Preferential sputtering observed in Auger electron spectroscopy sputter depth profiling of AlAs/GaAs superlattice using low-energy ions

摘要

Auger electron spectroscopy (AES) sputter depth profiling of an ISO reference material of the GaAs/AlAs superlattice was investigated using low-energy Ar+ ions. Although a high depth resolution of similar to1.0 nm was obtained at the GaAs/AlAs interface under 100 eV Ar+ ion irradiation, deterioration of the depth resolution was observed at the AlAs/GaAs interface. The Auger peak profile revealed that the enrichment of Al due to preferential sputtering occurred during sputter etching of the AlAs layer only under 100 eV Ar+ ion irradiation. In addition, a significant difference in the etching rates between the AlAs and GaAs layers was observed for low-energy ion irradiation. Deterioration of the depth resolution under 100 eV Ar+ ion irradiation is attributed to the preferential sputtering and the difference in the etching rate. The present results suggest that the effects induced by the preferential sputtering and the significant difference in the etching rate should be taken into account to optimize ion etching conditions using the GaAs/AlAs reference material under low-energy ion irradiation. Copyright (C) 2005 John Wiley Sons, Ltd.