Penetration has been investigated for other inhibitor approaches. With a molecular model and a combination of DFT and MD approaches, it was concluded that the precursor TMA physisorbs on the SAM layer and does not penetrate. For thiol-based SAMs on Ge, the penetration by the coreactant H2O through defects in the SAM layer was found feasible. The thus generated nucleation sites on the surface can then initiate ALD growth. This is in line with recent experimental findings of OH defects being responsible for the reactivity of the chemically closely related H-Si(001). Also for the CFx inhibitor layer on silicon, the penetration of the co-reactant was found feasible but not for the precursor itself.