Piazza, Gianluca
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Publication Multi-Frequency Pierce Oscillators Based On Piezoelectric AlN Contour-Mode MEMS Resonators(2008-09-01) Zuo, Chengjie; Sinha, Nipun; Van der Spiegel, Jan; Piazza, GianlucaThis paper reports on the first demonstration of multi-frequency (176, 222, 307, and 482 MHz) oscillators based on piezoelectric AlN contour-mode MEMS resonators. All the oscillators show phase noise values between –88 and –68 dBc/Hz at 1 kHz offset and phase noise floors as low as –160 dBc/Hz at 1 MHz offset. The same Pierce circuit design is employed to sustain oscillations at the 4 different frequencies, while the oscillator core consumes at most 10 mW. The AlN resonators are currently wirebonded to the integrated circuit realized in the AMIS 0.5 μm 5 V CMOS process. This work constitutes a substantial step forward towards the demonstration of a single-chip multi-frequency reconfigurable timing solution that could be used in wireless communications and sensing applications.Publication Demonstration of Low Voltage and Functionally Complete Logic Operations Using Body-Biased Complementary and Ultra-Thin ALN Piezoelectric Mechanical Switches(2010-01-01) Sinha, Nipun; Jones, Timothy; Guo, Zhijun; Piazza, GianlucaThis paper reports, for the first time, on the demonstration of low voltage and functionally complete logic elements (NAND and NOR) implemented by using body-biased complementary and ultra-thin (250 nm thick) Aluminum Nitride (AlN) based piezoelectric mechanical switches. This work presents, firstly, the importance of scaling AlN films for the demonstration of ultra-thin AlN switches and, secondly, the implementation of a new actuation scheme based on body biasing to lower the switch threshold voltage. Four of these ultra-thin switches were connected together to synthesize functionally complete MEMS logic gates (NAND and NOR) with a ± 2V swing and a body-bias voltage < 8 V.Publication Ultra-Thin-Film AlN Contour-Mode Resonators for Sensing Applications(2010-04-01) Rinaldi, Matteo; Zuniga, Chiara; Piazza, GianlucaThis paper reports on the design and experimental verification of a new class of ultra-thin-film (250 nm) aluminum nitride (AlN) microelectromechanical system (MEMS) contour mode resonators (CMRs) suitable for the fabrication of ultra-sensitive gravimetric sensors. The device thickness was opportunely scaled in order to increase the mass sensitivity, while keeping a constant frequency of operation. In this first demonstration the resonance frequency of the device was set to 178 MHz and a mass sensitivity as high as 38.96 KHz⋅μm2/fg was attained. This device demonstrates the unique capability of the CMR-S technology to decouple resonance frequency from mass sensitivity.Publication Single-Ended-to-Differential and Differential-to-Differential Channel-Select Filters Based on Piezoelectric AlN Contour-Mode MEMS Resonators(2010-06-01) Zuo, Chengjie; Piazza, GianlucaThis paper reports on the first demonstration of single-ended-to-differential and differential-to-differential (S2D and D2D) channel-select filters based on single-layer (SL) and dual-layer-stacked (DLS) AlN contour-mode MEMS resonators. The key filter performances in terms of insertion loss (as low as 1.4 dB), operating frequency (250-1280 MHz), and out-of-band rejection (up to 60 dB) constitute a significant advancement over all other state-of-the-art RF MEMS technologies. The fabrication process, namely stacking of two piezoelectric AlN layers (600 nm each) and three Pt electrode layers (100 nm each), is fully compatible with the previously demonstrated AlN RF MEMS switch process (also post-CMOS compatible), which makes it possible to implement multi-frequency switchable filter banks on a single chip. The S2D configuration is also able to combine the balun, filter, and impedance transformer functions in a single MEMS structure and only takes on a very small form factor (60×200 μm). These unique features will potentially revolutionize the field of RF and microwave IC design by enabling MEMS-IC co-design and the development of unconventional and low-power RF architectures.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.Publication Ultra-Thin Super High Frequency Two-Port ALN Contour-Mode Resonators and Filters(2009-06-21) Rinaldi, Matteo; Zuniga, Chiara; Zuo, Chnegjie; Piazza, GianlucaThis paper reports on the demonstration of a new class of ultra-thin (250 nm thick) super high frequency (SHF) AlN piezoelectric two-port resonators and filters. A thickness field excitation scheme was employed to excite a higher order contour extensional mode of vibration in an AlN nano plate (250 nm thick) above 3 GHz and synthesize a 1.96 GHz narrow-bandwidth channel-select filter. The devices of this work are able to operate over a frequency range from 1.9 to 3.5 GHz and are employed to synthesize the highest frequency MEMS filter based on electrically self-coupled AlN contour-mode resonators. Very narrow bandwidth (~ 0.35%) and high off-band rejection (~ 35 dB) were achieved at an operating frequency of 1.96 GHz. This first prototype showed insertion loss of 11 dB, which can be improved to few dB if parasitic elements are eliminated or device capacitance is increased.Publication Integration of AlN Micromechanical Contour-Mode Technology Filters with Three-Finger Dual Beam AlN MEMS Switches(2009-04-01) Sinha, Nipun; Zuo, Chengjie; Piazza, Gianluca; Mahameed, RashedIn this paper, we present the first demonstration of the monolithic integration of Aluminum Nitride (AlN) micromechanical contour mode technology filters with dual-beam actuated MEMS AlN switches. This integration has lead to the development of the first prototype of a fully-integrated all-mechanical switchable filter. Integration has been demonstrated by using AlN contour-mode MEMS filters at two center frequencies, i.e. 98.7 and 279.9 MHz. The micromechanical switch design used here is a novel three-finger dual-beam topology that improves the isolation and insertion loss of the switch by decreasing the parasitic coupling between the DC and RF signals over a previous AlN MEMS dual-beam design. With the use of just one switch fabricated right next to, and integrated with the filter, the AlN MEMS filter is effectively turned off and its pass-band transmission is lowered to the out of band level at 279.9 MHz.Publication Gravimetric chemical sensor based on the direct integration of SWNTS on ALN Contour-Mode MEMS resonators(2008-05-01) Rinaldi, Matteo; Zuniga, Chiara; Sinha, Nipun; Taheri, Marzie; Piazza, Gianluca; Khamis, Samuel M.; Johnson, Alan T.This paper reports on the first demonstration of a gravimetric chemical sensor based on direct integration of Single Wall Carbon Nanotubes (SWNTs) grown by Chemical Vapor Deposition (CVD) on AlN Contour-Mode MicroElectroMechanical (MEMS) resonators. In this first prototype the ability of SWNTs to readily adsorb volatile organic chemicals has been combined with the capability of AlN Contour-Mode MEMS resonator to provide for different levels of sensitivity due to separate frequencies of operation on the same die. Two devices with resonance frequencies of 287 MHz and 442 MHz have been exposed to different concentrations of DMMP in the range from 80 to 800 ppm. Values of mass sensitivity equal to 1.8 KHz/pg and 2.65 KHz/pg respectively have been measured.Publication Piezoelectric Aluminum Nitride Vibrating Contour-Mode MEMS Resonators(2006-12-01) Piazza, Gianluca; Stephanou, Philip J; Pisano, Albert PThis paper reports theoretical analysis and experimental results on a new class of rectangular plate and ring-shaped contour-mode piezoelectric aluminum nitride radio-frequency microelectromechanical systems resonators that span a frequency range from 19 to 656 MHz showing high-quality factors in air (Qmax = 4300 at 229.9 MHz), low motional resistance (ranging from 50 to 700 Ω), and center frequencies that are lithographically defined. These resonators achieve the lowest value of motional resistance ever reported for contour-mode resonators and combine it with high Q factors, therefore enabling the fabrication of arrays of high-performance microresonators with different frequencies on a single chip. Uncompensated temperature coefficients of frequency of approximately 25 ppm/°C were also recorded for these resonators. Initial discussions on mass loading mechanisms induced by metal electrodes and energy loss phenomenon are provided.Publication Piezoelectric aluminum nitride nanoelectromechanical actuators(2009-08-03) Sinha, Nipun; Wabiszewski, Graham E; Carpick, Robert W; Mahameed, Rashed; piazza, Gianluca; Felmetsger, Valery V; Tanner, Shawn MThis letter reports the implementation of ultrathin (100 nm) aluminum nitride (AlN) piezoelectric layers for the fabrication of vertically deflecting nanoactuators. The films exhibit an average piezoelectric coefficient (d31~−1.9 pC/N), which is comparable to its microscale counterpart. This allows vertical deflections as large as 40 nm from 18 µm long and 350 nm thick multilayer cantilever bimorph beams with 2 V actuation. Furthermore, in-plane stress and stress gradients have been simultaneously controlled. The films exhibit leakage currents lower than 2 nA/cm2 at 1 V, and have an average relative dielectric constant of approximately 9.2 (as in thicker films). These material characteristics and actuation results make the AlN nanofilms ideal candidates for the realization of nanoelectromechanical switches for low power logic applications.