Two-bit/four-level Pr₂O₃ trapping layer for silicon-oxide-nitride-oxide-silicon-type flash memory

This study proposes and demonstrates a silicon-oxide-nitride-oxide-silicon (SONOS)-type memory device based on a high-k dielectric praseodymium oxide (Pr₂O₃) trapping layer. In the proposed design, channel hot electron injection programming and band-to-band hot-hole injection erasing allow highly efficient two-bit and four-level device operation. The proposed design also has a total memory window of 5 V, a ten-year V_t retention window larger than 0.8 V between adjacent levels, and enough memory window for 10⁵ programming/erasing cycles of endurance. The proposed SONOS-type Pr₂O₃ trapping layer flash memory exhibits large memory windows, high program/erase speed, good endurance, and good disturbance characteristics.