Non-volatile semiconductor memory

摘要

This invention relates to the reduction of programming voltage in a non-volatile memory of the type having a double gate structure composed of a select-gate and a floating-gate. A channel region under the select-gate is highly doped and a channel region under the floating gate is lightly doped or doped to opposite conductivity type. Due to the different doping concentrations between these two channel regions, a large and steep surface potential gap appears at the transition region between the select-gate and the floating-gate in the programming operation thereby reducing the programming voltage.