3-DIMENSIONAL NUMERICAL-SIMULATION OF SINGLE EVENT UPSET OF AN SRAM CELL

Charge collection mechanisms in PMOS and NMOS transistors irradiated b y single energetic heavy ions and the corresponding response of an SRA M cell have been simulated. For an ion track through a p-channel, the RC network within the cell and the strength of the n-channel pull-down device will limit the amount of charge collected. In the case of the n-channel pull-down device, the direction of the ion strike (toward or away from the source) plays a major role in the upset of the cell. An ion path toward the source upsets at a lower LET than one away from t he source. This is the result of additional electrons injected from th e source due to barrier lowering.