Review on developments in LIS (laser ion source) at the IPPLM and its possible applications in photonics

One of the techniques which had the biggest impact on the development of microelectronics, optoelectronics, photonics and other similar technologies was doping the substrates with various elements. Although many techniques have been developed resulting in reliable industrial designs, still there is a need of further development and optimization of some of them for specific applications. A very interesting method of doping is the ion implantation based on LIS (Laser Ion Source). The great advantage of this method is its ability to implant ions from any solid state material onto any substrate. Besides – a control of the laser irradiation parameters gives also a flexibility in the parameters of the implantation process, i.e. the ion energy which corresponds to the implantation depth and the ion flux which results in the concentration. On the other hand there are also drawbacks of the direct method – usually the power density of the laser beam needs to be higher than that offered by standard industrial solution and together with the dopant the contaminations present in the projectile are implanted. Another issue for the applications requiring high precision of the implanted layer depth and width is the relatively broad energy spread of the laser produced ions. To deal with this problems the research at the IPPLM was focused on the extent characterization of laser produced ion streams in the direct variant of the method and optimization of the method with the application of electrostatic field to accelerate, focus and shape the ion beams.