Laser damage in silicon: energy absorption, relaxation and transport

Abstract

Silicon irradiated with an ultrashort 800 nm-laser pulse is studied theoretically using a two tem-perature description that considers the transient free carrier density during and after irradiation. A Drude model is implemented to account for the highly transient optical parameters. We analyze the importance of considering these density-dependent parameters as well as the choice of the Drude carrier collision frequency. In addition, degeneracy and transport effects are investigated. The im-portance of each of these processes for resulting calculated damage thresholds is studied. We report fit-free damage thresholds calculations that are in very good agreement with experimental results over a wide range of pulse durations. PACS numbers: 05.70.Ln, 79.20.Ap, 44.10.+i, 72.10.Di I