Integration of high-κ dielectrics and metal gate on gate-all-around si-nanowire-based architecture for high-speed nonvolatile charge-trapping memory

Abstract

This letter, for the first time, presents a metal high-κhigh-κ-oxide silicon-type charge-trapping nonvolatile memory fabricated on an advanced gate-all-around nanowire architecture with a top-down process. The high-κ materials are integrated with a high work-function TaN gate electrode. The fabricated Si nanowire TaN/ Al2O3/HfO2/SiO2/Si (TAHOS) memory can achieve a higher speed at a lower voltage compared with a similar wire-based SONOS device. For instance, at a 13-V programming pulse, the TAHOS memory device resulted in a Vth shift of 3.8 V in 10 μs, while the SONOS took a period of 1 ms to produce a similar shift. Faster program-and-erase speed, particularly the much improved erasing speed in the TAHOS device, could be ascribed to the enhanced electric-field drop in the tunnel oxide in addition to the suppressed gate-electron injection. In addition, good memory-reliability properties could also be observed in the nanowire TAHOS charge-trapping memory. © 2009 IEEE.