Charge Trap Flash Memory Devices Research Articles

The Effect of Fixed Oxide Charge in Al[sub 2]O[sub 3] Blocking Dielectric on Memory Properties of Charge Trap Flash Memory Devices

In this article, we report the effect of fixed oxide charge in Al 2 O 3 blocking dielectric on memory properties of charge trap flash memory devices using Fowler-Nordheim program/erase mode. It was found that negative fixed oxide charges in the Al 2 O 3 dielectric play a crucial role in improving erase efficiency of Al 2 O 3 /SiN/SiO 2 (ANO) stacks, and thus reinforces the advantages of a Al 2 O 3 blocking layer for charge trap flash devices. Compared to n + poly-Si/ONO stack, process-optimized ANO stack with high work-function metal gate shows dramatic improvements in retention vs minimum erase state.

High Work-Function Metal Gate and High-<tex>$kappa$</tex>Dielectrics for Charge Trap Flash Memory Device Applications

We report the impact of high work-function (/spl Phi//sub M/) metal gate and high-/spl kappa/ dielectrics on memory properties of NAND-type charge trap Flash (CTF) memory devices. In this paper, theoretical and experimental studies show that high /spl Phi//sub M/ gate and high permittivity (high-/spl kappa/) dielectrics play a key role in eliminating electron back tunneling though the blocking dielectric during the erase operation. Techniques to improve erase efficiency of CTF memory devices with a fixed metal gate by employing various chemicals and structures are introduced and those mechanisms are discussed. Though process optimization of high /spl Phi//sub M/ gate and high-/spl kappa/ materials, enhanced CTF device characteristics such as high speed, large memory window, and good reliability characteristics of the CTF devices are obtained.