Published online by Cambridge University Press: 25 February 2011
Device quality SiO2 films have been deposited by Remote Plasma Enhanced Chemical Vapor Deposition (RPECVD). The substrate surface cleaning, both ex-situ and insitu, influence the density of trapping states at the Si/SiO2 interface. Pre-deposition exposure to plasma-generated atomic-H significantly reduces hydrocarbon and 0 contamination, but damages the Si surface leading to high interface trap densities (Dit) in the Si band-gap. Pre-deposition exposure to plasma generated O-atoms, removes the residual hydrocarbons, and oxidizes the Si substrate while maintaining an atomically smooth interface. Metal Oxide Semiconductor (MOS) structure fabricated by RPECVD have midgap Dit values of ∼1-3×1010cm−2eV−1 for 0-plasma cleaned surface. Final rinse after RCA cleaning in HF solutions with different pH values affects surface morphology; however surface roughening by atomic-H is always the determinant contributor to high values of Dit.