Band-to-band hot-hole erase characteristics of 2-bit/cell NOR-type silicon-oxide-nitride-oxide-silicon flash memory cell with Spacer-type storage node on recessed channel structure

A novel 2-bit/cell silicon-oxide-nitride-oxide-silicon (SONOS) flash memory device was proposed and characterized for 50 nm non-volatile memory (NVM) technology. The proposed memory cell has spacer-type storage nodes on both sidewalls in a recessed channel region, and is erased (or programmed) by using hand-to-hand tunneling hot-hole injection (or channel hot-electron injection). For a bit-programmed cell, reasonable bit-erasing characteristics were shown with the bias and stress pulse time condition for 2-bit/cell operation. The channel surface potential was shown to show internal physics with erasing time. Proposed memory cell has two surface potential peaks at source and drain sides.