Theoretical modelling of phenomena in the pulsed-laser deposition process:Application to Ti targets ablation in low-pressure N-2

We present an analysis describing the phenomena that are involved in the in teraction process between high intensity UV laser radiation and a solid tar get in a low-pressure gas environment. The laser action upon the solid surf ace is described by solving the one-dimensional (1D) heat-conduction equati on. The 1D hydrodynamic model is further applied to describe the interactio n between laser radiation and the plasma expanding in front of the target. The laser radiation absorption in the vapor plasma is considered using a mu lticomponent fluid model. The transit of ablated material from target to co llector is treated by a Monte Carlo method. The time and space distribution s of the main plasma parameters (e.g., atom density and plasma electron tem perature and density) are calculated. Finally, the thickness profile of a f ilm deposited on a collector parallel to the target is predicted. For compa rison with available experimental data, the calculations were carried out f or the case of a Ti target submitted to a multipulse UV laser irradiation i n low-pressure nitrogen, when depending on gas pressure, stoichiometric TiN was deposited or mixtures of amorphous and crystalline Ti, TiN, Ti2N, and even Ti oxides were obtained. (C) 1999 American Institute of Physics. [S002 1-8979(99)06822-X].