A computational model of laser-induced melting and solidification with density change

✍ Scribed by R. Cěrný; P. Přikryl

• Publisher: Elsevier Science
• Year: 1992
• Tongue: English
• Weight: 699 KB
• Volume: 73
• Category: Article
• ISSN: 0010-4655
• DOI: 10.1016/0010-4655(92)90038-z

✦ Synopsis

A finite-element model of laser-induced thermal processes including density changes due to thermal expansion and phase change is presented. In contrast to the classical Stefan formulation of the models of ithase change, the local thermodynamic equilibrium condition is replaced by a relation between the solid/liquid interface velocity and its temperature, which follows from the Jackson-Chalmers theory. Moreover, the model accounts for the thermal expansion of both the phases and for the motion of the sample surface due to the density jump at the phase transition. This approach leads to a more accurate determination of the position of the phase interface. To solve the resulting system of heat conduction equations with moving boundaries, standard finite-element procedure is employed. Since the model is nonlinear an iterative procedure has to be used after space and time discretization. A detailed description of the algorithm is given. As an example, results of numerical experiments with XeCI-and ArF-excimer laser processing of mono-Si in ns regime are presented and discussed.