Comparison of heavy-ion induced SEU for D-and TMR-flip-flop designs in 65-nm bulk CMOS technology

Heavy ion experiments were performed on D flip-flop (DFF) and TMR flip-flop (TMRFF) fabricated in a 65-nm bulk CMOS process. The experiment results show that TMRFF has about 92% decrease in SEU cross-section compared to the standard DFF design in static test mode. In dynamic test mode, TMRFF shows much stronger frequency dependency than the DFF design, which reduces its advantage over DFF at higher operation frequency. At 160 MHz, the TMRFF is only 3.2x harder than the standard DFF. Such small improvement in the SEU performance of the TMR design may warrant reconsideration for its use in hardening design.