Implicit Enthalpy Method for Modelling Laser Induced Melting and Solidification of Silicon

This paper presents a numerical study of laser induced melting and solidification of crystalline Silicon (Si) using an implicit enthalpy method. The simulations are performed using the open source C++ solver known as OpenFOAM [1]. The model considers temperature dependent thermo-physical and optical properties for Si. To verify the numerical model, its predictions are compared with the experimental results for a nanosecond pulsed laser annealing of Si with pulse duration of 30 ns and wavelength (λ) of 308 nm. An excellent agreement with the experimental results is observed for both the melting depth and the melting duration. In the second part of this study, the KrF excimer laser (λ = 248 nm) annealing of Si wafer widely used for production of solar cells is simulated. The effects of substrate heating on the melting duration, and re-crystallisation velocity are then investigated. Our results show that, for a given pulse duration, the maximum re-crystallisation velocity is almost independent of the laser power but decreases with the substrate heating.