Transient simulation of the ERASE cycle of floating gate EEPROMs

The validity of a steady-state approach to the simulation of the WRITE/ERASE cycles of floating gate EEPROM cells is discussed. It is shown that, while the WRITE cycle can be always accurately modeled in such a framework, the simulation of the ERASE cycle sometimes requires a transient analysis to correctly account for the deep depletion of the drain during the leading edge of the ERASE pulse. An approximate method for the fast transient simulation of the ERASE cycle is presented. A comparison of experiments and simulations demonstrates the relevance of the non-steady-state effects, and supports the validity of the presented transient solution. In addition, it is shown that an accurate simulation of WRITE/ERASE cycles requires a reliable model for Fowler-Nordheim injection from an accumulated semiconductor.<>