Impact of Metal Work Function on Memory Properties of Charge-Trap Flash Memory Devices Using Fowler-Nordheim P/E Mode

摘要

This letter reports the impact of metal work function (Φ{sub}M) on memory properties of charge-trap-Flash memory devices using Fowler-Nordheim program/erase mode. For eliminating electron back tunneling and hole back tunneling through the blocking oxide during an program/erase operation, a gate with Φ{sub}M of 5.1-5.7 eV on an Al{sub}2O{sub}3-SiN-SiO{sub}2 (ANO) stack is necessary. Compared to a thickness optimized n+ poly-Si/ONO stack, a high-work-function gate on an ANO stack shows dramatic improvements in retention versus minimum erase state.