Although ALD can afford a conformal deposition, the lack of suitable carbon precursors makes ALD of carbides highly challenging. Some of the very few examples of carbides prepared via ALD include SiC and early transition metal carbides, e.g. WC , NbC 8 , TiC 9 and TaC 10 , which have been shown to be strong carbide formers . WC and NbC films were prepared by thermal ALD using metal halides (WCl5, NbCl5 and NbF5) and AlMe3 which acted as a carbon precursor, whereas the metalorganic precursors, TiNp4 and TaNp3Cl2 [Np= neopentyl, CH2C(CH3)3], functioned as single source precursors in the deposition of TiCx and TaCx films, respectively, in an ALD process with H2 plasma. The resulting TiCx and TaCx films were reported to be metal-rich and non-stoichiometric .