Reprogrammable non-volatile memory using a breakdown phenomena in an ultra-thin dielectric

Abstract

A reprogrammable non-volatile memory array and constituent memory cells is disclosed. The semiconductor memory cells each have a data storage element constructed around an ultra-thin dielectric, such as a gate oxide. The gate oxide is used to store information by stressing the ultra-thin dielectric into breakdown (soft or hard breakdown) to set the leakage current level of the memory cell. The memory cell is read by sensing the current drawn by the cell. A suitable ultra-thin dielectric is high quality gate oxide of about 50 Å thickness or less, as commonly available from presently available advanced CMOS logic processes. The memory cells are first programmed by stressing the gate oxide until soft breakdown occurs. The memory cells are then subsequently reprogrammed by increasing the breakdown of the gate oxide.