Formation of Ru nanocrystals by plasma enhanced atomic layer deposition for nonvolatile memory applications

Abstract

The formation of Ru nanocrystals is demonstrated on a $\mathrm{Si}{\mathrm{O}}_2$ substrate by plasma enhanced atomic layer deposition using diethylcyclopentadienyl ruthenium and $\mathrm{N}{\mathrm{H}}_3$ plasma. The island growth of Ru was observed at the initial stages of the film formation up to a nominal thickness of $11.1\mathrm{nm}$ . A maximum Ru nanocrystal spatial density of $9.7\times {10}^{11}∕{\mathrm{cm}}^2$ was achieved with an average size of $3.5\mathrm{nm}$ and standard deviation of the size of 20%. Electron charging/discharging effect in the Ru nanocrystals is demonstrated by measuring the flatband voltage shift in the capacitance-voltage measurement of metal-oxide-semiconductor memory capacitor structure.