A Novel Self-aligned Si-wire Flash Memory Featuring Multi-bit/cell Operation, Fast Edge +FN Erase, and Over-erasure Immunity

We present a new memory device using two self-aligned silicon wires for charge storage. Programming is by channel hot electron injection, and a large 2^nd bit V_T window ( >3 V) for multi-bit/cell operation is demonstrated. Erasing is by edge-enhanced +FN tunneling. Both program and erase operations can be performed at < 10 mus and the device is intrinsically immune to over-erasure. This new Si-wire device shows small program disturbance, small cycling-induced degradation, and adequate retention performance. This new device has all the benefits of nanocrystal device but is readily made by standard CMOS process and without the Coulomb blockade limitation. It is also more scalable than conventional floating gate devices.