Factors determining preferential sputtering in ingaas system: angle resolved small area XPS investigation

Different Ar+ energies (2 and 5 keV) were used to sputter (100) Ga0.73In0.27 As material at room temperature and under liquid nitrogen cooling. The preferential sputtering phenomena related to the different ion energies used have been investigated. Using angle-resolved small-area x-ray photoelectron spectroscopy (AR-SA-XPS), chemical composition variations of the sputtered surface have been put in evidence. The results show an indium depletion on the outermost Ga0.73In0.27 As layer operating at room temperature. Indeed, even though indium and arsenic depletion is observed under liquid nitrogen cooling, the AR-SA-XPS results show that the effect is lower with respect to the surfaces sputtered at room temperature. These results are discussed in the framework of models proposed for explaining preferential sputtering phenomena. Copyright (C) 2002 John Wiley Sons, Ltd.