Soft Error Triggering Criterion Based on Simplified Electrical Model of the SRAM Cell

In this paper, we propose a method for simulating the response of SRAM cells to particles through basic electrical models of the composing transistors without empirical parameters to be set. This simplified approach is motivated by the fact that the SPICE parameters are often not known by the end-user. In this approach, the transient currents induced by primary or secondary ions are calculated in the framework of the diffusion/collection model. Then, they are used to calculate the voltage variation at each node of the cell in which the current of each of the four latch transistors is accounted for and is given by a standard first-order model in which three major regions of operation are modeled (subthreshold, triode and saturation). Presented results are in good agreement with ion/neutron/proton experiment for 150 nm, 90 nm and 65 nm SRAMs. Even if the proposed approach would need further validation, this paper is a first step to give guideline on how calculating SEU cross section based on not detailed technological parameters instead of empirical ones. The strong point of our proposal is that it dynamically accounts for the behavior of the four transistors of refreshing loop in the cell.