An asymmetric two-side program with one-side read (ATPOR) device for MultiBit per cell MLC nitride-trapping flash memories

An asymmetric two-side program with one-side read (ATPOR) Flash memory device is proposed. In this nitride-trapping device, the interaction of stored charges in the two sides (second-bit effect) is utilized to achieve multilevel cell (MLC) V/sub t/ levels with the advantages of relatively small total charge. The small total charge can enhance both programming and erasing efficiency. The ATPOR device with programming and erasing times within 100 ns and 40 /spl mu/s are demonstrated. Excellent read disturb immunity of ATPOR device can provide high scaling capability. In addition, good data retention and P/E cycling endurance and reliability are achieved. For 2-bit/cell and 3-bit/cell MLC applications, the ATPOR device with tight level distributions less than 100 mV is illustrated.