Additionally, this allows us to evaluate the limitations of our approach for predicting the thin film morphology. For the purposes of this study we have selected W and Co as the dopants. These are more sustainable alternatives to currently used liner materials like Ru. Co was of particular interest to us, as it is known as a suitable liner material for Cu and its incorporation into TaN gives a likely candidate for a single, combined barrier + liner film. Co and W also allow us to further investigate the effects of the difference in ionic radius between Ta and the dopant, because Co has the smallest ionic radius of 0.55 Å (high-spin) or 0.61 Å (low-spin) and W, with an ionic radius of 0.66 Å, is very similar in size to Ta, with an ionic radius of 0.72 Å. Co is magnetic, therefore we tested the effects of high-spin vs low-spin on geometry and adsorption energy; this is discussed in the Supporting Information, Section S2. To the best of our knowledge, while neither W nor W x N y have been studied as a liner material, W x N y is a known barrier material. Finally, atomic layer deposition (ALD) process chemistries are known for Co, W and their respective nitrides, permitting their introduction into TaN through ALD.