Low Resistivity Titanium Nitride Thin Film Fabricated by Atomic Layer Deposition with TiCl4 and Metal-Organic Precursors in Horizontal Vias

Titanium nitride (TiN) thin films are utilized as diffusion barriers for Co and W metal layers as well as the gate metal barrier in CMOS and memory devices due to the material’s low resistivity; TiN is also used as a coating for hard disk drives [1] . Low resistivity TiN in commercial devices has been deposited by plasma-enhanced ALD (PE-ALD) and by physical vapor deposition. However, for high aspect ratio features and horizontal vias, deposition by thermal ALD is needed to enhance the conformality of the deposition process. In the present work, it is shown that the resistivity can be decreased below 220 uΩ-cm with a non-halogenated precursor at 425 °C by using a Ti precursor with high thermal stability and by reducing the oxygen and carbon contents in the films using a highly reactive co-reactant, anhydrous hydrazine (N 2 H 4 ).