화학공학소재연구정보센터
Journal of the Electrochemical Society, Vol.155, No.10, G218-G223, 2008
High-k Nd2O3 and NdTiO3 charge trapping layers for nonvolatile memory metal-SiO2-high-k-SiO2-silicon devices
In this article, we proposed high-k Nd2O3 and NdTiO3 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 Nd2O3 film, a MOHOS-type memory device prepared under the NdTiO3 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 Nd2O3 film, which helps to enhance the grain growth and suppress the formation of interfacial SiO2 and silicate layer at the NdTiO3/oxide interface, and produce a deeper trap energy level in the NdTiO3.