Zuo, Chengjie
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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 Demonstration of Inverse Acoustic Band Gap Structures in AlN and Integration with Piezoelectric Contour Mode Transducers(2009-06-01) Kuo, Nai-Kuei; Zuo, Chengjie; Piazza, GianlucaThis paper presents the first design and demonstration of a novel inverse acoustic band gap (IABG) structure in aluminum nitride (AlN) and its direct integration with piezoelectric contour-mode transducers. The experimental results indicate that the IABG structure has a stop band from 185 MHz to 240 MHz and is centered around 219 MHz with maximum rejection of 30 dB. The ABG-induced phonon scattering causes a frequency band gap that prohibits the propagation of certain acoustic wavelengths. In this work, the IABG unit cell consists of a high acoustic velocity (V) center material, which is formed by 2-μm-thick AlN sandwiched by 200-nm-thick platinum (Pt) and is held by four thin tethers and surrounded by a low acoustic velocity material (air). This cell arrangement enlarges the frequency band gap and eases the requirements on the thickness (d) to lattice constant (a) ratio, which was imposed by previous ABG demonstration in the very high frequency range. The finite element method (FEM) analysis indicates that the IABG can produce a gap-to-midgap ratio of 13.5% even when the d/a ratio is as small as 0.23. This advantage further allows the direct integration of the IABG with high frequency bulk acoustic wave (BAW) transducers.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 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 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 Novel Electrode Configurations in Dual-Layer Stacked and Switchable AlN Contour-Mode Resonators for Low Impedance Filter Termination and Reduced Insertion Loss(2010-01-01) Zuo, Chengjie; Sinha, Nipun; Piazza, GianlucaThis paper reports, for the first time, on the design and demonstration of two novel electrode configurations in dual-layer stacked Aluminum Nitride (AlN) piezoelectric contour-mode resonators to obtain low filter termination resistance (down to 300 Ω, which also results in better filter out-of-band rejection) and reduced insertion loss (IL as low as 1.6 dB) in multi-frequency (100 MHz – 1 GHz) AlN MEMS filters. The microfabrication process is fully compatible with the previously demonstrated AlN RF MEMS switches, which makes it possible to design and integrate multi-frequency switchable filter banks on a single chip.Publication Hybrid Ultra-Compact 4th Order Band-Pass Filters Based On Piezoelectric AlN Contour-Mode MEMS Resonators(2008-06-01) Zuo, Chengjie; Sinha, Nipun; Perez, Carlos R.; Mahameed, Rashed; Pisani, Marcelo B.; Piazza, GianlucaThis work reports on the design, fabrication and testing of a new class of hybrid (filter design using combined electrical and mechanical coupling techniques) ultra-compact (800×120 μm) 4th order band-pass filters based on piezoelectric Aluminum Nitride (AlN) contour-mode microelectromechanical (MEM) resonators. The demonstrated 110 MHz filter shows a low insertion loss of 5.2 dB in air, a high out-of-band rejection of 65 dB, a fractional bandwidth as high as 1.14% (hard to obtain when only conventional electrical coupling is used in the AlN contour-mode technology), and unprecedented 30 dB and 50 dB shape factors of 1.93 and 2.36, respectively. All these are achieved in an extremely small footprint and by using just half the space that any other 4th order filter would have taken. In terms of nonlinearities, the 110 MHz filter shows a 1 dB compression point higher than +63 dBmV and input third order intercept point (IIP3) values well beyond +153 dBmV. This new hybrid design represents a net improvement over the state of the art and constitutes a very promising solution for intermediate frequency (IF) filtering in many wireless communication systems.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 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.