Analytical Method to Evaluate Soft Error Rate Due to Alpha Contamination

An analytical model for the alpha-particle induced soft-error of SRAMs provides an expression based on the disintegration law of radioactive elements. Since highly scaled technologies are very sensitive to alpha particles, this model assumes that the critical charge is sufficiently low that all alpha particles that reach sensitive devices are capable of producing upsets. We discuss its validation for different technologies by comparing the error rate due to uranium and thorium contamination with that obtained from Monte Carlo simulations. This model shows a very good approximation for the nodes below 65 nm, and it is useful to predict the soft error rate for highly integrated technologies. The soft error expression allows us to study the effects of decay chain disequilibrium produced by enrichment of a radioactive element and its radioactive daughters on the error rate without having to run MC simulations that are costly in time.