FIELD TESTING FOR COSMIC-RAY SOFT ERRORS IN SEMICONDUCTOR MEMORIES

This paper presents a review of experiments performed by IBM to invest igate the causes of soft errors in semiconductor memory chips under fi eld test conditions. The effects of alpha-particles and cosmic rays ar e separated by comparing multiple measurements of the soft-error rate (SER) of samples of memory chips deep underground and at various altit udes above the earth. The results of case studies on four different me mory chips show that cosmic rays are an important source of the ionizi ng radiation that causes soft errors. The results of field testing are used to confirm the accuracy of the modeling and the accelerated test ing of chips.