Pulsed laser annealing of ion implanted insulators

Ion implantation of insulator surfaces offers opportunities to alter many surface properties, both from modifications of the pre-existing structures, to addition of new material and formation of thermodynamically metastable compounds. Optical applications have included production of waveguides, waveguide lasers, SHG waveguides, related devices and surface luminescence. Similarly, metallic implants have found considerable use in the generation of nanoparticles which are used in non-linear optics, or where the metallic nanoparticles are size and material selected to control the wavelength dependence of the reflectivity. In all these cases the initial results of the implantation generates variations in property which change with depth. The complex pattern of change is invariably accompanied by unwanted side effects. For example, for luminescence and laser signals derived from rare earth implants there is unwanted host lattice damage. This lattice damage cannot easily be thermally removed without unwanted clustering of the rare earth ions. Conversely, in metallic nanoparticle usage the clustering is desirable, but the implants form a depth dependent particle size distribution whereas a narrow sie distribution is preferred. Once again simple thermal treatments alone cannot establish the ideal conditions. A major value of laser pulsed annealing is that one can achieve controlled temperature excursions for a sufficiently short time duration that long term diffusion effects can be avoided. Wavelength selectivity can further allow treatment to initially couple energy either to the host or specific types of site.Examples variously include both the removal of damage and/or nanoparticles, and controlled particle growth or precipitation of new crystalline phases. These case studies show that pulse laser anneals can make major modifications in a wide range of properties. Some new experiments are proposed