Deposition of N-Heterocyclic Carbenes on Reactive Metal Substrates─Applications in Area-Selective Atomic Layer Deposition

Integrated circuits are presently constructed using top-down strategies composed of multiple etching and lithographic steps. As the feature sizes of these devices approach single-digit nm scales, existing fabrication methods introduce defects which require further corrective steps and are rapidly becoming ineffective for industry needs. To meet future scaling requirements, bottom-up fabrication methods which leverage differences in the local surface environment such as area-selective atomic layer deposition (AS-ALD) are promising but have been limited by the surface-binding energies of adsorbates. N-heterocyclic carbenes (NHCs) have shown excellent bonding to metal surfaces and are presented herein as next-generation carbon-based small molecule inhibitors (SMIs) for use in AS-ALD processes. NHCs demonstrate a preference for adsorbing onto metal surfaces over dielectric materials and enable the selective deposition of ZnO onto SiO 2 bands. NHC-based SMIs can be effectively removed by either thermal annealing at 350 °C or plasma treatment using hydrogen at 800 W for 60 s.