One and two port piezoelectric higher order contour-mode MEMS resonators for mechanical signal processing

Abstract

This paper reports on the design, fabrication and testing of novel one and two port piezoelectric higher order contour-mode MEMS resonators that can be employed in RF wireless communications as frequency reference elements or arranged in arrays to form banks of multi-frequency filters. The paper offers a comparison of one and two port resonant devices exhibiting frequencies approximately ranging from 200 to 800 MHz, quality factor of few thousands (1000-2500) and motional resistances ranging from 25 to 1000 Ω. Fundamental advantages and limitations of each solution are discussed. The reported experimental results focus on the response of a higher order one port resonator under different environmental conditions and a new class of two port contour resonators for narrow band filtering applications. Furthermore, an overview of novel frequency synthesis schemes that can be enabled by these contour-mode resonators is briefly presented. Keywords AbstractThis paper reports on the design, fabrication and testing of novel one and two port piezoelectric higher order contour-mode MEMS resonators that can be employed in RF wireless communications as frequency reference elements or arranged in arrays to form banks of multi-frequency filters. The paper offers a comparison of one and two port resonant devices exhibiting frequencies approximately ranging from 200 to 800 MHz, quality factor of few thousands (1,000-2,500) and motional resistances ranging from 25 to 1000 Ω. Fundamental advantages and limitations of each solution are discussed. The reported experimental results focus on the response of a higher order one port resonator under different environmental conditions and a new class of two port contour resonators for narrow band filtering applications. Furthermore, an overview of novel frequency synthesis schemes that can be enabled by these contour-mode resonators is briefly presented.

Gravimetric chemical sensor based on the direct integration of SWNTS on ALN Contour-Mode MEMS resonators

“…As previously reported [6], the resonance frequency of a width-extensional higher order contour-mode resonator ( Fig.1) is approximately set by the width, W, of a single finger and the material properties, E 0 and ρ 0 as shown in equation (2). (2)…”

“…The effective area is a key parameter for a gravimetric gas sensor since it plays a crucial role in the definition of the sensitivity to variations of the analyte concentration in the environment. In fact, the sensitivity to concentration is directly proportional to the effective area: (6) which, substituting A eff from (5) , can be expressed as: (7) Ultimately, the sensitivity of a contour-mode resonator to variations in the analyte concentration is significantly improved by the increased area dedicated to the sensing layer.…”

“…In this paper, Aluminum Nitride (AlN) Contour-Mode resonators first reported by Piazza et al [6] are investigated as novel and high performance gravimetric sensors for VOC detection. Since the resonance frequency of this kind of devices is lithographically set, multiple frequencies are easily achievable on the same chip.…”

“…Since the resonance frequency of this kind of devices is lithographically set, multiple frequencies are easily achievable on the same chip. Moreover, high frequency of operation, high quality factor in air (1,000-3,000) and low motional resistance have been demonstrated in AlN ContourMode resonators [6], therefore making these devices suitable for the fabrication of compact, low cost and wireless sensor platforms.…”

Nanoenabled microelectromechanical sensor for volatile organic chemical detection

“…1͒. The AlN MEMS resonator offers key advantages over previously demonstrated MEMS/NEMS resonator technologies because of the high frequency of operation ͑sensitivity scales with frequency squared͒, the high quality factor in air ͑1000-3000͒, 4 the large area available for sensing and especially the ability to provide for multiple frequencies on the same silicon substrate. 5 The device center frequency is in fact defined lithographically, which permits to attain different frequencies of operation ͑10 MHz to 3 GHz͒ and consequently enhance the dynamic range ͑defined as ratio of maximum to minimum concentration of detectable analyte͒ of the sensor platform in which it will be employed.…”