Tunnel‐oxide breakdown characteristics of floating‐gate‐type EEPROM

Abstract

This paper aims at the analysis of the breakdown characteristics and the mechanism of the tunnel oxide breakdown by the iterative rewriting of floating‐gate‐type EEPROM. The relation of number of rewritings until the tunnel oxide breakdown to the rewriting condition and the process condition is investigated. As a result, an approximate relation log NαQfg is derived, where N is the number of rewritings until the tunnel oxide breakdown and Qfg is the tunnel charge in rewriting. It was seen also that N is nearly proportional to the life of the tunnel oxide determined from TDDB characteristic. It is estimated that the major cause of the tunnel oxide breakdown is the trap of the electron in the tunnel oxide. The trapped electron can easily be released by the thermal treatment of some 5 hours, improving the life of the number of rewritings until breakdown.