Mn concentration depth profiles in Mn-doped GaAs thin films grown at substrate temperatures of 580 and 250 degrees C using various Mn cell temperatures have been investigated with dynamic secondary ion mass spectrometry and Auger electron spectroscopy. When the samples are grown at a low substrate temperature of 250 degrees C, the Mn distributes uniformly. For the samples grown at a high substrate temperature of 580 degrees C, the concentration depth profiles are easily fitted with a temperature-dependent Fermi function only if the Mn concentration is above the solubility limit. However, when the Mn concentration is below the solubility limit, unexpected peaks are observed in the concentration depth profiles. (C) 2007 American Vacuum Society.