Graphene-All-Around Cobalt Interconnect with a Back-End-of-Line Compatible Process

TL;DR

Researchers developed a new cobalt interconnect structure using graphene that improves performance and reliability for future computer chips.

Contribution

A graphene-all-around cobalt interconnect compatible with chip manufacturing processes is shown to significantly enhance performance and durability.

Findings

The graphene-all-around cobalt interconnect increases current density by 10.8% and reduces resistance by 27%.

The structure extends electromigration lifetime by 36 times and acts as an effective diffusion barrier.

Bonding between carbon and cobalt atoms enhances stability and reliability.

Abstract

The graphene-all-around
(GAA) structure has been verified to grow
directly at 380 °C using hot-wire chemical vapor deposition,
within the thermal budget of the back end of the line (BEOL). The
cobalt (Co) interconnects with the GAA structure have demonstrated
a 10.8% increase in current density, a 27% reduction in resistance,
and a 36 times longer electromigration lifetime. X-ray photoelectron
spectroscopy and density functional theory calculations have revealed
the presence of bonding between carbon and Co, which makes the Co
atom more stable to resist external forces. The ability of graphene
to act as a diffusion barrier in the GAA structure was confirmed through
time-dependent dielectric breakdown measurement. The Co interconnect
within the GAA structure exhibits enhanced electrical properties and
reliability, which indicates compatibility applications as next-generation
interconnect materials in CMOS BEOL.

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