Variation-Tolerance of a 65-nm Error-Hardened Dual-Modular-Redundancy Flip-Flop Measured by Shift-Register-Based Monitor Structures

We show measurement results of variation-tolerance of an error-hardened dual-modular-redundancy flip-flop fabricated in a 65-nm process. The proposed error-hardened FF called BCDMR is very strong against soft errors and also robust to process variations. We propose a shift-register-based test structure to measure variations. The proposed test structure has features of constant pin count and fast measurement time. A 65 nm chip was fabricated including 40k FFs to measure variations. The variations of the proposed BCDMR FF are 74% and 55% smaller than those of the conventional BISER FF on the twin-well and triple-well structures respectively. key words: soft error, hardened design, variability, test structure, shift register