ISLAND GROWTH IN ION-BEAM-ASSISTED METAL-ON-METAL DEPOSITION MODELED BY RATE-EQUATIONS

Island growth in ion beam assisted deposition (IBAD) is modelled by ra te equations, where deposition, diffusion driven aggregation, defect a nd target adatom production and island fragmentation are taken into ac count. It is shown that compared with results obtained for a thermal d eposition, deposition with ion bombardment induced island fragmentatio n causes the total island density to increase and average island size to decrease. The observed behaviour is in qualitative agreement with e xperimental findings. It is demonstrated how the appropriately scaled island size distributions depend crucially on the fragmentation proces s, but remain relatively unaffected by diffusion. Possibilities to use scaled distributions in recognizing experimentally the relative impor tance of different processes in IBAD are pointed out. (C) 1998 Elsevie r Science B.V. All rights reserved.