Failure rate predictions for 0.35 μm Flash EEPROM memories from accelerated read disturb tests

Anomalous stress-induced leakage current (SILC) through the tunnel oxide is one of the major reliability problems limiting the lifetime of Flash EEPROM memory in the 0.35 μm generation. The charge loss from the floating gate (FG) through the tunnel oxide under accelerated read disturb conditions is modelled with a statistical percolation model. The analysis allows extraction of the oxide trap density (Dot) as a function of the number of program/erase (P/E) cycles and a bit failure rate (BFR) prediction. For a typical tunnel oxide in 0.35 μm Flash memory, the BFR due to read disturb is low in the first two years and reaches a steady state regime afterwards. Both Dot and BFR are expressed as a function of the number of P/E cycles by means of a power law. The analysis allows prediction of the read-disturb lifetime of Flash memory for a given tunnel oxide.