Dynamics of the optical parameters of molten silicon during nanosecond laser annealing

摘要

Abstract: The behavior of the reflectivity of a Si single crystal during irradiation with two successive Nd:YAG pulses is investigated with ns resolution. The first pulse melts the surface, and therefore the reflection coefficient increases to the value of the metallic liquid at the melting temperature. Upon further heating of the surface with the second pulse, we observe a decrease of the reflection coefficient, resulting from the temperature dependent dielectric function of the molten Si. The largest decrease in the reflectivity that could be reached before damaging the surface amounted to 9% for both wavelengths 633 nm and 488 nm.!11