Laser induced single-crystal transition in polycrystalline silicon

Transition to single crystal of polycrystalline Si material underlying a Si crystal substrate of <100> orientation was obtained via laser irradiation. The changes in the structure were analyzed by reflection high energy electron diffraction and by channeling effect technique using 2.0 MeV He Rutherford scattering. The power density required to induce the transition in a 4500 Å thick polycrystalline layer is about 70 MW/cm² (50ns). The corresponding amorphous to single transition has a threshold of about 45 MW/cm².