The N incorporation is studied in AlGaNAs with low Al content grown by chemical beam epitaxy at low temperature using dimethylhydrazine as the N precursor. The incorporation efficiency is significantly enhanced by introducing a relatively low Al concentration. The relation between the N incorporation and NI(N+As) flow ratio for Al concentrations of 0-15% is presented. The highest N incorporation and the best AlGaNAs crystal quality are obtained between 400 degrees C and 440 degrees C, where the growth mode starts to change from 2D to 3D. The activation energies for N incorporation in both the 2D and 3D growth mode regions are extracted. (C) 2013 Elsevier B.V. All rights reserved,