Seminar by Dmitry Ivanov: "Modeling of femtosecond laser-silicon interactions with advanced atomistic-continuum approaches"

"Modeling of femtosecond laser-silicon interactions with advanced atomistic-continuum approaches"
D.S. Ivanov and T.E. Itina, Laboratoire Hubert Curien

Abstract

The modern applications of semiconductor materials assume their accurate laser processing on a nanometer scale with utilization of their variate phases and structural changes. For this reason, reliable knowledge of the mechanisms of laser-induced processes is demanded for controllable laser-assisted generation of surface structures and the surface properties modification. Here, we present a numerical study of the kinetics of non-equilibrium laser-induced phase transition in Si with the help of a hybrid atomistic-continuum numerical model. The model combines the advantages of Molecular Dynamics method for atomistic description of phase transitions and the continuum approach for addressing the effect of laser-generated free carriers to account on generation of the electron-hole pairs, their diffusion and thermal diffusion processes during the laser energy deposition and the electron-phonon coupling mechanism after. The model is used to determine the kinetics of phase transition processes in Si targets due to ultrashort laser pulses at different fluences. The simulation results reveal the dynamics of the electron and lattice temperature, pressure and the electron density inside the irradiated target and the melting depth as a function of the incident fluence. The obtained results allow for a better interpretation of the experimental measurements on structurization of Si surface due to ultrashort laser pulses.

This seminar will be held in English.