  Copper interconnects in modern integrated circuits require ultra-thin
barriers to prevent intermixing of Cu with surrounding dielectric materials.
Conventional barriers rely on metals like TaN, however their finite thickness
reduces the cross-sectional area and significantly increases the resistivity of
nanoscale interconnects. In this study, a new class of two-dimensional (2D) Cu
diffusion barriers, hexagonal boron nitride (h-BN) and molybdenum disulfide
(MoS2), is demonstrated for the first time. Using time-dependent dielectric
breakdown measurements and scanning transmission electron microscopy coupled
with energy dispersive X-ray spectroscopy and electron energy loss
spectroscopy, these 2D materials are shown to be promising barrier solutions
for ultra-scaled interconnect technology. The predicted lifetime of devices
with directly deposited 2D barriers can achieve three orders of magnitude
improvement compared to control devices without barriers.
