Microscopic description of thin film formation in pulsed laser deposition in the presence of a background gas

Analytical derivation of the thickness profiles of pulsed laser deposited (PLD) thin films starting out from a plausible velocity distribution of the ablated atoms proved to be appropriate in describing PLD in high vacuum. Since the presence of background gases is typical in most applications, there is a need for methods which do not suffer from the limitations of the analytical description, supposing collisionless transfer of the target atoms onto the substrate. We give a microscopic approach to the description of thin film formation by following the 'life story' of each ablated particle by Monte Carlo calculations. Bi and In film thickness profiles and TOF and kinetic energy spectra are presented for various pressures of the He, Ar and Xe background. The computer experiments are compared with real experiments on nonreactive PLD. It is demonstrated that the process can be handled satisfactorily in the framework of the hard-sphere collision model used. (C) 1998 Elsevier Science B.V.