Scaling, Leakage Current Suppression, and Simulation of Carbon Nanotube Field-Effect Transistors
Carbon nanotube field-effect transistors (CNTFETs) are becoming a strong competitor for the next generation of high-performance, energy-efficient integrated circuits due to their near-ballistic carrier transport characteristics and excellent suppression of short-channel effects. However, CNT FETs wi...
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2025-07-01
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| author | Weixu Gong Zhengyang Cai Shengcheng Geng Zhi Gan Junqiao Li Tian Qiang Yanfeng Jiang Mengye Cai |
| author_facet | Weixu Gong Zhengyang Cai Shengcheng Geng Zhi Gan Junqiao Li Tian Qiang Yanfeng Jiang Mengye Cai |
| author_sort | Weixu Gong |
| collection | DOAJ |
| description | Carbon nanotube field-effect transistors (CNTFETs) are becoming a strong competitor for the next generation of high-performance, energy-efficient integrated circuits due to their near-ballistic carrier transport characteristics and excellent suppression of short-channel effects. However, CNT FETs with large diameters and small band gaps exhibit obvious bipolarity, and gate-induced drain leakage (GIDL) contributes significantly to the off-state leakage current. Although the asymmetric gate strategy and feedback gate (FBG) structures proposed so far have shown the potential to suppress CNT FET leakage currents, the devices still lack scalability. Based on the analysis of the conduction mechanism of existing self-aligned gate structures, this study innovatively proposed a design strategy to extend the length of the source–drain epitaxial region (L<sub>ext</sub>) under a vertically stacked architecture. While maintaining a high drive current, this structure effectively suppresses the quantum tunneling effect on the drain side, thereby reducing the off-state leakage current (I<sub>off</sub> = 10<sup>−10</sup> A), and has good scaling characteristics and leakage current suppression characteristics between gate lengths of 200 nm and 25 nm. For the sidewall gate architecture, this work also uses single-walled carbon nanotubes (SWCNTs) as the channel material and uses metal source and drain electrodes with good work function matching to achieve low-resistance ohmic contact. This solution has significant advantages in structural adjustability and contact quality and can significantly reduce the off-state current (I<sub>off</sub> = 10<sup>−14</sup> A). At the same time, it can solve the problem of off-state current suppression failure when the gate length of the vertical stacking structure is 10 nm (the total channel length is 30 nm) and has good scalability. |
| format | Article |
| id | doaj-art-b3ff5598f264455b833e8b175af9f8c8 |
| institution | Kabale University |
| issn | 2079-4991 |
| language | English |
| publishDate | 2025-07-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Nanomaterials |
| spelling | doaj-art-b3ff5598f264455b833e8b175af9f8c82025-08-20T04:00:54ZengMDPI AGNanomaterials2079-49912025-07-011515116810.3390/nano15151168Scaling, Leakage Current Suppression, and Simulation of Carbon Nanotube Field-Effect TransistorsWeixu Gong0Zhengyang Cai1Shengcheng Geng2Zhi Gan3Junqiao Li4Tian Qiang5Yanfeng Jiang6Mengye Cai7School of Integrated Circuits, Jiangnan University, Wuxi 214122, ChinaSchool of Integrated Circuits, Jiangnan University, Wuxi 214122, ChinaSchool of Integrated Circuits, Jiangnan University, Wuxi 214122, ChinaSchool of Integrated Circuits, Jiangnan University, Wuxi 214122, ChinaSchool of Integrated Circuits, Jiangnan University, Wuxi 214122, ChinaSchool of Integrated Circuits, Jiangnan University, Wuxi 214122, ChinaSchool of Integrated Circuits, Jiangnan University, Wuxi 214122, ChinaSchool of Integrated Circuits, Jiangnan University, Wuxi 214122, ChinaCarbon nanotube field-effect transistors (CNTFETs) are becoming a strong competitor for the next generation of high-performance, energy-efficient integrated circuits due to their near-ballistic carrier transport characteristics and excellent suppression of short-channel effects. However, CNT FETs with large diameters and small band gaps exhibit obvious bipolarity, and gate-induced drain leakage (GIDL) contributes significantly to the off-state leakage current. Although the asymmetric gate strategy and feedback gate (FBG) structures proposed so far have shown the potential to suppress CNT FET leakage currents, the devices still lack scalability. Based on the analysis of the conduction mechanism of existing self-aligned gate structures, this study innovatively proposed a design strategy to extend the length of the source–drain epitaxial region (L<sub>ext</sub>) under a vertically stacked architecture. While maintaining a high drive current, this structure effectively suppresses the quantum tunneling effect on the drain side, thereby reducing the off-state leakage current (I<sub>off</sub> = 10<sup>−10</sup> A), and has good scaling characteristics and leakage current suppression characteristics between gate lengths of 200 nm and 25 nm. For the sidewall gate architecture, this work also uses single-walled carbon nanotubes (SWCNTs) as the channel material and uses metal source and drain electrodes with good work function matching to achieve low-resistance ohmic contact. This solution has significant advantages in structural adjustability and contact quality and can significantly reduce the off-state current (I<sub>off</sub> = 10<sup>−14</sup> A). At the same time, it can solve the problem of off-state current suppression failure when the gate length of the vertical stacking structure is 10 nm (the total channel length is 30 nm) and has good scalability.https://www.mdpi.com/2079-4991/15/15/1168carbon nanotube field-effect transistorleakage currentTCAD simulationvertically stacked structuresidewall gate structure |
| spellingShingle | Weixu Gong Zhengyang Cai Shengcheng Geng Zhi Gan Junqiao Li Tian Qiang Yanfeng Jiang Mengye Cai Scaling, Leakage Current Suppression, and Simulation of Carbon Nanotube Field-Effect Transistors Nanomaterials carbon nanotube field-effect transistor leakage current TCAD simulation vertically stacked structure sidewall gate structure |
| title | Scaling, Leakage Current Suppression, and Simulation of Carbon Nanotube Field-Effect Transistors |
| title_full | Scaling, Leakage Current Suppression, and Simulation of Carbon Nanotube Field-Effect Transistors |
| title_fullStr | Scaling, Leakage Current Suppression, and Simulation of Carbon Nanotube Field-Effect Transistors |
| title_full_unstemmed | Scaling, Leakage Current Suppression, and Simulation of Carbon Nanotube Field-Effect Transistors |
| title_short | Scaling, Leakage Current Suppression, and Simulation of Carbon Nanotube Field-Effect Transistors |
| title_sort | scaling leakage current suppression and simulation of carbon nanotube field effect transistors |
| topic | carbon nanotube field-effect transistor leakage current TCAD simulation vertically stacked structure sidewall gate structure |
| url | https://www.mdpi.com/2079-4991/15/15/1168 |
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