Molecular effect on surface topography of GaN bombarded with PF4 ions

We study surface topography and thickness of GaN layers implanted at room temperature with 1.3 keV/amu F, P, and PF4 cluster ions. Results show that the density of collision cascades has a dramatic effect on the surface roughness and the thickness of implanted layers. Surface roughness increases with increasing cascade density. For very dense cascades produced by PF4 ions, the evolution of layer thickness is dominated by ion-induced sputtering. In contrast, for the case of P ions producing less dense cascades, ion-induced swelling is observed.