Zuniga, Chiara
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Publication Nanoscaled Piezoelectric Aluminum Nitride Contour- Mode Resonant Sensors(2010-11-01) Piazza, Gianluca; Rinaldi, Matteo; Zuniga, ChiaraThis paper reports on a new class of nanoscaled piezoelectric aluminum nitride contour-mode resonant sensors (CMR-S) that have been developed for the gravimetric detection of volatile organic chemicals (VOC). The use of the CMR-S and its scaling for the making of large arrays of detectors is justified in terms of the superior sensitivity and limit of detection (LOD ~ zg/μm2) that this technology attains with respect to any other available acoustic device. The choice of a novel functionalization layer based on ss-DNA is introduced as an effective way to selectively detect multiple VOCs without altering the electromechanical characteristics of the resonator. Experimental results confirming the advantages of scaling the device dimensions and its frequency of operation in terms of improved LOD and measurement speed are presented. Furthermore, preliminary data showing selective detection of dymethyl-methylphosphonate (DMMP) and dinitroluene (DNT) (with LOD in the order of ppt) are reported.Publication 5-10 GHz AlN Contour-Mode Nanoelectromechanical Resonators(2009-01-01) Rinaldi, Matteo; Zuniga, Chiara; Piazza, GianlucaThis paper reports on the design and experimental verification of Super High Frequency (SHF) laterally vibrating NanoElctroMechanical (NEMS) resonators. For the first time, AlN piezoelectric nanoresonators with multiple frequencies of operation ranging between 5 and 10 GHz have been fabricated on the same chip and attained the highest f-Q product (4.6E12 Hz) ever reported in AlN contour-mode devices. These piezoelectric NEMS resonators are the first of their class to demonstrate on-chip sensing and actuation of nanostructures without the need of cumbersome or power consuming excitation and readout systems. Effective piezoelectric activity has been demonstrated in thin AlN films having vertical and lateral features in the range of 250 nm.Publication Super-High-Frequency Two-Port AlN Contour-Mode Resonators for RF Applications(2010-01-01) Rinaldi, Matteo; Zuniga, Chiara; Zuo, Chengjie; Piazza, GianlucaThis paper reports on the design and experimental verification of a new class of thin-film (250 nm) superhigh- frequency laterally-vibrating piezoelectric microelectromechanical (MEMS) resonators suitable for the fabrication of narrow-band MEMS filters operating at frequencies above 3 GHz. The device dimensions have been opportunely scaled both in the lateral and vertical dimensions to excite a contourextensional mode of vibration in nanofeatures of an ultra-thin (250 nm) AlN film. In this first demonstration, 2-port resonators vibrating up to 4.5 GHz have been fabricated on the same die and attained electromechanical coupling, kt^2, in excess of 1.5%. These devices are employed to synthesize the highest frequency MEMS filter (3.7 GHz) based on AlN contour-mode resonator technology ever reported.Publication Use of a Single Multiplexed CMOS Oscillator as Direct Frequency Read-Out for an Array of Eight AlN Contour-Mode NEMS Resonant Sensors(2010-11-01) Rinaldi, Matteo; Zuniga, Chiara; Duick, Brandon; Piazza, GianlucaThis paper reports on the first demonstration of a single multiplexed CMOS oscillator circuit employed as direct frequency readout for an array of 8 nanoscaled aluminum nitride Contour-Mode Resonant Sensors (CMR-S). In this first prototype 8 thin-film (250 nm) AlN CMR-S operating at 186 MHz were fabricated on the same chip and simultaneously wire-bonded to a Pierce-like oscillator circuit (fabricated in the ON Semiconductor 0.5 µm CMOS process) by means of 8 CMOS transmission gates addressed via a 3 bit on-chip decoder. The 8 CMR-S were simultaneously exposed to different concentrations of methanol (0.1–1% of the saturated vapor pressure) and their response was monitored in a time-multiplexed mode. Frequency shifts of 300 Hz corresponding to changes of mass per unit area of 7 ag/µm2 were experimentally detected. Values of phase noise derived Allan deviation as low as 0.9 Hz were measured. Such Allan deviation translates in an estimated limit of detection of 21 zg/µm2.Publication GHz Range Nanoscaled AlN Contour-Mode Resonant Sensors (CMR-S) with Self-Sustained CMOS Oscillator(2010-06-01) Rinaldi, Matteo; Zuniga, Chiara; Zuo, Chengjie; Piazza, GianlucaThis paper reports on the design and experimental verification of a new class of nanoscaled AlN Contour-Mode Resonant Sensors (CMR-S) for the detection of volatile organic chemicals (VOC) operating at frequencies above 1 GHz and connected to a chip-based CMOS oscillator circuit for direct frequency read-out. This work shows that by scaling the CMR-S to 250 nm in thickness and by operating at high frequencies (1 GHz) a limit of detection of ~35 zg/µm2 and a fast response time (<1 >ms) can be attained. In addition, the capability to detect concentrations of volatile organic compounds such as 2,6 dinitroluene (DNT) as low as 1.5 ppb (4.7 ag/µm2) is experimentally verified.Publication DNA-Decorated Carbon Nanotubes as Sensitive Layer for AlN Contour-Mode Resonant-MEMS Gravimetric Sensor(2009-01-25) Zuniga, Chiara; Rinaldi, Matteo; Khamis, Samuel M; Jones, Timothy S; Johnson, A T; Piazza, GianlucaIn this work a nano-enabled gravimetric chemical sensor prototype based on single-stranded DNA (ss-DNA) decorated single-walled carbon nanotubes (SWNT) as nano-functionalization layer for Aluminun Nitride (AIN) contour-mode resonant-MEMS gravimetric sensors has been demonstrated. Two resonators fabricated on the same silicon chip and operating at different resonance frequencies, 287 and 450 MHz, were functionalized with this novel bio-coating layer to experimentally prove the capability of two distinct single strands of DNA bound to SWNT to enhance differently the adsorption of volatile organic compounds such as dinitroluene (DNT, simulant for explosive vapor) and dymethyl-methylphosphonate (DMMP, a simulant for nerve agent sarin). The introduction of this bio-coating layer addresses the major drawbacks of recovery time (50% recovery in less than 29 seconds has been achieved) and lack of selectivity associated with gas sensor based on polymers and pristine carbon nanotube functionalization layers.Publication AlN Contour-Mode Resonators for Narrow-Band Filters above 3 GHz(2009-04-20) Rinaldi, Matteo; Zuniga, Chiara; Zuo, Chengjie; Piazza, GianlucaThis paper reports on the design and experimental verification of a new class of thin-film (250 nm) super high frequency (SHF) laterally-vibrating piezoelectric microelectromechanical (MEMS) resonators suitable for the fabrication of narrow-band MEMS filters operating at frequencies above 3 GHz. The device dimensions have been opportunely scaled both in the lateral and vertical dimensions in order to excite a contour-extensional mode of vibration in nano features of an ultra-thin (250 nm) aluminum nitride (AlN) film. In this first demonstration two-port resonators vibrating up to 4.5 GHz were fabricated on the same die and attained electromechanical coupling, kt^2, in excess of 1.5 %. These devices were employed to synthesize the highest frequency ever reported MEMS filter (3.7 GHz) based on AlN contour-mode resonator (CMR) technology.Publication ss-DNA Functionalized Ultra-Thin-Film AlN Contour-Mode Resonators with Self-Sustained Oscillator for Volatile Organic Chemical Detection(2010-01-01) Rinaldi, Matteo; Duick, Brandon; Zuniga, Chiara; Zuo, Chengjie; Piazza, GianlucaThis paper reports on the design and experimental verification of a new class of nanoscale gravimetric sensors based on ultra-thin-film AlN Contour-Mode Resonant Sensor (CMR-S) functionalized with ss-DNA and connected to a chip-based self-sustaining oscillator loop (fabricated in the ON Semiconductor 0.5 μm CMOS process) for direct frequency read-out. The 220 MHz oscillator based on the ultra-thin AlN CMR-S exhibits an Allan Variance of ∼20 Hz for 100 ms gate time. The sensor affinity for the adsorption of volatile organic chemicals such as 2,6 dinitroluene (DNT, a simulant for explosive vapors) is enhanced by functionalizing the top gold electrode of the device with a thiol-terminated single stranded DNA sequence (Thiol - 5’ CTT CTG TCT TGA TGT TTG TCA AAC 3’) enabling the detection of concentrations as low as 1.5 part per billion (ppb).Publication High Frequency Piezoelectric Resonant Nanochannel for Bio-Sensing Applications in Liquid Environment(2010-11-01) Zuniga, Chiara; Rinaldi, Matteo; Piazza, GianlucaThis paper reports on the first demonstration of a 457 MHz AlN Piezolectric Resonant Nanochannel (PRN) for biosensing applications in liquid environment. A novel process consisting of 7 lithographic steps was developed to fabricate the PRN. The new resonant device shows an unchanged value of the electromechanical coupling, kt 2 (about 0.8 %), whether the channel is filled with air or water and a quality factor, Q, in liquid of approximately 170. The value of kt 2 and Q are respectively about 2.7 and 2 times the ones recorded for conventional laterally vibrating AlN Contour Mode Resonant Sensors (CMR-Ss) submerged in water. Overall, these results translate in a ~ 5 fold enhancement in the figure of merit (kt 2 - Q product) of the resonant device when operated in liquid and simultaneously permit the efficient delivery of ultra-low concentrations of fluid samples directly on the surface of the sensor.Publication Nanoenabled microelectromechanical sensor for volatile organic chemical detection(2009-06-05) Zuniga, Chiara; Rinaldi, Matteo; Khamis, Samuel M.; Johnson, A. T.; Piazza, GianlucaA nanoenabled gravimetric chemical sensor prototype based on the large scale integration of single-stranded DNA (ss-DNA) decorated single-walled carbon nanotubes (SWNTs) as nanofunctionalization layer for aluminum nitride contour-mode resonant microelectromechanical (MEM) gravimetric sensors has been demonstrated. The capability of two distinct single strands of DNA bound to SWNTs to enhance differently the adsorption of volatile organic compounds such as dinitroluene (simulant for explosive vapor) and dymethyl-methylphosphonate (simulant for nerve agent sarin) has been verified experimentally. Different levels of sensitivity (17.3 and 28 KHz µm^2/fg) due to separate frequencies of operation (287 and 450 MHz) on the same die have also been shown to prove the large dynamic range of sensitivity attainable with the sensor. The adsorption process in the ss-DNA decorated SWNTs does not occur in the bulk of the material, but solely involves the surface, which permits to achieve 50% recovery in less than 29 s.