Atomic Layer Deposition of the Metal Pyrites FeS₂ , CoS₂ , and NiS₂

Atomic layer deposition (ALD) of the pyrite-type metal disulfides FeS₂ , CoS₂ , and NiS₂ is reported for the first time. The deposition processes use iron, cobalt, and nickel amidinate compounds as the corresponding metal precursors and the H₂ S plasma as the sulfur source. All the processes are demonstrated to follow ideal self-limiting ALD growth behavior to produce fairly pure, smooth, well-crystallized, stoichiometric pyrite FeS₂ , CoS₂ , and NiS₂ films. By these processes, the FeS₂ , CoS₂ , and NiS₂ films can also be uniformly and conformally deposited into deep narrow trenches with aspect ratios as high as 10:1, which thereby highlights the broad and promising applicability of these ALD processes for conformal film coatings on complex high-aspect-ratio 3D architectures in general.