The Ultra-Low-k Dielectric Materials for Performance Improvement in Coupled Multilayer Graphene Nanoribbon Interconnects

Abstract

The ultra-low-k dielectric material replacing the conventional SiO2 dielectric medium in coupled multilayer graphene nanoribbon (MLGNR) interconnects is presented. An equivalent distributed transmission line model of coupled MLGNR interconnects is established to derive the analytical expressions of crosstalk delay, transfer gain, and noise output for 7.5 nm technology node at global level, which take the in-phase and out-of-phase crosstalk into account. The results show that by replacing the SiO2 dielectric mediums with the nanoglass, the maximum reduction of delay time and peak noise voltage are 25.202 ns and 0.102 V for an interconnect length of 3000 µm, respectively. It is demonstrated that the ultra-low-k dielectric materials can significantly reduce delay time and crosstalk noise and increase transfer gain compared with the conventional SiO2 dielectric medium. Moreover, it is found that the coupled MLGNR interconnect under out-of-phase mode has a larger crosstalk delay and a lesser transfer gain than that under in-phase mode, and the peak noise voltage increases with the increase of the coupled MLGNR interconnect length. The results presented in this paper would be useful to aid in the enhancement of performance of on-chip interconnects and provide guidelines for signal characteristic analysis of MLGNR interconnects.

Collaborative Applying the Ultra-low-k Dielectric and the High-k Dielectric Materials for Performance Enhancement in Coupled Multilayer Graphene Nanoribbon Interconnects

“…Here W, S, T gnr , T ox , ε 1 and ε 2 are line width, line space, line height, thickness of the insulator dielectric medium, relative dielectric constant of the insulator dielectric medium and relative dielectric constant of interlayer dielectric material between two adjacent GNR layers, respectively. Here the common SiO 2 (i.e., ε 1 = 3.9) insulator dielectric medium can be replaced by the ultra-low-k dielectric material, such as the nanoglass (i.e., ε 1 = 1.3), to obtain a better interconnect performance as reported in [6]. In addition, here the conventional (pristine) MLGNR by inserting the high-k dielectric material (HfO 2 ) between successive GNR layers can also improve the performance of MLGNR interconnects.…”

“…Herein, in order to investigate the impact of highk dielectric material on the performance of SC-MLGNR interconnects, the relative dielectric constant ε 2 is adopted to represent the different interlayer dielectric materials inserted between adjacent GNR layers in this work. The total distributed capacitance C T of MLGNR interconnects consists of the equivalent quantum capacitance C eq and the electrostatic capacitance C el , and their relationship can be expressed as Equation (6). The p.u.l.…”

“…As shown in Fig. 3, the total ABCD parameter matrix of the decoupled victim MLGNR line can be deduced as [6],…”

“…Due to the outstanding electrical, mechanical and thermal properties, graphene material has captured considerable attention from the researchers that is regarded as a potential alternative to the traditional Cu for next-generation on-chip interconnect applications [4], [5]. High quality graphene has a long mean free path (MFP) on the order of several micrometers far over Cu material, which leads to a lower resistivity and achieves the ballistic transport at the shorter interconnects [6]- [8]. Moreover, graphene can carry a higher current density of the order of 10 9 A/cm 2 in comparison to its Cu counterpart that effectively alleviates the electro-migration phenomenon [9], [10].…”

“…Accordingly, it is urgent to seek a new technology to further improve the MLGNR interconnect performance in the VLSI circuits at the end of the roadmap. In our previous paper [6], the ultra-low-k dielectric material (nanoglass) replacing the traditional SiO 2 dielectric medium in coupled MLGNR interconnects to reduce the propagation delay and crosstalk noise and to enhance the transfer gain is proposed. Meanwhile, in [16], [19], it is reported that inserting the high-k dielectric (HfO 2 ) material between adjacent GNR layers in SC-MLGNR interconnect can reduce the propagation delay, crosstalk noise and energy-delay-product.…”