SIMULATION OF IR AND VIS-NIR SPECTRA OF SI+ IMPLANTED SIO2 GLASS

Si+ implanted silica glass has been investigated by IR reflectance and VIS-NIR transmittance spectroscopy. Spectra can be simulated with the complex dielectric functions of SiO2 glass and amorphous silicon by m eans of a simple effective medium theory and a multilayer model. It ca n be derived from the evaluation of the spectra that modification of t he glass structure is the preferred process for ion doses < 10(17) Si/cm(2). Higher ion doses lead to a formation of amorphous silicon prec ipitates. Simulation of the spectra allows determination of that part of implanted Si+ ions which is accumulated as elementary (metallic) si licon in the host substrate. Furthermore the results indicate that qua ntum confinement effects, which are known in the case of silicon nanoc rystals, also occur in amorphous silicon colloids.