Three-terminal single poly nmos non-volatile memory cell

Abstract

A three terminal non-volatile memory (NVM) cell for a CMOS IC is formed by a standard CMOS process flow. The NVM cell includes two transistors that share a common floating gate. The floating gate includes a first portion disposed over the channel region of the first (NMOS) transistor, a second portion disposed over the channel region of the second (NMOS or PMOS) transistor, and a third portion extending into an enlarged drain diffusion area away from the channel regions, whereby the gate-to-drain capacitance is higher than the gate-to-source capacitances. A pocket implant or CMOS standard LV N-LDD is formed under the second transistor to enhance CHE programming. Both HV LDD and LV LDD implants are introduced together enabling LDD implant merging under the floating gate extension. The floating gate is formed using substantially T-shaped, C-shaped, U-shaped, Y-shaped or O-shaped polysilicon structures. Various array addressing schemes are disclosed.