3D gate-all-around bandgap-engineered SONOS flash memory in vertical silicon pillar with metal gate

• A GAA BE-SONOS device are demonstrated for flash memory applications.
• The vertical Si pillar BE-SONOS with a Ti metal gate were fabricated.
• The devices exhibited well-behaved memory characteristics.
• The BE-SONOS can provide efficient hole tunneling for excellent erase performance.

In this paper, a gate-all-around bandgap-engineered silicon–oxide–nitride–oxide–silicon device with a vertical silicon pillar structure and a Ti metal gate are demonstrated for a potential solution to overcome the scaling-down of flash memory device. The devices were fabricated using CMOS-compatible technology and exhibited well-behaved memory characteristics in terms of the program/erase window, retention, and endurance properties. Moreover, the integration of the Ti metal gate demonstrated a significant improvement in the erase characteristics due to the efficient suppression of the electron back tunneling through the blocking oxide.