Radiation-induced trapped charge in metal-nitride-oxide-semiconductor structure

The radiation-induced trapped charge in insulation layer of metal-nitride-o xide-semiconductor (MNOS) structure has been investigated. The mechanism of charge trapping under irradiation is studied by the radiation-induced mid- gap voltage shift using a simple charge trap model. The depth profile of fi xed charge in insulator before irradiation was evaluated by the mid-gap vol tage of MNOS structures with varying insulator thicknesses using slanted et ching method. The irradiation tests were carried out using Co-60 gamma ray source up to 1 Mrad(Si) with the gate voltage of +6 or -6 V. The calculated results using the model can be fitted well to the experimental results, an d we confirmed the model is very useful to discuss the radiation-induced tr apped charge. By simulating the mid-gap voltage shift of RINGS structures, we considered the possibility for radiation hardened device.