Surface processing with ionized cluster beams: computer simulation

Molecular Dynamics (MD) and Monte Carlo (MC) models of energetic gas cluster irradiation of a solid surface have been developed to investigate the phenomena of crater formation? sputtering, surface treatment, and the material hardness evaluation by irradiation with cluster ions. Theoretical estimation of crater dimensions formed with Ar gas cluster ion irradiation of different substrates, based on hydrodynamics and MD simulation, are presented. The atomic scale shock waves arising from cluster impact were obtained by calculating the pressure, temperature and mass-velocity of the target atoms. The crater depth is given as a unique 1/3 dependence on the cluster energy and on the cold material Brinell hardness number (BHN). A new "true material hardness" scale which can be very useful for example for thin film coatings deposited on a soft substrate, is defined. This finding could be used as a new technique for measuring of a material hardness. Evolution of surface morphology under cluster ion irradiation was described by the surface relaxation equation which contains a term of crater formation at cluster impact. The formation of ripples on a surface irradiated with oblique cluster ion beams was predicted. MD and MC models of Decaborane ion (B10H14) implantation into Si and the following rapid thermal annealing (RTA) have been developed. (C) 1999 Published by Elsevier Science B.V. All rights reserved.