Inhibitor-Free Area-Selective Deposition of Titanium Nitride

An inhibitor-free approach to realizing the selective atomic layer deposition (ALD) of titanium nitride (TiN) is presented. This is achieved by exposing the surfaces of silicon oxides to a remote, inductively coupled plasma of nitrogen trifluoride, which causes a reduction of the surface hydrogen content and consequently prevents reaction and subsequent nucleation of ALD precursor molecules. Other surfaces are found to retain their ALD activity upon execution of this process, although measurements indicate that the mechanisms for TiN nucleation on these materials differ. It is shown that layers as thin as a single atomic monolayer are sufficient to activate an inhibiting silicon oxide surface. Demonstrations of TiN area-selective deposition (ASD) are presented, in which nucleation-promoting materials are combined with silicon oxides in patterned structures and surfaces. Owing to the tooling, materials, and processes used to achieve TiN ASD, this technique has the potential to be inserted into industrial fabrication schemes with relative ease.