Atomic force microscopy investigation of the O2 +-induced surface topography of InP

Abstract

The surface topography development of InP as a function of O2 + ion energy and incident angle was investigated using atomic force microscopy (AFM). Cone formation was found to be the dominant surface feature under various O2 + ion bombarding conditions. However, variations in the density and size of the cones at different O2 + ion bombardment conditions were observed. The variation of surface topography with O2 + ion bombardment conditions is correlated with changes in InP surface composition. The results support an intrinsic model of cone formation, which postulates that the sputtering of InP causes In enrichment at the surface due to the preferential sputtering of phosphorus from InP. Furthermore, radiation-enhanced surface diffusion results in agglomeration of indium atoms into indium clusters. These indium clusters seed the development of sputter cones due to the difference in sputter rates of InP and indium. © 1998 John Wiley & Sons, Ltd.