Tania Tsvetkova

By Tania Tsvetkova

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.

Part of the book: Ion Beam Applications

By Tania Tsvetkova

The work presented here is related to some developments in providing a new generation ultrastable (>100 years), ultrahigh density (>1 Tbit/sq.in.) data storage materials for archival applications. The chosen material to write nanoscale data by finely focused ion beams is hydrogenated amorphous silicon carbide (a-SiC:H) films. Wide bandgap a-SiC:H has been chosen for its appropriate optical, chemical and mechanical properties. Ga+ was prefered as the implant species for the focused ion beam (FIB) implantation due to its widespread uses in FIB equipment and its modifying effects on the amorphous silicon carbide target. A range of a-SiC:H film samples have been FIB patterned under different implantation conditions for this study. The emphasis in these investigations was the influence of different substrate temperatures on the patterning process. The effects of further annealing of room temperature implanted samples were also studied. The FIB patterned samples under different conditions were analysed using near-field techniques, like atomic force microscopy (AFM), to define optimum implantation parameters for archival data storage applications. Using the established optimal conditions for the FIB patterning process of a-SiC:H films, it is expected to achieve the aimed ultrahigh density and stability with this novel data storage method for archival applications.

Part of the book: Multilayer Thin Films