Browsing by Author "Ravichandran, Arul Vigneswar"
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Item Evaluation and Integration of Graphene Field Effect Devices(2020-04-22) Ravichandran, Arul Vigneswar; Kim, Jiyoung; Young, Chadwin D.Graphene field effect devices have potential applications in emerging analogue and sensing technology. However, to use them in end applications, evaluation of such devices in terms of mobility, contact resistivity, and sheet resistance is pivotal. These fundamental parameters will dictate and enable the designing of futuristic graphene-based devices. Finally, these devices should be packaged depending on the final application or for further evaluation in an industrial perspective. This work explores the evaluation of graphene field effect devices that has been fabricated using Chemical Vapor Deposition (CVD) graphene source with optimization of the device fabrication process flows on 90 nmSiO2 using materials characterization techniques such as Raman spectroscopy, Atomic Force Microscopy, X-ray photoelectron spectroscopy, and spectroscopic ellipsometry. The issues arising with dual-gated graphene transistor is identified and one of the potential solutions to downscale the back-gate dielectric is demonstrated. Critical device parameters like mobility, contact resistivity of graphene devices are evaluated and final integration of such devices at a package level is demonstrated. For commercialization of graphene nanoelectronics, heterogeneous integration of graphene devices on commercially available CMOS substrate is the key and process flow for such devices is demonstrated. Additionally, a novel device architecture to electrically dope graphene in the contact regions is identified and this could pave way for implementation of futuristic graphene devices with tailored device properties.Item The Graphene Field Effect Transistor: A Large Scale Integration Approach(2016-12) Ravichandran, Arul Vigneswar; Kim, JiyoungOwing to the continuous down scaling of devices as per Moore’s law and the simultaneous need to increase the processing efficiency of the transistor, graphene was found to be the potential candidate for the post silicon electronics due to its predicted theoretical mobility of 200,000 cm2/V. s and one atom thickness. However, due to its semi metallic nature with no bandgap and a linear electronic dispersion structure, the use of graphene field effect transistors in logic circuits is not feasible as there is no off state and the on to off ratio is lesser than the required criteria of 104. Nevertheless, its usability in radio frequency applications is still significant because of the higher cut-off frequency and the predicted ability to saturate the mobility at higher electric fields. Mechanically exfoliated, epitaxially grown graphene has limitations in terms of reproducibility and scalability. CVD graphene is a viable source for fabricating transistors on a large scale. Different processes developed with the objective of making consistent and reliable graphene field effect transistors, packaging them for practical applications are discussed in this thesis.