A novel junctionless all-around-gate SONOS device with a quantum nanowire on a bulk substrate for 3D stack NAND flash memory

A novel junctionless all-around-gate (AAG) SONOS device with a homogeneously n⁺-doped silicon nanowire (SiNW) is demonstrated on a bulk substrate. The diameter and gate length of the quantum-scale SiNW are 4 nm and 20 nm, respectively. A deep RIE process is developed for the formation of the SiNWs. The junctionless AAG SONOS device shows a high read current (>; 10 μA), a large V_T margin (>; 6.5 V), a narrowed distribution of the erased V_T, and improved cyclic endurance (10⁵ cycles). Moreover, the proposed process is applied to implement vertically integrated 9-layer single-crystal SiNWs for 3D NAND.