Aluminum nitride (AlN) thin film has been synthesized by the direct nitridization of aluminum with heated NH3 gas. The infrared heating with focusing capability was adopted as a heat source and the reaction zone was constantly translated by controlling the sample stage. The metallic Al layer was deposited on the amorphous fused silica glass substrate using a thermal evaporation system at 3.0 × 10−6 Torr and the temperature profile of the reaction zone could be arbitrary chosen by varying the focal length of the IR reflector in the range of 600 ~ 800 oC. The polycrystalline AlN thin film was obtained with <100 nm thickness in a single step and the thickness of the AlN layer could be increased by the iterated steps. The morphology and the crystalline quality of the AlN thin film have been characterized by the XRD, SEM, and EDS analyses.

Keywords: AlN thin film, Direct nitridization, IR heater, Directional solidification