A macro analysis of soft errors in static RAMs

In the soft error phenomenon in static RAMs (SRAMs), the mechanism of data upset is more complicated than in dynamic RAMs (DRAMs) because the storage nodes in the memory cells are connected to the power supply via load element. Therefore the critical charge has been evaluated only by computer simulation. The charge which is supplied via load element is estimated analytically, assuming alpha -particle-induced current being constant. The charge which is fed through the load element contributes to the increase of the critical charge in a 1-kbit emitter-coupled logic (ECL) RAM with a 10-k Omega resistor load. In ECL RAMs or MOS SRAMs with a larger resistor, the contribution of the charge which is fed through the load element is hardly expected, and the critical change in such RAMs is evaluated by the stored charge like DRAMs.<
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