Silver nanoparticles formation in thermal oxide on silicon by negative-ion implantation

Nanoparticles in insulators exhibit unique electrical properties due to single electron effect. This paper studied about formation of nanoparticles in thin silicon dioxide film by negative ion implantation and electrical properties, such as Coulomb blockade. By silver negative-ion implantation of 30 keV, 1 × 10 ions/cm² into 50-nm-thick SiO₂ film on Si, Ag nanoparticles with diameter of 3 nm were created in the film. After annealing at 700°C, the film showed considerably clear steps in I-V curve measured at room temperature. These steps are considered to be due to Coulomb blockade of the Ag nanoparticles. Thus, negative ion implantation was found to be applicable to form metal nanoparticles with sufficiently small size for obtaining Coulomb blockade phenomena at room temperature.