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Analysis of Crosstalk Deviation for Bundled MWCNT
with Process Induced Height and Width Variations
Jainender Kumar, Manoj Kumar Majumder,
Brajesh Kumar Kaushik, and Sudeb Dasgupta
Microelectronics and VLSI Group, Department of Electronics and Communication Engg.
Indian Institute of Technology Roorkee, Roorkee - 247667, India
{jainenderkumariitr,manojbesu}@gmail.com,
{bkk23,sudeb}fec@iitr.ernet.in
Abstract.
Process variation is an important design concern in current nanoscale
regime. This research paper analyzes the effect of process induced height and
width variations for a multi-walled carbon nanotube (MWCNT) bundle
interconnects. For different bundle heights and widths, the average deviation in
crosstalk delay is analyzed for bundles having MWCNTs with different number
of shells. A capacitively coupled interconnect line is used to analyze the
crosstalk delay by using the Monte Carlo simulations with 100 different
samples. Using Gaussian distributed widths and heights, a bundle having
MWCNTs with higher number of shells exhibits least deviation in crosstalk.
Keywords:
Carbon nanotube (CNT), Multi-walled CNT (MWCNT) bundle,
crosstalk deviation, process variation, VLSI interconnects.
1
Introduction
Carbon nanotubes (CNTs) have aroused lot of research interests for their applicability
as VLSI interconnects [1]. CNT possess superior electrical properties as compared to
Cu or other interconnect materials due to the unique band structure of graphene that
leads to zero effective mass of electrons and holes [2]. In deep submicron and nano
scale regime, conventional interconnect materials such as Al and Cu suffers from
electromigration [3, 4], skin effect, resistive parasitic [5-7] etc. CNTs can be
constructed with length-to-diameter ratio of up to 132,000,000:1 [8], which is
significantly larger than any other material. The
sp
2
bonding in graphene is stronger
than the
sp
3
bonds in diamond [2] that makes graphene the strongest material. CNTs
have large current carrying capability [9], long ballistic transport length, higher
thermal conductivity [10] and mechanical strength [11].
Structure of CNTs depend on chiral indices (
n,m
) that represents the rolling up
direction of graphene sheets. CNTs can be either metallic or semiconducting in nature
depending on their chiral indices. Based on the number of concentrically rolled up
graphene sheets, CNTs are categorized as single- (SWCNT) and multi-walled CNTs
(MWCNTs). MWCNTs consist of several concentric shells with different diameters
