The Effect of Fixed Oxide Charge in Al_2O_3 Blocking Dielectric on Memory Properties of Charge Trap Flash Memory Devices

摘要

In this article, we report the effect of fixed oxide charge in Al_2O_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_2O_3 dielectric play a crucial role in improving erase efficiency of Al_2O_3/SiN/SiO_2 (ANO) stacks, and thus reinforces the advantages of a Al_2O_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.