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 SiO₂, and exfoliated graphene on SiO₂. CVD graphene on h-BN shows approximately 19 times and 8 times improved conductivity as compared with CVD graphene on SiO₂ and exfoliated graphene on SiO₂, respectively. For graphene on h-BN, an ultrahigh carrier mobility (~ 15 000 cm²/V·s at a carrier density of 1 × 10¹² cm^-2) is observed. The breakdown power density is much increased, attributed to the higher thermal conductivity of h-BN (than that of SiO₂) that facilitates heat dissipation. Electrical annealing reduces graphene sheet resistance. Unlike the case for SiO₂ 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 SiO₂ substrate.