Analytical model for the programming of source side injection SST superflash split-gate cell using two-dimensional analysis

An analytical model for source side injection programming of E2PROM is presented based on two-dimensional analysis on SST SuperFlash cells. Owing to SST cells dual-gate specific configuration and programming bias conditions, two maximum peaks are expected in the lateral electric field distribution along the channel. However, only hot electrons generated at the gap region, where the vertical field is in favor of electrons collection can effectively contribute to the gate current. A virtual gate with linearly increased potential is assumed in the gap region to solve the channel electric field distribution. By applying analytical electric field results to the Lucky-Electron model and impact-ionization model, SST cell gate current and substrate current models are derived and verified by experimental data.