Use of Bilayer Gate Insulator in GaN-on-Si Vertical Trench MOSFETs: Impact on Performance and Reliability
We propose to use a bilayer insulator (2.5 nm Al<sub>2</sub>O<sub>3</sub> + 35 nm SiO2) as an alternative to a conventional uni-layer Al<sub>2</sub>O<sub>3</sub> (35 nm), for improving the performance and the reliability of GaN-on-Si semi vertical tren...
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MDPI AG
2020-10-01
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| Online Access: | https://www.mdpi.com/1996-1944/13/21/4740 |
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| author | Kalparupa Mukherjee Carlo De Santi Matteo Borga Shuzhen You Karen Geens Benoit Bakeroot Stefaan Decoutere Gaudenzio Meneghesso Enrico Zanoni Matteo Meneghini |
| author_facet | Kalparupa Mukherjee Carlo De Santi Matteo Borga Shuzhen You Karen Geens Benoit Bakeroot Stefaan Decoutere Gaudenzio Meneghesso Enrico Zanoni Matteo Meneghini |
| author_sort | Kalparupa Mukherjee |
| collection | DOAJ |
| description | We propose to use a bilayer insulator (2.5 nm Al<sub>2</sub>O<sub>3</sub> + 35 nm SiO2) as an alternative to a conventional uni-layer Al<sub>2</sub>O<sub>3</sub> (35 nm), for improving the performance and the reliability of GaN-on-Si semi vertical trench MOSFETs. This analysis has been performed on a test vehicle structure for module development, which has a limited OFF-state performance. We demonstrate that devices with the bilayer dielectric present superior reliability characteristics than those with the uni-layer, including: (i) gate leakage two-orders of magnitude lower; (ii) 11 V higher off-state drain breakdown voltage; and (iii) 18 V higher gate-source breakdown voltage. From Weibull slope extractions, the uni-layer shows an extrinsic failure, while the bilayer presents a wear-out mechanism. Extended reliability tests investigate the degradation process, and hot-spots are identified through electroluminescence microscopy. TCAD simulations, in good agreement with measurements, reflect electric field distribution near breakdown for gate and drain stresses, demonstrating a higher electric field during positive gate stress. Furthermore, DC capability of the bilayer and unilayer insulators are found to be comparable for same bias points. Finally, comparison of trapping processes through double pulsed and V<sub>th</sub> transient methods confirms that the V<sub>th</sub> shifts are similar, despite the additional interface present in the bilayer devices. |
| first_indexed | 2024-03-10T15:23:34Z |
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| id | doaj.art-53b1b53bdec14de1a3f97623ce0da18c |
| institution | Directory Open Access Journal |
| issn | 1996-1944 |
| language | English |
| last_indexed | 2024-03-10T15:23:34Z |
| publishDate | 2020-10-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Materials |
| spelling | doaj.art-53b1b53bdec14de1a3f97623ce0da18c2023-11-20T18:17:01ZengMDPI AGMaterials1996-19442020-10-011321474010.3390/ma13214740Use of Bilayer Gate Insulator in GaN-on-Si Vertical Trench MOSFETs: Impact on Performance and ReliabilityKalparupa Mukherjee0Carlo De Santi1Matteo Borga2Shuzhen You3Karen Geens4Benoit Bakeroot5Stefaan Decoutere6Gaudenzio Meneghesso7Enrico Zanoni8Matteo Meneghini9Department of Information Engineering, University of Padua, 35131 Padua, ItalyDepartment of Information Engineering, University of Padua, 35131 Padua, ItalyIMEC, Kapeldreef 75, 3001 Leuven, BelgiumIMEC, Kapeldreef 75, 3001 Leuven, BelgiumIMEC, Kapeldreef 75, 3001 Leuven, BelgiumCMST imec/UGent, 9052 Ghent, BelgiumIMEC, Kapeldreef 75, 3001 Leuven, BelgiumDepartment of Information Engineering, University of Padua, 35131 Padua, ItalyDepartment of Information Engineering, University of Padua, 35131 Padua, ItalyDepartment of Information Engineering, University of Padua, 35131 Padua, ItalyWe propose to use a bilayer insulator (2.5 nm Al<sub>2</sub>O<sub>3</sub> + 35 nm SiO2) as an alternative to a conventional uni-layer Al<sub>2</sub>O<sub>3</sub> (35 nm), for improving the performance and the reliability of GaN-on-Si semi vertical trench MOSFETs. This analysis has been performed on a test vehicle structure for module development, which has a limited OFF-state performance. We demonstrate that devices with the bilayer dielectric present superior reliability characteristics than those with the uni-layer, including: (i) gate leakage two-orders of magnitude lower; (ii) 11 V higher off-state drain breakdown voltage; and (iii) 18 V higher gate-source breakdown voltage. From Weibull slope extractions, the uni-layer shows an extrinsic failure, while the bilayer presents a wear-out mechanism. Extended reliability tests investigate the degradation process, and hot-spots are identified through electroluminescence microscopy. TCAD simulations, in good agreement with measurements, reflect electric field distribution near breakdown for gate and drain stresses, demonstrating a higher electric field during positive gate stress. Furthermore, DC capability of the bilayer and unilayer insulators are found to be comparable for same bias points. Finally, comparison of trapping processes through double pulsed and V<sub>th</sub> transient methods confirms that the V<sub>th</sub> shifts are similar, despite the additional interface present in the bilayer devices.https://www.mdpi.com/1996-1944/13/21/4740GaNvertical GaNtrench MOSgate dielectricbreakdowntrapping |
| spellingShingle | Kalparupa Mukherjee Carlo De Santi Matteo Borga Shuzhen You Karen Geens Benoit Bakeroot Stefaan Decoutere Gaudenzio Meneghesso Enrico Zanoni Matteo Meneghini Use of Bilayer Gate Insulator in GaN-on-Si Vertical Trench MOSFETs: Impact on Performance and Reliability Materials GaN vertical GaN trench MOS gate dielectric breakdown trapping |
| title | Use of Bilayer Gate Insulator in GaN-on-Si Vertical Trench MOSFETs: Impact on Performance and Reliability |
| title_full | Use of Bilayer Gate Insulator in GaN-on-Si Vertical Trench MOSFETs: Impact on Performance and Reliability |
| title_fullStr | Use of Bilayer Gate Insulator in GaN-on-Si Vertical Trench MOSFETs: Impact on Performance and Reliability |
| title_full_unstemmed | Use of Bilayer Gate Insulator in GaN-on-Si Vertical Trench MOSFETs: Impact on Performance and Reliability |
| title_short | Use of Bilayer Gate Insulator in GaN-on-Si Vertical Trench MOSFETs: Impact on Performance and Reliability |
| title_sort | use of bilayer gate insulator in gan on si vertical trench mosfets impact on performance and reliability |
| topic | GaN vertical GaN trench MOS gate dielectric breakdown trapping |
| url | https://www.mdpi.com/1996-1944/13/21/4740 |
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