FORMATION OF AMORPHOUS AND NANO-CRYSTALLINE CARBON IN C+ IMPLANTED SILICA GLASS

Rutherford backscattering spectrometry, VIS-NIR transmission of IR ref lection measurements as well as Raman investigations have been used to characterize C+ implanted (30 keV, 0.5 x 10(16) cm(-2)) silica glass. Distribution of implanted ions can be described by a Gaussian profile with a maximum at about 80 nm. C+ ions penetrate to a depth of 180 nm in the substrate material. Transmission spectra in the VIS-NIR region were simulated with the dielectric functions of substrate glass and a morphous carbon using a multilayer model. Evaluation of the IR reflect ance spectra indicates the creation of CO and a damage of the glass st ructure up to a depth of about 300 nm. Raman measurements of implanted samples show the aggregation of amorphous carbon. Anneling of samples for one hour at 700 or 1000 degrees C in nitrogen atmosphere leads to the formation of nano-crystalline carbon precipitates. Furthermore, t he relaxation of the glass structure and the existence of Si-C bonds h as been observed after heal treatment.