Capacitance characteristics of metal-oxide-semiconductor capacitors with a single layer of embedded nickel nanoparticles for the application of nonvolatile memory

This paper reports that metal-oxide-semiconductor(MOS) capacitors with a single layer of Ni nanoparticles weresuccessfully fabricated by using electron-beam evaporation and rapidthermal annealing for application to nonvolatile memory.Experimental scanning electron microscopy images showed that Ninanoparticles of about 5~nm in diameter were clearly embedded in theSiO₂ layer on p-type Si (100). Capacitance--voltagemeasurements of the MOS capacitor show large flat-band voltageshifts of 1.8~V, which indicate the presence of charge storage inthe nickel nanoparticles. In addition, the charge-retentioncharacteristics of MOS capacitors with Ni nanoparticles wereinvestigated by using capacitance--time measurements. The resultsshowed that there was a decay of the capacitance embedded with Ninanoparticles for an electron charge after 10$^{4}$~s. But only aslight decay of the capacitance originating from hole charging wasobserved. The present results indicate that this technique ispromising for the efficient formation or insertion of metalnanoparticles inside MOS structures.