Density and spatial distribution of MERIE-like plasma induced defects in SiO2

Abstract

Generation of electrically active defects by Magnetron Enhanced Reactive Ion Etching (MERIE)-like He plasma in thin (12 nm) SiO2–Si structures is investigated by C–V and I–V techniques. It is found that the plasma creates positive charge near the Si–SiO2 interface and negative one near the Al–SiO2 interface, both with significant density (>1012 cm−2). The centroid and the density of the negative oxide charge depend strongly on plasma conditions and location of wafers during the plasma exposure. It is established that the negative charge generated behaves as “fixed” oxide charge and cannot be charged or discharged. The trapping properties of the plasma damaged structures are studied by a constant current stress. The density of the trapped charge is generally small and its sign depends on the level of injection current. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)