Low energy electron-excited nanoscale luminescence: A tool to detect trap activation by ionizing radiation

Ultra-thin SiO2/Si gate dielectric structures exposed to heavy X-ray irradi ation exhibit optical emission characteristic of interface traps. Low energ y electron-excited luminescence spectroscopy with nanometer-scale depth res olution yields a characteristic spectral energy and excitation depth depend ence. Ultra-thin (5 nm) oxide films on Si substrates exposed to 10 keV, 7.6 Mrad(SiO2) [13.7 Mrad (Si)] X-ray irradiation introduces trap densities on the order of 10(11) cm(-2)eV(-1), localized near the intimate SiO2-Si inte rface. This density is consistent with the trapped oxide and interface char ge densities expected based on observed capacitance- voltages shifts of thi cker oxides, their corresponding charge densities, and the proportionally s maller charge densities expected for the thinner oxide layers in this study .