  Mn concentration depth profiles in Mn-doped GaAs thin films grown at
substrate temperatures of 580 and 250 {\deg}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 {\deg}C, the Mn distributes uniformly. For the
samples grown at a high substrate temperature of 580 {\deg}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.
