We have analyzed a multiple quantum well (MQW) structure in a vertical cavity surface emitting laser (VCSEC) epitaxial wafer using secondary ion mass spectrometry (SIMS). The two energy sputtering method is a very powerful method for providing a depth profile of a GaAs/Al0.2Ga0.8As MQW with a sufficient depth resolution and a large number of data points in a practical measurement time. This method consists of rapid high-energy sputtering for a top mirror layer and subsequent low-energy sputtering for an active layer. The resulting profiles were quantitatively evaluated using the mixing-roughness-information depth (MRI) model. The values of C concentration in modulation-doped Al0.2Ga0.8As barrier layers have been extracted from the original in-depth concentration profile reconstructed by the MRI model. The relationship between depth resolution of the resulting profile and surface morphology measured by atomic force microscopy (A-FM) is also discussed. (c) 2006 Elsevier B.V. All rights reserved.