Metallization of grafted silicon surfaces: Sputtering-related damage effects

Metal sputtering is known to affect metal-insulating-semiconductor (MIS) devices where the insulator is an organic monolayer grafted onto crystalline substrates. We comparatively discuss current-voltage characteristics in MIS devices, where the insulating layer is either a thin oxide layer or an organic monolayer covalently grafted onto single-crystal silicon. Variation of the sputtering geometry from on-axis to off-axis configuration is analyzed to compare differences between them, obtaining the reduction of damages in the oxide layer accordingly to the supposed conduction mechanism, but no changes in organic layer of aliphatic molecules. Effects of ultraviolet radiations, already present during metal deposition, are also discussed.