SEU in SOI SRAMs -- A static model

The sensitivity to heavy ions of CMOS/SOI devices is mostly determined by the parasitic bipolar transistor that amplifies the deposited charge. A simple static model is proposed, which gives a relation between the LET threshold and the bipolar amplification factor β*. An analytical expression for β* versus transistor dimensions and ion LET is established, based on electrical measurements and numerical simulations on elementary transistors. Predictions from this model are in good agreement with experimental data obtained on SRAMs