A method which was based upon positron annihilation was used to investigate defects at interfaces between a thin (1 to 5nm) over-layer and a substrate. This method, when applied to 38 typical SiO2/Si interfaces, revealed that high concentrations of di-vacancies existed in Si domains at interfaces, formed with natural oxides, after etching. It was concluded that the positrons saw the same annihilation state at various SiO2/Si interfaces; whether the oxides were commercial, thermally grown, native, or produced during rapid thermal annealing.

H.Kauppinen, C.Corbel, L.Liszkay, T.Laine, J.Oila, K.Saarinen, P.Hautojärvi, M.F.Barthe, G.Blondiaux: Journal of Physics - Condensed Matter, 1997, 9[48], 10595-601