The effects of oxygen-insertion technology and low-energy fluorine (F) implantation on the Schottky barrier height (ΦBp) of a Pt/Ti/p-type Si metal–semiconductor contact are studied via electrical characterizations of Schottky diodes, physical analyses by secondary ion mass spectrometry , and chemical analyses by x-ray photoelectron spectroscopy. It is found that both oxygen-inserted (OI) layers and F can reduce ΦBp due to Ti 2p and Si 2p binding energy shifts before forming gas anneal (FGA) and due to retarded Pt diffusion into Si (facilitating low-ΦBp Pt mono-silicide formation) during FGA. The experimental findings also suggest that OI layers are more effective than F for reducing ΦBp.