Radiation defects introduced by MeV electrons in argon implanted MOS structures

The influence of MeV electron irradiation on the interface states of argon implanted thin oxide MOS samples has been studied by the thermally stimulated current (TSC) method. The oxide thickness of the structures is 18 nm. Two groups of n-type MOS structures non-implanted and implanted with 20 keV Ar+ ions and a dose of 5 x 1012 cm-2 are examined. Both groups are simultaneously irradiated by 23 MeV electrons with doses of 1.2 x 1016, 2.4 x 1016 or 6.0 x 1016 el/cm2. The energy position and density of the interface states (generated by electron irradiation, ion implantation or both treatments of the samples) are determined. It is shown that MeV electron irradiation decreases the concentration of interface states (like an oxygen-vacancy and di-vacancy) slightly and creates additional interface states (like an impurity-vacancy) at the Si-SiO2 interface of argon implanted MOS structures. (orig.)