Refractory Vertically Aligned Carbon Nanotube-Boron Nitride Nanocomposites for Scalable Electrical Anisotropic Interconnects

Traditional metal interconnect technology faces several challenges when scaling down, such as electromigration and poisoning. Carbon nanotubes (CNTs) have been introduced in an attempt to solve these problems while providing on par performance. However, unexpected issues, such as great difficulty in manufacturing perfectly aligned CNTs and the undesired current leakage caused by electron percolation, still exist. In this work, we present novel vertically aligned CNT (VACNT)-based nanocomposites utilizing hexagonal boron nitride (h-BN) as intertube insulating/shielding layers that can be prepared in a scalable and controllable fashion. This composite material inherits the full advantages of the directional conductivity of VACNTs which are strongly enhanced by the intertube h-BN layer and demonstrate excellent electrical anisotropy. This composite material achieves conductivities of 1060.43 and 4.43 S m^-1 along the directions parallel and perpendicular to the VACNTs, respectively, while the previously reported electrical conductivity of CNT-polymer and CNT-ceramic counterparts are well below 10^-3 S m^-1 isotropically. Because of its refractory ability, the h-BN layer can also protect the prepared nanocomposites from harsh oxidation and erosion, showing ultrahigh stability up to 1400 °C. These results reflect a giant step toward a simple, turnkey solution to an advanced CNT-based composite material for future electrical interconnect applications.