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Mo J, Shankar S, Pezone R, Zhang G, Vollebregt S. A high aspect ratio surface micromachined accelerometer based on a SiC-CNT composite material. Microsyst Nanoeng 2024; 10:42. [PMID: 38523654 PMCID: PMC10957932 DOI: 10.1038/s41378-024-00672-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 01/17/2024] [Accepted: 02/01/2024] [Indexed: 03/26/2024]
Abstract
Silicon carbide (SiC) is recognized as an excellent material for microelectromechanical systems (MEMS), especially those operating in challenging environments, such as high temperature, high radiation, and corrosive environments. However, SiC bulk micromachining is still a challenge, which hinders the development of complex SiC MEMS. To address this problem, we present the use of a carbon nanotube (CNT) array coated with amorphous SiC (a-SiC) as an alternative composite material to enable high aspect ratio (HAR) surface micromachining. By using a prepatterned catalyst layer, a HAR CNT array can be grown as a structural template and then densified by uniformly filling the CNT bundle with LPCVD a-SiC. The electrical properties of the resulting SiC-CNT composite were characterized, and the results indicated that the electrical resistivity was dominated by the CNTs. To demonstrate the use of this composite in MEMS applications, a capacitive accelerometer was designed, fabricated, and measured. The fabrication results showed that the composite is fully compatible with the manufacturing of surface micromachining devices. The Young's modulus of the composite was extracted from the measured spring constant, and the results show a great improvement in the mechanical properties of the CNTs after coating with a-SiC. The accelerometer was electrically characterized, and its functionality was confirmed using a mechanical shaker.
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Affiliation(s)
- Jiarui Mo
- Laboratory of Electronic Components, Technology and Materials (ECTM), Department of Microelectronics, Delft University of Technology, Delft, The Netherlands
| | - Shreyas Shankar
- Laboratory of Electronic Components, Technology and Materials (ECTM), Department of Microelectronics, Delft University of Technology, Delft, The Netherlands
| | - Roberto Pezone
- Laboratory of Electronic Components, Technology and Materials (ECTM), Department of Microelectronics, Delft University of Technology, Delft, The Netherlands
| | - Guoqi Zhang
- Laboratory of Electronic Components, Technology and Materials (ECTM), Department of Microelectronics, Delft University of Technology, Delft, The Netherlands
| | - Sten Vollebregt
- Laboratory of Electronic Components, Technology and Materials (ECTM), Department of Microelectronics, Delft University of Technology, Delft, The Netherlands
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Pezone R, Anzinger S, Baglioni G, Wasisto HS, Sarro PM, Steeneken PG, Vollebregt S. Highly-sensitive wafer-scale transfer-free graphene MEMS condenser microphones. Microsyst Nanoeng 2024; 10:27. [PMID: 38384678 PMCID: PMC10879197 DOI: 10.1038/s41378-024-00656-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 11/02/2023] [Accepted: 12/14/2023] [Indexed: 02/23/2024]
Abstract
Since the performance of micro-electro-mechanical system (MEMS)-based microphones is approaching fundamental physical, design, and material limits, it has become challenging to improve them. Several works have demonstrated graphene's suitability as a microphone diaphragm. The potential for achieving smaller, more sensitive, and scalable on-chip MEMS microphones is yet to be determined. To address large graphene sizes, graphene-polymer heterostructures have been proposed, but they compromise performance due to added polymer mass and stiffness. This work demonstrates the first wafer-scale integrated MEMS condenser microphones with diameters of 2R = 220-320 μm, thickness of 7 nm multi-layer graphene, that is suspended over a back-plate with a residual gap of 5 μm. The microphones are manufactured with MEMS compatible wafer-scale technologies without any transfer steps or polymer layers that are more prone to contaminate and wrinkle the graphene. Different designs, all electrically integrated are fabricated and characterized allowing us to study the effects of the introduction of a back-plate for capacitive read-out. The devices show high mechanical compliances Cm = 0.081-1.07 μmPa-1 (10-100 × higher than the silicon reported in the state-of-the-art diaphragms) and pull-in voltages in the range of 2-9.5 V. In addition, to validate the proof of concept, we have electrically characterized the graphene microphone when subjected to sound actuation. An estimated sensitivity of S1kHz = 24.3-321 mV Pa-1 for a Vbias = 1.5 V was determined, which is 1.9-25.5 × higher than of state-of-the-art microphone devices while having a ~9 × smaller area.
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Affiliation(s)
- Roberto Pezone
- Laboratory of Electronic Components, Technology and Materials (ECTM), Department of Microelectronics, Delft University of Technology, Delft, The Netherlands
| | | | - Gabriele Baglioni
- Kavli Institue of Nanoscience, Department of Quantum Nanoscience, Delft University of Technology, Delft, the Netherlands
| | | | - Pasqualina M. Sarro
- Laboratory of Electronic Components, Technology and Materials (ECTM), Department of Microelectronics, Delft University of Technology, Delft, The Netherlands
| | - Peter G. Steeneken
- Kavli Institue of Nanoscience, Department of Quantum Nanoscience, Delft University of Technology, Delft, the Netherlands
- Department of Precision and Microsystems Engineering (PME), Delft University of Technology, Delft, The Netherlands
| | - Sten Vollebregt
- Laboratory of Electronic Components, Technology and Materials (ECTM), Department of Microelectronics, Delft University of Technology, Delft, The Netherlands
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Baglioni G, Pezone R, Vollebregt S, Cvetanović Zobenica K, Spasenović M, Todorović D, Liu H, Verbiest GJ, van der Zant HSJ, Steeneken PG. Ultra-sensitive graphene membranes for microphone applications. Nanoscale 2023; 15:6343-6352. [PMID: 36916300 DOI: 10.1039/d2nr05147h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Microphones exploit the motion of suspended membranes to detect sound waves. Since the microphone performance can be improved by reducing the thickness and mass of its sensing membrane, graphene-based microphones are expected to outperform state-of-the-art microelectromechanical (MEMS) microphones and allow further miniaturization of the device. Here, we present a laser vibrometry study of the acoustic response of suspended multilayer graphene membranes for microphone applications. We address performance parameters relevant for acoustic sensing, including mechanical sensitivity, limit of detection and nonlinear distortion, and discuss the trade-offs and limitations in the design of graphene microphones. We demonstrate superior mechanical sensitivities of the graphene membranes, reaching more than 2 orders of magnitude higher compliances than commercial MEMS devices, and report a limit of detection as low as 15 dBSPL, which is 10-15 dB lower than that featured by current MEMS microphones.
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Affiliation(s)
- Gabriele Baglioni
- Kavli Institute of Nanoscience, Delft University of Technology, The Netherlands.
| | - Roberto Pezone
- Laboratory of Electronic Components, Technology and Materials, Delft University of Technology, The Netherlands
| | - Sten Vollebregt
- Laboratory of Electronic Components, Technology and Materials, Delft University of Technology, The Netherlands
| | - Katarina Cvetanović Zobenica
- Center for Microelectronic Technologies, Institute of Chemistry, Technology and Metallurgy, University of Belgrade, Serbia
| | - Marko Spasenović
- Center for Microelectronic Technologies, Institute of Chemistry, Technology and Metallurgy, University of Belgrade, Serbia
| | | | - Hanqing Liu
- Department of Precision and Microsystems Engineering, Delft University of Technology, The Netherlands
| | - Gerard J Verbiest
- Department of Precision and Microsystems Engineering, Delft University of Technology, The Netherlands
| | | | - Peter G Steeneken
- Kavli Institute of Nanoscience, Delft University of Technology, The Netherlands.
- Department of Precision and Microsystems Engineering, Delft University of Technology, The Netherlands
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Gurke J, Naegele TE, Hilton S, Pezone R, Curto VF, Barone DG, List-Kratochvil EJW, Carnicer-Lombarte A, Malliaras GG. Hybrid fabrication of multimodal intracranial implants for electrophysiology and local drug delivery. Mater Horiz 2022; 9:1727-1734. [PMID: 35474130 PMCID: PMC9169700 DOI: 10.1039/d1mh01855h] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 04/21/2022] [Indexed: 05/31/2023]
Abstract
New fabrication approaches for mechanically flexible implants hold the key to advancing the applications of neuroengineering in fundamental neuroscience and clinic. By combining the high precision of thin film microfabrication with the versatility of additive manufacturing, we demonstrate a straight-forward approach for the prototyping of intracranial implants with electrode arrays and microfluidic channels. We show that the implant can modulate neuronal activity in the hippocampus through localized drug delivery, while simultaneously recording brain activity by its electrodes. Moreover, good implant stability and minimal tissue response are seen one-week post-implantation. Our work shows the potential of hybrid fabrication combining different manufacturing techniques in neurotechnology and paves the way for a new approach to the development of multimodal implants.
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Affiliation(s)
- Johannes Gurke
- University of Cambridge, Electrical Engineering Division, 9 JJ Thomson Ave, Cambridge, CB3 0FA, UK.
| | - Tobias E Naegele
- University of Cambridge, Electrical Engineering Division, 9 JJ Thomson Ave, Cambridge, CB3 0FA, UK.
| | - Sam Hilton
- University of Cambridge, Electrical Engineering Division, 9 JJ Thomson Ave, Cambridge, CB3 0FA, UK.
| | - Roberto Pezone
- University of Cambridge, Electrical Engineering Division, 9 JJ Thomson Ave, Cambridge, CB3 0FA, UK.
| | - Vincenzo F Curto
- University of Cambridge, Electrical Engineering Division, 9 JJ Thomson Ave, Cambridge, CB3 0FA, UK.
| | - Damiano G Barone
- University of Cambridge, Electrical Engineering Division, 9 JJ Thomson Ave, Cambridge, CB3 0FA, UK.
- University of Cambridge, School of Clinical Medicine, Department of Clinical Neurosciences, Cambridge Biomedical Campus, Cambridge CB2 0QQ, UK
| | - Emil J W List-Kratochvil
- Humboldt-Universität zu Berlin, Department of Chemistry and of Physics and IRIS Adlershof, Hybrid Devices Group, Zum Großen Windkanal 2, 12489 Berlin, Germany
- Helmholtz-Zentrum für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, 14109, Berlin, Germany
| | | | - George G Malliaras
- University of Cambridge, Electrical Engineering Division, 9 JJ Thomson Ave, Cambridge, CB3 0FA, UK.
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Pezone R, Baglioni G, Sarro PM, Steeneken PG, Vollebregt S. Sensitive Transfer-Free Wafer-Scale Graphene Microphones. ACS Appl Mater Interfaces 2022; 14:21705-21712. [PMID: 35475352 PMCID: PMC9100512 DOI: 10.1021/acsami.2c03305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Accepted: 04/12/2022] [Indexed: 06/14/2023]
Abstract
During the past decades micro-electromechanical microphones have largely taken over the market for portable devices, being produced in volumes of billions yearly. Because performance of current devices is near the physical limits, further miniaturization and improvement of microphones for mobile devices poses a major challenge that requires breakthrough device concepts, geometries, and materials. Graphene is an attractive material for enabling these breakthroughs due to its flexibility, strength, nanometer thinness, and high electrical conductivity. Here, we demonstrate that transfer-free 7 nm thick multilayer graphene (MLGr) membranes with diameters ranging from 85-155 to 300 μm can be used to detect sound and show a mechanical compliance up to 92 nm Pa-1, thus outperforming commercially available MEMS microphones of 950 μm with compliances around 3 nm Pa-1. The feasibility of realizing larger membranes with diameters of 300 μm and even higher compliances is shown, although these have lower yields. We present a process for locally growing graphene on a silicon wafer and realizing suspended membranes of patterned graphene across through-silicon holes by bulk micromachining and sacrificial layer etching, such that no transfer is required. This transfer-free method results in a 100% yield for membranes with diameters up to 155 μm on 132 fabricated drums. The device-to-device variations in the mechanical compliance in the audible range (20-20000 Hz) are significantly smaller than those in transferred membranes. With this work, we demonstrate a transfer-free method for realizing wafer-scale multilayer graphene membranes that is compatible with high-volume manufacturing. Thus, limitations of transfer-based methods for graphene microphone fabrication such as polymer contamination, crack formation, wrinkling, folding, delamination, and low-tension reproducibility are largely circumvented, setting a significant step on the route toward high-volume production of graphene microphones.
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Affiliation(s)
- Roberto Pezone
- Laboratory
of Electronic Components, Technology and Materials (ECTM), Department
of Microelectronics, Delft University of
Technology, 2628 CD Delft, The Netherlands
| | - Gabriele Baglioni
- Kavli
Institue of Nanoscience, Department of Quantum Nanoscience, Delft University of Technology, 2628 CD Delft, The Netherlands
| | - Pasqualina M. Sarro
- Laboratory
of Electronic Components, Technology and Materials (ECTM), Department
of Microelectronics, Delft University of
Technology, 2628 CD Delft, The Netherlands
| | - Peter G. Steeneken
- Kavli
Institue of Nanoscience, Department of Quantum Nanoscience, Delft University of Technology, 2628 CD Delft, The Netherlands
- Department
of Precision and Microsystems Engineering (PME), Delft University of Technology, 2628 CD Delft, The Netherlands
| | - Sten Vollebregt
- Laboratory
of Electronic Components, Technology and Materials (ECTM), Department
of Microelectronics, Delft University of
Technology, 2628 CD Delft, The Netherlands
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Gentile V, Porta R, Chiosi E, Spina A, Valente F, Pezone R, Davies PJ, Alaadik A, Illiano G. tTGase/G alpha h protein expression inhibits adenylate cyclase activity in Balb-C 3T3 fibroblasts membranes. Biochim Biophys Acta 1997; 1357:115-22. [PMID: 9202182 DOI: 10.1016/s0167-4889(97)00024-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Stably transfected Balb-C 3T3 fibroblasts (clone 5), overexpressing a catalytically active tissue transglutaminase, showed a basal adenylate cyclase activity lower than control cells (clone 1). Several modulators of the adenylate cyclase activity (forskolin, Mn2+ and pertussis toxin) showed the existence of a marked negative control on the adenylate cyclase activity present in clone 5 cells. Very interestingly, this same marked negative control was also found in a Balb-C 3T3 fibroblast clone stably transfected with a mutagenized human tissue transglutaminase (mut277 cys > ser) virtually devoid of transglutaminase catalytic activity (clone Ser). Conversely, a significant increase of the adenylate cyclase activity was observed in bovine aortic endothelial cells after the lowering of tissue transglutaminase expression levels by the transfection of an eukaryotic expression vector containing the gene for tissue transglutaminase in antisense orientation. All these findings suggest a possible role for type II tissue transglutaminase as a negative modulator of the adenylate cyclase activity in different cell types, beside its transglutaminase enzyme activity.
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Affiliation(s)
- V Gentile
- Department of Biochemistry and Biophysics, Second University of Naples, Italy
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