A series of Al-C-N thin films with different Al contents were deposited on Si (100) substrates by closed unbalanced reactive magnetron sputtering in the mixture of argon and nitrogen gases. Their configurations and structures were subsequently investigated by X-ray photoelectron spectroscopy, diffraction, Raman spectroscopy measurement, cross-sectional field emission scanning electron and high-resolution transmission electron microscopy, while their electrical conductivities and Hall were studied by physical property measurement system. The results indicated that all deposited Al-C-N films were amorphous. There were three bonds, C-N. C-C and Al-N, in Al-C-N thin films irrespective content. Increase of Al content increased the amount of Al-N bonding at the cost of that of C-C Higher Al content led to less sp(2) C-C bonding. The films with low Al content were essentially semiconductor. Increase of Al content increased the electrical resistance, making the film transform to insulation, which was attributed to increase of band gap. Hall coefficient was increased increase of Al content, which was contributed to decrease in concentration and mobility of hole in the (C) 2010 Published by Elsevier B V.