Abstract
The C-V characteristics of MOS diodes were measured at the gate bias of 10, 0 and -10 V during the irradiation by 60Co γ-rays. It is found that C/C0 curves shift to more negative voltage with the increase of irradiation dose and saturate at about 3×106 rads.
The results are explained by introducing the assumption of donor centers which are formed probably by the mismatching between silicon and oxygen atoms in the oxide-silicon interface. The donor centers interact with the generated holes and make the trapped positive charge in the oxide-silicon interface. The formation of the trapped positive charge is studied by several bias conditions and the number of Nss is estimated.
