Abstract

Laser processing of semi-conductors such as silicon has numerous applications in nano-structuring and fabrication industry, and requires a detailed understanding of the dynamics. The interaction involves complex processes such as photo-absorption, recombination, impact ionization and re-distribution of the energy due to carrier-phonon dynamics. Numerical modeling proves to be useful in understanding the physics of the interaction. Based on the density-dependent Two-Temperature model (nTTM) [1], we have developed a one-dimensional Three-Temperature model (1D-3TM) and studied the laser-excitation process and damage in silicon [2]. In 1D-3TM, three subsystems for electrons, holes and the lattice are considered and their evolution dynamics are calculated separately. This approach gives a more clear picture of the electron dynamics and the evolution of quasi-temperatures in the system. We also take into account the evolution of optical properties of silicon during the interaction and the effect of band-gap re-normalization on them. The laser field is modeled using finite difference time domain (FDTD) method [2].

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