Graphene-Based Interconnects on Hexagonal Boron Nitride Substrate

We demonstrated graphene interconnects on layered insulator-hexagonal boron nitride ( h-BN). Performance metrics are compared among three material systems: CVD graphene on h-BN, CVD graphene on SiO
₂
, and exfoliated graphene on SiO
₂
. CVD graphene on h-BN shows approximately 19 times and 8 times improved conductivity as compared with CVD graphene on SiO
₂
and exfoliated graphene on SiO
₂
, respectively. For graphene on h-BN, an ultrahigh carrier mobility (~ 15 000 cm
²
/V·s at a carrier density of 1 × 10
¹²
cm
^-2
) is observed. The breakdown power density is much increased, attributed to the higher thermal conductivity of h-BN (than that of SiO
₂
) that facilitates heat dissipation. Electrical annealing reduces graphene sheet resistance. Unlike the case for SiO
₂
substrate, the absence of positive shift of Dirac point could be due to the interface-state-free nature of h-BN substrate. The research suggests that h-BN could be used as an alternative substrate material for graphene-based interconnects, overcoming performance limit and reliability issues caused by the SiO
₂
substrate.