We present a new method of determining the depth profile of the doping concentration in Si delta-doped GaAs layers and GaAs-based heterostructures by micro-Raman spectroscopy. In-depth resolution is obtained by scanning the laser spot along a shallow bevel synthesized in the structure of interest. The doping level is determined by assessing changes in the ratio of the transversal to the longitudinal optical phonon lines intensities. The determined doping concentration values are in good agreement with those determined by secondary ion mass spectroscopy and capacitance -voltage methods. (c) 2005 Elsevier B.V. All rights reserved.