Charge pumping analysis of radiation effects in LOCOS parasitic transistors

We have performed current-voltage and charge pumping measurements on LOGOS parasitic transistors submitted to x-ray irradiation. The electrical behavior and the charge pumping response of these non-planar structures have been analyzed by two-dimensional computer simulations. We report how this experimental approach allows us to obtain quantitative information about oxide charge and interface trap densities in different parts of the complete structure. Our results show a maximum of oxide charge trapping and interface trap buildup in the bird's beak regions after irradiation. The generation of radiation-induced interface and border traps along the LOGOS SiO2/Si interface is discussed, in terms of trap density and frequency response.