With the need for fast and low-power radiation-hardened processors, advanced technology process is applied to obtain both high performance as well as high reliability. However, scaling down of the size of the transistor makes the transistor sensitive to outside disturbances, such as soft error introduced by the strikes of the cosmic neutron beams. Besides aerospace applications, such reliability should also be taken into consideration for the sub-100[Formula: see text]nm CMOS designs to ensure the robustness of the circuit. In such circumstances, several radiation-hardened flip-flops are designed and simulated under SMIC 40[Formula: see text]nm process. Simulation results show that with five aspects (performance, power, area, PVT variation and reliability) taken into consideration, TSPC-based DICE and TMR combined architecture has the best soft-error robustness in comparison with other radiation-hardened flip-flops, and the critical charge of such architecture is 490[Formula: see text]fC, which is 12.5X higher than the traditional unhardened flip-flop.