Further, we investigated the chemical environment of the deposited film, both at the opening and within the structure after removing the top membrane, as presented in Fig. . The Al 2p XPS core level spectra at the opening revealed two distinct peaks. The major peak, centered at 74.1 eV, was assigned to the Al-N bond, while the minor peak, centered at 72.5 eV, was assigned to elemental Al in the film. The small contribution of elemental Al is assumed to be sputter induced reduction, since NH3 cannot act as a reducing agent. The spectra obtained by probing within the structure also resulted in two distinct peak positions, the Al-N signal was slightly shifted to 74.2 eV, and the intensity of the elemental Al signal was reduced and shifted to 72. Finally, we see no reason why this approach to enhance the SC of an ALD process cannot be applicable to other ALD process of similar kind. From Graham's law of diffusion, we propose that the added gas must be heavier than the precursors that should diffuse further down the recessed features. The added gas must also be inert to the deposition chemistry to not leave any impurities in the film. Thus, the molecular weight and the chemistry of the precursors dictates which gases can be used as diffusion additives. Furthermore, the precursor molecules must exhibit a significant contrast in their reactivity during the ALD process in which they are utilized. We hope that future studies can uncover more details on the exact physical and chemical nature of this type of ALD process.