Screening methods combining DFT calculations and experiments have been employed to identify the largest differences in chemisorption reaction barriers for a class of precursors used in the AS-ALD of SiO2, targeting growth on SiO2 (GS) while minimizing growth on SiN (NGS). The experimentally used DIPAS turned out to be the best choice by this measure. For fast screening, a cluster approach with a minimal cluster of the SiO2 surface was used here as well as in many other studies. Although it has been shown that the adsorption energies and reaction barriers are not converged with respect to the cluster size using such small clusters, the trends can often be reproduced quite accurately. Screening was also conducted on the surface site using a range of basic and acidic oxides to explain the trend in selectivity based on surface acidity.