LASER PROCESSING OF HIGH DOSE ION IMPLANTED SILICON: THE SOLID PHASE REGIME

The mechanism of pulsed laser annealing of Si is studied by developing a computer model for the temperature rise and career concentration induced in Si by laser pulses. The model gives results consistent with the hypothesis that annealing with nanosecond pulses causes melting of the sample surface, suggesting that this mode of laser processing is not a solid phase phenomenon.; The temperatures produced in Si by cw laser and arc lamp radiation are calculated using the Kirchhoff transform for the nonlinear heat flow problem.; The laser induced solid phase epitaxial regrowth of implantation amorphized Si is found to proceed at rates which are more than an order of magnitude higher than the rates extrapolated from low temperature furnace annealing data. However, complete regrowth of thick amorphous layers cannot be achieved: the epitaxial regrowth is stopped by the spontaneous formation of polycrystalline Si at the surface.; It is found that cw laser annealing is capable of completely activating As and P concentrations well above the solid solubility limit. Thermal annealing causes the metastable concentrations to relax to equilibrium, which feature is used to measure the solubilities of As and P as electrically active dopants in Si. Electron mobilities are measured in concentrations up to 1.2 x 10('21) cm('-3). The deactivation process of As is also characterized.; Rapid thermal and cw arc lamp annealing are also observed to activate implanted As concentrations in excess of solubility. This shows that the formation of the metastable concentrations is a result of the solid phase epitaxial regrowth, rather than a product of the laser irradiation per se.