Effect of Varying Dielectric Constant on Relative Stability for Graphene Nanoribbon Interconnects Maryam Farrokhi 1, a , Rahim Faez 2,b , Saeed Haji Nasiri 3,c and Bita Davoodi 4,d 1 Department of Electrical Engineering, Qazvin Islamic Azad University, Qazvin, Iran 2 Electrical faculty, Sharif University of technology, Tehran, Iran 3 Department of Electrical Engineering, Qazvin Islamic Azad University, Qazvin, Iran 4 Department of Electrical Engineering, Qazvin Islamic Azad University, Qazvin, Iran a m.farrokhi@qiau.ac.ir, b Faez@sharif.edu, c s.nasiri@qiau.ac.ir, d b.davoodi@qiau.ac.ir Keywords: Graphene, Interconnect, Nanoribbon, Dielectric Constant, Nyquist stability criterion. Abstract. The remarkable properties of graphene nanoribbons (GNRs) make them attractive for nano-scale devices applications, especially for transistor and interconnect. Furthermore, for reduction interconnects signal delay, low dielectric constant materials are being introduced to replace conventional dielectrics in next generation IC technologies. With these regards, studding the effect of varying dielectric constant (ɛ r ) on relative stability of graphene nanoribbons interconnect is an important viewpoint in performance evaluation of system. In this paper, Nyquist stability analysis based on transmission line modeling (TLM) for graphene nanoribbon interconnects is investigated. In this analysis, the dependence of the degree of relative stability for multilayer GNR (MLGNR) interconnects on the dielectric constant has been acquired. It is shown that, increasing the dielectric constant of each ribbon, MLGNR interconnects become more stable. Introduction Graphene, a single layer graphite structure, has been studied intensively both in theoretical and experimental work after it can be prepared in conventional setups [1]. Graphene have many attractive properties, including high carrier mobility, ability to carry a high-density current and high mechanical strength [2]. Compared to CNTs, GNRs are believed to be more controllable from a fabrication point of view. This is due to the planar nature of graphene, which can be patterned using high-resolutions lithography [3]. The electrical resistance of a single graphene nanoribbon is relatively high. Hence, for interconnect applications, a multilayer GNR with a reduced equivalent resistance must be used [4]. Transmission Line Modeling Fig. 1 shows a schematic representation of a typical RLC model for an MLGNR interconnect made of N layer single GNR layers of the same lengths l and widths W. In this figure, R C , R Q , and R S represent the equivalent resistances introduced by the imperfect contacts, the quantum effect, and the carriers’ scatterings, respectively. One can approximate the quantum contact resistance as R Q ≈ h {2e 2 N ch N layer } −1 [5], wherein h, e, and N ch are the Plank’s constant, electron charge, and number of conducting channels in each GNR. When the length of each GNR is greater than its carrier’s mean free path (λ), the equivalent distributed ohmic resistance (per unit length) introduced by carrier scatterings with defects, substrate-induced disorders, and phonons can be written as R S ≡ R Q /λ [6]. Also shown in Fig. 1, C E ≈ εW/d and C Q ≈ {R Q v F } −1 are the per unit length values of the equivalent capacitances induced by the electrostatic and quantum effects, respectively, in which ε and ν F are the dielectric permittivity and the Fermi velocity in graphite, respectively. Note that, in order to approximate C E , MLGNR is assumed to be a bundle of ribbons displaced from a ground plane by the same distance d [5]. Since the separation between any two subsequent layers is much smaller than d, the effect of the electrostatic capacitances between any two subsequent GNR layers is negligible. Furthermore, L K = R Q /ν F and L M ≈ µd/WN layer represent the per unit length values of the kinetic and magnetic inductances, in the presence of the ground plane, wherein µ is the graphene permeability. In a practical case, L M << L K [5]. Applied Mechanics and Materials Vols. 229-231 (2012) pp 201-204 Online available since 2012/Nov/29 at www.scientific.net © (2012) Trans Tech Publications, Switzerland doi:10.4028/www.scientific.net/AMM.229-231.201 All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of TTP, www.ttp.net. (ID: 216.47.136.20, Galvin Library Tech Serv, Chicago, United States of America-12/06/13,02:03:30)