The influence of annealing time on an amorphous As cap layer and the depth distribution of Mn atoms have been investigated. The results show that a similar to 1600 angstrom thick As cap layer is completely desorbed after 3 h of annealing time. The depth distributions of Mn indicate that interstitial Mn atoms have diffused to the outer surface and being passivated. The thickness of the Mn passivation layer was around 90 angstrom. (c) 2006 Elsevier B.V. All rights reserved.