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43 results on '"Simeoni, Pietro"'

1. ScAlN-on-SiC Ku-Band Solidly-Mounted Bidimensional Mode Resonators

Author

Colombo, Luca, Spagnuolo, Luca, Saha, Kapil, Giribaldi, Gabriel, Simeoni, Pietro, and Rinaldi, Matteo

Subjects
Electrical Engineering and Systems Science - Systems and Control
Abstract

This letter reports on Solidly-Mounted Bidimensional Mode Resonators (S2MRs) based on 30% Scandium-doped Aluminum Nitride (ScAlN) on Silicon Carbide (SiC), operating near 16 GHz. Experimental results demonstrate mechanical quality factors (Qm) as high as 380, electromechanical coupling coefficients (kt2) of 4.5%, an overall Figure of Merit (FOM = Qmkt2) exceeding 17, and power handling greater than 20 dBm for devices closely matched to 50 ohm. To the best of the authors' knowledge, S2MRs exhibit the highest Key Performance Indicators (KPIs) among solidly mounted resonators in the Ku band, paving the way for the integration of nanoacoustic devices on fast substrates with high-power electronics, tailored for military and harsh environment applications., Comment: Submitted to IEEE EDL

Published
2024

2. 18 GHz Solidly Mounted Resonator in Scandium Aluminum Nitride on SiO2/Ta2O5 Bragg Reflector

Author

Barrera, Omar, Ravi, Nishanth, Saha, Kapil, Dasgupta, Supratik, Campbell, Joshua, Kramer, Jack, Kwon, Eugene, Hsu, Tzu-Hsuan, Cho, Sinwoo, Anderson, Ian, Simeoni, Pietro, Hou, Jue, Rinaldi, Matteo, Goorsky, Mark S., and Lu, Ruochen

Subjects
Physics - Applied Physics
Abstract

This work reports an acoustic solidly mounted resonator (SMR) at 18.64 GHz, among the highest operating frequencies reported. The device is built in scandium aluminum nitride (ScAlN) on top of silicon dioxide (SiO2) and tantalum pentoxide (Ta2O5) Bragg reflectors on silicon (Si) wafer. The stack is analyzed with X-ray reflectivity (XRR) and high-resolution X-ray diffraction (HRXRD). The resonator shows a coupling coefficient (k2) of 2.0%, high series quality factor (Qs) of 156, shunt quality factor (Qp) of 142, and maximum Bode quality factor (Qmax) of 210. The third-order harmonics at 59.64 GHz is also observed with k2 around 0.6% and Q around 40. Upon further development, the reported acoustic resonator platform can enable various front-end signal-processing functions, e.g., filters and oscillators, at future frequency range 3 (FR3) bands., Comment: 5 pages, 9 figures, 5 tables

Published
2024
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3. Scandium Aluminum Nitride Overmoded Bulk Acoustic Resonators for Future Wireless Communication

Author

Gubinelli, Walter, Simeoni, Pietro, Tetro, Ryan, Colombo, Luca, and Rinaldi, Matteo

Subjects
Electrical Engineering and Systems Science - Systems and Control
Abstract

This work reports on the modeling, fabrication, and experimental characterization of a 13 GHz 30% Scandium-doped Aluminum Nitride (ScAlN) Overmoded Bulk Acoustic Resonator (OBAR) for high-frequency Radio Frequency (RF) applications, notably in 5G technology and beyond. The Finite Element Analysis (FEA) optimization process targets the top and bottom metal electrode thicknesses, balancing the electromechanical coupling coefficient and acoustic energy distribution to enhance device Figure of Merit (FOM). Experimental results on fabricated devices employing platinum and aluminum as bottom and top electrode, respectively, demonstrate a quality factor at resonance (Qs) of 210 and a coupling coefficient (kt2) of 5.2% at 13.3 GHz for the second bulk thickness overtone, effectively validating the simulation framework and hinting at the possible implementation of OBARs for advanced RF filters in 5G networks., Comment: 4 pages, 4 figures, submitted to 2024 Hilton Head Workshop Proceedings

Published
2024

4. Millimeter Wave Thin-Film Bulk Acoustic Resonator in Sputtered Scandium Aluminum Nitride Using Platinum Electrodes

Author

Cho, Sinwoo, Barrera, Omar, Simeoni, Pietro, Wang, Ellie Y., Kramer, Jack, Chulukhadze, Vakhtang, Campbell, Joshua, Rinaldi, Matteo, and Lu, Ruochen

Subjects
Electrical Engineering and Systems Science - Signal Processing
Abstract

This work describes sputtered scandium aluminum nitride (ScAlN) thin-film bulk acoustic resonators (FBAR) at millimeter wave (mmWave) with high quality factor (Q) using platinum (Pt) electrodes. FBARs with combinations of Pt and aluminum (Al) electrodes, i.e., Al top Al bottom, Pt top Al bottom, Al top Pt bottom, and Pt top Pt bottom, are built to study the impact of electrodes on mmWave FBARs. The demonstrated FBAR with Pt top and bottom electrodes achieve electromechanical coupling (k2) of 4.0% and Q of 116 for the first-order symmetric (S1) mode at 13.7 GHz, and k2 of 1.8% and Q of 94 for third-order symmetric (S3) mode at 61.6 GHz. Through these results, we confirmed that even in the frequency band of approximately 60 GHz, ScAlN FBAR can achieve a Q factor approaching 100 with optimized fabrication and acoustic/EM design. Further development calls for stacks with better quality in piezoelectric and metallic layers., Comment: 4 pages, 7 figures, accepted by IEEE MEMS 2024

Published
2023
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7. Millimeter Wave Thin-Film Bulk Acoustic Resonator in Sputtered Scandium Aluminum Nitride

Author

Cho, Sinwoo, Barrera, Omar, Simeoni, Pietro, Marshall, Emily N., Kramer, Jack, Motoki, Keisuke, Hsu, Tzu-Hsuan, Chulukhadze, Vakhtang, Rinaldi, Matteo, Doolittle, W. Alan, and Lu, Ruochen

Subjects
Electrical Engineering and Systems Science - Signal Processing
Abstract

This work reports a millimeter wave (mmWave) thin-film bulk acoustic resonator (FBAR) in sputtered scandium aluminum nitride (ScAlN). This paper identifies challenges of frequency scaling sputtered ScAlN into mmWave and proposes a stack and new fabrication procedure with a sputtered Sc0.3Al0.7N on Al on Si carrier wafer. The resonator achieves electromechanical coupling (k2) of 7.0% and quality factor (Q) of 62 for the first-order symmetric (S1) mode at 21.4 GHz, along with k2 of 4.0% and Q of 19 for the third-order symmetric (S3) mode at 55.4 GHz, showing higher figures of merit (FoM, k2xQ) than reported AlN/ScAlN-based mmWave acoustic resonators. The ScAlN quality is identified by transmission electron microscopy (TEM) and X-ray diffraction (XRD), identifying the bottlenecks in the existing piezoelectric-metal stack. Further improvement of ScAlN/AlN-based mmWave acoustic resonators calls for better crystalline quality from improved thin-film deposition methods., Comment: 3 pages, 7 figures, submitted to JMEMS

Published
2023
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8. A 5.3 GHz Al0.76Sc0.24N Two-Dimensional Resonant Rods Resonator with a kt2 of 23.9%

Author

Zhao, Xuanyi, Kaya, Onurcan, Pirro, Michele, Assylbekova, Meruyert, Colombo, Luca, Simeoni, Pietro, and Cassella, Cristian

Subjects
Electrical Engineering and Systems Science - Signal Processing
Abstract

This work reports on the measured performance of an Aluminum Scandium Nitride (AlScN) Two-Dimensional Resonant Rods resonator (2DRR), fabricated by using a Sc-doping concentration of 24%, characterized by a low off-resonance impedance (~25 Ohm) and exhibiting a record electromechanical coupling coefficient (kt2) of 23.9% for AlScN resonators. In order to achieve such performance, we identified and relied on optimized deposition and etching processes for highly-doped AlScN films, aiming at achieving high crystalline quality, low density of abnormally oriented grains in the 2DRR's active region and sharp lateral sidewalls. Also, the 2DRR's unit-cell has been acoustically engineered to maximize the piezo-generated mechanical energy within each rod and to ensure a low transduction of spurious modes around resonance. Due to its unprecedented kt2, the reported 2DRR opens exciting scenarios towards the development of next generation monolithic integrated radio-frequency (RF) filtering components. In fact, we show that 5th-order 2DRR-based ladder filters with fractional bandwidths (BW) of ~11%, insertion-loss (I.L) values of ~2.5 dB and with >30 dB out-of-band rejections can now be envisioned, paving an unprecedented path towards the development of ultra-wide band (UWB) filters for next-generation Super-High-Frequency (SHF) radio front-ends., Comment: 10 pages, 11 figures, 5 tables, submitted to JMEMS

Published
2022
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17. A Radiofrequency Threshold Temperature Sensor Using a Hf0.5Zr0.5O2 Device and a Microacoustic Piezoelectric Resonant Sensor

Author

Kaya, Onurcan, Colombo, Luca, Simeoni, Pietro, Davaji, Benyamin, Rinaldi, Matteo, and Cassella, Cristian

Abstract

This article presents the first prototype of a novel threshold sensing system operating in the radiofrequency (RF) range, capable of passively detecting and recording instances of temperature violations with high sensitivity and without the need of DC-biased memory devices. The system comprises a microfabricated hafnium zirconium oxide (HZO) ferroelectric varactor, a microfabricated lithium niobate (LiNbO3) shear-horizontal (SH0) Lamb wave microacoustic resonator used as a temperature sensor, and an inductor. All components have been soldered onto a printed circuit board for testing and characterization. Through this threshold sensing system, we also provide the first demonstration of ferroelectric switching in a HZO varactor triggered exclusively by an RF signal without requiring any DC voltages. The findings reported in this paper offer a promising pathway for future RF passive tags leveraging micro- and nanosystems to implement a programmable threshold sensing functionality with high sensitivity and with embedded memory capabilities. [2023-0215]

Published
2024
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22. Compact and wideband nanoacoustic pass-band filters for future 5G and 6G cellular radios

Author

Giribaldi, Gabriel, Colombo, Luca, Simeoni, Pietro, and Rinaldi, Matteo

Abstract

The last half a century has seen an enormous growth in mobile communication, reflecting into an increasingly interconnected world. Nevertheless, the incessant demand for faster data-rates requires a shift to higher carrier frequencies, which translates to the need for more ubiquitous hardware due to the increased wave propagation losses. The 7-20 GHz range, located between the sub-6 GHz (5G FR-1) and the mm-wave (5G FR-2) spectrum, provides an excellent trade-off between network capacity and coverage. Such spectrum portion constitutes a yet-to-explore third frequency range (FR-3) for future 5G applications, and is foreseen to become the 6G mid-band, devoted to crowded urban area coverage. This work proposes a technological platform able to deliver CMOS-compatible, on-chip multi-frequency low-loss, wideband, and compact passband filters for cellular radios operating at mid-band frequencies, exploiting the micro-to-nano scaling of acoustic electromechanical resonators and filters. The presented results showcase the first-ever demonstrated low insertion loss bank of 7 nanoacoustic passive passband filters in the X-band, spanning more than 3 GHz of operation, all fabricated on the same substrate with state-of-the-art and low-complexity micro-machining process. Most of the filters showcase fractional bandwidths above 3% and sub-dB loss per stage, all in an extremely compact form factor, enabling the manufacturing of X-band filters and duplexers that can be integrated in mobile handsets at each antenna element. The novelty of the current results stems from the adoption of a high-crystallinity piezoelectric Sc-doped AlN thin film, together with an optimized resonator topology in terms of design and fabrication.

Published
2023
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35. Sub-GHz X-Cut Lithium Niobate S ₀ Mode MEMS Resonators.

Author

Colombo, Luca, Kochhar, Abhay, Vidal-Alvarez, Gabriel, Simeoni, Pietro, Soysal, Umut, and Piazza, Gianluca

Subjects
LITHIUM niobate, MEMS resonators, QUALITY factor, RESONATORS, MICROELECTROMECHANICAL systems, LAMB waves
Abstract

This paper reports on the design, fabrication, and characterization of $S_{0}$ mode X-cut Lithium Niobate Laterally Vibrating Resonators (LVRs) operating between 100 MHz and 1 GHz. In the first Section of this work, analytical and numerical models are implemented to investigate the impact of topology and geometrical features on the Electromechanical Coupling ($k_{t}^{2}$) and Quality Factor ($Q_{s}$) of this class of devices. The models are used to define the design of experiments aimed at characterizing the resonator performance. The resonators are fabricated and tested in atmospheric, vacuum, and cryogenic ($T$ = 10 K) conditions to assess their performance and identify the main sources of discrepancies in $k_{t}^{2}$ and $Q_{s}$ with respect to the analytical and numerical models. Under vacuum quality factors exceeding a few thousands are recorded across the investigated spectrum, with measured $k_{t}^{2}$ as high as 28.9%. At 100 MHz, measured $Q_{s}$ and $k_{t}^{2}$ of 8,279 and 28.5%, respectively, combine into a record-breaking Figure of Merit ($FOM$) of 2,688, while cryogenic testing highlighted $Q_{s}$ as high as 26,511. In the last section, by analyzing the differences in $k_{t}^{2}$ and $Q_{s}$ between experiments and models, best design approaches to maximize the $FOM$ and minimize spurious modes responses are reported, with a focus on the 100 to 550 MHz range. [2022-0081] [ABSTRACT FROM AUTHOR]

Published
2022
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36. Piezoelectric Nanoscale Ultrasound Transducers (pnuts) for Miniaturized Internet of Things Receivers

Author

Simeoni, Pietro

Subjects
90699 Electrical and Electronic Engineering not elsewhere classified, FOS: Electrical engineering, electronic engineering, information engineering, ComputerSystemsOrganization_SPECIAL-PURPOSEANDAPPLICATION-BASEDSYSTEMS
Abstract

The landscape of connected devices has both grown in size and changed in nature in the last few decades. When the internet came along, it represented a first wave of connectivity that enabled communication between desktop computers. As computers moved to smaller form factors such as laptops and more recently smartphones, the need for connectivity was extended to this class of devices. This second wave was wireless in nature, and came with theadditional constraint of lower power consumption as these devices are powered by batteries. We are now going through a third wave of connectivity, where everyday appliances and sensor nodes distributed in the environment are equipped with the ability to remotely receive andreport back information. This third wave is commonly referred to as the internet of things (IoT), and as it rolls out, the constraints on form-factor and power consumption become increasingly tight and challenging to engineer.Because of the high density of wireless nodes, radio frequency bands are becoming a scarce resource and they constitute yet another constraint to account for during the system design. The number of wireless nodes is increasing exponentially and we expect to have a trillion sensors deployed by the year 2030. To make the deployment of a trillion sensors feasible, these nodes must be small and function on limited power budgets. For a subset of IoT applications, a network of sensors would need to be installed in a localized area, where the required communication range is less than 10 m and where a central hub can orchestrate the connection between different nodes.For such applications, ultrasound between 40 kHz and 100 kHz becomes an attractive candidate to overcome several of the constraints outlined above. This frequency range offerstwo important advantages: 1) The acoustic waves attenuation is low and permits communication over several meters (loss < 3 dB/m). 2) The node electronics can operate at extremely low power, potentially extending its lifetime to several years while drawing power from a miniaturized battery. If ultrasound is used in place of RF waves, we must replace the node antenna with an ultrasound transducer. In this work we introduce a novel ultrasound sensor that we dub the piezoelectric nano-scale ultrasound transducer (pNUT). The pNUTs are characterized by piezoelectric films that are only 100 nm thick and by a footprint that is 1 to 2 orders of magnitude smaller than the state of the art, while showing similar performance. A model for the scaling of ultrasound transducers is presented to offer guidelines for the design of miniaturized ultrasound sensors. Finally, we design a circuit with accessible off-the-shelf components to demonstrate a low-power pNUT-based ultrasound wake-up receiver (WuRx). The WuRx presents a communication range of several meters, confirming the feasibility ofminiaturized ultrasound tags for distributed sensors networks.

Published
2021
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38. A 5.3 GHz Al 0.76 Sc 0.24 N Two-Dimensional Resonant Rods Resonator With a k t 2 of 23.9%.

Author

Zhao, Xuanyi, Kaya, Onurcan, Pirro, Michele, Assylbekova, Meruyert, Colombo, Luca, Simeoni, Pietro, and Cassella, Cristian

Subjects
ALUMINUM nitride, RESONATORS, MECHANICAL energy, ACOUSTIC filters, RESONANCE
Abstract

This work reports on the measured performance of an Aluminum Scandium Nitride (AlScN) Two-Dimensional Resonant Rods resonator (2DRR), fabricated by using a Sc-doping concentration of 24%, characterized by a low off-resonance impedance ($\sim $ 25 $\Omega $) and exhibiting a record electromechanical coupling coefficient (${k}_{t}^{\textit {2}}$) of 23.9% for AlScN resonators. In order to achieve such performance, we identified and relied on optimized deposition and etching processes for highly-doped AlScN films, aiming at achieving high crystalline quality, low density of abnormally oriented grains in the 2DRR’s active region and sharp lateral sidewalls. Also, the 2DRR’s unit-cell has been acoustically engineered to maximize the piezo-generated mechanical energy within each rod and to ensure a low transduction of spurious modes around resonance. Due to its unprecedented ${k}_{t}^{\textit {2}}$ , the reported 2DRR opens exciting scenarios towards the development of next generation monolithic integrated radio-frequency (RF) filtering components. In fact, we show that $5^{th}$ -order 2DRR-based ladder filters with fractional bandwidths (BW) of $\sim $ 11%, insertion-loss (I.L) values of $\sim $ 2.5 dB and with $>$ 30 dB out-of-band rejections can now be envisioned, paving an unprecedented path towards the development of ultra-wide band (UWB) filters for next-generation Super-High-Frequency (SHF) radio front-ends. [2022-0024] [ABSTRACT FROM AUTHOR]

Published
2022
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40. Effect of Substrate-RF on Sub-200 nm Al 0.7 Sc 0.3 N Thin Films.

Author

Pirro, Michele, Zhao, Xuanyi, Herrera, Bernard, Simeoni, Pietro, and Rinaldi, Matteo

Subjects
THIN films, ALUMINUM nitride, RESIDUAL stresses, PIEZOELECTRIC materials, DIELECTRIC properties, LEAD titanate
Abstract

Sc-doped aluminum nitride is emerging as a new piezoelectric material which can substitute undoped aluminum nitride (AlN) in radio-frequency MEMS applications, thanks to its demonstrated enhancement of the piezoelectric coefficients. Furthermore, the recent demonstration of the ferroelectric-switching capability of the material gives AlScN the possibility to integrate memory functionalities in RF components. However, its high-coercive field and high-leakage currents are limiting its applicability. Residual stress, growth on different substrates, and testing-temperature have already been demonstrated as possible knobs to flatten the energy barrier needed for switching, but no investigation has been reported yet on the whole impact on the dielectric and ferroelectric dynamic behavior of a single process parameter. In this context, we analyze the complete spectrum of variations induced by the applied substrate-RF, from deposition characteristics to dielectric and ferroelectric properties, proving its effect on all of the material attributes. In particular, we demonstrate the possibility of engineering the AlScN lattice cell to properly modify leakage, breakdown, and coercive fields, as well as polarization charge, without altering the crystallinity level, making substrate-RF an effective and efficient fabrication knob to ease the limitations the material is facing. [ABSTRACT FROM AUTHOR]

Published
2022
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