STP799: Laser Damage of Crystalline Silicon by Multiple 1.06μm, Picosecond Pulses

    Walser, RM
    Electronics Research Center and Department of Electrical Engineering The University of Texas at Austin, Austin, Texas

    Becker, MF
    Electronics Research Center and Department of Electrical Engineering The University of Texas at Austin, Austin, Texas

    Sheng, DY
    Electronics Research Center and Department of Electrical Engineering The University of Texas at Austin, Austin, Texas

    Pages: 11    Published: Jan 1983


    Abstract

    Recent studies [1] have shown that the iso-intensity damage kinetics of crystalline silicon irradiated by picosecond 1.06μm pulses could be fit to the equations of classical nucleation and growth. These results suggested that laser damage be viewed as a non-equilibrium phase transition in which the threshold intensity produced excursions across a first order phase boundary into a metastable region of the material phase diagram.

    In the present work we discuss a simplified electronic phase diagram for silicon that we believe is relevant to the picosecond damage experiments. The physics of the metastable region are as yet uncertain, but its presence requires that the statistics of laser damage be determined by the activated nucleation of embryos (charge density fluctuations) to near liquid phase charge densities.

    The thermodynamic perspective suggests a new laser damage mechanism in which incident photons are resonantly absorbed by the collective electronic oscillations (surface plasmons) of critical embryos. Evidence supporting this mechanism has been obtained from high resolution SEM studies of the damage morphology showing that a coherent radiative interaction occurred between resonant surface plasmon embryos on adjacent sites just prior to liquid-like phase nucleation. Calculations show that the surface plasmon of a spherical embryo with a near liquid charge density of ∼2 × 1022/cm3 is resonantly coupled to the laser photons.

    Keywords:

    laser damage, crystalline silicon, picosecond pulses, non-equilibrium phase transition, damage kinetics, damage morphology, damage nuclei, resonant surface plasmons


    Paper ID: STP37232S

    Committee/Subcommittee: F01.02

    DOI: 10.1520/STP37232S


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