Radiation Damage in the Silicon Dioxide (SiO₂) Layer

The most sensitive part of a metal-oxide-semiconductor (MOS) structure to ionizing radiation is the oxide insulating layer. When ionizing radiation passes through the oxide, the energy deposited creates electron/ hole pairs. Oxide trapped charge cause a negative shift in capacitance-voltage (C-V) characteristics. These changes are the results of firstly, increasing trapped positive charge in the oxide, which causes a parallel shift of the curve to more negative voltages, and secondly increasing interface trap density, which causes the curve to stretch out. (author)