The Effect of Active Delay Element Resistance on Limiting Heavy Ion SEU Upset Cross-Sections of SOI ADE/SRAMs

This paper discusses the effective limiting heavy-ion induced single-event upset cross section of radiation-hardened 150 nm SOI SRAM and the resistance of the active-delay element (ADE) used in the memory cell. The effective limiting upset cross-section of ADE/SRAM is found to be proportional to the product of the limiting upset cross-section of the 6T SRAM of the same CMOS technology and a dimensionless function of the normalized ADE resistance. In addition, a cross-section higher than this effective limiting cross-section at high effective LET (>250 MeV-cm
²
/mg) is observed. This additional contribution to the cross-section is attributed to the upset caused by the high effective LET heavy ion hitting the on-transistor in the memory cell.