Relationship between single-event upset immunity and fabrication processes of recent memories

Single-Event Upset (SEU) immunity for commercial devices were evaluated by irradiation tests using high-energy heavy ions. We show test results and describe the relationship between observed SEU rate and structures/fabrication processes. In this experiment, single-ion Multiple-Bit Upsets (MBUs) in 4 Mbit SRAM, 16 Mbit DRAM and 64 Mbit DRAM were observed. These MBUs were also discussed.