Formation and nonvolatile memory characteristics of multilayer nickel-silicide NCs embedded in nitride layer

The authors provided the formation and memory effects of nonvolatile multilayer nickel-silicide nanocrystal memory in this study. This proposed structure can efficiently improve the drawbacks of current floating gate and single-layer nanocrystal memories for the next-generation nonvolatile memory application. The charge trapping layer of multilayer structure was deposited by sputtering a commixed target (Ni0.3Si0.7) in the argon and nitrogen ambiance, and then used a low temperature rapid thermal annealing to form uniform nanocrystals. Transmission electron microscope images clearly show the multilayer and single-layer nanocrystal structures embedded in SiNx. X-ray photoelectron spectroscopy and x-ray diffraction also present the chemical states and crystallization of nanocrystals under different annealing temperature treatments. The capacitor with different memory structures was also studied and exhibited hysteresis characteristics after electrical operation. In addition, the multilayer nanocrystals revealed better charge storage ability and reliability than the single-layer nanocrystals. (C) 2008 American Institute of Physics. [DOI: 10.1063/1.3006126]