Polyimide-On-Silicon 2D Piezoelectric Micromachined Ultrasound Transducer (PMUT) Array
This paper presents a fully addressable 8 × 8 two-dimensional (2D) rigid piezoelectric micromachined ultrasonic transducer (PMUT) array. The PMUTs were fabricated on a standard silicon wafer, resulting in a low-cost solution for ultrasound imaging. A polyimide layer is used as the passive layer in t...
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| Format: | Article |
| Language: | English |
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MDPI AG
2023-05-01
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| Series: | Sensors |
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| Online Access: | https://www.mdpi.com/1424-8220/23/10/4826 |
| _version_ | 1797598415203336192 |
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| author | Sanjog Vilas Joshi Sina Sadeghpour Michael Kraft |
| author_facet | Sanjog Vilas Joshi Sina Sadeghpour Michael Kraft |
| author_sort | Sanjog Vilas Joshi |
| collection | DOAJ |
| description | This paper presents a fully addressable 8 × 8 two-dimensional (2D) rigid piezoelectric micromachined ultrasonic transducer (PMUT) array. The PMUTs were fabricated on a standard silicon wafer, resulting in a low-cost solution for ultrasound imaging. A polyimide layer is used as the passive layer in the PMUT membranes on top of the active piezoelectric layer. The PMUT membranes are realized by backside deep reactive ion etching (DRIE) with an oxide etch stop. The polyimide passive layer enables high resonance frequencies that can be easily tuned by controlling the thickness of the polyimide. The fabricated PMUT with 6 µm polyimide thickness showed a 3.2 MHz in-air frequency with a 3 nm/V sensitivity. The PMUT has shown an effective coupling coefficient of 14% as calculated from the impedance analysis. An approximately 1% interelement crosstalk between the PMUT elements in one array is observed, which is at least a five-fold reduction compared to the state of the art. A pressure response of 40 Pa/V at 5 mm was measured underwater using a hydrophone while exciting a single PMUT element. A single-pulse response captured using the hydrophone suggested a 70% −6 dB fractional bandwidth for the 1.7 MHz center frequency. The demonstrated results have the potential to enable imaging and sensing applications in shallow-depth regions, subject to some optimization. |
| first_indexed | 2024-03-11T03:20:54Z |
| format | Article |
| id | doaj.art-e708158966d34812a064d6d8736ac15d |
| institution | Directory Open Access Journal |
| issn | 1424-8220 |
| language | English |
| last_indexed | 2024-03-11T03:20:54Z |
| publishDate | 2023-05-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Sensors |
| spelling | doaj.art-e708158966d34812a064d6d8736ac15d2023-11-18T03:13:12ZengMDPI AGSensors1424-82202023-05-012310482610.3390/s23104826Polyimide-On-Silicon 2D Piezoelectric Micromachined Ultrasound Transducer (PMUT) ArraySanjog Vilas Joshi0Sina Sadeghpour1Michael Kraft2Department of Electrical Engineering (ESAT-MNS), KU Leuven, 3000 Leuven, BelgiumDepartment of Electrical Engineering (ESAT-MNS), KU Leuven, 3000 Leuven, BelgiumDepartment of Electrical Engineering (ESAT-MNS), KU Leuven, 3000 Leuven, BelgiumThis paper presents a fully addressable 8 × 8 two-dimensional (2D) rigid piezoelectric micromachined ultrasonic transducer (PMUT) array. The PMUTs were fabricated on a standard silicon wafer, resulting in a low-cost solution for ultrasound imaging. A polyimide layer is used as the passive layer in the PMUT membranes on top of the active piezoelectric layer. The PMUT membranes are realized by backside deep reactive ion etching (DRIE) with an oxide etch stop. The polyimide passive layer enables high resonance frequencies that can be easily tuned by controlling the thickness of the polyimide. The fabricated PMUT with 6 µm polyimide thickness showed a 3.2 MHz in-air frequency with a 3 nm/V sensitivity. The PMUT has shown an effective coupling coefficient of 14% as calculated from the impedance analysis. An approximately 1% interelement crosstalk between the PMUT elements in one array is observed, which is at least a five-fold reduction compared to the state of the art. A pressure response of 40 Pa/V at 5 mm was measured underwater using a hydrophone while exciting a single PMUT element. A single-pulse response captured using the hydrophone suggested a 70% −6 dB fractional bandwidth for the 1.7 MHz center frequency. The demonstrated results have the potential to enable imaging and sensing applications in shallow-depth regions, subject to some optimization.https://www.mdpi.com/1424-8220/23/10/4826piezoelectric thin filmsPZTpiezo-memsultrasound transducersPMUTmedical imaging |
| spellingShingle | Sanjog Vilas Joshi Sina Sadeghpour Michael Kraft Polyimide-On-Silicon 2D Piezoelectric Micromachined Ultrasound Transducer (PMUT) Array Sensors piezoelectric thin films PZT piezo-mems ultrasound transducers PMUT medical imaging |
| title | Polyimide-On-Silicon 2D Piezoelectric Micromachined Ultrasound Transducer (PMUT) Array |
| title_full | Polyimide-On-Silicon 2D Piezoelectric Micromachined Ultrasound Transducer (PMUT) Array |
| title_fullStr | Polyimide-On-Silicon 2D Piezoelectric Micromachined Ultrasound Transducer (PMUT) Array |
| title_full_unstemmed | Polyimide-On-Silicon 2D Piezoelectric Micromachined Ultrasound Transducer (PMUT) Array |
| title_short | Polyimide-On-Silicon 2D Piezoelectric Micromachined Ultrasound Transducer (PMUT) Array |
| title_sort | polyimide on silicon 2d piezoelectric micromachined ultrasound transducer pmut array |
| topic | piezoelectric thin films PZT piezo-mems ultrasound transducers PMUT medical imaging |
| url | https://www.mdpi.com/1424-8220/23/10/4826 |
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