Si-nanowire based gate-all-around nonvolatile SONOS memory cell

Abstract

This letter presents a high-speed silicon-oxide-nitride-oxide-silicon (SONOS) nonvolatile memory cell in gateall-around Si-nanowire (NW) architecture, which is fabricated by using a top-down process technology. The NW cell exhibits faster program and erase (P/E) speed compared to the corresponding planar device; 1 μs for programming and 1 ms for erasing at VGS = ±11 V with a threshold voltage shift "ΔVTH" of 2.6 V using the Fowler-Nordheim tunneling mechanism. At these P/E conditions, the planar device does not show appreciable change. The improvement is originated from: 1) increased electric field at the Si-SiO2 interface; 2) reduced effective tunnel barrier width; and 3) low electric field in the blocking oxide, as analyzed through simulation. In addition, good data retention makes the NW-based SONOS cell a potential candidate for future high-speed low-voltage NAND-type nonvolatile Flash memory applications. © 2008 IEEE.