A novel high-speed, 5-volt programming EPROM structure with source-side injection

Abstract

A novel source-side injection EPROM (SIEPROM) structure [1] capable of 5-volt only, high speed programming is described. The cell is an asymmetrical n-channel stacked-gate MOSFET, with a short weak gate-control region introduced close to the source. Under high gate bias, a strong channel electric field is created in this local region even at a relatively low drain voltage. Furthermore, the gate oxide field in this region is favorable for hot-electron injection into the floating gate. As a result, a programming speed of 10 µs at a drain voltage of 5 volts has been demonstrated. Also, a soft-write endurance time of 10 years with a read current larger than 100 µA per µm width can be readily achieved.