Total Dose Hardness Assurance Implications of Field-Sensitive Interface States

We have observed the generation of interface states in SiO2 MOS capacitors that are field-and time-dependent as well as thermally activated. The number of interface states generated is linearly dependent on the applied field with a threshold field for occurrence. There is a t1/4 time dependence for interface state generation. The generation of these field-sensitive interface states is thermally activated with a field-dependent activation energy. A model based on oxygen-derived defects in SiO2 is proposed to explain the data. Finally, strong correlation has been found between these metastable interface states and the radiation hardness of the MOS devices.