A time-of-flight static secondary ion mass spectrometry and X-ray photoelectron spectroscopy study of 3-aminopropyltrihydroxysilane on water plasma treated chromium and silicon surfaces

We have used time-of-flight static secondary ion mass spectrometry (ToF-SSIMS), and X-ray photoelectron spectroscopy (XPS), to study films produced by exposure of water plasma treated chromium and silicon surfaces to aqueous solutions of 3-aminopropyltrihydroxysilane (3-APTHS). The chemical structure of positive and negative secondary ions produced by these films was deduced by a combination of exact mass determination and the use of isotopically labelled 3-APTHS. Ions characteristic of the 3-APTHS overlayer were observed for both surfaces. The use of O-18 labelled 3-APTHS yields interesting insight into the cross-linking nature of the films studied, suggesting no further cross-linking of the silane as a function of in situ thermal exposure. XPS studies of these samples support the ToF-SSIMS data showing similarity of 3-APTHS bonding to the two surfaces studied.