Sub-10V 4-bit/cell Schottky barrier nanowire nonvolatile memory

This study reports experimentally a novel sub-10V 4-bit/cell nanowire silicon-oxide-nitride-oxide-silicon (SONOS) memory cell for use in nonvolatile NAND Flash memories. Applying metallic Schottky barrier source/drain in the silicon gate-all-around nanowire SONOS cells enables the multi-level 4-bit/cell SONOS memory to operate at sub-10V gate voltages using efficient electron programming and hole erasing through Fowler-Nordheim mode tunneling. Examples of 2-bit/cell, 3-bit/cell, and 4-bit/cell applications in this Schottky barrier nanowire SONOS memory cell are demonstrated with multi-level electron programming. Reliability characterization confirms these multi-bit cells to operate well after 10K cycling endurance and 125°C high temperature retention stress.