Surface doping of semiconductors by pulsed-laser irradiation in reactive atmosphere

Intense pulsed-laser irradiation in a suitable chemical atmosphere can produce a significant incorporation of chemical species from the environment to the surface molten layer. This process has been used to produce p-n junctions in silicon and GaAs irradiated, respectively, in PCl₃ and SiH₄ atmospheres. A modelling of the incorporation process, taking into account the solid-liquid-solid transition of the surface layer, has been developed following both a numerical and a semi-analytical approach. The modelling of the doping process gives results in a reasonably good agreement with the experimental doping profiles, obtained by irradiating Si samples in PCl₃ atmosphere.