Pattern dependence in synergistic effects of total dose on single-event upset hardness

The pattern dependence in synergistic effects was studied in a 0.18 mu m static random access memory (SRAM) circuit. Experiments were performed under two SEU test environments: 3 MeV protons and heavy ions. Measured results show different trends. In heavy ion SEU test, the degradation in the peripheral circuitry also existed because the measured SEU cross section decreased regardless of the patterns written to the SRAM array. TCAD simulation was performed. TID-induced degradation in nMOSFETs mainly induced the imprint effect in the SRAM cell, which is consistent with the measured results under the proton environment, but cannot explain the phenomena observed under heavy ion environment. A possible explanation could be the contribution from the radiation-induced GIDL in pMOSFETs.