Use of Laser to Explain Heavy Ion Induced SEFIs in SDRAMs

In this work, using heavy ion and pulsed laser tests on a 110 nm 256 Mbit SDRAM, different SEFI types and other logic-related radiation effects are studied and explained. Effects seen using heavy ions were reproduced and localized on the die with the laser. Among the effects, Fuse-Latch Upsets were found to be responsible of typical addressing errors and were more particularly investigated. Moreover, an unusual logic-related effect, called SET in Voltage Buffer, was induced using heavy ions, and localized afterward with the laser. Soft SEFI and Hard SEFI were also investigated.