Performance enhancement of multilevel cell nonvolatile memory by using a bandgap engineered high-κ trapping layer

Abstract

A high-κ based charge trap flash (CTF) memory structure using bandgap engineered trapping layer HfO2/Al2O3/HfO2 (HAH) has been demonstrated for multilevel cell applications. Compared to a single HfO2 trapping layer, a CTF memory device based on the HAH trapping layer exhibits a larger memory window of 9.2 V, faster program/erase speed, and significantly improved data retention. Enhancements of memory performance and reliability are attributed to the modulation of charge distribution by bandgap engineering in trapping layer. The findings provide a guide for future design of CTF.