Design and Characterization of Backside Termination Structures for Thick Fully-Depleted MAPS
Fully Depleted Monolithic Active Pixel Sensors (FD-MAPS) represent an appealing alternative to hybrid detectors for radiation imaging applications. We have recently demonstrated the feasibility of FD-MAPS based on a commercial 110 nm CMOS technology, adapted using high-resistivity substrates and bac...
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| Format: | Article |
| Language: | English |
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MDPI AG
2021-05-01
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| Series: | Sensors |
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| Online Access: | https://www.mdpi.com/1424-8220/21/11/3809 |
| _version_ | 1797531855009873920 |
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| author | Thomas Corradino Gian-Franco Dalla Betta Lorenzo De Cilladi Coralie Neubüser Lucio Pancheri |
| author_facet | Thomas Corradino Gian-Franco Dalla Betta Lorenzo De Cilladi Coralie Neubüser Lucio Pancheri |
| author_sort | Thomas Corradino |
| collection | DOAJ |
| description | Fully Depleted Monolithic Active Pixel Sensors (FD-MAPS) represent an appealing alternative to hybrid detectors for radiation imaging applications. We have recently demonstrated the feasibility of FD-MAPS based on a commercial 110 nm CMOS technology, adapted using high-resistivity substrates and backside post-processing. A p/n junction diode, fabricated on the detector backside using low-temperature processing steps after the completion of the front-side Back End of Line (BEOL), is reverse-biased to achieve the full depletion of the substrate and thus fast charge collection by drift. Test diodes including termination structures with different numbers of floating guard rings and different pitches were fabricated together with other Process Control Monitor structures. In this paper, we present the design of the backside diodes, together with results from the electrical characterization of the test devices, aiming to improve understanding of the strengths and limitations of the proposed approach. Characterization results obtained on several wafers demonstrate the effectiveness of the termination rings in increasing the breakdown voltage of the backside diodes and in coping with the variability of the passivation layer characteristics. A breakdown voltage exceeding 400 V in the worst case was demonstrated in devices with 30 guard rings with 6 μm pitch, thus enabling the full depletion of high-resistivity substrates with a thickness larger than or equal to 300 μm. Additionally, we show the first direct comparison for this technology of measured pixel characteristics with 3D TCAD simulations, proving a good agreement in the extracted operating voltages. |
| first_indexed | 2024-03-10T10:50:46Z |
| format | Article |
| id | doaj.art-5e1629e533934be1ada36692d1533e34 |
| institution | Directory Open Access Journal |
| issn | 1424-8220 |
| language | English |
| last_indexed | 2024-03-10T10:50:46Z |
| publishDate | 2021-05-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Sensors |
| spelling | doaj.art-5e1629e533934be1ada36692d1533e342023-11-21T22:13:52ZengMDPI AGSensors1424-82202021-05-012111380910.3390/s21113809Design and Characterization of Backside Termination Structures for Thick Fully-Depleted MAPSThomas Corradino0Gian-Franco Dalla Betta1Lorenzo De Cilladi2Coralie Neubüser3Lucio Pancheri4Dipartimento di Ingegneria Industriale, Università degli Studi di Trento, 38123 Trento, ItalyDipartimento di Ingegneria Industriale, Università degli Studi di Trento, 38123 Trento, ItalyDipartimento di Fisica, Università degli Studi di Torino, 10125 Torino, ItalyTrento Institute for Fundamental Physics and Applications–Istituto Nazionale di Fisica Nucleare (TIFPA-INFN), 38123 Trento, ItalyDipartimento di Ingegneria Industriale, Università degli Studi di Trento, 38123 Trento, ItalyFully Depleted Monolithic Active Pixel Sensors (FD-MAPS) represent an appealing alternative to hybrid detectors for radiation imaging applications. We have recently demonstrated the feasibility of FD-MAPS based on a commercial 110 nm CMOS technology, adapted using high-resistivity substrates and backside post-processing. A p/n junction diode, fabricated on the detector backside using low-temperature processing steps after the completion of the front-side Back End of Line (BEOL), is reverse-biased to achieve the full depletion of the substrate and thus fast charge collection by drift. Test diodes including termination structures with different numbers of floating guard rings and different pitches were fabricated together with other Process Control Monitor structures. In this paper, we present the design of the backside diodes, together with results from the electrical characterization of the test devices, aiming to improve understanding of the strengths and limitations of the proposed approach. Characterization results obtained on several wafers demonstrate the effectiveness of the termination rings in increasing the breakdown voltage of the backside diodes and in coping with the variability of the passivation layer characteristics. A breakdown voltage exceeding 400 V in the worst case was demonstrated in devices with 30 guard rings with 6 μm pitch, thus enabling the full depletion of high-resistivity substrates with a thickness larger than or equal to 300 μm. Additionally, we show the first direct comparison for this technology of measured pixel characteristics with 3D TCAD simulations, proving a good agreement in the extracted operating voltages.https://www.mdpi.com/1424-8220/21/11/3809MAPSradiation detectorsCMOSdevice characterizationTCAD simulation |
| spellingShingle | Thomas Corradino Gian-Franco Dalla Betta Lorenzo De Cilladi Coralie Neubüser Lucio Pancheri Design and Characterization of Backside Termination Structures for Thick Fully-Depleted MAPS Sensors MAPS radiation detectors CMOS device characterization TCAD simulation |
| title | Design and Characterization of Backside Termination Structures for Thick Fully-Depleted MAPS |
| title_full | Design and Characterization of Backside Termination Structures for Thick Fully-Depleted MAPS |
| title_fullStr | Design and Characterization of Backside Termination Structures for Thick Fully-Depleted MAPS |
| title_full_unstemmed | Design and Characterization of Backside Termination Structures for Thick Fully-Depleted MAPS |
| title_short | Design and Characterization of Backside Termination Structures for Thick Fully-Depleted MAPS |
| title_sort | design and characterization of backside termination structures for thick fully depleted maps |
| topic | MAPS radiation detectors CMOS device characterization TCAD simulation |
| url | https://www.mdpi.com/1424-8220/21/11/3809 |
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