Since some of the established nomenclature in AS-ALD research is not always used in the same manner, the choices for this review are initially outlined. It has been discussed before that in AS-ALD the "substrate" is the more accurate term than the "surface". The reason is that the surface changes its chemical composition during the process. Thus, while initially an SiO2 surface is found for the ALD reaction of Al2O3, the surface transitions towards an Al2O3 surface step by step. Therefore, "substrate" is used here to express the general surface site exposed during the ALD cycle. The term "surface" is used only when it clearly refers to a clean and chemically uniform entity. ALD consists of two half-cycles of reactions (Fig. .a). It is common practice to use the word "precursor" for the adsorbate carrying the (non-oxygen) element to be deposited, while "co-reactant" is used for the second adsorbate. While arguments have been put forward that this expression can be misleading, the established nomenclature precursor and co-reactant will be used here. The term co-reactant also applies to the plasma in such ALD experiments. To avoid the clumsy term "precursor and/or co-reactant", often only precursor is used in the text. In inhibitorbased approaches, the resulting substrate termination is often called the "blocking layer". Here, the expression "inhibitor layer" is used instead to avoid confusion with two terms for the same aspect.