Effects of Random Dopant Fluctuations (RDF) on the Single Event Vulnerability of 90 and 65 nm CMOS Technologies

Random dopant fluctuation (RDF) induced threshold voltage variations affect two critical parameters used as a measure of single event (SE) hardness (i) single event transient (SET) pulse widths and (ii) critical charge . This causes an increase in the spread of SET pulse widths in sequential logic circuits and in the required for single event upsets (SEUs) in static random access memory cells (SRAMs). Monte Carlo simulations show this can affect the hardness characterization in a commercial 90 nm process and a generic 65 nm technology. This necessitates statistical design approaches for validating conventional hardening schemes, to assure a required level of radiation tolerance in these deep sub-micron technologies.