CF₄ plasma treatment on nanostructure band engineered Gd ₂O₃-nanocrystal nonvolatile memory

The effects of CF₄ plasma treatment on Gd₂O ₃ nanocrystal (NC) memory were investigated. For material analysis, secondary ion mass spectrometry and x-ray photoelectron spectroscopy analyses were performed to characterize the fluorine depth profile of the Gd ₂O₃-NC film. In addition, an UV-visible spectrophotometer was used to obtain the Gd₂O₃ bandgap and analyzed to suggest the modified structure of the energy band. Moreover, the electrical properties, including the memory window, program/erase speed, charge retention, and endurance characteristics were significantly improved depending on the CF₄ plasma treatment conditions. This can be explained by the physical model based on the built-in electric field in the Gd₂O ₃ nanostructure. However, it was observed that too much CF ₄ plasma caused large surface roughness induced by the plasma damage, leading to characteristics degradation. It was concluded that with suitable CF₄ plasma treatment, this Gd₂O₃-NC memory can be applied to future nonvolatile memory applications.