A new SIMS approach is proposed for quantified depth profiling of III-V semiconductor alloys. We show that the ratio of MCs+ ion intensities to the sum of all element intensities (M1Cs+ + M2Cs+...) from semiconductor alloys gives accurate elemental mole fraction when elements from the same periodic group are considered. Results obtained using SIMS show good agreement with data acquired using XPS and RBS. (c) 2006 Elsevier B.V All rights reserved.