Angle‐resolved x‐ray photoelectron spectroscopy (ARXPS) has been used to study the Ar incorporation and surface compositional changes in InP(100) after 1–5 keV Ar+bombardment at various ion fluences. The ARXPS measurements showed that the incorporated Ar concentration achieved saturation at ion bombardment fluences of >1016cm−2. The surface Ar concentration decreased with increasing bombardment energy. No Ar bubbles were observed by atomic force microscopy, suggesting that Ar bubble formation was not the main Ar trapping mechanism. The altered layers were, on average, In rich up to the sampling depth of the ARXPS technique. However, the altered layers were inhomogeneous as a function of depth and appeared more In rich at the surface than in the subsurface region. The results are compared with those obtained by other authors and discussed in the context of preferential sputtering, radiation‐enhanced diffusion and segregation, and Ar incorporation. Although the altered layers were In rich, a P‐rich phase induced by Ar+bombardment was identified in the altered layers. ©1996 American Institute of Physics.