Failure rate predictions for 0.35 /spl mu/m Flash EEPROM memories from accelerated read disturb tests

Abstract

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 /spl mu/m 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 /spl mu/m 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.