XPS analysis of AlN thin films deposited by plasma enhanced atomic layer deposition

Graphical abstract: - Highlights: • AlN films were grown using plasma-enhanced atomic layer deposition. • The depositions were carried out at 250 °C. • High-resolution XPS was used to analyze the films at various depths. • Oxygen impurity was observed before and after exposure to air. • In-depth analysis of the nature of oxygen impurity is offered. - Abstract: X-ray photoelectron spectroscopy has been used to investigate the properties of AlN films deposited using a low temperature plasma-enhanced atomic layer deposition process. Aluminum, nitrogen and oxygen peaks were observed in the survey spectra. A thin layer of sputtered aluminum was used as a diffusion barrier, in order to distinguish between oxygen introduced during deposition and post-deposition. The results show no post-deposition oxidation. Furthermore, the samples were scanned at various depths, and the peaks were then deconvolved into the constituent subpeaks. The results show no Al–O–N bonding in the film. This result supports the models that propose that oxygen at low concentrations in AlN bonds exclusively to aluminum and forms planes of aluminum oxide octahedrons dispersed in the lattice