AES, EELS and XPS study of ion‐induced GaAs and InP(110) surface and subsurface modifications

Abstract

AbstractLow‐energy Ar+‐induced modifications of III–V semiconductor (110) surfaces have been investigated. XPS, angle‐resolved AES and Auger profiles have been used to check the in‐depth composition over the range of tens to hundreds of angstroms. The actual composition of the sputtered surfaces has been determined by either the elemental standard method or normalization to the cleaved surface signals. Auger and XPS lineshape analysis and EELS spectra provided information on the chemical state of the components in the sputter‐altered region.GaAs and InP surfaces have been found to be metal enriched, the enrichment being larger at high ion beam energy. The 5 keV Ar+bombardment of the cleaved InP target results in the steady‐state composition In(67)P(33) at the surface. The composition is graded in the subsurface region up to the stoichiometric value In(50)P(50). Although the sputter‐altered GaAs region can be depicted roughly as As‐depleted, the As concentration is larger at the surface than in the subsurface region. The surface ‘spike’ and the subsurface ‘dip’ in the As concentration strongly depend on the ion beam energy in terms of both the intensity and the extension in depth. These results indicate that As radiation‐enhanced Gibbsian segregation and P preferential sputtering are the dominant mechanisms of surface modification in GaAs and InP, respectively.