Formation Of Silicon Nanoparticles Research Articles

Silicon Nanoparticle Formation in Si+-Implanted Thermal Oxide Films and Visible Photoluminescence Behavior

We have investigated optical properties and microstructures of Si+-implanted thermal oxide films grown on crystalline Si wafer, as-implanted and after subsequent annealing. We found two types of visible luminescence bands similar to those of silica glasses: one peaked around 2.0 eV, observed in as-implanted specimens and annealed completely at about 600 °C, and the other peaked around 1.7 eV, observed only after heating specimens to about 1100 °C, the temperature at which Si segregates from SiOx. Though the shapes of these luminescence spectra are quite different from those having been observed in Si+-implanted silica glasses caused by interferences, the origins of these bands are the same as in silica glasses. Moreover, the direct evidence for the formation of nanometer-sized Si crystals in amorphous silicon dioxide matrix after annealing at 1100 °C is presented by high-resolution transmission electron microscopy.