High-k materials and poly-Si nanowires in nonvolatile memory for 3D flash memory and display panel applications

摘要

This work presents the feasibility of two Silicon-Oxide-Nitride-Oxide-Silicon (SONOS) type nonvolatile memory (NVM) devices. The first NVM device is TaN-Al_2O_3-Si_3N_4-SiO_2-Si (TANOS) NVM with Pi-gate (π-gate) and poly-Si nanowire channels (NWs) structure. This TANOS NVM device is characterized by a fast program/erase (P/E) speed, a 3 V memory window (ΔV_(th)) that can be achieved by applying V_g = 18 V in 10 μs, a feature in which 70% of the initial memory window is maintained after 10~4 P/E-cycle stress, and a two-bit operation. The other NVM device has a Pi-gate poly-Si NWs structure with a HfO_2 charge trapping layer (SOHOS), as well as a HfO_2 charge trapping layer that has a higher program efficiency, the better retention characteristics and more P/E cycles than that with the Si_3N_4 charge trapping layer.