Ion Beams for Nanoscale Optical Data Storage

The ion beam techniques have been investigated as a novel approach for properties modification and optimization of wide-bandgap materials with view of their uses in submicron lithography and high-density data storage for archival purposes. Focused ion-implantation has been used to write nanoscale optical data into wide-bandgap amorphous materials (hydrogenated amorphous silicon carbide (a-SiC:H) and tetrahedral amorphous carbon (ta-C) films). Scanning near-field optical microscopy is proposed as a novel technique for characterizing the ion-implanted patterns fabricated in amorphous silicon carbide (a-SiC:H). Although a considerable thickness change (thinning tendency) has been observed in the ion-irradiated areas, the near-field measurements confirm increases of optical absorption in these areas. The results are discussed in terms of the competition between the effects of ion implantation and surface milling by the ion beam. The observed effects are important for amorphous silicon carbide and tetrahedral amorphous carbon thin films as extremely stable materials in adverse environments to be used for permanent data archiving. The observed values of the optical contrast modulation are sufficient to justify the efficiency of the method for optical data recording using focused ion nanobeams.