MONTE-CARLO PREDICTION OF CRATER FORMATION BY SINGLE-ION IMPACT ON SOLID-SURFACE

A method is presented for predicting the topography changes following the impact of one energetic ion on the plane surface of a monatomic am orphous solid. This is done in two stages. The first is a Monte Carlo calculation of the sputter yield and interior distribution relocated a toms, with no compensation for local departures from equilibrium densi ty. In the second stage there is a systematic relaxation of the solid, in which the density returns to its previous constant value and a cra ter develops in the surface. Two alternative methods of carrying out s tage two are compared. In the first the solid is subdivided into cells within which relaxation is carried out normal to the surface, as in p revious one-dimensional studies. The second method treats the solid as a 3-dimensional incompressible medium. Both seem to reproduce quite w ell the main features found experimentally.