Modeling and Simulation of Pulsed Laser annealing and ablation of Solid Materials

Abstract

Several different aspects of laser annealing and laser ablation have indicated the need for two-dimensional (2-D) modeling of heat transfer and phase-change effects. We have in mind particularly the laser-induced formation and propagation of buried liquid layers for the case of a-Si on a crystalline silicon substrate, questions related to the early stages of the laser ablation of insulators such as MgO where it is believed that the absorption of the laser radiation occurs at localized but extended regions of high concentrations of defects, and the ejection of particulate material during laser ablation. To deal with these phenomena, a 1-D computational model originally developed for laser annealing has been extended to two-dimensions. the 2-D modeling examines the heat flow and phase changes associated with localized heat sources embedded in a planar material. Concepts such as the state diagram and state array used in the 1-D work have been extended to 2-D and refined. the 2-D program has been rewritten for massively parallel machines such as the intel Paragons in ORNL's Center for Computational Sciences, thus allowing larger and more accurate calculations for complex systems to be carried out in reasonable times.