title: Intercalation Doped Multilayer-Graphene-Nanoribbons for Next-Generation Interconnects.
abstract: Copper-based interconnects employed in a wide range of integrated circuit (IC) products are fast approaching a dead-end due to their increasing resistivity and diminishing current carrying capacity with scaling, which severely degrades both performance and reliability. Here we demonstrate chemical vapor deposition-synthesized and intercalation-doped multilayer-graphene-nanoribbons (ML-GNRs) with better performance (more than 20% improvement in estimated delay per unit length), 25%/72% energy efficiency improvement at local/global level, and superior reliability w.r.t. Cu for the first time, for dimensions (down to 20 nm width and thickness of 12 nm) suitable for IC interconnects. This is achieved through a combination of GNR interconnect design optimization, high-quality ML-GNR synthesis with precisely controlled number of layers, and effective FeCl3intercalation doping. We also demonstrate that our intercalation doping is stable at room temperature and that the doped ML-GNRs exhibit a unique width-dependent doping effect due to increasingly efficient FeCl3diffusion in scaled ML-GNRs, thereby indicating that our doped ML-GNRs will outperform Cu even for sub-20 nm widths. Finally, reliability assessment conducted under accelerated stress conditions (temperature and current density) established that highly scaled intercalated ML-GNRs can carry over 2 × 108A/cm2of current densities, whereas Cu interconnects suffer from immediate breakdown under the same stress conditions and thereby addresses the key criterion of current carrying capacity necessary for an alternative interconnect material. Our comprehensive demonstration of highly reliable intercalation-doped ML-GNRs paves the way for graphene as the next-generation interconnect material for a variety of semiconductor technologies and applications.
authors.affiliation: Department of Electrical and Computer Engineering, University of California , Santa Barbara, California 93106, United States.
authors.forename: Junkai
authors.initials: J
authors.lastname: Jiang
authors.affiliation: Department of Electrical and Computer Engineering, University of California , Santa Barbara, California 93106, United States.
authors.forename: Jiahao
authors.initials: J
authors.lastname: Kang
authors.affiliation: Department of Electrical and Computer Engineering, University of California , Santa Barbara, California 93106, United States.
authors.forename: Wei
authors.initials: W
authors.lastname: Cao
authors.affiliation: Department of Electrical and Computer Engineering, University of California , Santa Barbara, California 93106, United States.
authors.forename: Xuejun
authors.initials: X
authors.lastname: Xie
authors.affiliation: Department of Electrical and Computer Engineering, University of California , Santa Barbara, California 93106, United States.
authors.forename: Haojun
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Department of Electrical and Computer Engineering, University of California , Santa Barbara, California 93106, United States.
authors.forename: Jae Hwan
authors.identifier: 0000-0002-1361-4445
authors.initials: JH
authors.lastname: Chu
authors.affiliation: Department of Electrical and Computer Engineering, University of California , Santa Barbara, California 93106, United States.
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
authors.affiliation: Department of Electrical and Computer Engineering, University of California , Santa Barbara, California 93106, United States.
authors.forename: Kaustav
authors.identifier: 0000-0001-5344-0921
authors.initials: K
authors.lastname: Banerjee
keywords: Graphene; Raman spectroscopy; breakdown; contact resistance; graphene-nanoribbon; intercalation doping; interconnect; resistivity