Amorphous molybdenum nitride thin films prepared by reactive sputter deposition

Amorphous molybdenum nitride thin films were prepared by pulsed direct current (dc) reactive sputter deposition. The effect of the sputtering gas nitrogen content on the structure of as-deposited thin film was investigated. The nitrogen content in the sputtering gas affected the crystallinity of deposited thin films. When the sputtering gas contained from 10 to 30% nitrogen, crystalline γ-Mo2N was observed. A decrease in the γ-Mo2N peak intensity along with peak shifting and broadening was observed in X-ray diffraction (XRD) spectra as the deposition nitrogen content increased. An amorphous molybdenum nitride thin film was obtained as the nitrogen content in the sputtering gas increased to 50%. X-ray photoelectron spectroscopic analysis (XPS) of the as-deposited thin films showed that the binding energy of Mo 3d3/2, Mo 3d5/2 and Mo 3p3/2 peaks as well as the amount of nitrogen in thin film increased as the nitrogen content in sputtering gas increased. Thermal treatment of the amorphous thin film showed that the amorphous film had survived 700 °C thermal annealing with no evidence of crystallization and reaction. However, crystallization of amorphous film and reaction of the amorphous thin film with Si substrate were observed after thermal annealing at 800 °C.