Structural and electrical characteristics of a high-k Lu2O3 charge trapping layer for nonvolatile memory application

In this article, we reported a metal-oxide-high-k-oxide-silicon (MOHOS)-type memory structure fabricating a high-k Lu2O3 film as a charge trapping layer for flash memory applications. X-ray diffraction and X-ray photoelectron spectroscopy revealed the structural and chemical features of these films after they had been subjected to annealing at various temperatures. The high-k Lu2O3 MOHOS-type devices annealed at 800 °C exhibited a larger threshold voltage shift (memory window of ∼2.93 V operated at Vg = 9 V at 1 s) and better data retention (charge loss of ∼18% measured time up to 104 s) than that had been subjected to other annealing conditions. This result suggests the higher probability for trapping of the charge carrier due to the formation of the crystallized Lu2O3 with a high dielectric constant of 12.8.

► We report a MOHOS-type memory structure incorporating a high-k Lu2O3 charge trapping layer.
► We used XRD and XPS to analyze the structural and chemical features of Lu2O3 films.
► The MOHOS-type memory device annealed at 800 °C exhibited better electrical characteristics.