The effects of oxidation conditions on structural and electrical properties of siliconnanoparticles obtained by ultra-low-energy ion implantation

Abstract

In this paper, we have studied the effect of annealing under slightly oxidizing ambient(N2+O2) onthe structural and electrical characteristics of a limited number of silicon nanoparticles embedded in anultra-thin SiO2 layer. These nanoparticles were synthesized by ultra-low-energy (1 keV) ion implantationand annealing. Specific experimental methods have been used to characterize the ncspopulations. They include transmission electron microscopy (TEM) Fresnel imaging forevaluating the distances and widths of interest and spatially resolved electron energy lossspectroscopy (EELS) using the spectrum-imaging mode of a scanning transmissionelectron microscope (STEM) to measure the size distribution and density of the ncspopulation. To perform electrical measurements of these particles, a nanoscale contact(100 nm × 100 nm) was patterned over the samples by electron-beam nanolithography. Room-temperatureI–V characteristics of these nano-MOS structures exhibit discrete current peakswhich have been associated with single-electron charging of the nanoparticlesand electrostatic interaction of the trapped charges with the tunnellingcurrent. The effect of the progressive oxidation of the Si nanoparticles on theseI(V) characteristics has been studied and related to the nanocrystal characteristics.