LASER-PULSE ENERGY-DEPENDENCE OF ANNEALING IN ION-IMPLANTED SI AND GAAS SEMICONDUCTORS

Crystallization of amorphous layers in ion implanted Si and GaAs samples has been obtained by single pulse ruby laser irradiation. The channeling effect with MeV He backscattering was adopted to investigate the structure of the irradiated layer. Using 50 and 20 ns duration time of the Q-switched laser pulse it has been found that the transition to single crystal for a given material amorphous layer thickness requires nearly the same energy density. The energy density to induce the single crystal transition in Si amorphous layer is about 50% higher than that in GaAs layer of the same thickness. The threshold energy value, the absence of partial regrowth and the excellent agreement of the energy density difference between Si and GaAs with estimated value from thermal properties support the formation of a liquid-solid system during laser irradiation. © 1978.