The bonding of nitrogen in low N-content AlxGa1-xAs1-yNy with x≤0.05 and y≤0.04 has been studied by Raman spectroscopy. Upon the addition of Al to GaAsN, additional vibrational modes are observed at around 450 cm-1, which is below the GaN-like longitudinal optical (LO) phonon mode centered at 470 cm-1. These modes are attributed to the formation of Al and N containing complexes with Al-to-N bonding. With increasing Al content the Al–N related modes gain intensity at the expense of the GaN-like mode, and they become the dominant N-related feature for an Al-content of 5% at a fixed N content of 1%. On the other hand, increasing the N content from 0% up to 4% at a constant Al concentration of 5% results first in the appearance and eventual saturation in intensity of the AlN-like modes, accompanied by a steep increase in intensity and eventual dominance of the GaN-like vibrational mode. Simultaneously the AlAs-like LO2 phonon mode shows a drastic decrease in intensity for N contents exceeding 2%. All these observations strongly indicate that there is a preferential formation of AlN bonds in low N- and Al-content AlGaAsN, which is in direct contrast to GaInAsN, where even after thermal annealing the GaN-like mode remains dominant in the Raman spectrum compared to the InN-like modes. © 2002 American Institute of Physics.