Nonvolatile memories using deep traps formed in Al[sub 2]O[sub 3] by metal ion implantation

Abstract

We demonstrate the feasibility of an approach to nonvolatile memory (NVM) that exploits charge trapping at deep-energy levels formed in Al₂O₃ by metal doping. Our calculations show that V and Nb are expected to form such deep energy levels in the band gap of Al₂O₃. To demonstrate the effectiveness of this approach these metal ions were ion-implanted into test structures based on an Al₂O₃ trapping layer. Several structural analysis techniques and photocurrent spectroscopy show that the doped metal ions are located close to the Al₂O₃/SiO₂ interface and exhibit characteristics consistent with some of the deep levels predicted in calculations. The resulting test devices are shown to exhibit promising NVM characteristics. Show more