Analysis of body-tie effects on SEU resistance of advanced FD-SOI SRAMs through mixed-mode 3-D Simulations

The 128-kb SOI SRAMs without body-ties had a threshold LET of 3.6 MeV/(mg/cm/sup 2/), which was increased to 9.0 MeV/(mg/cm/sup 2/) by adding body-ties. We used a mixed-mode three-dimensional simulation to analyze the effects of the body-ties on SEU resistance for FD SOI SRAMs with 0.2-/spl mu/m design rules. The simulations revealed an increase in the threshold LET from 5.8 to 8.1 MeV/(mg/cm/sup 2/) that was mostly due to the reduced bipolar gain of the parasitic bipolar transistor and partly due to the added capacitance, which were both related to the body-ties.