Impact of temperature on non-equilibrium Fowler-Nordheim EEPROM programming

High-field Fowler-Nordheim electron injection to the drain of EEPROM's is studied using a specific time-resolved measurement technique. A transient injection regime is observed only in the case of moderately doped drain, but a non-equilibrium stationary injection regime is always evidenced, resulting, for a given temperature, in a current higher than expected for thermal equilibrium conditions. The magnitude of the phenomenon is shown to decrease with temperature and doping level. As a consequence, the memory cell programming window change with temperature, which is controlled by the total FN characteristics voltage shifts with temperature, should depend on drain doping and programming current.