We propose two possible pathways for the consumption of OH. Firstly, TDMAH can react with acidic protons to form nuclei on the surface and volatile by-products. Secondly, the protons can react with the dehydrogenated ligands. This can lead either to the formation of less dehydrogenated species or, potentially, to their desorption. Similar to our observation on CoO(100), a comparison of the evolution of the integrated peak area of the CH region as compared to those associated with dehydrogenated ligands reveals a change in ratio. At small exposures, the surface-bound dehydrogenated ligand signals dominate the spectrum. At large exposure, most of the surface-bound ligands are lost and the -Hf(NMe2)x signals dominate the spectrum. Consequently, we suggest that the stoichiometry of the -Hf(NMe2)x species varies over the course of the experiment, with TDMAH losing more ligands at the beginning of the ALD half cycle than at later stages.