Fluid dynamics calculation of sputtering from a cylindrical thermal spike

M.M. JAKAS; E.M. BRINGA; R.E. JOHNSON

PHYSICAL REVIEW B - CONDENSED MATTER AND MATERIALS PHYSICS

American Physical Society

Año: 2002 vol. 65 p. 1 - 9

0163-1829

The sputtering yield Y from a cylindrical thermal spike is calculated using a two-dimensional fluid-dynamics model which includes the transport of energy, momentum, and mass. The results show that the high pressure built up within the spike causes the hot core to perform a rapid expansion both laterally and upwards. This expansion appears to play a significant role in the sputtering process. It is responsible for the ejection of mass from the surface and causes fast cooling of the cascade. The competition between these effects accounts for the nearly linear dependence of Y with the deposited energy per unit depth that was observed in recent molecular-dynamics simulations. Based on this we describe the conditions for attaining a linear yield at high excitation densities and give a simple model for this yield.