Formation of nickel-based nanocrystal monolayers for nonvolatile memory applications

A simple method for fabricating metal silicide nanocrystal layers with narrow spatial distributions is demonstrated and shown to produce structures suitable for nonvolatile memory applications. The method is based on high-temperature annealing of a sandwich structure comprised of a thin metal (Ni) film sandwiched between two silicon-rich oxide (SiO_x) layers and has the feature in which the size of the NCs can be controlled by varying the silicon concentrations in the SiO_x layers or the initial nickel film thickness. The typical nanocrystal diameters and densities are 3.6 nm and 1.2×10¹² cm^-2, respectively. Capacitance-voltage (C-V) measurements on test structures with these characteristics are shown to have C-V characteristics suitable for nonvolatile memory applications, including a C-V memory window of 11.7 V for sweep voltages between -12 V and +12.