Growth Mechanism of Nickel Carbide Thin Film by Atomic Layer Deposition: A Quartz Crystal Microbalance Study

The nickel carbide thin films were grown at 95℃ by H₂-plasma enhanced atomic layer deposition (PEALD) with Ni (amd) ₂ or Ni (dad) ₂ as Ni and C precursors. The influence of the atomic hydrogen on the growth was investigated by in-situ monitoring with quartz crystal microbalance (QCM). The preliminary results show that the atomic hydrogen had a major impact. To be specific, on the one hand, dehydrogenation of the adsorbed hydrocarbons and formation of nickel carbide and amorphous carbon were enhanced by the reaction of atomic hydrogen with chemisorbed Ni (amd) ₂ and Ni (dad) ₂ precursors, because, accompanied by Ni-releasing, the volatile N-tertbutylacetamidinate and C_xH_y, formed in the reaction, could be easily adsorbed and decomposed on Ni-surfaces. On the other hand, atomic hydrogen possibly etched the amorphous carbon and graphite adsorbed on nickel carbide surfaces or decomposed the nickel carbide into catalytically active Ni.