This Ph.D. thesis focuses on the high-frequency electrical capabilities of the carbon-nanotube, field-effect transistor (CNFET). The thesis can be categorized into three stages, leading up to an assessment of the RF capabilities of realistic array-based CNFETs.
In the first stage, the high-frequency and time-dependent behavior of ballistic CNFETs is examined by numerically solving the time-dependent Boltzmann transport equation (BTE) self-consistently with the Poisson equation. The RF admittance matrix, which contains the transistor’s y-parameters, is extracted. At frequencies below the transistor’s unity-current-gain frequency fT, the y-parameters are shown to agree with those predicted from a quasi-static equivalent circuit, provided that the partitioning factor for the device charge is properly extracted. It is also shown that a resonance behavior exists in the transistor’s y-parameters.
In the second stage, non-quasi-static effects in ballistic CNFETs are examined by analytically developing a transmission-line model from the BTE and Poisson equation. This model includes nonclassical transistor elements, such as the "quantum capacitance" and "kinetic inductance," and it is shown to represent the intrinsic (contact-independent) transistor’s behavior at high frequencies, including a correct prediction of the resonances in the y-parameters. Moreover, it is shown that the kinetic inductance can be represented using lumped elements in the transistor’s small-signal equivalent circuit, and it is demonstrated that the resulting circuit is capable of modeling intrinsic CNFET behavior to frequencies beyond fT.
In the last stage, by building upon the first two stages, a comprehensive study is performed to assess the RF performance potential of array-based CNFETs. First, phonon scattering is incorporated into the time-dependent BTE to study the impacts of collisions on different aspects of intrinsic CNFET operation, including the intrinsic fT and the small-signal equivalent circuit. These results are then further extended by adding the effects of extrinsic (contact-dependent) parasitics and then examining the behavior of key RF figures of merit, such as the extrinsic fT, the attainable power gain, and the unity-power-gain frequency. The results are compared to those of state-of-the-art high-frequency transistors and to the next generation of RF CMOS, and they provide an indication of the potential advantages of array-based CNFETs for RF applications. / Micro-Electro-Mechanical Systems (MEMS) and Nanosystems
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:AEU.10048/1883 |
| Date | 06 1900 |
| Creators | Paydavosi, Navid |
| Contributors | Vaidyanathan, Mani (Electrical and Computer Engineering), Barlage, Douglas (Electrical and Computer Engineering), Pramanik, Sandipan (Electrical and Computer Engineering), DeCorby, Ray (Electrical and Computer Engineering), Cadien, Ken (Chemical and Materials Engineering), Guo, Jing (Electrical and Computer Engineering, University of Florida) |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | 2972424 bytes, application/pdf |
| Relation | N. Paydavosi et al., "Understanding the frequency- and time-dependent behavior of ballistic carbon-nanotube transistors," IEEE Trans. Nanotechnol., vol. 8, no. 2, pp. 234-244, Mar. 2009., N. Paydavosi et al., "Non-quasi-static effects and the role of kinetic inductance in ballistic carbon-nanotube transistors," IEEE Trans. Nanotechnol., vol. 9, no. 4, pp. 449-463, Jul. 2010. |
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