Signal integrity analysis of graphene nano-ribbon (GNR) interconnects
01 Dec 2012-pp 227-230
TL;DR: In this paper, signal integrity analyses of single and multi-layered GNR (SLGNR and MLGNR) interconnects are carried out based on their equivalent circuit models, with crosstalk effects characterized theoretically.
Abstract: Graphene nano-ribbons (GNR) have been proposed for building up interconnects for 3-D ICs, due to their superior performance over conventional metallic materials In this paper, signal integrity analyses of single- and multi-layered GNR (SLGNR & MLGNR) interconnects are carried out based on their equivalent circuit models, with crosstalk effects characterized theoretically It is shown that longer length and larger width of the SLGNR interconnect will result in higher crosstalk voltage, but it cannot exceeds its threshold one While for MLGNRs, their advantages over Cu wires are kept even with the worst crosstalk
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TL;DR: In this paper, a reduced thickness multilayer graphene nanoribbon (MLGNR) interconnect model was proposed to reduce crosstalk effects, and the authors have shown that the reduced thickness side-contact GNR interconnects can achieve a better performance compared with the traditional copper interconnect.
Abstract: In this research article, we propose a reduced thickness multilayer graphene nanoribbon (MLGNR) interconnect model to reduce crosstalk effects. The $$10\times $$10? higher current capability of MLGNR than copper (Cu) makes it an attractive choice to alleviate electromigration problem. The lower resistance of MLGNR is also an important factor to reduce interconnect delay. We have shown that a reduced thickness interconnect structure using MLGNR can reduce the crosstalk effects significantly without compromising the other benefits. The analysis is performed for side-contact GNR (SC-GNR) and top-contact GNR (TC-GNR) structure. Our analysis shows that the reduced thickness side-contact GNR interconnects can achieve $$\sim $$~1.02 to $$2.36\times $$2.36? reduction in crosstalk induced delay as compared with Cu. Our analysis also shows that the top-contact GNR structure with few layers can also achieve $$\sim $$~1.58 to $$1.95\times $$1.95? reduction in crosstalk induced delay as compared with Cu. We have performed crosstalk noise and overshoot/undershoot analysis using our proposed model. It is shown that the near-end and far-end crosstalk noise and overshoot/undershoot for SC-GNR and TC-GNR structures are significantly smaller than that of Cu.
20 citations
TL;DR: In this paper, an electro-thermal analysis of crosstalk effects in pristine (undoped) and intercalation doped multilayer graphene nanoribbon interconnects (MLGNRs) is presented.
Abstract: This work presents the electro-thermal analysis of crosstalk effects in pristine (undoped) and intercalation doped multilayer graphene nanoribbon interconnects (MLGNRs). A temperature dependent distributed $T-$ network model of MLGNR interconnects has been developed for analyzing the crosstalk induced effects. Further, a temperature-aware gate oxide reliability model has been proposed to compute the crosstalk induced overshoot/undershoot impact on ultra-thin gate oxide for CMOS devices in terms of failure-in-time (FIT) for side-contact (SC) pristine as well as top-contact (TC) Arsenic pentafluoride ( $AsF_{5}$ ), Ferric chloride ( $FeCl_{3}$ ) and Lithium ( $Li$ ) intercalation doped and undoped MLGNR interconnects. Subsequently, comparisons with $Cu$ -based interconnects are made over a range of chip operating temperature from 233K to 450K.
18 citations
Cites background from "Signal integrity analysis of graphe..."
...Delay and noise due to crosstalk effects are studied for different structures of MLGNR interconnects in few works [7], [8], [9]....
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TL;DR: From the gate oxide reliability perspective, perfectly specular, doped multilayer zigzag GNR interconnects are great advantageous to copper interConnects for the future integrated circuit technology generations.
14 citations
TL;DR: A bandwidth and stability analysis for coupled multilayer graphene nanoribbon (MLGNR) interconnects that is inquired for the first time shows that with increasing the length or decreasing the width of the MLGNRs, the stability in near-end output increases, whereas any increase in the width or inductive coupling increases the bandwidth.
12 citations
TL;DR: In this paper, the relative stability analysis for the monolayer SWCNT interconnects is carried out by investigating the relative position of the Nyquist diagram with respect to the critical point -1, 0.
Abstract: In this paper, the monolayer single-walled carbon nanotube SWCNT interconnects are modeled and investigated comprehensively. On the basis of the ratio of the resistance-capacitance values between Cu and SWCNT interconnects, it is demonstrated that the monolayer SWCNT interconnect can provide comparable and even better performance than Cu wire at the 19nm technology node and beyond. Furthermore, the relative stability analysis is carried out for the monolayer SWCNT interconnects by investigating the relative position of the Nyquist diagram with respect to the critical point -1, 0. It is shown that the relative stability can be improved by increasing the length and decreasing the SWCNT diameter. Meanwhile, the relative stability also can be improved with the technology advancement. Finally, the crosstalk effects are studied on the basis of the tri-interconnect architecture. As the monolayer SWCNT interconnects possess much smaller capacitance, the signal integrity can be improved, with the peak noise voltage suppressed greatly. Copyright © 2014 John Wiley & Sons, Ltd.
11 citations
References
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TL;DR: The authors' ab initio calculations show that the origin of energy gaps for GNRs with armchair shaped edges arises from both quantum confinement and the crucial effect of the edges, which differs from the results of simple tight-binding calculations or solutions of the Dirac's equation based on them.
Abstract: Based on a first-principles approach, we present scaling rules for the band gaps of graphene nanoribbons (GNRs) as a function of their widths. The GNRs considered have either armchair or zigzag shaped edges on both sides with hydrogen passivation. Both varieties of ribbons are shown to have band gaps. This differs from the results of simple tight-binding calculations or solutions of the Dirac's equation based on them. Our ab initio calculations show that the origin of energy gaps for GNRs with armchair shaped edges arises from both quantum confinement and the crucial effect of the edges. For GNRs with zigzag shaped edges, gaps appear because of a staggered sublattice potential on the hexagonal lattice due to edge magnetization. The rich gap structure for ribbons with armchair shaped edges is further obtained analytically including edge effects. These results reproduce our ab initio calculation results very well.
4,471 citations
TL;DR: In this paper, the state-of-the-art of carbon-based nanomaterials, particularly the one-dimensional (1-D) forms, carbon nanotubes (CNTs) and graphene nanoribbons (GNRs), are reviewed.
Abstract: This paper reviews the current state of research in carbon-based nanomaterials, particularly the one-dimensional (1-D) forms, carbon nanotubes (CNTs) and graphene nanoribbons (GNRs), whose promising electrical, thermal, and mechanical properties make them attractive candidates for next-generation integrated circuit (IC) applications. After summarizing the basic physics of these materials, the state of the art of their interconnect-related fabrication and modeling efforts is reviewed. Both electrical and thermal modeling and performance analysis for various CNT- and GNR-based interconnects are presented and compared with conventional interconnect materials to provide guidelines for their prospective applications. It is shown that single-walled, double-walled, and multiwalled CNTs can provide better performance than that of Cu. However, in order to make GNR interconnects comparable with Cu or CNT interconnects, both intercalation doping and high edge-specularity must be achieved. Thermal analysis of CNTs shows significant advantages in tall vias, indicating their promising application as through-silicon vias in 3-D ICs. In addition to on-chip interconnects, various applications exploiting the low-dimensional properties of these nanomaterials are discussed. These include chip-to-packaging interconnects as well as passive devices for future generations of IC technology. Specifically, the small form factor of CNTs and reduced skin effect in CNT interconnects have significant implications for the design of on-chip capacitors and inductors, respectively.
411 citations
TL;DR: In this paper, a comprehensive conductance and delay analysis of GNR interconnects is presented using a simple tight-binding model and the linear response Landauer formula, and both global and local GNR delays are analyzed using an RLC equivalent circuit model.
Abstract: Graphene nanoribbons (GNRs) are considered as a prospective interconnect material. A comprehensive conductance and delay analysis of GNR interconnects is presented in this paper. Using a simple tight-binding model and the linear response Landauer formula, the conductance model of GNR is derived. Several GNR structures are examined, and the conductance among them and other interconnect materials [e.g., copper (Cu), tungsten (W), and carbon nanotubes (CNTs)] is compared. The impact of different model parameters (i.e., bandgap, mean free path, Fermi level, and edge specularity) on the conductance is discussed. Both global and local GNR interconnect delays are analyzed using an RLC equivalent circuit model. Intercalation doping for multilayer GNRs is proposed, and it is shown that in order to match (or better) the performance of Cu or CNT bundles at either the global or local level, multiple zigzag-edged GNR layers along with proper intercalation doping must be used and near-specular nanoribbon edge should be achieved. However, intercalation-doped multilayer zigzag GNRs can have better performance than that of W, implying possible application as local interconnects in some cases. Thus, this paper identifies the on-chip interconnect domains where GNRs can be employed and provides valuable insights into the process technology development for GNR interconnects.
335 citations
TL;DR: In this article, a model for conductance of GNRs as functions of chirality, width, Fermi level, and the type of electron scatterings at the edges is presented.
Abstract: Graphene nanoribbons (GNRs), which are single graphene sheets, share many of the fascinating electronic, mechanical, and thermal properties of carbon nanotubes. Compact physical models for conductance of GNRs as functions of chirality, width, Fermi level, and the type of electron scatterings at the edges are presented. For widths below 8 nm, the models demonstrate that single-layer GNRs can potentially outperform copper wires with unity aspect ratio
251 citations
TL;DR: In this article, physics-based equivalent circuit models are presented for armchair and zigzag graphene nanoribbons (GNRs), and their conductances have been benchmarked against those of carbon nanotubes and copper wires.
Abstract: Physics-based equivalent circuit models are presented for armchair and zigzag graphene nanoribbons (GNRs), and their conductances have been benchmarked against those of carbon nanotubes and copper wires. Atomically thick GNRs with smooth edges can potentially have smaller resistances compared with copper wires with unity aspect ratios for widths below 8 nm and stacks of noninteracting GNRs can have substantially smaller resistivities compared to Cu wires. It is shown that rough edges can increase the resistance of narrow GNRs by an order of magnitude. This fact highlights the need for patterning methods that can produce relatively smooth edges to fabricate low resistance GNR interconnects.
234 citations