ECE Seminar: Zafer Mutlu
Tuesday, October 17, 2023 - 2 p.m.
Zafer Mutlu
Assistant Professor
Materials Science and Engineering
University of Arizona
"Graphene Nanoribbon-Based Field-Effect Transistors for High-Performance Logic Technology"
ECE 530 | Zoom
Abstract
Silicon has powered computing for decades through miniaturization, facilitated by innovations such as strained silicon, high-k dielectrics, Fin field-effect transistor (FinFET), and the latest industry trend: gate-all-around FET (GAAFET) architectures. However, silicon is reaching its limits as miniaturization yields diminishing benefits. This necessitates a new 'wonder' material that can potentially take some pressure off silicon’s shoulders and meet the increasing demands of computationally intensive technologies such as AI. Bottom-up synthesized, atomically precise graphene nanoribbon (GNRs) feature extremely high theoretical charge carrier mobility and on-state drive current capability at the atomic scale, making them highly promising transistor channel materials compared to silicon for high-performance logic applications. In this seminar, I will begin with an introduction to GNRs, explaining the features that make them promising for FETs, detailing the bottom-up synthesis, discussing techniques used for their characterization and device fabrication, presenting the current state of the art with transistors made from them, and addressing the remaining key issues. In the next part, I will detail our recent studies, involving enhancing electrostatic control of the GNR channel through the deposition of an ultrathin 2.5 nm high-k top HfO2 dielectric layer [1], ultimately scaling transistors with GNRs down to an 8 nm channel length [2,3], and optimizing the channel-contact interface through contact engineering to reduce contact resistance [4,5]. Finally, I will address the remaining challenges and potential enhancements in materials, processes, device integration, and related areas that could enable GNRs to approach outstanding theoretical predictions and explore future opportunities in the field.
References:
[1] Z. Mutlu et al., Short-Channel Double-Gate FETs with Atomically Precise Graphene Nanoribbons, IEDM, 2021.
[2] Z. Mutlu et al., Bottom-Up Synthesized Graphene Nanoribbon Transistors, EDTM, 2022.
[3] Y. Lin, Z. Mutlu et al., Scaling and Statistics of Bottom-up Synthesized Armchair Graphene Nanoribbon Transistors, Carbon, 2023.
[4] Christina Dinh and Z. Mutlu, Graphene Nanoribbons with Ohmic-Like Contacts, TECHCON 2023
[5] Z. Mutlu, Christina Dinh et al., Contact Engineering for Graphene Nanoribbon Devices, Applied Physics Reviews, 2023.
Bio
Zafer Mutlu is an assistant professor of materials science and engineering at the University of Arizona. Before joining the MSE faculty, he completed his postdoctoral research in electrical engineering and computer sciences at the University of California, Berkeley and Lawrence Berkeley National Laboratory with Professor Jeffrey Bokor. He earned his Ph.D. in MSE at the University of California, Riverside, in 2016 under the supervision of Professor Cengiz Ozkan. Prof. Mutlu leads the "Advanced Nanoelectronics & Nanostructures" group, primarily focusing on 1D graphene nanoribbons (GNRs) as transistor channel materials for high-performance logic applications, while also conducting recent research on the semiconductor properties of chalcopyrite minerals and nano- and micro-fabrication of acoustic devices. The group’s research is supported by funding from several agencies and companies, including the Semiconductor Research Corporation (SRC) Logic and Memory Device (LMD) program, the National Science Foundation (NSF) Future of Semiconductors (Fuse) program, the NSF New Frontiers of Sound (NewFoS) Science and Technology Center (STC), TSMC, and Freeport-McMoRan. The research has been published in prestigious conferences and journals, including IEEE IEDM, IEEE EDTM, SRC Techcon, Applied Physics Reviews, Advanced Functional Materials, ACS Nano, JACS, Nano Energy, Carbon, and Small.