Angular distribution of particles sputtered from III-V compound semiconductors by Ar+-ion bombardment

Angular distributions (ADs) of sputter-ejected particles from GaP(100) and InAs(100) surfaces were measured for 1 and 3 keV Ar+-ion bombardment at room temperature. Every distribution exhibited an over-cosine tendency that became more pronounced with increasing sputtering energy, independent of the target material. AD of gallium was almost identical with that of phosphorus for the GaP targets, implying that the in-depth composition is close to homogeneous within the information depth. AD of particles ejected from InAs was characterized by a forward-peaked distribution of indium, suggesting the enrichment of arsenic at the outermost layer followed by the depletion of arsenic in the subsurface region. From a comparison of the present results with those reported previously for InP and GaAs surfaces, it was concluded that Group V elements play a key role in the surface compositional change induced by ion bombardment. Although the Ari-induced segregation of arsenic at the outermost surface is a common feature for arsenic-based III-V compound semiconductors, the observed arsenic segregation is not explicable in terms of either the bond-breaking model or the strain theory. (C) 1999 Elsevier Science B.V. All rights reserved.