THE EFFECT OF TARGET TEXTURE AND TOPOGRAPHY ON THE SPATIAL-DISTRIBUTION OF MATERIAL SPUTTERED FROM TUNGSTEN

The spatial distributions of sputtered particles have been investigate d both experimentally and by computer simulation using the TRIM.SP cod e for 30 keV argon-ion bombardment of tungsten in a wide range of prim ary-ion incidence angles (0-degrees-80-degrees). Two sets of the targe ts were used. One of them was prepared from fine-grained polycrystalli ne ingot, another one from rolled sheet W. It was found that the exper imental results for these targets were different. For rolled tungsten a typical Wehner-spot picture, although smeared, is observed. For fine -grained tungsten the sputtered particle spatial distributions are pra ctically cupola-shaped. Some differences between the experimental resu lts and computer-simulation data can be attributed to the effect of su rface topography either initial or developed during the ion bombardmen t.