Metal-oxide-semiconductor structures (MOS) with the embedded Co nanoparticles (NPs) were efficiently fabricated by utilizing an external laser irradiation technique for the application of nonvolatile memory. Images of high resolution transmission electron microscopy measurements exhibited that the Co NPs of 5 nm in diameter were clearly embedded in SiO2 gate oxide. Capacitance-voltage measurements certainly exhibited flat-band voltage shift of 2.2 V from 2 V to -8 V in sweeping range. The retention characteristics of MOS capacitors with the embedded Co NPs were also studied as a function of tunnel oxide thickness to confirm the suitability of nonvolatile memory devices with metal NPs. The experimental results reveal that our unique laser process will give possible promise for experimental efficient formation or insertion of metal NPs inside the gate oxide. (c) 2006 Elsevier B.V. All rights reserved.