Island size distributions in submonolayer growth in hyperthermal deposition

In ion beam assisted deposition (IBAD) and other related hyperthermal deposition techniques island growth is in clear contrast with growth obtained without bombardment, and a greatly enhanced density of small islands is observed. In this contribution we study the effects of island breakup and adatom detachment on growth during IBAD using computer simulations based on the particle coalescence method. It is shown that in both cases a quasi-stationary state occurs, and a new scaling behaviour appears. The scaling properties observed are different, which makes it possible to distinguish the dominant growth mode experimentally. Results support the conclusion that, in IBAD, fragmentation and detachment explain the enhanced island density and thus promote the layer-by-layer growth.