Anodically Bonded Photoacoustic Transducer: An Approach towards Wafer-Level Optical Gas Sensors
We present a concept for a wafer-level manufactured photoacoustic transducer, suitable to be used in consumer-grade gas sensors. The transducer consists of an anodically bonded two-layer stack of a blank silicon wafer and an 11 µm membrane, which was wet-etched from a borosilicate wafer. The membran...
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-01-01
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| Series: | Sensors |
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| Online Access: | https://www.mdpi.com/1424-8220/22/2/685 |
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| author | Simon Gassner Rainer Schaller Matthias Eberl Carsten von Koblinski Simon Essing Mohammadamir Ghaderi Katrin Schmitt Jürgen Wöllenstein |
| author_facet | Simon Gassner Rainer Schaller Matthias Eberl Carsten von Koblinski Simon Essing Mohammadamir Ghaderi Katrin Schmitt Jürgen Wöllenstein |
| author_sort | Simon Gassner |
| collection | DOAJ |
| description | We present a concept for a wafer-level manufactured photoacoustic transducer, suitable to be used in consumer-grade gas sensors. The transducer consists of an anodically bonded two-layer stack of a blank silicon wafer and an 11 µm membrane, which was wet-etched from a borosilicate wafer. The membrane separates two cavities; one of which was hermetically sealed and filled with CO<sub>2</sub> during the anodic bonding and acts as an infrared absorber. The second cavity was designed to be connected to a standard MEMS microphone on PCB-level forming an infrared-sensitive photoacoustic detector. CO<sub>2</sub> sensors consisting of the detector and a MEMS infrared emitter were built up and characterized towards their sensitivity and noise levels at six different component distance ranging from 3.0 mm to 15.5 mm. The signal response for the sample with the longest absorption path ranged from a decrease of 8.3% at a CO<sub>2</sub> concentration of 9400 ppm to a decrease of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>0.8</mn></mrow></semantics></math></inline-formula>% at a concentration of 560 ppm. A standard deviation of the measured values of 18 ppm was determined when the sensor was exposed to 1000 ppm CO<sub>2</sub>. |
| first_indexed | 2024-03-10T00:32:39Z |
| format | Article |
| id | doaj.art-91ca3e580c454d9b8cca6919353b70c5 |
| institution | Directory Open Access Journal |
| issn | 1424-8220 |
| language | English |
| last_indexed | 2024-03-10T00:32:39Z |
| publishDate | 2022-01-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Sensors |
| spelling | doaj.art-91ca3e580c454d9b8cca6919353b70c52023-11-23T15:22:46ZengMDPI AGSensors1424-82202022-01-0122268510.3390/s22020685Anodically Bonded Photoacoustic Transducer: An Approach towards Wafer-Level Optical Gas SensorsSimon Gassner0Rainer Schaller1Matthias Eberl2Carsten von Koblinski3Simon Essing4Mohammadamir Ghaderi5Katrin Schmitt6Jürgen Wöllenstein7Department of Microsystems Engineering (IMTEK), Albert-Ludwigs-Universität Freiburg, 79085 Freiburg im Breisgau, GermanyInfineon Technologies AG, 81549 Neubiberg, GermanyInfineon Technologies AG, 81549 Neubiberg, GermanyInfineon Technologies Austria AG, 9500 Villach, AustriaDepartment of Electrical and Computer Engineering, Technical University of Munich, 80333 München, GermanyInfineon Technologies AG, 81549 Neubiberg, GermanyDepartment of Microsystems Engineering (IMTEK), Albert-Ludwigs-Universität Freiburg, 79085 Freiburg im Breisgau, GermanyDepartment of Microsystems Engineering (IMTEK), Albert-Ludwigs-Universität Freiburg, 79085 Freiburg im Breisgau, GermanyWe present a concept for a wafer-level manufactured photoacoustic transducer, suitable to be used in consumer-grade gas sensors. The transducer consists of an anodically bonded two-layer stack of a blank silicon wafer and an 11 µm membrane, which was wet-etched from a borosilicate wafer. The membrane separates two cavities; one of which was hermetically sealed and filled with CO<sub>2</sub> during the anodic bonding and acts as an infrared absorber. The second cavity was designed to be connected to a standard MEMS microphone on PCB-level forming an infrared-sensitive photoacoustic detector. CO<sub>2</sub> sensors consisting of the detector and a MEMS infrared emitter were built up and characterized towards their sensitivity and noise levels at six different component distance ranging from 3.0 mm to 15.5 mm. The signal response for the sample with the longest absorption path ranged from a decrease of 8.3% at a CO<sub>2</sub> concentration of 9400 ppm to a decrease of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>0.8</mn></mrow></semantics></math></inline-formula>% at a concentration of 560 ppm. A standard deviation of the measured values of 18 ppm was determined when the sensor was exposed to 1000 ppm CO<sub>2</sub>.https://www.mdpi.com/1424-8220/22/2/685gas sensorphotoacousticpressure transducerwafer-levelCO<sub>2</sub> |
| spellingShingle | Simon Gassner Rainer Schaller Matthias Eberl Carsten von Koblinski Simon Essing Mohammadamir Ghaderi Katrin Schmitt Jürgen Wöllenstein Anodically Bonded Photoacoustic Transducer: An Approach towards Wafer-Level Optical Gas Sensors Sensors gas sensor photoacoustic pressure transducer wafer-level CO<sub>2</sub> |
| title | Anodically Bonded Photoacoustic Transducer: An Approach towards Wafer-Level Optical Gas Sensors |
| title_full | Anodically Bonded Photoacoustic Transducer: An Approach towards Wafer-Level Optical Gas Sensors |
| title_fullStr | Anodically Bonded Photoacoustic Transducer: An Approach towards Wafer-Level Optical Gas Sensors |
| title_full_unstemmed | Anodically Bonded Photoacoustic Transducer: An Approach towards Wafer-Level Optical Gas Sensors |
| title_short | Anodically Bonded Photoacoustic Transducer: An Approach towards Wafer-Level Optical Gas Sensors |
| title_sort | anodically bonded photoacoustic transducer an approach towards wafer level optical gas sensors |
| topic | gas sensor photoacoustic pressure transducer wafer-level CO<sub>2</sub> |
| url | https://www.mdpi.com/1424-8220/22/2/685 |
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