 1 3 the anchor loss, this is due to the energy losses caused by metallic electrodes, TED, interface between material layers, materials and unknown others (Piazza et al 2006;Villanueva et al 2014). Therefore, the Q of these resonators can generally expressed by depending on anchor Q (Q anchor ), electrode Q (Q electrode ), TED Q (Q TED ), interface Q (Q interface ), material Q (Q material ) and unknown Q (Q unknown ).…”