Atomic layer deposition of hafnium nitrides using ammonia and alkylamide precursors

We use DFT to investigate an atomistic mechanism for the ALD of hafnium nitride films grown using Hf[N(CH3)2]4 and NH3. We find a ligand-exchange mechanism similar to those thought to occur in the ALD of HfO2 using the same Hf source and H2O. Although the Hf[N(CH3)2]4 half-reaction at NH* sites has a barrier similar to that of reaction with OH* sites, the barrier for the NH3 half-reaction on the Hf [ N ( CH 3 ) 2 ] x ∗ terminated surface is significantly larger than for reaction between H2O and Hf [ N ( CH 3 ) 2 ] x ∗ . Thus, the NH3 half-cycle will be prone to oxygen incorporation into Hf–nitride from residual H2O.