Volatile and non-volatile memories in silicon with nano-crystal storage

Abstract

A single transistor memory structure, with changes in threshold voltage exceeding /spl ap/0.25 V corresponding to single electron storage in individual nano-crystals, operating in the sub-3 V range, and exhibiting long term to non-volatile charge storage is reported. As a consequence of Coulombic effects, operation at 77 K shows a saturation in threshold voltage in a range of gate voltages with steps in the threshold voltage corresponding to single and multiple electron storage. The plateauing of threshold shift, operation at ultra-low power, low voltages, and single element implementation utilizing current sensing makes this an alternative memory at speeds lower than those of DRAMs and higher than those of E/sup 2/PROMs, but with potential for significantly higher density, lower power, and faster read.