High- k Nd₂O₃ and NdTiO₃ charge trapping layers for nonvolatile memory metal-SiO₂-high-k-SiO ₂-silicon devices

In this article, we proposed high- k Nd2 O3 and NdTi O3 films as the charge trapping layer in metal-oxide-high- k -oxide-silicon (MOHOS)-type nonvolatile memory devices. X-ray diffraction, X-ray photoelectron spectroscopy, and atomic force microscopy were used to study the structural, compositional, and morphological features of these films after annealing at different temperatures. Compared to the Nd2 O3 film, a MOHOS-type memory device prepared under the NdTi O3 film exhibited superior memory characteristics, such as a higher window of 9 V in the capacitance-voltage hysteresis loop, a larger flatband voltage shift of 4 V, and a lower charge loss rate of 3% at room temperature. The improvement can be explained by the Ti content in the Nd2 O3 film, which helps to enhance the grain growth and suppress the formation of interfacial Si O2 and silicate layer at the NdTi O3 /oxide interface, and produce a deeper trap energy level in the NdTi O3.