Proton beam induced luminescence of silicon dioxide implanted with silicon

Light emission from a silicon dioxide layer enriched with silicon has been studied. Samples used had structures made on thermally oxidized silicon substrate wafers. Excess silicon atoms were introduced into a 250-nm-thick silicon dioxide layer via implantation of 60 keV Si+ ions up to a fluence of 2 × 1017 cm−2. A 15-nm-thick Au layer was used as a top semitransparent electrode. Continuous blue light emission was observed under DC polarization of the structure at 8–12 MV/cm. The blue light emission from the structures was also observed in an ionoluminescence experiment, in which the light emission was caused by irradiation with a H2+ ion beam of energy between 22 and 100 keV. In the case of H2+, on entering the material the ions dissociated into two protons, each carrying on average half of the incident ion energy. The spectra of the emitted light and the dependence of ionoluminescence on proton energy were analyzed and the results were correlated with the concentration profile of implanted silicon atoms.