High-Breakdown and Low-Leakage 4H-SiC MOS Capacitor Based on HfO<sub>2</sub>/SiO<sub>2</sub> Stacked Gate Dielectric in Trench Structures
The progression of SiC MOSFET technology from planar to trench structures requires optimized gate oxide layers within the trench to enhance device performance. In this study, we investigated the interface characteristics of HfO<sub>2</sub> and SiO<sub>2</sub>/HfO<sub>2&...
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MDPI AG
2025-02-01
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| author | Qimin Huang Yunduo Guo Anfeng Wang Lin Gu Zhenyu Wang Chengxi Ding Yi Shen Hongping Ma Qingchun Zhang |
| author_facet | Qimin Huang Yunduo Guo Anfeng Wang Lin Gu Zhenyu Wang Chengxi Ding Yi Shen Hongping Ma Qingchun Zhang |
| author_sort | Qimin Huang |
| collection | DOAJ |
| description | The progression of SiC MOSFET technology from planar to trench structures requires optimized gate oxide layers within the trench to enhance device performance. In this study, we investigated the interface characteristics of HfO<sub>2</sub> and SiO<sub>2</sub>/HfO<sub>2</sub> gate dielectrics grown by atomic layer deposition (ALD) on SiC trench structures. The trench structure morphology was revealed using scanning electron microscopy (SEM). Atomic force microscopy (AFM) measurements showed that the roughness of both films was below 1nm. Spectroscopic ellipsometry (SE) indicated that the physical thicknesses of HfO<sub>2</sub> and SiO<sub>2</sub>/HfO<sub>2</sub> were 38.275 nm and 40.51 nm, respectively, demonstrating their comparable thicknesses. X-ray photoelectron spectroscopy (XPS) analysis of the gate dielectrics revealed almost identical Hf 4f core levels for both HfO<sub>2</sub> and the SiO<sub>2</sub>/HfO<sub>2</sub> composite dielectrics, suggesting that the SiO<sub>2</sub> interlayer and the SiC substrate had minimal impact on the electronic structure of the HfO<sub>2</sub> film. The breakdown electric field of the HfO<sub>2</sub> film was recorded as 4.1 MV/cm, with a leakage current at breakdown of 1.1 × 10<sup>−3</sup>A/cm<sup>2</sup>. The SiO<sub>2</sub>/HfO<sub>2</sub> stacked film exhibited significantly better performance, with a breakdown electric field of 6.5 MV/cm and a marked reduction in leakage current to 3.7 × 10<sup>−4</sup> A/cm<sup>2</sup>. A detailed extraction and analysis of the leakage current mechanisms were proposed, and the data suggested that the introduction of thin SiO<sub>2</sub> interfacial layers effectively mitigated small bandgap offset issues, significantly reducing leakage current and improving device performance. |
| format | Article |
| id | doaj-art-4354d40c8ae74ebdb16d22388f35f410 |
| institution | DOAJ |
| issn | 2079-4991 |
| language | English |
| publishDate | 2025-02-01 |
| publisher | MDPI AG |
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| series | Nanomaterials |
| spelling | doaj-art-4354d40c8ae74ebdb16d22388f35f4102025-08-20T02:59:15ZengMDPI AGNanomaterials2079-49912025-02-0115534310.3390/nano15050343High-Breakdown and Low-Leakage 4H-SiC MOS Capacitor Based on HfO<sub>2</sub>/SiO<sub>2</sub> Stacked Gate Dielectric in Trench StructuresQimin Huang0Yunduo Guo1Anfeng Wang2Lin Gu3Zhenyu Wang4Chengxi Ding5Yi Shen6Hongping Ma7Qingchun Zhang8Institute of Wide Bandgap Semiconductors and Future Lighting, Academy for Engineering & Technology, Fudan University, Shanghai 200433, ChinaInstitute of Wide Bandgap Semiconductors and Future Lighting, Academy for Engineering & Technology, Fudan University, Shanghai 200433, ChinaInstitute of Wide Bandgap Semiconductors and Future Lighting, Academy for Engineering & Technology, Fudan University, Shanghai 200433, ChinaInstitute of Wide Bandgap Semiconductors and Future Lighting, Academy for Engineering & Technology, Fudan University, Shanghai 200433, ChinaInstitute of Wide Bandgap Semiconductors and Future Lighting, Academy for Engineering & Technology, Fudan University, Shanghai 200433, ChinaInstitute of Wide Bandgap Semiconductors and Future Lighting, Academy for Engineering & Technology, Fudan University, Shanghai 200433, ChinaInstitute of Wide Bandgap Semiconductors and Future Lighting, Academy for Engineering & Technology, Fudan University, Shanghai 200433, ChinaInstitute of Wide Bandgap Semiconductors and Future Lighting, Academy for Engineering & Technology, Fudan University, Shanghai 200433, ChinaInstitute of Wide Bandgap Semiconductors and Future Lighting, Academy for Engineering & Technology, Fudan University, Shanghai 200433, ChinaThe progression of SiC MOSFET technology from planar to trench structures requires optimized gate oxide layers within the trench to enhance device performance. In this study, we investigated the interface characteristics of HfO<sub>2</sub> and SiO<sub>2</sub>/HfO<sub>2</sub> gate dielectrics grown by atomic layer deposition (ALD) on SiC trench structures. The trench structure morphology was revealed using scanning electron microscopy (SEM). Atomic force microscopy (AFM) measurements showed that the roughness of both films was below 1nm. Spectroscopic ellipsometry (SE) indicated that the physical thicknesses of HfO<sub>2</sub> and SiO<sub>2</sub>/HfO<sub>2</sub> were 38.275 nm and 40.51 nm, respectively, demonstrating their comparable thicknesses. X-ray photoelectron spectroscopy (XPS) analysis of the gate dielectrics revealed almost identical Hf 4f core levels for both HfO<sub>2</sub> and the SiO<sub>2</sub>/HfO<sub>2</sub> composite dielectrics, suggesting that the SiO<sub>2</sub> interlayer and the SiC substrate had minimal impact on the electronic structure of the HfO<sub>2</sub> film. The breakdown electric field of the HfO<sub>2</sub> film was recorded as 4.1 MV/cm, with a leakage current at breakdown of 1.1 × 10<sup>−3</sup>A/cm<sup>2</sup>. The SiO<sub>2</sub>/HfO<sub>2</sub> stacked film exhibited significantly better performance, with a breakdown electric field of 6.5 MV/cm and a marked reduction in leakage current to 3.7 × 10<sup>−4</sup> A/cm<sup>2</sup>. A detailed extraction and analysis of the leakage current mechanisms were proposed, and the data suggested that the introduction of thin SiO<sub>2</sub> interfacial layers effectively mitigated small bandgap offset issues, significantly reducing leakage current and improving device performance.https://www.mdpi.com/2079-4991/15/5/343trench MOSALDhigh-kgate dielectricMIS capacitor |
| spellingShingle | Qimin Huang Yunduo Guo Anfeng Wang Lin Gu Zhenyu Wang Chengxi Ding Yi Shen Hongping Ma Qingchun Zhang High-Breakdown and Low-Leakage 4H-SiC MOS Capacitor Based on HfO<sub>2</sub>/SiO<sub>2</sub> Stacked Gate Dielectric in Trench Structures Nanomaterials trench MOS ALD high-k gate dielectric MIS capacitor |
| title | High-Breakdown and Low-Leakage 4H-SiC MOS Capacitor Based on HfO<sub>2</sub>/SiO<sub>2</sub> Stacked Gate Dielectric in Trench Structures |
| title_full | High-Breakdown and Low-Leakage 4H-SiC MOS Capacitor Based on HfO<sub>2</sub>/SiO<sub>2</sub> Stacked Gate Dielectric in Trench Structures |
| title_fullStr | High-Breakdown and Low-Leakage 4H-SiC MOS Capacitor Based on HfO<sub>2</sub>/SiO<sub>2</sub> Stacked Gate Dielectric in Trench Structures |
| title_full_unstemmed | High-Breakdown and Low-Leakage 4H-SiC MOS Capacitor Based on HfO<sub>2</sub>/SiO<sub>2</sub> Stacked Gate Dielectric in Trench Structures |
| title_short | High-Breakdown and Low-Leakage 4H-SiC MOS Capacitor Based on HfO<sub>2</sub>/SiO<sub>2</sub> Stacked Gate Dielectric in Trench Structures |
| title_sort | high breakdown and low leakage 4h sic mos capacitor based on hfo sub 2 sub sio sub 2 sub stacked gate dielectric in trench structures |
| topic | trench MOS ALD high-k gate dielectric MIS capacitor |
| url | https://www.mdpi.com/2079-4991/15/5/343 |
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